Overweight and fat distribution
Associationswithaspectsof morbidity
/<=,/!/
'--/
^o c\$i
Promotor:
dr. J. G. A.J. Hautvast
hoogleraar indeleervandevoedingende
voedselbereiding
Co-promotor: dr. P.Deurenberg
universitair hoofddocent
J. C. Seidell
Overweight and fat distributionAssociations with aspects of morbidity
Proefschrift
Terverkrijging vandegraadvan
doctor inde landbouwwetenschappen,
opgezagvanderector magnificus,
dr. C. C. Oosterlee,
inhetopenbaar te verdedigen
opvrijdag 3oktober 1986
desnamiddagstevieruur indeaula
vande Landbouwuniversiteit te
Wageningen
\W.HutQH
Aanmijn ouders en Ellen
Financial support bythe Dutch Preventiefonds throughout the
study and theNetherlands Heart Foundation for thepublication
thisthesisisgratefully acknowledged.
I'. V...IOTHEEK
LA1TOB0TJWHOGKSCHOOL
WAGENINGKN
Ur/072^
STELLINGEN
l.Bijherzieningvanhetadviesinzakeadipositasvande
gezondheidsraad (1984)verdienendevolgendepuntenextra
aandachtindeaanbevelingen:
-Hetbelangvanpreventievemaatregelenvoorovergewicht.
-Hetbelangvandevetverdelinginderelatieovergewichten
morbiditeit.
- Leeftijdsspecifieke grenswaardenvoorovergewicht.
2.Deweegschaal iseenbelangrijk instrumentvoordehuisarts,
eenmeetlintismogelijknogbelangrijker.
3.De verschillen inpsychosociale problematiek rond overgewicht
tussenmannenenvrouwengevenaandat'gewichtsbeleving'een
onderwerpiswatdringend emancipatiebehoeft.
4.De vetzuursamenstellingvanvetweefseluithetomentumzal
eerderveranderingen indevetzuursamenstellingvande
voeding reflecterendandievanvetweefseluithetfemorale
engluteale gebied.
5.Hetfeitdatbijhetouderworden relatiefmeervetinde
buikholtewordt opgeslagenendeopvattingdatjuistdit
intra-abdominalevetweefsel ongunstige eigenschappen heeft
zijnintegenspraakmetdebevindingdathet
gezondheidsrisicobijeenbepaaldematevanovergewicht
afneemtbijtoenemendeleeftijd.
6.Correlationsontheaggregate levelofnationsdonotprove
anything;theironlypurposeinresearchistostimulatethe
generationofhypotheses
F.deWaard.NutritionandCancer1986;8:5-8.
7.Hetzouiniedersbelang zijnwanneerdeadviezenvande
Gezondheidsraad,hoedeskundigzeookopgesteldmogenzijn,
voorpublicatieaanmultidisciplinairepanels zoudenworden
voorgelegd.
8.Hetalgemeengebruikvanmultipele regressie vergelijkingen
bij studiesnaardedeterminantenvanhart-envaatziekten
waarbij,naasteenmaatvoor obesitas,ookdeandere bekende
risicofactorenvoordeeindpuntenwordenbetrokken,geveneen
sterkeonderschattingvanhetgezondheidsrisico behorendbij
eenbepaaldematevanovergewicht.
9.Hetverouderenvaneenpopulatie gaatgepaardmeteen
toenemende heterogeniteitvanfysiologische variabelen.Het
opstellenvanvoedingsrichtlijnen voorouderenzalgebaseerd
moetenzijnopdeze heterogeniteit.
BI!-.I.IOTHEEK
IANDBOUWKOG* •'HOOl
WAGENINGEN
/o^V
w
10.Andthenthere issignificance -aword that isprobably the
single greatest intellectual pathogen inbothbiological and
statistical domainstoday.
FeinsteinA.R.'Clinicalepidemiology'.Philadelphia,W.B.
Saunders1981.
11.Theissuesofpreventivemedicine have little todowith
science, relative risks,and risk factors.Theycouldbemore
profitablydebatedwithin the framework towhich theybelong
- ethics,politics,andvested interests.
Skrabanek P.Lancet1986;i:143-4.
12.Een 'population strategy'eneen 'high risk strategy' voor
hetgunstigbeinvloedenvan risicofactoren zijngeen elkaar
uitsluitende alternatievenmaardienenbeiden tegelijkertijd
teworden toegepast.
zieook:LewisB,MannJ.I.,Mancini M.Lancet1986;i:956-9.
13.Hetschrijvenvaneenonderzoeksvoorstel zouopgenomenmoeten
zijnalsonderdeel vaneenverplicht onderwijselementinhet
studiecurriculum 'Voedingvandemens'.
14.Diegenendievanvermagereneenafval-racemakenlopeneen
grote kansalseerstenaantekomen.
Stellingen behorend bijhetproefschriftvanJaapC.Seidell.
Overweight and fatdistribution -associationswithaspectsof
morbidity.
Wageningen, 3oktober 1986.
CONTENTS
Abstract
Voorwoord
Chapter 1.Obesityand fatdistribution inrelationtohealthcurrent insightsand recommendations
(WrldRevNutrDiet1986 (inpress))
1
Chapter 2.Associationsofmoderateandsevereoverweightwith
self reported illnessandmedical careinDutchadults
(AmJPublicHealth1986;76:264-9)
38
Chapter 3.Utilizationofprimaryhealthcareofoverweightand
non-overweight subjects-a sixyear follow-upstudy
(submitted)
56
Chapter 4.Overweightandchronic illness-a restrospective
cohortstudywitha follow-upof6-17 years,inmen
andwomenof initially20-50yearsofage
(JChronDis1986 (inpress))
72
Chapter 5.The relationbetweenoverweightandsubjectivehealth
- withattentiontotheeffectsofage,socialclass,
slimmingbehaviorand smokinghabitsonthis relation
(AmJPublicHealth1986;76: (inpress))
88
Chapter 6. Fatdistributionofoverweightpersons inrelationto
morbidityand subjectivehealth
(IntJObesity 1985;9:363-74)
104
Chapter 7.Assessmentof intra-abdominal fat- relationbetween
anthropometryandcomputed tomography
(AmJClinNutr (inpress))
GeneralDiscussion
123
135
Samenvatting
139
Summary
143
CurriculumVitae
146
VOORWOORD
Inditproefschriftwordenenkeleonderzoekenbeschrevennaardeassofciaties
tussenovergewichtenparametersvandegezondheidstoestand.HoeweldeVakgroep
HumaneVoedingvandeLandbouwHogeschool teWageningendethuisbasiswasvoor
deonderzoeken,werdhetgrootstedeelvanhetwerkuitgevoerd insamenwerking
methetCentraalBureauvoordeStatistiek,hetNijmeegsUniversitairHuisartsen
InstituutenhetInstituutvoorRadiodiagnostiekvandeKatholiekeUniversiteit
teNijmegen.
Indegenoemdeinstituten ishetleeuwendeelvande onderzoeksgegevens
verzameld.Hetisnatuurlijk onmogelijkallebetrokkenmedewerkersvandeze
institutenmetnametenoemen.Eenaantalwaar ik rechtstreeksmeeheb
samengewerktheb,wilikhieronderbedankenvoordeplezierigewijzewaaropde
samenwerkingsteedsisverlopen.Nietalleenbijhetverzamelenofhetter
beschikking stellenvandegegevensbenikdoorvelengeholpenmaarookbijhet
verwerkenvandiegegevens,de interpretatievande resultatenenhet schrijven
vandeartikelen zijnvelenbetrokkengeweest.
Ineerste instantiegaatmijndankuitnaarmijnpromotorProf.dr.J.G.A.J.
Hautvastenmijnco-referentdr.P.Deurenbergdiebeideneenvoortduijende
stimulanswarenvoorhetonderzoek enmijsteedsopuitstekendewijzehebben
begeleid.Hetvertrouwendatzijinmijsteldenhebiksteedszeergewaardeerd.
DepraktischeentheoretischemedischekennisvanKarelBakxenArieOosterlee
wasnietalleenonontbeerlijkvoorhetonderzoekmaarvooraldeenthousiaste
wijzewaaropzijdezekenniswistenovertebrengenmaaktede samenwerkingmet
hen steedsextraprettigenleerzaam.
JanBuremadie zowelinwetenschappelijk alsmuzikaalopzichtdebassocontinuo
was inhetONNO-projectdank ikvoordenauwgezetheidwaarophij statistische
adviezengafenmanuscriptencorrigeerde.
Voordevele inspirerendediscussiesenmuzikaleavondurenwil ikMattiRookus
enWijavanStaverendanken.OokdevelegesprekkenmetJanWeststrateenhet
kritischcommentaarvanMartijnKatanwarenvanbelang.
Hetmeestetypewerkvoorditproefschrift isopvoortreffelijkewijzeverzorgd
doorWilKnuiman-HijlenAnnemarie Zijlmans.DeEngelsetekstenwerden
gecorrigeerddoorSeamusWardenJ.Burrough.Demedewerkersvandetekenkamer
vanhetBiotechnion stondengarantvoorgrafischwerkvanhogekwaliteit.
DeonnavolgbaremanierwaaropBenScholteenGebcaVelemacomputerproblemenin
hetalgemeenendievanmijinhetbijzonderwistenoptelossendientteworden
vermeldevenalsdewijzewaaropLisettedeGrootdeC.B.S.bestandenwistuitte
pluizen.
Dedoctoraalstudentendieikhebbegeleid:EllydeBoer,Gerdavan'tBos,Hans
Groenendijk,GerdaDoornbos,LeoHenskensenRitaSchoutenwilikbedankenvoor
nunbelangrijkebijdragenaanallerleionderdelenvanverschillendeonderzoeken.
Ookwilikgraagallenognietgenoemdevasteentijdelijkemedewerkersvande
VakgroepHumaneVoedingbedankenvoordefijnesfeerwaarinikhebkunnen
werken.Specialedanknogvoordemedewerkersvanhetsecretariaatendeheer
Middelburgdie,wanneererpractischeproblemenwaren,altijdtijdvrijmaakten
ommedaarmeetehelpen.
VandevelemedewerkersvanhetNijmeegsUniversitairHuisartsenInstituutwil
ikvooralProf.dr.F.J.A.Huygen,HenkvandenHoogenenPierreHoppener
bedanken.Zijzijnhetgeweestdiehetmogelijkhebbengemaaktomgegevensvan
devoorepidemiologischonderzoekzeerwaardevolleContinueMorbiditeits
Registratietegebruiken.Debijdezeregistratieaangeslotenartsen,ennun
assistentes,hebbenveelwerkvoormijverzet.DorienKaaijkassisteerdebijde
anthropometricineenvandepraktijken.
VandemedewerkersvandeafdelingGezondheidsstatistiekenvanhetCentraal
BureauvoordeStatistiekwilikiniedergevalJanvanSonsbeekenJaapvande
BergbedankenvoordehulpbijhetverwerkenvandeGezondheidsenquetes.
ProfessorJ.H.Ruijsendrs.MartinThijssenbegeleiddenmijbijde
werkzaamhedenmetdeCT-scanner.Deartsenenlaborantenvandeafdeling
Rontgen-diagnostiekwarenbijdepraktischeuitvoeringeenenormesteun.
Prof.dr.W.P.T.James(Edinburgh)benikerkentelijkvoordeinspiratiebijhet
opzettenvanhetonderzoek.Dediverseledenvanbegeleidingscommisieswilik
dankenvoornuninteresseinmijnwerkzaamheden.Naasthetwetenschappelijkwerk
werdiksteedsgemotiveerddoormijnouders,mijnbroerRoel(dieookdeomslag
vanhetproefschriftverzorgde),enzusLydia.
TenslottewilikEllenbedankenvoordesteundoordikendun.
OVERWEIGHTAND FATDISTRIBUTION -ASSOCIATIONSWITHASPECTSOF MORBIDITY
THESIS,DEPARTMENTOFHUNANNUTRITION,AGRICULTURAL UNIVERSITY,WAGENINGEN, THE
NETHERLANDS, 3OKTOBER 1986.
J.C. Seidell
ABSTRACT
This thesis reportsontheassociation betweenestimatesof theamount;aftd
distribution of fatmasswithaspects ofmorbidity inDutchadults.A literature
reviewonthe current insights intotheseassociations isincluded.The results
of several cross-sectional and retrospective cohort studiesarepresented. The
prevalence of severeoverweight,defined asaBodyMass Index (BMI=kg/m )higher
than 30kg/m ,isabout 6% inwomenand 4%inmen,while about_34%of themen
and 24%of thewomenaremoderately overweight (BMI25-30kg/m ).Among
overweight persons,especiallywhen severelyoverweight,theprevalence and
incidence ofvarious chronic disorders anduseofaspects ofmedical cairewas
higher than innon-overweight persons.Forgoutandarteriosclerotic disease,
overweight appeared tobea risk factoratlower levelsofBMI inmen than in
women.The.incidencewasparticularly high inmenwithan initial BMI between
27-30kg/m .Theassociation betweenBMIand subjective healthwasmore
pronounced inwomen than inmen.Thiswastrue for certain somatic aswell as
psychosomatic complaints.
Fatdistribution,asmeasuredwith thewaist-hip circumference ratio or
waist-thigh circumference ratio,was showntobe related totheprevalence of
certain chronicdisorders inmenandwomen.Theseassociationswere independent
ofageandBMI.A study inwhichComputed Tomography scans,takenatthe level
of theL4vertebra,were related toanthropometric measurements, revealed that
correlations of circumference ratioswith theamountof intra-abdominal fatwere
higher thanwith subcutaneous abdominal fat.
Itisconcluded thatoverweight isrelated toaspects ofmorbidity butthat it
maybeparticularly relevant toinclude fatdistribution measurements ihthe
evaluation ofhealth risks inoverweight subjects.
-1-
CHAPTER1
CBESITYAND FATDISTRIBUTION INRELATIONTOHEALTH CURRENT INSIGHTSAND RECOMMENDATIONS
J.C.Seidell,P.Deurenberg,J.G.A.J.Hautvast
WrldRevNutrDiet (inpress)
GENERAL INTRODUCTION
Obesity researchhas receivedmuchattentionduring thepastdecades,during
whichnewevidence foraetiologic andprognostic aspectsofobesityand
underlying mechanismshasbeenaccumulating. The recommendations for prevention
and therapy,however,havenot changeddramatically. InFebruary 1985,a
consensuspanelattheNational Institute ofHealth inBethesda,Maryland,
discussed theavailable knowledge onthehealth consequences ofobesity and
formulated recommendations for thetreatment ofobesity.Someaspectsof the
evidence that formed thebasis forthese recommendations arediscussed inthe
firstpartof this review.
The consensuspanel concluded that recentevidence strongly suggests that the
regionaldistribution ofbody fatisan importantdeterminant for the occurrence
ofclinical correlates ofobesity suchascardiovascular disease,strokeand
diabetes.The current knowledge oftheassessment and consequences of typesof
fatdistribution isdiscussed inthe second partofthis review. Itcanbe
expected that,inthenear future,measuresof fatdistributionwill be included
in recommendations forthediagnosisand treatment ofhuman obesity.
1.OBESITY,CURRENT RECOMMENDATIONS
1.1.Definition andassessment ofoverweight andobesity;agreement onan
international standard
Bray [25]haspointed outthat itisimportant todistinguish between overweight
andobesity.Overweight isdefined asan increase inbodyweight above some
arbitrary standarddefined in relation tohealth.Obesity isdefined asan
abnormally highproportion ofbody fat.Theterm 'abnormal'indicates that
obesity corresponds totheupper end of rangeof thebody fat percentages
observedinaparticularpopulation.Overweightandobesitycanbedistinguished
onlyiftheamountofbodyfatcanbemeasured.Themethodsforassessingbody
fatcanbedividedintodirectandindirectmethods.Thesemethodshaverecently
beenwellreviewedbyGarrow [51].Table1givesasummaryofmethodscurrently
inuse.Theyareofvaryingaccuracyanditisdifficulttopinpointoneofthe
indirectmethodsasthemostvalidone.
Table1.Quantitativemethodsforthedeterminationofbodyfatinhuman
(adaptedfromBray1985)[25]
1)Directcarcassanalyis
2)Bodydensityandbodyvolume(byunderwaterweighing;plethysmography)
3)Isotopeorchemicaldilution
-Amountofbodyfat,bymeasuringthedistributionofcyclopropaneor
Krypton
-Amountofleanbodymass,bymeasurementofPotassium(40K)inthebody
-Amountofbodywater,bymeasuringthedistributionoftritiatedwater
(3H20)orantipyrine
4)Anthropometricmeasurements
-Heightandweighttablesorindices(sometimesincludingmeasuresofframe
size)
-Skinfoldthickness(usuallytriceps,biceps,supra-iliac,subscapular
skinfolds)
-Circumferencemeasurements(nowoftenusedfortheassessmentofbodyfat
distribution,usuallythigh,hipsandwaistcircumferences)
5)Electricalconductivityofthebody
-Totalbodyelectricalconductivity(TOBEC)
-Bioelectricimpedance
6)Imagingtechniques
-Ultra-soundwaves
-Computerizedtomography (CT)ornuclearmagneticresonance(NMR)
ThedifficultyofvalidatingthemethodshasrecentlybeendiscussedbyGarrow
[51].Anewmethodofdeterminingbodyfatcontent,whichallowsspecification
ofbodyfatdistributionoverdifferentbodyfatdepotsiscomputedtonography.
Thismethodwillbediscussedinmoredetailinsection2.1.3ofthisreview.
Thismethodcanprobablyberegardedasthebestindirectmethodavailable,but
itinvolves radiationofsubjects.NuclearMagneticResonance imaging (NMR)may
beagoodalternative tocomputed tomography [43]butthis requires further
investigation.
Currently,weight-height indicesarethemostwidelyusedmeasuresofadiposity
andoverweight.Theyhavetheadvantageofeasycalculationandcanbeused in
epidemiologic studiesonlargegroupsof individuals.Theysuffer,however,from
misclassificationbias.Weight-height indicesareconstructed onthebasisof
threecriteria.
a)Zerocorrelationwithbodyheight.
b)Highcorrelationwithbodyfatness.
c)Correlationwithmortality.
Thesecriteriawillnowbediscussed.
a)Onthebasisofthecriterionofnocorrelationwithheight,Benn [11]
proposedweight/height"asanobesity index,inwhichp isapopulationspecificvalue,obtainedbyminimizing thecorrelationofthe indexwith
height [11].Garrowargued thatadisadvantage ofthisindex isthatitcan
beapplied toindividualsonlyafter thecorrectvalue forphasbeen
determined intheappropriatepopulation [51].Anotherdisadvantage isthat
results fromdifferentpopulationsaredifficult tocompareand to interpret
[49].Quetelet [81]observed in1869thatindividuals'weightswere roughly
proportional toheightsquared.Since thentheindexweight/height hasbeen
2
showntosatisfy thecriterionoflowcorrelationwithheight.Useofa fixed
pvalue (i.e.2)doesnothavethedisadvantagesoftheBennIndex.
b)Although thecorrelationofQuetelet'sIndex,orthe 'BodyMass Index',with
thepercentageofbodyfat (asdeterminedby,forinstance,under-water
weighing)isgenerally foundnottobeveryhigh (around0.7 - 0.8),other
indices rarely showhigher correlations [49].GarrowandWebster [51a]
criticallyexamined the relationofQuetelet'sindextobodyfatand
demonstrated that threestandardmethods (underwaterweighing,water
dilutionorpotassium counting),yield considerablydifferent resultsand,in
addition,showed thatQuetelet'sIndexshouldnotbe related topercentage
body fat,because itisameasureoftheamountoffat (kg).Indiceswhich
takemeasuresof framesize intoaccount,shownomeaningful improvement in
estimatingbody fatness inyoungadults [10,86].Theimportanceof frame
size inotheragegroups requiresfurther investigation[90].
c)On thebasisofanalysisofexistingmortalitydata,Garrow [50]proposed a
classificationofobesityonthebasisofQuetelet's Index (Table2 ) .
Table2.Garrow'sclassificationofobesityincategoriesofBodyMassIndexor
Quetelet'sIndex(kg/m)[50]
BMI(kg/m)
InterpretationofBMIin
category
<20
Underweight
Grade0obesity
20-24.9
Acceptableweight
Grade1obesity
25-29.9
Moderateoverweight
Grade2obesity
30-39.9
Severeoverweight,obese
Grade3obesity
>,40
Morbidlyobese
Someinvestigatorshavepreferredtouse27kg/m asacut-offpointfor
obesityinmen[65,98].AsQuetelet'sIndexhasbeenshowntobesomewhat
inferiortoBenn'sIndexwith1.5asvalueforpinwomen,someinvestigators
15
haveusedweight/height" forwomen [97].Tomakecomparisonsbetweenmenand
womenmoreeasytheytransformedthedifferentindicesintostandardscores.The
advantagesofthisapproachremaintobeproven.
Sofar,Quetelet'sIndexhasbeenacceptedbyexpertcommitteesasthemost
usefulmeasureofobesitywhenonlyheightandweightdataareavailable[29,
53,87,91]. OtherindicesasBroca'sindexortheponderalindexarenow
generallyconsideredtobelesssuitableindicesofbodyfatness.
1.2.Prevalenceofoverweightandobesityinindustrialcountries
Table3.Prevalenceofmoderateandsevereoverweight(obesity)insome
industrializedcountries(inpercentages)
Quetelet'sIndex
UnitedKingdom TheNetherlands UnitedStates Australia
(kg/m2)
men
women
men
women
men
women menwomen
moderateoverweight;25-29.9
34
24
34
24
31
24
12
12
severe
overweight:>,30
34; 24
Inthe fourcountries shownintable 3,moderateoverweightappearstobemore
common inmenthaninwomen.InEuropeancountries,obesity isslightlymore
common inwomenthaninmen.Obesityappearstobemoreprevalent intheUnited
States inbothmenandwomenthaninanyoftheother industrial countries in
the table
1.3.Body fatnessandmortality-epidemiological evidence
1.3.1.Epidemiological evidence
Oneof themost comprehensive reviewsonobesityandmortalitywaspublished by
SimopoulosandVan Itallie in1984 [90].Their reviewisbasedonthe
conclusionsofaworkshoponbodyweight,healthand longevityheld inBethesda,
Maryland,in1982.They reviewedanumber of largepopulation studies inwhich a
relationshipbetweenoverweightandmortalityhadbeendemonstrated.Some
characteristics ofthese studies,towhichweadda recentlypublished
population study fromNorway [107],are shownintable4.
Itistypical forallthese studiesthatlargepopulationshad tobe followed up
foratleast10yearsbeforeanyeffectofbodyweightonmortalitywas
detectable.Bjorntorp [15]hasproposed thatthedelayedeffectmaybeexplained
bythepossibility thatexcessmortality (especially from cardiovascular
disease)ispresentmainly inasubgroupoftheobesepopulation.Lumpingall
typesofobesityintoonecategorymaycausestatisticaldilutionofaneffect
ofbody fatnessonmortality inasubpopulationoftheobese.Another featureof
the studies summarized intable 4istheJ-shaped relationbetweenBodyMass
Indexandmortality.ExcessmortalityatbothendsoftherangeofBodyMass
Indexareevaluated insection1.3.2.
Smoking appears tobean importantconfounding factor inthe relationship
betweenbodyfatnessandmortality,andneedstobetakenintoaccountassessing
the riskofoverweightandobesity.
Theavailableepidemiological evidencehasledtotheconclusion that
'overweightpersons (i.e.personswhoseweightsareaboveaverage)tendtodie
younger thanaverageweightpersons,particularly thosewhoareoverweightat
younger ages' [90].Similar conclusionsweredrawnby theRoyalCollegeof
Physicians in1983 [87).
It remainstobedetermined,however,whetherpersonswhoaremoderately
overweightbutnotobesemightbenefitfromweight reductionwhenthere isno
indicationofabnormalities (e.g.hypertension,impairedglucosetolerance,
-6-
Table 4.Someaspects ofstudiesdemonstratingarelationshipbetweenanobesity indexandmortality
(adapted fromSimopoulosand VanItallie [90]
Typeofstudies
Mathematical
Weightwith
Sexandage
Average/
Remarkson
Follow-up
relation
minimum
difference
max
studypopulation
after which
mortality
of relation
follow-
BMIand
up(yrs)
an increased
risk became
mortality
apparent(yrs
Life insurance
statistics
4.2 -BuildStudy 1979
J-shaped
weightbelow
million
average
moreapparent
6.6/22
inmenage15-
Policy-holders,
mainlymale,middle-*-
39thanin
class,ofapparently
age40-69
- Providentmutual
weightbelow
lifestudy
goodhealth
onlymen
/34
Malepolicy holders
average
Prospective studies
750000 -AmericanCancer
J-shaped
10-20%belowof
Society
5209 -FraminghamHeart
J-shaped
Study
3983
-Manitoba Study
6/14
Predominantly middl*
averageweight
classhealthyvolunteers
(non-smokers)
self-reporteddata
+ 20%below
effect inmen
averageweight
decreasedwith
(non-smokers)
age
belowaverage
most apparent
-/26
-/26
Residents ofFramin^haa
Malepilots
inmen20-40yrs
1.2
-Norway
J-shaped
million
BMI's between
flattercurve
23and 27kg/m
forwomen
10/15
formalesand
minimum increase
General population
females
J-shaped
(after
aroundaBMI of
2
23kg/m'
adjustmentof
weightchange
inadulthood
BMI=BodyMass Index (weight/height inkg/m)
-/10
Middleagedmen
hyperuricaemiaorhyperlipoproteinemia)andnoevidenceofclinicalillnessora
geneticpredispositionforsuchillness.ThispointhasbeenstressedbyBerger
etal[12]andAndres[2]whohavesincebeenfrequentlymisquotedasbeing
proponentsoftheviewthatoverweightsubjectsshouldnotbetreatedunless
2
theyarereallyobese(BMI>30kg/m).
Themainproblemofoverweightsubjectsisthattheyareatriskofbecoming
obese,andforpreventionpurposesthisgrouprequiresattention[50,59]. More
importantisthefindingthatfatdistribution,eveninverymoderatedegreesof
overweight,seemstohaveasubstantialimpactonhealthrisk.Are-evaluation
ofexistingevidencemightleadtonewdiagnosticcriteriaforestimatingthe
riskofoverweightandobeseindividuals(Seesection2formoredetails).
Anotherfactorthatneedstobetakenintoaccountintheevaluationof
overweightindividualsistheirage,asithasbeenshownthatweightatminimum
mortalityincreaseswithage[2].InfacttheNIHconsensusdevelopment
conferenceconcludedfromtheFraminghamandAmericanCancerSocietiesstudy
thattheincreaseinmortalitywithrelativeweightissteeperforthoseunder
50yearsofage,suggestingincreaseddesirabilityoftreatmentinyoungerage
groups.
1.3.2.Causesofdeathinoverweightandunderweightindividuals
Asdiscussedintheprevioussection,ithasbeenshownthatmortalityratesare
increasedatbothendsofthedistributionoftheBodyMassIndex.Themain
causesofdeathintheunderweightandtheoverweightpartofthepopulationare
dissimilar.Waaler[107]identifiedlungdiseases(includinglungcancer,
tuberculosisandobstructivelungdisease)andstomachcancerastypicalcauses
ofdeathofunderweightindividuals.Itmustbenoted,however,thatno
adjustmentshadbeenmadeforpossibleconfoundingeffectsofsmoking.
Cardiovasculardisease,cerebrovasculardiseaseanddiabeteswerefoundtobe
characteristiccausesofdeathinoverweightsubjects.Similarconclusionshave
beendrawnfromotherinvestigations,whereincreasedcancerincidencewas
observedinunderweightsubjectsandincreasedcardiovascularriskwasapparent
inoverweightsubjects[9,46].Suchillnessmightalsobethecauseof
underweight.
FromaNorwegianstudy[107]itwascalculatedthatobesityisresponsiblefor
4%ofalldeathsinwomenand5%inmen.Thisisofthesameorderasforlung
cancerinmenandbreastcancerinwomen.
LewandGarfinkel[74]intheirmuchcitedanalysisoftheAmericanCancer
-8-
Society Study found thatmenwithweightsmore than40%above theaveragewere
at increased riskofcancer of the colon,rectumandprostate.Inobesewomen,
increased risk for cancer ofthegallbladder,breast,cervix (especially
post-menopausal),endometrium,uterusandovariumwas found (especially inlower
socio-economicgroups).More evidence for increased risk ofcancer at particular
sites inbothunderweight andoverweight subjects showsthat itisimpossible to
give anoptimalweight forcancer risk,especially sincenutritional factorsmay
be important intheassociation ofbodyweight andcancer risk [46].Garn
proposed thatlowserumand tissue levelsofvitamins (particularly vitamin A)
and lowcholesterol levelsmightexplaintheincreasedmortality risk inthe
underweight partofthepopulation.
Cardiovascular mortality
Apart fromthepossible statistical dilutioneffectdue tothe failure to take
theheterogeneity ofhumanobesity intoaccount,sophisticated analysesmay
blurr thepicture. Ithasbeenproposed [65]thatobesity isnotamajor risk
factor forcardiovascular disease since itprovednot tobea risk factor
independently ofother risk factors,suchaselevated blood pressure,ECG
abnormalities,cholesterol andglucose tolerance.Themechanism bywhich obesity
could lead topremature cardiovascular deathprobably involves these risk
factorsand itisnot fullyclearhowastatistically independent effectof Body
Mass Indexoncardiovascular disease shouldbeinterpreted[87].
Brunzell [27]hasargued that,sincecardiovascular disease risk is particularly
elevated inyoung adults,genetic factorsmayplayamajor role inthe
association.Thishypothesis has tobe investigated further.
Hubert etal [60]ina26yearof follow-up studyof 5209menandwomen,
concluded thatMetropolitan relativeweight atbaseline examinationwasan
independent predictor ofanginapectorisandother coronarydisease inmenand
women. Inwomen itwasalsoapredictor of stroke,congestive failure and
coronary and cardiovascular death.Inthis relationadjustmentsweremade for
age,cholesterol,systolic blood pressure,smoking,leftventricular hypertrophy
and glucose tolerance.Asdiscussed above,there isnoobvious underlying
mechanism for the independent relationship isnotdirectly athand.Thejdataof
theFraminghamstudy [60]also revealed thatweight gain inyoungadultyears
conveyed an increased risk ofcardiovascular disease inmenandwomen,that
could notbeattributed toinitialweight or to risk factors thatmay result
fromweightgain.
From this important study itwas concluded thatintervention inobesity isan
-9advisable goal intheprimaryprevention ofcardiovascular disease.
1.4.Obesity andmorbidity
Fromanextensive reviewof theliterature,Berger etal [13]concluded that the
associations ofobesitywith several chronicdisorders arewellestablished, but
that theevidence forother claimed associations isnotalwaysconclusive.A
listing ofthedisorders found,orclaimed, tobeassociatedwithoverweight is
shown intable 5.
Table 5.Diseases andmetabolic abnormalities provenorclaimed tobe related
toobesity (adapted fromBerger etal 1985 [13]
Diseases related toobesity
Diseases related toobesity
(welldocumented evidence)
(notwelldocumented evidence)
hypertension
gall stones
hyperlipoproteinaemia
kidney stones
gout
musculo-skeletaldisorders
diabetesmellitis
hernia
glucose intolerance
pulmonary insufficiency
cardiovascular disease
alveolar hypoventilation
venous stasis
haemmorrhoids
severe impairment of self-image
susceptibility topsychoneuroses
impairment of sexual and reproductive functions
riskofendometrial andbreast cancers
An important problemwith thediseases thatarenot firmly related toobesity,
shown intable 5,isthat theyaredifficult tostudy inprospective studies.
Severalvariables,associatedwithenvironment andlife style,may confound the
relation.Available evidence isbasedmainly on self-reported dataor
case-control studies inselected populations.Aswill bediscussed inthe next
section,fatdistributionmaycomplicate thedetectionofexistingassociations.
Furthermore,slimming effortsmightcontribute totheonsetofdiseases such as
gallstonedisease andmaythus lead tospuriousassociationswithoverweight.
-10Clearly,therelationofbodyweighttomorbidityisaverycomplexfieldto
study.TheNIHconsensuspanel,discussingthissubject,placedconsiderable
weightonevidencefromthetwoNationalHealthandNutritionSurveys(NHANES)
conductedbytheNationalCenterforHealthStatistics(NCHS)intheUSA.The
NHANESII(1976-1980)studyrevealedstrongassociationsofhypertension,
hypercholesterolemiaanddiabeteswithBMIvaluesatorabove27.8formenand
27.3forwomen(the85thpercentilelevelintheUSA),especiallyinyoung
adults(ages20-44).
Recommendationsforweightreduction,basedonincreasedriskofmorbidityand
mortalitywithoverweight,weremadeforthefollowingcircumstances(adapted
from[29]).
(i)Excessbodyweightof20percentormore.ThiscorrespondstoaBMI
above26.4formenand25.8forwomen(1959Metropolitantables),or
above27.2formenand26.9forwomen(1983Metropolitantables).For
extremeobesity,risksaremuchgreater,includingariskofdangerous
cardiopulmonaryconditions,
(ii)Familyhistoryorriskfactorsformaturityonset(Type-Il)diabetes,
(iii)Highbloodpressure,
(iv)Hypertriglyceridemiaorhypercholesterolemia.
(v)Coronarydisease(oratherosclerosis),
(vi)Gout,
(vii)Functionalimpairmentduetoheartdisease,chronicobstructive
pulmonarydisease,orosteoarthritis(spine,hipsandknees,whichbear
weight),
(viii)Historyofchildhoodobesity.
Diagnosticandcardiopulmonaryfitnessassessmentsshouldinvolvethephysician,
andprogramsofweightreductionshouldbringinotherhealthprofessionalsas
well.
Oneoftheresearchareasstressedbythepanelasbeinganimportantareafor
futurestudywasresearchondeterminantsofbodyfatdistribution,andonthe
mechanismsofitsadverseeffects.
Wemayconcludethat,althoughsomeassociationsremaintobeclarified,obese
oroverweightindividualswhohavemusculoskeletalorrespiratorycomplaints,
elevatedbloodpressure,hyperlipoproteinemia,diabetestypeII,orglucose
tolerancecanbeexpectedtobenefitfromweightreduction[16, 59].
-11-
2. FATDISTRIBUTION;ANEWDIMENSION INOBESITY RESEARCH
2.1. Introduction
Intheprevious section some recommendations madebythe consensuspanel of the
NIH inBethesda,Maryland in1985were cited.Fromthe reportsof thepanel it
was clear that throughout thediscussions thetopic of fatdistributionwas a
recurrent theme.Similarly,atmany important international congresses on
obesity research (e.g.the International CongressonObesity inNewYork in1984
and the International SymposiumontheMetabolic Consequences ofObesity in
Marseille in1985)increasing attention hasbeenpaid totheclassification of
typesofbody fatdistribution and its relations todisease.Although the
importance ofadistinctionbetween central andperipheral typesof fat
distributionwas stressedbyVague intheearly fourties,the subjectof human
fatdistribution hasbeenasomewhat neglected subject inobesity research until
recentyears.
Investigators frommany countries (especially Sweden,Franceand theUnited
States)arenowclarifying themetabolicbasis for theobserved relations
betweendifferent typesof fatdistribution andvarious clinical associates of
obesity.
Table 6showsasummaryof someofthe relationships established between a fat
distribution type, inwhich fat ispredominantly stored intheabdominal region,
andvariousdiseases.
Table 6.Diseasesormetabolic abnormalities shown tobe related to abdominal
fat distribution
Men
Women
Prospective
Only incross-
Prospective
Only incross-
studies
sectional studies
studies
sectional studies
ischemic heart
arthrosis
myocardial
hypertension
disease
hypertension
infarction
glucose intolerance
stroke
glucose intolerance
angina
hyperinsulemia
diabetes
hyperinsulemia
pectoris
menstrual
stroke
abnormalities
unclear:gout,gallstones,kidney stones
-12-
Inthenextsectionofthisreviewwewillfirstdiscusssomeofthemethods
usedfortheclassificationoftypesoffatdistribution,andthenconsiderthe
functionalcharacteristicsoffatstoredindifferentregionsofthebody.
Finally,therelations,summarizedintable6,willbediscussedinsomedetail.
2.1.Anoverviewofmethodsusedfortheclassificationoftypesoffat
distribution
2.1.1.Subcutaneousfatpatterning
JeanVaguecanberegardedasoneofthepioneersinresearchonbodyfat
distribution.Heintroduced,intheearlyfourties,theconceptsofandroidand
gynoidtypesoffatdistribution [101].Forclassificationpurposeshedeveloped
anIndexofMasculineDifferentiation (IMD)basedontheaverageofthenapeto
sacrumskinfoldratio(correctedforthetotalthicknessofthefatinthetwo
regions)andthe'Brachio/FemoralAdipoMusculoRatio'(B/FAMR).THEB/FAMR
wascalculatedfromskinfoldsattheproximalpartsofthearmandthighand
circumferencesofthelimbsatthesamelevel [103].Relativelyhighvaluesof
theIMDweretypicallyfoundinmen(androidfatdistribution)whilelower
valueswerefoundtobecharacteristicinwomen(gynoidfatdistribution).
Vague'sobservationsofassociationsofthesetypesoffatdistributionwith
specificdisordersandmetabolicabnormalitiesstimulatedresearchinthisarea.
Othermethodsusedforthedescriptionofsubcutaneousfatpatternsinclude
Z-scorepatternprofiles [45],ratiosofskinfoldssuchastriceps/subgcapular
ratios[42],andtheratioofsumoftrunkskinfoldstothesumofskinfoldson
extremities[36,23,30].Principalcomponentsanalysisofsubcutaneousfat
siteshasalsobeenusedinthestudyofhumanfatpatterning,andthe
usefulnessofthisapproachhasrecentlybeenconfirmed[34,79].Joosetal
[62]useddiscriminantanalysisofskinfoldthicknessessinordertodistinguish
diabeticsfromnondiabetics.Itwasshownthatinmenacontrastofsubscapular
withwaistandlegskinfoldsandinwomenofsubscapularandleg(calf)
skinfoldsprovidedthebestbasisfortheclassificationofsubjectsinto
diabeticsandnon-diabetics.
Inobesityresearchthesemethodshavecertaindrawbacks,sinceskinfold
thicknessmeasurementsinobesesubjectsareoftendifficulttomeasureandhave
poorreproducibility[26].
Anotherdrawbackisthatmeasurementofthedistributionofsubcutaneousfat
alonefailstotaketheintra-abdominalfatdepotintoaccount.
-13-
2.1.2.Circumferenceratiosfordescribingfatdistributionpatterns
Methodsofdescribingmorethanthesubcutaneousfatpatternaloneinvolve,for
instance,somatotyping.Insuchmethods,thatwerefrequentlyusedinthe
fiftiesandsixtiesofthiscentury,classificationoftypicalformsofbody
buildismadebytrainedraters.CraigandBayer[31]usedphotographsand
outlinesofobesewomenandclassifiedthemintocategoriesrangingfrom
hyperfemininetohypofeminine.Damonetal[32]classifiedFraminghammales
accordingtothetypologyofSheldonandrelateddifferenttypesofbodybuild
tohealth.
Ashwelletal[6]redevelopedtheconceptsofgynoidandandroidfat
distributionandratedpicturesofobesewomenasandroidandgynoid.
DiscriminantanalysiswasusedtoconstructaFatDistributionscore(FD-score)
basedonbodydimensionmeasurements.Withthisscoreasimilarclassification
ofobesesubjectsintotypesoffatdistributionwasobtainedcomparedtothe
classificationbasedonthephotographsandtheclassificationsystemthatwas
developedbyVague.ThescoreofAshwelletalwascalculatedfromtheratioof
waistdiametertothighdiameter [6].Latertheyprovedthatthis'Fat
Distributionscore'washighlycorrelatedwiththeratioofwaisttothigh
circumferences [7].
InSweden,collaboratorsinresearchonfatcellmetabolismandmetabolic
complicationsfoundthatthewaistcircumferencewashighlycorrelatedwith
metaboliccomplications.Asthewaistcircumferencewascloselydependentonthe
sizeoftheindividual,theratioofthewaisttohipscircumferencewasusedin
theanalysesinordertocorrectforbodysize[68].Inanepidemiologicalstudy
of15532obesewomeninaslimmingorganizationintheUSA,theratioof
reportedwaistgirthandhipsgirthwasusedasanindexofbodyfat
distributionas'itwassimilartotheindexreportedbyAswelletal,andthe
IndexproposedbyVague'[57].Evansetal[38]laterconfirmedthatthe
simplestmethodfordescribingfatdistribution(i.e.waist/hipscircumference
ratio)wasatthesametimethemostusefulonewithrespecttometabolic
complications[38].Later,thisratioofwaisttohipscircumferencewasfound
tobeastrongpredictorofmortalityinmenandwomen[73,72].Waist/thigh
ratioisprobablyanequallyusefulmeasureoffatdistribution[16,88]
althoughinpracticesubjectsmaybemorereluctanttohavetheirthigh
circumferencemeasuredthantheirhipscircumference.
-14Thewaist/hipsandwaist/thighcircumference ratiosdoesmeasurethe
predominance of fatstorage ineithertheabdominal regionor,respectively,the
gluteal and femoral region.Theabdominal fatdepot indicatedbythemagnitude
ofthewaistcircumference includesboththesubcutaneous fatdepotandthe
intra-abdominal fatdepot.These fatdepotshavedifferentmorphological and
metabolic characteristics,and itmaybe importantto distinguish thetwoin
studiesofmetabolic complications,morbidityandmortality.Computed tomography
hasbeenfound tobeauseful toolforestimating theamountofabdominalfat
stored internallyandsubcutaneously.
2.1.3.Computed tomography infatdistribution research
In1982,Borkanetal [21]published the resultsofan investigationwhich
demonstrated thevalueofCTscanning inassessingabdominal fatcontent.Data
from8malepatients revealed thatasingle scanattheleveloftheulnbilicus
provided themostuseful informationonintra-abdominaland subcutaneous
abdominal fat.Dixon [35]comparedCT-scansof25menand 25womenatthislevel
(whichcorresponds inmostcasestotheleveloftheL4vertebra)andobserved
thatmenhad significantlymore fatwithintheabdominal cavity.Thetotal
amountofbody fatinthis regionwas foundtobe similar inmenandwomen,but
inwomenagreaterproportionofthe fatwasstoredsubcutaneously.Grauer etal
[55]studied 50adultmalesand62adultfemalesandassessed fatdistribution
atseveralothervertebral levels (Ll,L3and L5). Theyconfirmed thatthe
proportionofsubcutaneous fatisgreater inwomen thaninmenbut foundthat
total fatvolume inwomenwashigherthan inmen.Similar resultswere obtained
fromobese subjects [100].Borkanetal [22]showed thattotal fatmassinmen
didnotdifferbetweenmiddleaged (meanage46years)andoldermen (meanage
69years),butthattheproportionofsubcutaneousabdominal fatwaslowerand,
correspondingly, theproportionof intra-abdominal fatwashigher intheolder
men.Aswell etal [8]studied in28womenthe relationshipsbetweenthe
circumference ratiosdescribedaboveand the ratioof subcutaneousabdominal fat
tosubcutaneous fatattheumbilicus (L4)level.Therewasa significant
correlationbetween thewaist/hips circumference ratioand theproportionof
intra-abdominal fat.These correlations remained significantafter adjustments
forageanddegreeofobesity.Theauthorssuggest thattheobserved
relationshipbetweenahighwaist/hips ratioandmetabolic complicationsmight,
at least inwomen,reflecta relativelylargeamountof intra-abdominalfat.
-15-
Ifthisisproventobethecase,itmightprovideafurtherexplanationforthe
higherrisksthatmenhaveformetaboliccomplications,comparedtowomen,at
thesamedegreeofobesity [68].Ontheotherhand,thereisadiscrepancy
betweentheobservedinternalizationoffatwithincreasingageandthedecrease
inmorbidityriskofobesitywithadvancingage.Furtherresearchisneededto
clarifythisapparentparadox.Figures1and2illustratetheuseofcomputed
tomographyperformedontwomalepatients.Thepatientinfigure2isolderand
fatterthanthepatientinfigure1.Thelargeramountofbodyfatinthe
abdominalregioninpatient2isclearlypredominantlystoredasintraabdominalfat.
Figures1and2:
ComputedtomographicscansatL4levelintwomalepatients.
Figure1.Age:33years;BMI:21.1kg/m;Surfaceofintra-abdominalbodyfat:
2
2
30cm;Surfaceofsubcutaneousbodyfat:124cm.
-16-
Figure2.Age:55years;BMI:26.5kg/m;Surfaceofintra-abdominalbodyfat:
2
2
157cm;Surfaceofsubcutaneousbodyfat:179cm.
-17-
2.2.Functional characteristicsoffatstored indifferent regions
2.2.1.Morphologyofadipocytes indifferent regions
Ithasbeenknown foralongtimethatwomenhavemorebodyfatthanmen [77].
Sjostrometal [92]showed,inastudyof11maleand12femalestudents,whose
weightswerewithinthenormal range,thatwomenhadmore subcutaneousbody fat
thanmenand thatthisdifferencecouldbeattributed toalarger fatcell
number inwomenthaninmen.Thiswasdemonstrated fortheepigastric,
hypogastricand femoral regionbutnot forthegluteal region.Inthegluteal
regionthedifference insubcutaneous fatthicknessbetweenmenandwomenwas
due tolarger fatcell size inwomen.Krotkiewski etal [67]foundthat
non-obesemiddleagedwomenhadmorebody fatthannon-obeseyoungwomen,owing
mainly tothelarger fatcellsintheolderwomen,particularly intheabdominal
region.Thisfinding indicated thatfatcellsoftheabdominal regionaremore
responsivetonutritionalorhormonal factorsthanfatcellsfromotherregions.
WhenKrotkiewski etal [68]extended their studiestoalargepopulation (n=
930)ofobese individualstheyfoundthatfatcellweightinobesemenwas
similar inall four studied regionsbut fatcellnumberwas found tobehighest
intheabdominal region.Inobesewomen,asinwomenofnormalweight,fatcell
sizeand fatcellweightwerehighest intheglutealregion.
Thus, thetypicalcharacteristicsoffatcellmorphologyand fatdistribution in
menandwomenofnormalweight remainspresent inobesity.Itwas shownthat in
theobese,the increasingamountofbody fatleadstoanincreased fatcell
size,uptoacriticalvalueof 0.7 -0.8 ugper cell.After thisincrease,a
more rapidincreaseof fatcellnumberwasobserved inall regions.This finding
challenged thehypothesis (whichwashotlydebated someyearsago)that fatcell
number isacharacteristicdetermined early inlifeandpredisposing fat infants
tolifelongobesity.Thishypothesishasnowbeengenerally rejected [56,63].
Thedifferencesbetweenmenandwomenwith regardtofatcellmorphologyand fat
distributionmaybe,according toBjorntorp [14],explainedbythespecific
controlof femoral-gluteal fatcellsby femalesexhormones.
The roleofhormonal regulationofbody fatdistributionand fatcell sizewas
furtherelucidatedbywork ofRebuffe-Scriveetal [83]who foundthat fatcells
were larger inbothabdominaland femoral regionsinlactatingwomenthanin
pregnantandnon-pregnantwomen.Lipo-proteinLipase (LPL)activitywashigher
inthe femoral than intheabdominal region innon-pregnant andpregnantwomen.
Thus, fatispreferentially stored inthe femoral regionundernormal conditions
and inpregnancy inwomen.Duringlactation,however,LPLactivitywasmarkedly
reduced inthefemoral regionwhile therewasnochange intheabdominal region.
Basaland catecholamine stimulated lipolysiswere foundtobemoreactive inthe
abdominal region (ashadalsobeenobserved inother studies [5,76,69]).
Duringlactation,incontrasttootherconditions,lipolysis increased inthe
femoral regions.These findingsledtothehypothesisthatthe characteristic
female fatstorage intheglutealand femoral fatdepotshavea functionfor the
storageof triglyceridesthatcanbeused toprovidetheextraenergyneeded for
lactation.Thiscanprobablybe regardedasanadaptationthatwasadvantageous
inpre-industrialcivilizationsbutisnolongerofmuchgreatphysiological
importanceand is,ironically,thecauseofcosmetic concern inwomenliving in
populationswhere food isabundant inallseasons.
Ithasbeen reported that inthepost-menopausalstatewomenbecomemore similar
tomenwith regard toregionaldifferences infatcellmorphology,andmaybe
influencedbytheuseofestrogenmedication [14,15].Other findingswhich
supportthehypothesisofhormonal regulationofbody fatdistributionwere
publishedbyEvansetal [39].Theystudiedadipocytemorphologyandmetabolic
profiles in80healthypre-menopausalwhitewomenwithbodyweights ranging from
normal tomarkedlyobese.They reported thatincreasingandrogenicity (reflected
indecreasedplasma- sexhormonebindingglobulinandan increased percentage
of freetestosterone)wascorrelatedwithincreasingwaist-hipscircumference
ratioandan increase infatcellsizeintheabdominalbutnotinthefemoral
region.
Althoughthedetailsofthemechanisms involved remaintobeelucidated,
evidence sofar strongly suggeststhatspecificendocrine regulationof
abdominaland femoraladipocytesexplainsatleastsomeofthedifferences
betweenmenandwomenandbetweentypesofbodyfatdistributionwithregard to
the regionalvariation inmorphologyanddistributionofadipocytes.
2.2.2.Additional factorsthatmay influence regionaldifferences infat
celldistributionandmetabolism
2.2.2.1.Weight reductionand fasting
Ashasbeendiscussed intheprevioussections,theabdominal fatdepot
appearstobeamorelabiledepotoftriglycerides.Itmightthereforebe
expected thatweight reductionwould leadtoa reduction incell size,
particularly intheabdominal region.Thishypothesis issupportedby findings
-19ofArner etal [4],whoobserved that,in25obesemiddleagedwomen,fatcell
volumedecreased intheabdominalbutnotinthefemoral regionduringoneweek
of fasting.LPLactivitydecreased,and lipolyticactivity increased,inthe
femoral regionas resultof fasting,buttheseeffectswere foundtobemuch
morepronounced intheabdominal region.Similarobservationsweremadeby
Smithetal [94]who studied seriouslyobesepatientsbeforeandafter
jejuno-ilealby-pass.Fatpatternswould thereforebe likelytobealtered
after substantialweight reduction.Manystudiesinthepast,however,have
beenunable toconfirm this. Forexample,Edwards [37]observed in1950that in
womenwho lostmorethan12.7kgtherewasabasic fatpatternthat remained
stableoverabroadweight range.G a m [45]studied 13menduring controlled
weight lossandfoundthatthe relative fatpattern remainedconstant.Craig
andBayer [31]re-examined 50women2-10yearsafter conspiciousweight lossor
gain,andconcludedonthebasisofoutlinesthatwhetherweightwas lostor
gained thedistributionoffatandtheandrogynicpattern remained thesame.
Vague in1974 reported that inastudyof13obesemales,28obese femalesand
21leanfemalesduringweight lossorgaintheadipomuscular ratiosin
individualsweremoreorlesscharacteristicandwere inclined toreappear
whateverweightvariationswere imposedonthesubject [105].Ashwelletal [6]
foundnocorrelationoftheir 'FatDistributionScore'withweight lossand
proposed that fatdistributionwas relativelyconstantandpossiblygenetically
determined.Thework ofBorjeson [20]in1976onmonozygoticanddizygotic
twinssuggested that fatdistributionmight indeedhaveanimportantgenetic
component.A recent investigationofweight lossin187severelyobesewomenby
Lanskaetal [69]demonstrated thattheratioofwaisttohipsgirthwasnota
usefulprognostic indicator ofweightchange forthesewomenwith,itshouldbe
noted, refractory severeobesity.Theassumptionthatobesity ismore catching
intheabdominal regionandthatfemoral regionsaremore resistanttoslimming
[3]maybeunwarranted [52].On theotherhand,Albrink andMeigsshowed,in
1964, that in419male factoryworkers,skinfold thicknessofthetrunkwas
correlatedwiththeamountofweightgained sinceagetwenty five,but forearm
skinfold thicknessshowednosuchcorrelation [1].Theyhypothesized that
forearmskinfold thickness reflected innatelifelongobesity,while skinfold
thicknessof thetrunk reflected,atleast inpart,obesityacquiredduring
adultlife.Geneticallydetermined fatstorage capacity indifferent regions
maybecomeapparentonly inlaterlifeundertheinfluencesofenvironmental
factors.Thishypothesis,thatfatintheextremities isincreased ininherited
butnot inacquiredobesity,isstrengthenedbythe reportofStrendberg
-20-
(quotedbyWells[108])ofafullthicknessskingraftfromtheabdominalwall
tothehandofaslimyounggirl.Asanadultthisgirlacquiredexcessweight
aboutthegirthandtheskingraftofthehandalsobecameobese,althoughthe
neighboringforearmadiposetissuedidnotincreaseinsize.Theresult,a
grotesqueboxinggloveappearancetothehand,suggeststhatthereisagreater
potentialforabdominalfattoexpandthanforfatoftheextremities.Thus,
environmentalinfluencesmaybenecessaryfortheexpressionofgeneticfactors
thatdeterminefatdistribution.Ifthisisindeedthecase,weightgaininthe
'innate'obeseshouldnotinfluencefatdistribution,butinthosewithadult
onsetobesityitshoulddoso.Theconflictingresultsdescribedabovecouldbe
duetodifferencesintheaetiologyoftheobesesubjectsthatwerestudied.
Anotherfeatureofthestudiesdescribedaboveisthattheyconsideredonly
subcutaneousfatpatterningbeforeandafterweightloss,andmayhavefailed
totakealterationsintheintra-abdominalfatdepotintoaccount.Aswas
discussedintheprevioussection,thisdepot,ofallthemajorfatdepots,is
themostlabilepooloftriglycerides.Studiesinwhichsubjectswithaclear
abdominalfatdistributionarecomparedtothosewithfatstoragepredominantly
inglutealandfemoraldepots,beforeandaftercontrolledweightreduction,
areneededtoclarifythisissue.Althoughitwillbedifficulttoidentify
themwithoutmisclassification,individualswhoaregeneticallypredisposed
towardsobesityshouldbeseparatedfromthosewithnofamilyhistoryof
obesityatall.Insuchstudies,notonlyshouldsubcutaneousfatdistribution
bestudied;variationintheamountoffatwithintheabdominalcavityshould
alsobeincluded.StudiesofBouchardetal[24]suggestthatabout60%ofthe
subcutaneousfatpatternmightbeexplainedbygeneticandenvironmental
factors,whicharebothequallyimportant.Theimportantimplicationsforthe
treatmentofabdominalobesitymeanthatpriorityshouldbegiventostudiesof
theeffectsofweightreductionbyvariousmethodsonfatdistributionand
associatedriskfactors.
2.2.2.2.Age,degreeofobesity,ageofonsetofobesity,parity
Studiesofsubcutaneousfatpatternshaverevealedthat,withincreasingage,
fatshiftsfromtheextremitiestowardsthetrunk[47,48,93].Aswelletal
[6]showedthatolder,fatterwomenaremorelikelytohaveacentraltypeof
fatdistribution.ThiswasconfirmedinastudybySeidelletal[88]inwhich
BodyMassIndexexplained15.9%ofthevariationinthewaist-thighratioof
overweightwomen,andageexplained9.0%.Inoverweightmen,agewas
-21-
significantlycorrelatedwiththewaist-thighratio(r2=16.5%),andtoa
smallbutsignificantextent,socialclasswasnegativelycorrelatedwiththe
2
waist-thighratio(r =3.3%).
DatafromalargecrosssectionalsurveyintheUnitedStates(52953womenwho
participatedinaTOPS,'TakeOffPoundsSensibly',programme)revealedsimilar
results[70].Inthisstudy,inwhichself-reportedwaistandhipgirthswere
used,thewaisttohipcircumferenceratioincreasedwithageandbodyweight.
Theseeffectscouldnotbeaccountedforonthebasisofparity,menopausal
statusorobesityhistory.Obesityhistorywasdefinedasthegreatestpercent
over 'IdealBodyWeight'attainedduringtheteenageyears.Thestudyhasthe
advantageofalargenumberofsubjects,buttheinformationwasobtainedfrom
aratherselectivepopulationandmightbebiasedbyself-reportingofthe
data.InthestudyofSeidellelal[88],self-reportedweighthistoryrevealed
thatwomenbelongingtotheuppertertileofwaistthighratiohadalater
onsetofobesitythanthoseinthelowertertileoftheratio.Inmen,nosuch
aneffectofonsetofobesitywasfound.Suchfindingshaveledinvestigators
tohypothesizethatobesity,acquiredearlyinlifewouldleadtogeneralized
obesitywithexpansionofallfatdepots,whileinadultonsetobesitythis
expansionwouldbeconfinedtotheabdominalregion.Asfatnessinchildrenis
associatedwithearlymaturation,onemightexpectlong-termdifferencesinthe
fatdistributionofearly-andlate-maturingindividuals[44].Theeffectof
maturationonbodyfatdistributionhasbeenstudiedbyFrisanchoandFlegel
[44]whoexaminedthedatafromtheNationalHealthandNutritionExamination
SurveyIintheUnitedStates(NHANESI).Percentagetrunkfat(definedas
subscapularskinfolddevidedbythesumofthetricepsandthesubscapular
skinfold)wasfoundtoberelatedtoboneage(inchildren)andageofmenarche
(inadultwomen). Theirresultssuggestedthatearlymaturationfrom7years
onwards(exceptformalesaged13to16years)isassociatedwithlarger
tricepsandsubscapularskinfoldthickness.Thiswasmoreevidentinthe
subscapularskinfold.Theauthorsconcludedthatadvancedmaturationis
associatedwithanaccentuationofthecentripetal (abdominal)distributionof
fatduringadolescenceandadulthood.Theysuggestedthatenvironmental
influencesmaybringabouttheexpressionofgeneticfactorsthatdeterminefat
distribution.TheirpaperwascritisizedbyDeutchandMueller [34]whoargued
thatinfemalesthedifferenceascribedtomaturitywaslikelytobea
secondaryeffectofthecorrelationbetweenpercentagetrunkfatandbody
fatness.IncontrasttoFrisanchoandFlegel,theyfoundthat,usingprincipal
componentanalysisofsubcutaneousfatdistributioninadolesenceandyoung
T-i-
adults,obesity inadolescence andyoungadulthoodwasassociatedwith fat
concentrated intheupper partof the trunk.Thiseffectwas independentof
maturity,whichwas found tobeasignificant correlate of the trunk/extremity
patterning componentbutnotof theupper/lower trunk-fatcomponent (inmales).
Only long termprospective studies,inwhichbothbodyweight development and
fatdistribution are followed, canclearlygive theanswer tothe question
whether fatdistribution is related totheonsetofobesity,menopausal status,
and/or parity.
2.2.2.3.Regionaldifferences infattyacidand glucosemetabolism in
adipocytes.
Itisdifficult tostudycells fromthe intra-abdominal fatdepot.Those who
have studied these cells,obtained them fromtheomentummajor of patients
undergoing abdominal surgery.Omental fatcellswere found todiffer from
subcutaneous fatcells intheir lipolytic response.Ithasbeen demonstrated
thatomental fatcellsaremore responsive tothe lipolytic effect of
epinephrine andnor-epinephrine [54].Bolinder etal [18]showed that innonobeseadultmenandwomen,omental fatwasless responsive tothe antiliipolytic
effect of insulin thansubcutaneous abdominal fat.Theydemonstrated that the
difference could beexplained bydifferences ininsulin receptor affinity,and
byadifference ininsulinactionat thepost-receptor level.Itcanbe
expected, therefore,that invivo relatively largeamountsof free fatty acids
will be released fromabdominal adipocytes intothebloodstream. From the
intra-abdominal fatdepot the free fattyacidswilldraindirectly intothe
portalvein,sotheliverwillbeexposed toan increased concentrationof free
fattyacids. Fromthe subcutaneous fatdepot the released free fattyacidswill
go intothe systemic circulation. Figure 3showsatentative overviewof the
possible consequences of the releaseof largeamountsof free fattyacids (FFA)
by theabdominal depots (adapted fromBjorntorp14,15).
-23-
Subcutaneous
abdominal fat
depot
FFA insysfltemiccirculation
high exposure of
peripheral tissues
toFFA
deranged
f glucose
metabolism
inperiphery
iglyceridemia (VLDL increase)
Intra-abdominal
fatdepot
Figure 3,Schematic representation of the (hypothetical) mechanismsby which
increased fatmassmay lead tometabolic complications.
(Adapted fromBjSrntorp(15).
The relationbetweenpredominance of trunk fat (asopposed to faton the
extremities) andplasma triglycerideswas shownbyAlbrink andMeigs in 1964
[1], and has sincebeen confirmed several times [40,64].Asdiscussed inthe
previous section,Albrink andMeigs founda correlation of trunk fat (butnot
forearm fat)withweight gain sinceage twenty-five.Inmenwith slender
forearms,triglyceride concentration increased significantlywith abdominal
skinfold thickness. Inmenwith fat forearmsnosuchcorrelationwas found.
Albrink andMeigs suggested thatthis finding,and the fact thatmean
triglyceride levels in innately thinmen (withslender forearms)who became
obese later inlifewerehigher thaninthe innately fatmen (with fat
forearms),mayhavebeenthe resultofoverloading ofexisting adipose cells.
Despres etal [33]inastudyon234womenand 238menof18- 50yearsofage,
confirmed thatabdominal and subscapular fatdepotsaremore closely associated
with serum lipids thanother fatdepots,particularly inmen.Theabdominaland
subscapular skinfoldswere foundtobepositively correlated with serum
triglicerides and total cholesterol,negativelywithHDL-cholesterol,and most
stronglywith the ratioofHDL-cholesterol tototal cholesterol.This regional
trend remained significant after correction forconcomitant variables suchas
age,cigarette smoking,habitual energy intakeand energy expenditure,maximal
aerobic power andalcohol consumption. Suchassociationswere less clear in
womenwho,although theywere fatter than themen inthestudy,had lower
triglyceride and total cholesterol concentrations andhighervaluesof theHDL
cholesterol/total cholesterol ratiothan themen.More recentlyotherparts of
themechanismdescribed infigure 3havebeenproven.Thiebaud etal [99]
demonstrated that increased plasma FFAlevels in25healthyyoungvolunteers,
established bymeansof intralipid infusion,impaired theabilityof insulin to
stimulate glucoseoxidation and storage.Thisinhibitoryeffectofelevated FFA
levelsonglucose storage contributed more tothe impairment of glucose
tolerance than thedefect inglucoseoxidation.They foundnoeffectofFFAon
baseline insulin levels.Smithhas recently cited evidence [95]that perfusion
with ahigh free fattyacid concentration inthe rat,reduced insulin
clearance.Decreased hepatic insulin removal isan important causeof
hyperinsulinemia inobesity,especially indiabetics [19].High FFAinthe
portal veinmight thus,as suggested in figure 3,be responsible for
hyperinsulinemia.Althoughmore evidence isneeded tounderstand the mechanisms
described infigure 3,this fieldof research isdeveloping rapidly,and it can
be expected thatwithina fewyears thetruecascadeofeventswill be
established.Onequestionofparticular importance iswhichofthe two
abdominal fatdepots (intra-abdominal or subcutaneous)causes the metabolic
aberrations associated withacentral fatdistribution.
-252.3.Clinical correlatesofhumanfatdistribution
Thehypotheticalmechanisms showninfigure 3provideapossibleexplanation
forthefindingsofepidemiological andclinical research revealingan
associationbetweenabdominal obesityanddisorderssuchas ischemicheart
disease,diabetesmellitus (type II), hypertension,and stroke.Theevidence
for theseassociationswillnowbediscussed inmoredetail.
2.3.1. Ischemicheartdisease
JeanVaguewasprobablythefirsttoreporta relationshipbetween fatlocated
intheupperpartofthebodyandischemicheartdisease (characteristic inhis
android typeofobesity).Hecalled fatmasslocated intheupperpartofthe
body, 'diabetogenic'and 'atherogenic'fatmass [101,102,103,104,105].In
1959heandhisco-workerspublisheda studyon82obesemenand 158obese
women [106].Theycompared subjectswithclinical symptomsofatherosclerotic
disease tothosewithoutevidenceofsuchdisease.Itwas foundthatbetween
thegroupstherewerenodifferences inageandtotal fatmass,butthatthe
B/FAMRwassignificantlyhigher inthemenandwomenwithsymptomsof
atheroscleroticdisease.Theyproposed,onthebasisofpreliminaryevidence,
thatminorhypercorticism,thatwouldaccompanyandroidobesity,could,in
part,be responsible fortheprogressionofobesity towardsatherosclerosis.
His retrospective evidence ina rather selectivepopulationhaslong remained
unrecognized.Damonetal [32]found thatinFraminghammalescasesofcoronary
heartdiseasewere 'fatter,moremuscularandstockier'thanothers .The
relationshipswerenotveryclearand itisdifficult totranslatebodybuild
intotermsof fatdistribution.
Only recentlyhave clear relationshipsbetweenabdominal fatdistributionand
several cardiovascular endpointsbeenestablished inlargeprospectivestudies.
InGoteborg, inSweden,investigators includedwaistandhips circumference
measurements intheir setofanthropometricbaselinedata,when theystarted
their long-term followupstudiesofmalesand females.A thirteen-year followupof 54-yearoldmenbornin1913revealed thata significant association
between thewaist tohipscircumference ratioandtheoccurrenceof ischemic
heartdisease.Infact,itproved tobethemostpowerfulpredictor for these
endpoints,ofalltheanthropometricvariablesstudied (includingBodyMass
Index)[73].
Thewaist tohips ratiopredicted ischemicheartdisease independentlyof
-26measuresofobesity,butnotwhen risk factorslikesmoking,systolic blood
pressure and serum cholesterolwere taken intoaccount.What isremarkable is
that the risk for ischemicheartdiseasewashighest inmen inthe highest
tertile ofwaist tohips ratioand inthelowest tertileofBodyMass Index.
These findingswere confirmed intheParisprospective heart study [36J.In
this studycircumferences hadnotbeenmeasured atbaseline examination,but an
index of fatdistributionwasconstructed on thebasisofskinfoldsat several
sites.The ratioof the sumof skinfoldsonthe trunk tothe sumof skinfolds
on theextremitiesproved tobeanindependent predictor of cardiovascular
endpoints ina10-year followupofmiddle-aged men.Lapidus etal [721 showed
that ina12-year followupofwomenaged 38-60years,similar associations
were found tobeevenmore pronounced than inmen.Thewaist/hips rati©was
associated with the incidence ofmyocardial infarction andanginapectoris even
whenage,bodymass index,smokinghabits,serumcholesterol and triglycerides,
and systolic blood pressurewere taken intoaccount.Onedrawback of these
studies isthat subsequent eventsarelinked only tomeasurements at baseline
examination: changes inbodyweight and fatdistribution during follow-up
cannot betaken intoaccount.Suchanapproachwould involve frequent
re-examinations,whichare impossible inpractice.The studyofLarsonetal
raise thequestionwhy relatively leanmenwithhighwaist/hips ratios,have
thehighest risk fordeveloping coronaryheartdisease.
Studies oneightnon-obesewomenwith familial partial lipodystrophy[85],
which ischaracterized by fatstoragepredominantly as subcutaneous abdominal
fat,andapatientwithWerner's syndrome [96],showed thateven innon-obese
individuals an increased ratioofcentral toperipheral fat isassociated with
metabolic complications.
2.3.2.DiabetesMellitus,glucose intolerance andhyperinsulinemia
DiabetesMellitus type IIwas the firstdisorder found tobeassociated with
abdominal,upper bodyand/or android typesof fatdistribution was.Vague
observed that inobesepatients increasing severityofdiabeteswas
accompanied byanincrease inB/FAMR [106]. Lister andTanner [75]contpared
'acutely'diabetic patientswith 'non-acute'diabetics and found that thenonacutediabeticsweremoreendomorphicthanthosewhosediabeteshad appeared
during early life.Endomorphyischaracterized by roundness of the body
contour,atendency toobesity,asmooth skinwith finehair,and short
tapering limbswith smallhandsand feet.Itisclear thatthesepersons,who
-27canbe regarded astypical type IIdiabetics,would alsohaveahighwaist to
thigh circumference ratio.Otherworkershavecompared skinfoldmeasurements of
diabetics andnon-diabetics andconcluded thatdiabeticshave relatively larger
skinfolds on the trunk thanontheextremities [42,62].Kissebah etal [66]
later confirmed the findingsofVaguebut,insubsequent research, preferred
theuse ofwaist tohips ratio formeasuring fatdistribution. Ina seriesof
experiments onabout90womenKissebahandhisco-workersexamined the
mechanismsunderlying the relationbetween fatdistribution anddiabetes [38,
39, 40,41].They concluded fromtheir experiments thatdiminished skeletal
muscle insulin sensitivitywith impaired glucose storage capacity contributes
tothe insulin resistance and,inturn,totheassociated glucose intolerance
andhyperinsulinemiaofupper body segmentobesity (orabdominal obesity). This
effectmaybe the resultofa reduction ininsulin receptor numberwhich could,
inturn,besecondary topersistently elevated fastingplasma insulin levels
[38, 39,40, 41].
Themechanism described above isbased on correlations betweenmany variables
involved inthecomplex glucose-insulin regulatory system,andhas still tobe
experimentally validated.
Recently, Smith [95]cited evidence suggesting thathigh Free FattyAcid (FFA)
concentrations,whichwere found tobeassociatedwith abdominal fat
distribution (see figure 3 ) ,causeadecrease in insulin clearancewhich could
lead tohyperinsulinemia. Lipolysisactivitymay,therefore,be thekey factor
inthe relationbetweenabdominal obesityanddiabetes.
Thus,although theepidemiological evidence for sucha relation is fairly
strong and consistent,themechanism behind thecausal relationshipbetween an
abdominal typeof fatdistribution anddiabetes appears tobevery complex.
Theepidemiological evidence comes fromcross-sectional surveys [58]inwhich
theprevalence of self-reported diabetes increased with waist/hips
circumference ratio.This relationwas independent of thedegree of obesity.
Ohlsenetal [80]showed that,intheir prospective studyofmiddle-aged men,
the incidence ofdiabeteswasassociated withwaist/hips circumference ratios
atbaseline examination.
Inobese non-diabetic andotherwise apparently healthy subjects,the relation
between glucose intolerance andhyperinsulinemia and thewaist tohips
circumference hasalsobeendemonstrated[64].
2.3.3. Hypertension
Vague noted in1956 [102]thatandroid obesepersons hadatendency todevelop
hypertension. In recentclinical andepidemiological studies thishasbeen
confirmed [58,39,17,88].Itshouldbenoted thatKrotkiewski [68]f((>undthat
body fatinobesewomenand fatcell size inobesemenwere, in stepwise
regression analysis,more important than thewaist/thigh circumference ratio.
Hartzetal [58],intheir large studyonTOPSmembers,compared obesewomen in
theupper quartile ofwaist/hips circumference ratiowithwomen inthe lowest
quartile of the ratio.They founda relative risk of 1.74,adjusted for effects
ofageand relativeweight.Relative risk forwomen intheupper quartile of
relativeweight,comparedwith thatof those inthelowestquartilewas 4.01
adjusted forageandwaist tohips ratio.Theeffects ofbody fat distribution
andexcess fatmassthusseemtobe independent. Itisnotyetclearhowthis
association ofbody fatdistribution canbeexplained. Thehyperinsulinemia,
that isfound tobeassociatedwithabdominal obesity (figure 1), mightbe
involved inthemechanism. Itiswellknownthathyperinsulinemia causes sodium
retention andactsonthe sympathicnervous system. Effectsofhormonal factors
onboth fatdistribution andbloodpressure cannotbe excluded.
Sincehypertension isa risk factor forcardiovascular disease and
cerebrovascular accidents,theobserved relationbetween abdominal fat
distribution andhypertension may inpartexplain theepidemiological findings
inwhich central fatdistribution hasbeen found tobeassociated with
cardiovascular disease and stroke.
2.3.4.Other clinical correlates ofbody fat distribution
AlthoughVague andhisco-workers played an important role in stimulating
research onbody fatdistribution, someoftheir evidencewas poorly
documented. Inhismuch cited paper in1956,Vague [102]stated that android
obesitywasassociatedwithgout,uricacid crystalsand gallstones.Gynoid
obesity,on theotherhand,wasassociatedwithdirectmechanical complications
(respiratory and circulation problems).These findingswerebased on
'observations on thousandsofpatients'butnodatawerepresented. Vague
proposed that theseassociationswerepossibly related tohormonal differences
that caused both fatpatterns and thecomplications.
Hartzetal [58]argued that ifVague'shypothesiswas true theassociations of
body fatdistributionwithmenstrual abnormalitieswouldbeevenmore
-29pronounced thanwith otherdisorders.They studied the relationshipbetween the
waist tohip ratioand reportedmenstrual abnormalities (irregular cycles,
oligomenorrhea andhirsutism) in11791womenaged 20- 39years.They confirmed
that suchanassociationexisted,butthat itwasno stronger than thosewith
diabetes,hypertension orgallbladder disease[58].
Therefore Hartzetalproposed another mechanismbywhichbody fat distribution
influences synthesisofestradione fromplasma androstenedione.Adipose tissue
seems indeed to influence thisconversion [59,78].Whether adipose tissue in
different regionsbehavedifferently inthis respectneeds tobe investigated.
Asmentioned above,Hartzetalobserved a relationof fatdistribution with
gallbladder disease.Itwas suggested thatcholesterol metabolism maybe
involved inthis relation.
InaDutch study ithasbeen found thatarthrosis inobesemen ismore
prevalent inthosewithahighwaist/thigh ratiothan inthosewitha low
waist/thigh ratio [88].Silberberg, ina reviewof the relation between
arthrosis and obesity,concluded thatarthrosis ismore closely associated with
abnormalities in fatmetabolism thanwithweight-induced wear and tear [89].In
fact,after adjustment for fatdistribution,Seidell etal [88]founda
negative association betweenBodyMass Indexandarthrosis.For the
interpretation of this finding itshould benoted intoaccount that this study
involved obesemenonly.The same study revealed thata lowwaist/hips ratioor
waist/thigh ratiowasassociatedwithahighprevalence ofvaricoseveins[88].
This isinagreementwith findingsbyVaguewhoproposed that 'venous
insufficiency' wasoneof thecharacteristics ofgynoid obesity [102].
Whether this relation indicates thatwhen fat isstoredpredominantly inthe
thighorhips regionblood flow inperipheral tissuesof theseareas is
impaired remains tobeproven.
2.4.General conclusions
The consistency of the relationships described intheprevious section leads to
the conclusion thatpredominance of fat stored intheabdominal region is
hazardous tohealth.Thusprevious research inwhichexcess fathasbeen
treated asasimple entitymustbe interpretedwith caution.The implications
of these findings forthediagnosis and treatment ofobese individuals have
been summarized byBjorntorp [15].Heproposes thatabdominal obesity (awaist
hips ratiogreater than 1.0 inmenand greater than 0.8 inwomen) isdangerous
and should bediagnosed early andexamined forassociated risk factorsonwide
-30indications (plasma insulinandlipids,glucose tolerance,bloodpressure).
Future research should focusonmanipulating fatdistribution,andon
evaluationof theeffectsof thismanipulationonmorbidityandmortality.
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-38-
CHAPTER 2
ASSOCIATIONSOFMODERATEANDSEVEREOVERWEIGHTWITHSELF-REPORTED ILLNESSAND
MEDICALCAREINDUTCHADULTS
J.C.Seidell,C.P.G.M. deGroot,J.L.A.vanSonsbeek,P.Deurenberg,
J.G.A.J.Hautvast
AmJPublHealth 1986;76:264-269
ABSTRACT
Dataonheight,weight,illness,medicalcareconsumption,anddemographic
variables for19,126Dutchadultsaged 20yearsorolderwereobtained from
threeannualHealth InterviewSurveys.Dataonseverely (BodyMass Index 30.02
2
40.0kg/m )andmoderately (BMI25.0- 29.9kg/m )overweight subjectswere
2
comparedwiththoseonnon-overweightpersons (BMI20.0-24.9kg/m ),taking
intoaccounteffectofsex,age,andeducational level.Inmen,severe
overweightwasassociatedwithhypertension,especially inmenunder 50yearsof
age. Inwomen,severeoverweightwasassociatedwithhypertension,diabetes,
varicoseveins,asthma/bronchitis,andhemorrhoids.Increasedutilizationof
medical careandmedicationswerealsoassociatedwithsevereoverweight.For
moderatelyoverweight subjects,theseassociationswerelessclearorabsent.
INTRODUCTION
Obesity isconsidered tobeoneofthemostprevalentmedicalandpublichealth
1-3
problems inaffluent societies
although thisassumptionhasbeen
45
criticized. ' The importanceofobesityasapublichealthproblemhasbeen
reviewed recently inthe reportsofexpertcommitteesonoverweightand obesity
fi
?
7
inEngland, and theUSA, and inTheNetherlands .These reports recommend the
2
useof theBodyMass Index (BMIorQuetelet'sIndexinkg/m )asacrude
indicator ofthebody'sfatcontent.Fromdataavailable fromseveral relatively
small surveys,itcanbeestimated thatalargeproportionoftheDutchadult
2 7910
population isatleastmoderately overweight (BMI>25kg/m ).'' Itis
important toknow ifoverweight indifferentdegreesofseverity isassociated
withahigherprevalence ofchronicdisordersorotherhealthcomplaints,
-39related inturntoanincreaseduseofmedical servicesandmedicines,than
couldbeexpectedinsubjectswithaBMIwithinthedesirable range.Evaluation
oftheriskscouldbehelpfulindecidingwhether todirectpublichealth
programsatreductionofbodyweightthroughoutthepopulation,orwhetherthe
effort shouldbeconcentratedontheseverelyoverweight.
Inthisstudy,theassociationsofBMI(calculated fromself-reportedheightand
weight)with reported chronic illnessandaspectsofmedical consumption
were investigated,usingdataonarepresentativepopulationof19,126Dutch
adults.
METHODS
Subjects
Subjectswere intervieweesintheannualContinuousDutchHealth Interview
Surveys.Eachyear since1981,theDutchCentralBureauofStatistics (CBS)has
approacheda representative sampleofthetotalnon-institutionalized population
inTheNetherlands.Thestudydescribedhereexcluded thosewithoutDutch
nationalityandthoseunder20yearsofage.SubjectswhoseBMIexceeded40
2
kg/m wereexcluded (0.8%ofthetotal studypopulation).Close inspectionof
theirdataaroused strongsuspicionsaboutthevalidityofthereportedweight
(e.g.,weightexpressedinpoundsinsteadofkilograms).Theremaining
populationofthesurveysof1981,1982,and1983comprised9,369menand9,757
women. IndividualswithaBMIbelowthedesirable range (i.e.<20kg/m)were
2
excluded fromthecomparisonofseverelyandmoderately overweightwith
non-overweight sincetheyareknowntohave increased riskofmorbidity. ' '
Theaveragenon-response ratesforthesesurveyswereabout33percent.About
22percent refusedtoparticipate,8percentwerenotathomeand3percent
wereunabletoanswerbecauseofmedical,linguistic,orother reasons.More
1415
detailsofnon-respondersaredescribed elsewhere. '
Sampling, Variables
Samplingwasdone intwosteps.Inthefirststep,arepresentative sampleof
allmunicipalitiesinTheNetherlandswastaken.Inthesecond step,asampleof
householdsoutofevery sampledmunicipalitywastaken.Trained interviewers
visited thesehouseholdsthroughouttheyear,askedthequestionstothemembers
ofthehousehold,andnotedtheanswersinaprestructuredquestionnaire.
16
Furtherdetailshavebeendescribedelsewhere.
111213
-40-
Inconstructing thevariablesused inanalysis,agewascategorized into
intervalsof 20-34, 35-49,50-64,and65yearsorolder.Education servedasan
indicator ofsocio-economicstatus:lowlevel=primaryschooland some
occupational training;middlelevel= secondaryschool;highlevel=university
andother tertiary institutions.BodyMassIndex (orQuetelet's Index)was
calculated fromself-reportedheight (without shoes)andweight (without
clothes),dividingweight inkilogramsbythesquareoftheheight inmeters.
Q
ThreecategoriesofBMIweredistinguished,using theclassificationofGarrow.
2
- BMI=20.0-24.9kg/m (Desirable rangeorgrade 0obesity).
2
- BMI«25.0-29.9kg/m (Moderateoverweightorgrade Iobesity).
2
- BMI- 30.0- 40.0kg/m (Severeoverweightorgrade IIobesity).
Subjectswereaskedwhether theysuffered fromlong-standing illnesses,
handicaps,or theconsequencesofaccidentslistedonacardwith 19items.Each
personcouldmentionup tofourillnesses.
Subjectswereasked the reasonsforuptosixconsultationswith thegeneral
practitioner and,inaseparatequestion,withmedical specialists,inthethree
months (twomonths inthe1983survey)preceding theinterview. Consultations
bytelephone (exceptthose formakingappointments)wereincluded.Treatmentsby
medical specialistsduringhospitalizationwereexcluded,butoutpatient
clinicaltreatments (e.g.,firstaidandx-ray)were included.
Subjectswereaskedaboutanyhospitalization (formorethanonedayandone
night)intheyearpreceding theinterview.Subjectswereaskedaboutany
medicinesprescribedbyaphysician inthe14dayspreceding the interview
(excludingoralcontraceptives),and inaseparatequestionabouttheuseof
medicineswithoutapresciption (adescriptionofchronicdisordersand
categoriesofmedicalcare isgiven inAppendix IenII).
Analysis
Data fromthe1981surveywereused tomakeapreliminary selectionofthe
medical consumptionvariablesapparently associatedwithoverweight inanalysis
of contingency tables.The strengthsoftheassociationswereevaluatedwith the
extendedversionoftheMantel-Haenszel chi-square statistic for contingency
tables. Whenage-specific or stratum-specific estimatesof riskweredifferent
fromone (p<0.10),thedependentvariable (diseaseormedical consumption)was
selected for furtherstudy.
Ina stepwise forwardmultivariate logistic regressionanalysis (usingthe
18
packageprogramBMDPLR), dummyvariableswereused forcategoriesofBMI,age,
andeducational leveland interaction terms (BMIxageandBMIx education).The
-41threecategorizedindependentvariablesandtheinteractiontermswereadded(p
<0.10)orremoved(p>0.15)inpvalueorder.Thedependentdichotomous
variablewaspresenceorabsenceofaparticulardiseaseorreasonformedical
careoruseofatypeofmedicine.
UsingthecoefficientsofregressiononBMIcategories,oddsratioswere
calculatedadjustedfortheothervariablesinthemodel,comparingsevereand
moderateoverweighttonon-overweight.Wecalculated95percentconfidence
intervalsfortheoddsratios,usingthestandarderrorsof,andthe
correlationsbetween,themultiplelogisticregressioncoefficients,according
19
totheproceduredescribedbyLemeshowandHosmer.
Thesameprocedureoflogisticregressionanalysiswasfollowedfortheselected
dependentvariables,usingthedatafromthecombinedsurveys.Thedata
presentedbelowwerecalculatedfromthecombinedsurveysunlessstated
otherwise.
RESULTS
Accordingtothecriteriausedinthisstudy,about4percentofadultmenand
6percentofadultwomeninTheNetherlandsareseverelyoverweight.The
prevalenceofmoderateoverweightcanbeestimatedas34percentinmenand24
percentinwomen.Intables1and2,somecharacteristicsofthestudy
populationareshownforthecombinedsurveys.Theprevalenceofsevereand
moderateoverweightisinverselyrelatedtoeducationallevel.
Table1.Meanweight,height,bodymassindex(BMI)ofthestudypopulation,
bysex,combinedsurveys1981-83
men
n =9369
women
n= 9757
Mean
Sd
Mean
Sd
Weight(kg)
76,5
10,0
65,0
10,4
Height(cm)
177,3
24,3
7,7
2,9
166,1
BMI(kg/m2)
23,6
6,4
3,7
Age(years)
43,9
16,5
44,9
17,0
Characteristics
T~P
-42-
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-43-
Table2.Distributionofeducational levelswithindifferent categoriesof
bodymassindex (BHI),according tosex
BMI (kg/m)
n
Lowlevel
Middlelevel
High level
Men
20.0-24.9
5214
46.3%
36.4%
17.3%
25.0-29.9
3275
62.5%
27.5%
10.0%
30.0-40.0
368
70.9%
22.0%
7.1%
TOTAL
8857
Women
20.0-24.9
5349
62.1%
27.0%
10.9%
25.0-29.9
2379
81.1%
14.1%
4.8%
30.0-40.0
581
80.0%
17.1%
2.8%
TOTAL
8309
Figure 1showstheagegroup-specificdistributionsofBMIcategories foreach
sex.For subjectsyounger than65years,theprevalence ofmoderate and severe
overweight increaseswithage.
Resultsofthe stepwise logistic regressionanalysis,using thedataofthe
combined surveys,arepresented inTables 3and 4.Table 3showsthevariables
included inthelogisticmodel.Only themodels inwhichBMIappeared are
presented. Interactionsareevaluated onamultiplicative scale.Table 4shows
theodds ratios (with95percentconfidence intervals)formoderatelyand
severelyoverweight compared tonon-overweightsubjects.
-44-
Table 3.Variables included inaforward stepwisemultiple logistic regressionmodel
Variables
Gender
Dependent variable
Number ofcases
Variables included inthemodel H
description
BMIx
BMI age education
Chronical illnessess
men
hypertension
diabetes
women
hypertension
diabetes
varicoseveins
generalpractitioner*
Reason for consulting
medical specialist
Hospitalization*
*
116 (1.3%
474 (5.7%
152 (1.8%
197 (2.4%
asthma
218 (2.6%
haemorrhoids
123 (1.5%
atleast 1illness
Reason for consulting
281 (3,2%
2519 (30.3%
men
trunk/extremities
women
cardiovascular complaints 339 (4.1%
310 (3.4%
routinehandlings
818 (9.8%
men
trunk/extremities
127 (1.4%
women
at least1consultation
women
at least 1hospitalization 736 (8.9%)
**
back/joints/muscles
Onlymodelsthat included BMIarepresented
Duringthreemonthspreceding the interview
***
Inoneyearpreceding theinterview
147 (1.7%
1900 (22.9%
BMI>
age educati
-45-
Table4.Odds ratios (OR)adjustedforageandeducational leveland95%
1
1
confidence intervals(CI)formoderately andseverely overweight
subjectsvssubjectsnotoverweight
Odds ratios (OR)and95%confidence
intervals (CJiof:
Variables
Gender Dependentvariable
Chronic
men
illness
Moderately
Severely
overweight
overweight
OR
CI
OR
CI
hypertension
1.64
1.27-2.13
2.48
1.57-3.90
diabetes
0.61
0.71-0.92
1.39
0.70-2.76
1.84
1.55-2.19
2.63
1.96-3.53
women hypertension
diabetes
1.39
0.95-2.03
3.34
2.13-5.22
varicoseveins
1.53
1.21-1.94
3.06
2.03-4.62
asthma/bronchitis
1.07
0.78-1.47
1.80
1.18-2.76
haemorrhoids
0.75
0.47-1.17
2.28
1.37-3.80
atleast1illness
1.15
1.03-1.28
1.72
1.43-2.06
Reasonfor
consulting
men
trunk/extremities
1.24
0.97-1.59
2.17
1.38-3.43
general
women
cardiovascular
1.32
1.03-1.68
1.93
1.36-2.73
routinematters
1.18
1.01-1.40
1.68
1.31-2.14
practitionar *
Reasonfor
men
consulting
trunk/extremities
1.50
1.04-2.17
2.27
1.14-4.50
back/joints/muscles
1.38
0.97-1.96
2.17
1.14-4.09
atleast
0.91
0.82-1.02
1.51
1.28-1.78
1.14
0.98-1.33
1.72
1.38-2.16
medical
.,. *
specialist
women
Hospitali-
women atleast
zation**
1consultation
1consultation
*Consultationsinthreemonthsprecedingtheinterview (detaileddescription
ofdependentvariablesavailableinAppendixII)
**Hospitalizationinoneyearprecedingtheinterview (detailsinAppendixII)
1
?
Moderateoverweight:BMI 25.0-29.9kg/m;Severeoverweight:BMI 30.0-40.0
2
7
kg/m .Thereference categoryisBMI20.0-24.9kg/m
Source:dataobtained fromCentralBureauofStatisticsHealth Interview
Surveys1981-83 (n=17166)
-46Compared tonon-overweightwomen,severelyoverweightwomen reported that they
suffered fromhypertension,diabetes,varicose veins,asthma/bronchitisand
haemorrhoids more often,andconsulted their general practitioner about
cardiovascular complaintsorroutinematters,andmedical specialistsforall
reasonscombined.Theyhadalsobeenhospitalized moreoftenintheyear
precedingtheinterview.
Severely overweightmenreportedhavinghypertension moreoften thandid
non-overweight men,andtheyalsohadconsulted theirgeneralpractitioneror
medical specialistmore oftenabout complaintsofthetrunkorextremities.In
addition,theywerealsomore likelytohave consultedamedical specialist
about joint,back,ormuscle complaints.Levelofeducationappeared tomodify
thislatter association:Table5showsthatthisassociationwasmost evident
inmenwithanintermediate levelofeducation.
Age appeared tomodifytherelationbetweenoverweightandhypertensionfor
men;themagnitudeandstrengthofthisassociationdecreaseswithageandis
notevidentatage65andover.
Table 5.Odds ratiosinstrataofeffect-modifyingvariables (interactiontermsofthevariablewithBMI
included intheregressionmodel
Stratum-specific OddsRatios
(95% Confidence Intervals)
Moderately
Severely
Interaction termin
Stratumeffect
Overweight
Overweight
RegressionModel
Modifier
OR
95%CI
OR
95% CI
BMIxAge
20- 34yrs
4.17
1.94-8.95
6.94
1.85-26.09
35-49yrs
2.23
1.30-3.83
5.48
2.67-11.28
50-64yrs
1.15
0.79-1.66
1.75
0.89- 3.42
65+yrs
1.67
0.99-2.83
1.09
0.32- 3.72
Low
1.38
0.92-2.08
1.30
0.55- 3.07
Specialist for
Middle
1.12
0.50-2.52
7.28
3.03-17.51
back/joint/muscles
High
2.16
0.82-5.73
3.97
0.57-28.87
Dependent variable
Hypertension (men)
ConsultingMedical
BMIxEducation
(men)
2
Moderately overweight:BMI25.0- 29.9kgkg/m ;severelyoverweight:BMI30.0-40.0kg/m;
the reference category wasBMI 20.0- 24.9kg/m
2
-47Table6.odds ratios,adjusted foreffectsofageandeducational level,fortheuseofprescribed andunprescribed
drugsaccording tosexindifferent categoriesofBodyMass Index,in14dayspreceding interview
Typeofmedicines
Number ofcases
Odds ratios (OR)and95%confidence intervals (CI)
(%population)
For stomach and intestinal
17 (0.6%)
Moderately overweight
Severely overweight
OR
CI
OR
2.92
1.73-4.92
CI
2.96
1.00-8.85
complaints (unprescribed)
Diuretics (prescribed)
For cardiovascular/circulation
76 (2.7%)
2.00
1.52-2.65
4.57
3.30-6.34
147 (5.3%)
1.78
1.46-2.15
2.69
2.07-3.50
problems (including hypertension;
(prescribed)
Sleepingpill,sedatives,
125 (4.5%)
tranquilizers (prescribed)
For stomach and intestinal
complaints;
forwomenunder age50
**
(prescribed)
29 (1.1%)
nouseforseverely
overweight women
2
Moderatele overweight:BMI25.0-29.0kg/m ;severely overweight:BMI 30.0-40.0kg/m;
Referencecategory:BMI 20.0- 24.9kg/m
Agemodified theassociationwith overweight
2
-48Formoderateoverweighttheassociationsobservedbetweensevereoverweightand
thevariouscomplaintswereweakerorabsent (table 4). Compared to
non-overwightwomen,moderatelyoverweightwomen,reportedhypertensionand
varicoseveinsmoreoftenand consultationswiththeirgeneralpractitioner
aboutcardiovascular complaintsand routinemattersslightlymoreoften.
Moderatelyoverweightmenunder 50yearsofage reportedmorehypertension than
non-overweightmen, (table5)andconsultedamedical specialistmoreoften for
complaintsoftrunkandextremities.Table6showstheodds ratiosforseverely
andmoderatelyoverweightcompared tonon-overweightmenandwomen.Severely
andmoderatelyoverweightmen reportedmoreuseofnon-prescriptionmedicines
for stomachand intestinalcomplaintsthannon-overweightmen.Moderatelyand
severelyoverweightwomen reportedmoreuseofprescribeddiuretics,sleeping
pillsorsedatives,andmedicinesusedtotreatcardiovascular and circulation
disordersthannon-overweightwomen.Moderatelyoverweightwomenunderage 50
usedmedicines forstomachand intestinalcomplaintsmoreoftenthan
non-overweightwomen.
DISCUSSION
Basedontheself-reporteddata fromthecross-sectional surveys,itcanbe
concluded thatsevereoverweight,especially inwomen,isaccompanied byan
excessofchronicdisordersand increaseduseofmedical care.Moderate
overweight isfarmorecommonthansevereoverweightand,although itisnota
strong risk factoronanindividual level,itmayhave substantial impacton
theprevalenceofsomechronicdisordersandthedemandonhealthcarefacilities.Theassociationsbetweenbodyfatnessandhypertensionanddiabetes
mentionedarewelldocumented innumerousstudies. ' Data fromlarge
prospective studies,liketheFraminghamstudy,donotconfirmour observation
thatobesityandhypertensionareassociated onlyinmenunder 50yearsof
20
Varicoseveinsaremorecommoninoverweightwomenthaninthosewhoare
2122
notoverweight. ' Results froma recentstudyonfatdistribution indicate
age.
thatwhilehypertension,diabetes,andarthrosisweremoreprevalent inobese
subjectswithanabdominal typeoffatdistribution,varicoseveinsweremore
commoninobesewomenwhosefatwaspredominantly storedaroundhipsand
thighs. 23
Theassociationsofsevereoverweightwithhaemmorhoidsandasthma/bronchitis
inwomenarelessclearlyestablished intheliterature,although itiswell
knownthat respiratory function isoften impaired inobese subjects. ~
-49Reducedphysicalactivity,resulting fromchronic illness,mighthave
contributed totheexcessofweight.Therefore,associationsfound inthis
studydonotnecessarily implycausalrelations.
Comparing self-reporteddataofthehealthstatusofoverweightandnotoverweightsubjectsmaybebiased.Undiagnosed illnessmightbemorecommonin
27
thosewhoarenotoverweight ;whileontheotherhand,takingmedication
(e.g.,anti-hypertensive)mightleadtounderestimationof risk.Although it
hasbeenfound thatpeopletendtoreporttheirheightandweight inthe
directionofculturallydesirablevalues (i.e.,slimwomen,tallmen),
investigatorsgenerallyagreethatforlargegroups,self-reporteddataare
sufficientlyaccurateanddonotsubstantiallyaffectconclusions.
28—32
Any
bias introducedbytheunderreportingofweightwouldprobablybetoward the
nullhypothesis.Thetrueprevalenceofmoderateand severeoverweight inThe
Netherlandsmightbesomewhatunderestimated inthisstudy.
Overweight,inthisstudy,wasalsofoundtobeassociatedwithmedical care
notnecessarily resulting fromtheassociationswithchronicdisorders
describedabove.
More than70percentofDutchadultsarepublicly insured formedical careand
34
arenotpermitted tocontactaspecialistdirectly. The findingthatseverely
andmoderatelyoverweightmenmoreoftenconsultedamedical specialistfor
somecombinationsofcomplaints (Table4)impliesthatthese complaints
generallywereconsidered seriousenoughbytheirgeneralpractitionar,who
usuallyprovidesprimarymedical care,for referraltoa specialist.Forwomen,
itwasshownthatsevereoverweightwasaccompaniedbyhigheruseofmedical
careatall levels.Itisnotsurprising thatoverweightwomenwere found to
usemorediureticsandmedicinesused totreatcardiovascular disorders
(includinghypertension)sincethesedrugsareoftenprescribed forwomen in
TheNetherlands.The findingthatseverelyoverweightwomenuse sleeping pills
or sedativesmoreoftenthanwomenwhoarenotoverweightmaybethe
consequenceofeither thesocialstigmathatobesitycarriesinaffluent
societies,
or thatstressfactors
=ssfac mayhaveleadtoeatinghabitsthat,in
37,38
turn,causedweightgain.
IntheNetherlands,itwas recently recommended thattreatment isindicated in
everyonewho isseverelyoverweightand inthosewhoaremoderately overweight
accompanied byincreased levelson risk factors,orwho suffer fromchronic
disorders. The findingsofthisstudysupportthese recommendations.Once
severeoverweight isestablished,however,itisverydifficult totreat
successfully inthelongterm.Thepreventionofweightgain,especially in
-50-
youngadults,seemsamatterdeservingattention.Thegeneralpractitionar,who
playsanimportantroleasafamilyphysicianandwhoprovidescontinuous
primarycaretopatients,mightbeinanexcellentpositiontoidentifyand
treatthosewhoareatriskofbecomingseverelyoverweight.Prospective
studiesshouldbecarriedouttoinvestigatethepossiblebenefitsofsuchan
approach.
ACKNOWLEDGEMENTS
ThisworkwasconductedunderacooperativeagreementbetweentheDepartmentof
HumanNutritioninWageningenandtheCentralBureauofStatisticsinVoorburg,
supportedbyagrantfromtheDutchPraeventiefonds.Theauthorswouldliketo
thankJ.BuremaandS.Wardforhelpfulcomments.Partsofthispaperwere
presentedattheannualmeetingoftheDutchworking-groupofepidemiologic
research (WEON),May2-3,1985.
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53AppendixI
ListofchronicalillnessessorhandicapsshowntosubjectsintheC.B.S.
HealthInterviewSurvey.Subjectscouldstatethepresenceofmaximal4
differentitems
Descriptionofcomplaints
1.Asthma,chronicalbronchitisornasalcavityinflammation
2.Heartdiseaseorfunctionaldisturbancesoftheheart
3.Highbloodpressure
4.Stroke
5.Varicoseveins
6.Haemmorrhoids
7.Pepticulcerorotherchronicstomachcomplaints
8.Chronicintestinalcomplaints
9.Gallstones,gallbladderorliverdisease
10.Rupture
11.Renalcalculus,chronicalinflammationofthebladder
12.Prostatecomplaints (men),prolapse(women)
13.Diabetesmellitus
14.Thyroiddysfunction
15.Rheumatism,jointdisease,slippeddisc
16.Epilepsy,migraine,skindisease
17.Canceroustumoursorgrowth
18.Consequencesofaccident
19.Otherchronicaldisorders
34-
Appendix II
Classificationsof illnesses,complaintsoractionswhichwere characteristic
fora reported consultationofageneralpractitionar ormedical specialist in
3monthspreceeding the intervieworhospitalization in1yearpreceedingthe
interview
Groupdescription
Abbreviation (thesewere
used inthetext)
1
Childhooddiseases
Childhooddisease
2
Commoncold,flue,infalammationsofthroat,tonsils,
Commoninfections/
cavityof jaw,frontal sinus,nasalcavity
3
Chronicalbronchitis,asthma,respiratoryillness
inflammations
Respiratory
thighnessofchest,coughing,hay-fever,pneumonia,
pulmonaryaffection
4
Heartdisease,stroke,hypertension,hypotension,
Cardiovascular
anemia,varicoseveins,heammorroids,soreleg
5
Toothache
Toothache
6
Pepticulcer,duodenumulcer,stomachcomplaints
Internalorgans/
indigestion,intestinal complaints,diarrhea,
digestive tract
constipation,gastroenteritis,liverandgallbladder
disease,appendicitis
7
Renalcalculus,nephritis,cystitis,menstrual
Urogenital
abnormalities,fleshygrowths,menopausal complaints
8
Pregnancy,miscarriage,delivery,anticonceptiva,
sterilization
Reproduction/
fertility
Disordersofthethyroidgland,diabetes,overweight
Metabolicdisorders
10
Cancer
Cancer
11
Complaintsordiseasesconcerningears,eys,speech
9
Ears/eyes
12 Allergy,eczemaor skindisease
Allergy/skin
13
Backacheforvarious reasons,myelitis,rheumatoid
Back/joint/muscles
14
Fracturse,injuries,concussionof thebrain,
complaints,arthrosis,sprain,achingmuscles
Accidents
contusions,burns,intoxications
15
Insomnia,fatigue,vertigo,headaches,migraine,
nerves
Nervous/stress
-5516 Complaintsofneck,shoulder,extremities,chest,
Trunk/extremities
ribs,hips
17 Painsnotincategoriesabove,itchings,fever
18 Injections,bloodpressurecontrol,recipies,
Pain
Routine
generalexaminations,referrals
19 Operations
Operations
AppendixIII
CategoriesofmedicinesusedintheDutchHealthInterviewSurveys(prescribed,
andnotprescribed)
a.Painrelieversandmedicinesusedtotreatfever(e.g.aspirin)
b.Medicinesusedtotreatcoughs,commoncold,flue,anginaetc
c.Medicineslikevitamins,mineralsandtonics
d.Medicinesusedtotreatdisordesoftheheart,circulationandraisedblood
pressure
e.Diuretics
f.Medicinesusedtotreatconstipation
g.Medicinesusedtotreatstomach-andintestinalcomplaintsandindigestion
h.Sleepingdrugs,sedativesandtranquilizers
i.Antibiotics (likepencillin)andsulphonamides
j.Medicinesusedtotreatskindisorders(includingeczema,itchings,
dandruff)
k.Medicinesusedtotreatrheumatismandarthritis
1.Medicinesusedtotreatallergy
m.Medicinesusedtotreatbronchialastma
n.Medicinesnotdescribedabove
-56-
CHAPTER3
UTILIZATIONOFPRIMARYHEALTHCAREOFOVERWEIGHTANDNON-OVERWEIGHTSUBJECTS
-ASIXYEARFOLLOW-UPSTUDY
J.C.Seidell,J.C.Bakx,F.J.A.Huygen,H.J.M.vandenHoogen,P.Deurenberg,
J.G.A.J.Hautvast
SocSciMed(submittedforpublication)
ABSTRACT
Inthisstudy,315adultmenand562adultwomenfromfourgeneralpractisesin
TheNetherlandswerefollowedforsixyearsinacontinuousmorbidity
registration.Follow-upbeganintheyeartheywereregisteredasoverweightby
theirgeneralpractitioner.Theincidenceofnewspellsofillnessinthis
overweightgroupwascomparedwiththatinacontrolgroupof438menand618
womenwho,foreachcalendaryearofstartoffollow-upwerematchedtothe
overweightgroupaccordingtothegeneralpractisetheywerein,andtheirsex
andage.Itwasshownthatnewspellsofillnessthatarenotlife-threatening
orlongterm,weremorefrequentlyregisteredintheoverweightgroup.This
differencewasalsoapparentafterstratificationforsex,age,andsocial
class.Specificafflictionsthatwereregisteredmoreoftenintheoverweight
groupwerecommoncoldandinfluenza,psychoneuroticcomplaints,skinproblems,
myalgiaandlumbago,distortions(inmenandwomen),menstrualabnormalities(in
women),andminorinjuries(inmen).
Comparingscreeningdatafrom1978withtheoverweightandhypertensionstatus
asgiveninthemorbidityregister,justpriortothescreening,indicatedthat
thesensitivityoftheregistrationofoverweightandofhypertensionincreases
withage(withtheexceptionofoverweightinwomen).Usingthescreeningdata,
itcanbeinferredthatoverweightindicatesariskofhypertension,andthis
riskisgreatertheyoungerthatobesityisconfirmed.Oddsratioscalculated
theregistrationdataindicatedthatthesedatamaybebiased:however,no
consistentpatternofthestrengthanddirectionofthisbiaswasseenin
differentageandsexgroups.Itwasconcludedthatoverweightpatientsin
generalpractisesdoshowmorenewspellsofillnessthanthosewhoarenot
knowntobeoverweightbythegeneralpractitioners.
INTRODUCTION
The relationshipbetweenoverweight and the incidence ofvarious chronic
disorders iswell known from reviewstudies [1]andhas recentlybeen confirmed
inTheNetherlands [2].Theassociation ofoverweightwith less severe andmore
commonafflictions islesswell known.Self-reported data from overweight
persons indicated that theyvisited general practitioners andmedical
specialistsmore frequently for specific reasons [3,4]. Self-reported datamight
suffer frommisclassificationbiasand subjects canonlybeasked about previous
medical care that coversashortperiod of time,because ithasbeen shown they
soon forget [5], Inorder tostudymedical careandoverweightmore objectively
we studied the incidence ofafflictions ina retrospective cohort study
comparing registered overweight subjectswith subjects thathadnever been
registered asoverweight.
Ithasbeensuggested thatsuchdatamightalsobebiased by general
practitioners whohaveatendency to register asoverweight those subjects who
have ahigher morbidity. Inaddition, inoverweight subjectswho receive medical
caremore oftenandmore specifically itmaybemore likely that certain
disorderswillbedetected than innon-overweight subjects [6].Therefore,we
paid special attention tothevalidityof the registration ofhypertension and
overweight and tothepossibility ofdifferential misclassification of these
conditions by thegeneral practitioners.
Our studyalso indicates theextraworkload forgeneral practitioners that can
beattributed totheiroverweightpatients.
POPULATIONAND METHODS
Morbidity registration
Thecontinuous morbidity registration of theDepartment ofGeneral Practise of
theUniversity ofNijmegenwas started in1967 intwopractises,andwas
augmented by twoothers in1971.These generalpractices comprise about 12,000
patients andare located inabig industrial town,asmall town,urbanized
countryside anda rural area. Inthese fourpractises,alldiagnoses and
referralsare registered daily,according totheE-list,which isan adapted
version of the International Classification ofDiseases [7]used inThe
Netherlands.A distinction ismadebetweennewspellsof illnessand diagnoses
and contactswithpatientsbecauseofan illness thathaspreviously been
-58-
recorded.Thisenabledustorestrictourstudytonewspellsofillnessonly.
Inthispapertheresultsofanalysingalldefinitenewdiagnosesoveraperiod
of6yearsretrospectivefollow-uparepresented.Totalmorbiditywasdivided
intothreegroupsofseverityasclassifiedbytheDepartmentofGeneral
Practise[8]: highestlevelofseverity=potentiallylife-threatening,or
long-termillness;middlelevelofseverity=temporarilythreatening;lower
levelofseverity=generallynotthreatening.Thegroupsofillnessstudiedin
thispaperaredescribedinAppendicesIandII.
Population
Theoverweightgroupcomprisedallpatientswho,atanagebetween20and50
years,hadbeendiagnosedbytheirgeneralpractitionerasbeingoverweight.The
criterionforoverweightwasaBodyMassindex(BMI=weightdividedbyheight
2
2
squared)exceedingabout26kg/m (forwomen)or27kg/m (formen).Weightand
heightwasmeasuredbythegeneralpractitioner (eitheratroutineexamination
orattheinitiativeofthepatientorthegeneralpractitioner).Theseweights
andheightswerenotenteredinthemorbidityregistration.
Foreachcalendaryearofstartoffollow-up,acontrolgroupthathadnever
beenregisteredasoverweightintheperiod1967-1984wasselectedfromthe
totalpopulation.Thesepersonswererandomlyassignedtostartingyearsof
follow-upintheperiod1967-1978,followedbyafrequencymatchingprocedure
doneaccordingtogeneralpractise,sexandageatstartoffollow-up(in5-year
agegroups).Somecharacteristicsofthestudypopulationareshownintable1.
Estimateofinformationbias
In1977/1978patientswerescreenedforcardiovascular riskfactorsinthreeof
thefourpracticesthatparticipateinthemorbidityregistration.Eighty
percentofallpatientsagedbetween20and50yearswereweighed(withoutshoes
andwearingindoorclothingonly)andtheirheightandbloodpressurewere
measured.Bloodpressurewasmeasuredusingasphygmomanometer,ascommonlyused
ingeneralpractices[9]withthesubjectsitting,after15minutes'rest.
Diastolicpressurewasreadatthedisappearanceofsounds(KorotkovphaseV ) .
Theaverageoftworeadings,taken15minutesapart,wasusedforclassification
ofhypertension(cut-offpoint100mmHg,whichcorrespondstothecriterion
usedinthemorbidityregistration).Detailsofthescreeninghavebeengiven
elsewhere[10J. Subjectswhosediastolicpressurewasbelowthecut-offpoint
forhypertension,butwhoserecordsshowedtheywerereceivinganti-hypertension
medicationwereclassifiedashypertensivesinthescreeningdata.Atthe
-59-
screeningexaminationBMIwasused toidentifyoverweight subjects (cut-off
2
2
points:26kg/m forwomen,27kg/m formen).
Statisticalmethods
Category-specific andadjusted risk ratiosandodds ratios (comparing overweight
withnon-overweight subjects)werecalculated andtheirconfidence intervals
estimatedusingTaylor seriesapproximation forvariance,asdescribed elsewhere
[11].Thenumbersofafflictionswerecomparedusing theWilcoxon rank-order
testofunpaired samples [12].Pvalues (two-sided)weretakentobe significant
whensmaller than0.05.
RESULTS
Table 1showsthedistributionofsubjectsintheoverweightand thecontrol
groupovercategoriesofsocialclassandofage.Intheoverweightgroupthe
distribution isshifted towardsthelower socialclasses.
Table 1.Distributionofthe studypopulationovercategoriesofsocial class
(according toprofessionoftheheadofthehousehold)andover
categoriesofage (atstartof follow-up)
Social class
Women
Men
OverweightNon-overweight Overweight Non-overweight
n(%)
n[V)
ni%J
n(%)
low
middle
high
359(63.9)
174(31.0)
29( 5.1)
296(47.9)
255(41.3)
67(10.8)
562( 100)
618( 100)
202(64.1) 208(47.5)
100(31.8) 177(40.4)
13( 4.1)
53(12.1)
315( 100)
438( 100)
68(21.2)
113(35.2)
140(43.6)
91(20.8)
160(36.5)
187(42.7)
321( 100)
438( 100)
Age
20- 29
30- 39
40- 50
140(24.9)
183(32.6)
239(42.5)
562( 100)
163(26.4)
208(33.6)
247(40.0)
618( 100)
-60-
Tabl« 2.Relative risks,adjusted forageandsocialclass,foratleast onenewspellofillnessbeing registered;
overweight persons versusnot overweight persons
Women
Men
Ilnness
RR(95% confidence
Registeredas
RR(95%confidence
Registered as
(codes)
interval)
exhibiting illness
interval)
exhibiting illness
Overweight
%
Control
Overweight
%
%
Common cold&
influenza
1.16(1.09 - 1.24)
1.16(1.06 - 1.26)
(240-3, 245)
Anemia (111)
Psychoneurosis
0.80(0.52 -1.22)
1.09(1.01 -1.18)
7.7
66.2
1.40(1.22 - 1.61)
1.44(0.94 - 2.22)
8.3
1.52(0.84 -2.76)
1.17(0.94 -1.45)
25.0
1.83(0.88 - 3.82)
(135)
Otitis externa
(182)
Cystitis acuta
(313)
Menstrual
1.36(1.13 -1.63)
31.7
disorders
(325, 327-9)
Skinproblems
1.33(1.12 -1.59)
1.27(1.01 - 1.59)
(370,372,377,381)
Myalgia, lumbago 1.13(1.01 - 1.27)
1.39(1.22 - 1.57)
(407, 408)
Distortions
1.54(1.08 - 2.21)
1.51(1.02 - 2.24)
(480)
Minor injuries
(4951
p <0.05
1.14(0.95 - 1.37)
1.27(1.08 -1.481
Control
%
-61-
Intable2therelativerisksfortheincidenceofoneormorediagnosesofnew
spellsofillnessduringthesixyearsoffollow-upareshownfortheoverweight
groupvis-a-visthenon-overweightgroup.Althoughformostofthediseases
showninthetabletherisksareonlymoderatelyelevated,thehighratesof
incidencedoindicateconsiderablymorecasesofsuchillnessesinthe
overweightgroup.
Thepercentagesofpersonswhomanifestedatleastonenewillnessduringthe
sixyearsoffollow-up,asshownintable3,showthatalmosteveryoneinthe
studypopulationwasseenbythegeneralpractitioneratleastonce.This
tendencywasmorepronouncedintheoverweightgroup(especiallyinthelower
andmiddlesocialclasses).
Table3.Percentageofpersonsexperiencingatleastoneillnessinthecourse
ofsixyearsfollow-upinamorbidityregistration,stratified
accordingtosocialclass.Adjustedforage.Illnessesclassifiedby
severityasdescribedinAppendixII)
Men
Women
Severityof
Social Overweight Non overweight
illness
class
low
middle
high
%
a
"6
Overweight Non
%
overweight
%
low
97.4
90.3
92.9*
**
83.5
97.5
middle
95.0
92.8
**
81.3
high
80.5
85.1
84.6
75.5
low
95.6
92.5
88.5*
**
83.9
92.3
middle
95.0
87.5*
**
76.8
high
72.4
80.6
84.6
71.7
low
17.0
15.6
15.3
17.8
*
10.7
15.1
middle
16.7
12.6
20.0
high
20.5
14.9
7.7
* p<0.10 (Nonoverweightcomparedtooverweight)
**p<0.05 (Nonoverweightcomparedtooverweight)
-G2-
The totalnumberofcomplaints inthesix-yearperiod,as reflected inthe
averagenumber ofafflictions reportedperperson,washigher fornewspellsof
illnessintheoverweight groupthaninthenot-overweightgroup (exceptforthe
most severe illnesses). Illnessesof lowerandmiddle levelofseverity showa
higheraveragenumber ofafflictions inwomenthaninmenandadecrease in
incidencewith increasing socialstatus.
Table 4.Averagenumber ofafflictionsperpersonduringsixyearsof follow-up
inamorbidity registration,stratifiedbysocialclass.Weighted
averagesofagegroups.Illnessesclassifiedbyseverity (see
Appendix II)
Women
Severityof Social
illness
low
middle
high
Men
OverweightNonoverweight
OverweightNonoverweight
class
low
8.3
7.0
6.9
5.3
middle
7.8
5.7*
4.4
3.8
high
6.4
4.6
3.7
3.0
low
6.4
4.6
middle
4.6
3.7
high
3.4
5.9
4.4
4.2
3.0
3.6
3.6
2.0
*
low
0.2
0.2
0.2
0.2
middle
0.2
0.1
0.2
0.2
high
0.3
0.2
0.1
0.1
* p <0.10 (Nonoverweightcompared tooverweight)
**p <0.05 (Nonoverweight compared tooverweight)
Note
Average istotalnumberof registrations inasex/age/social classcategory,
dividedbythenumberofsubjectsinthatcategory.Differencesbetween groups
were testedusingtheWilcoxon rank test
-63-
Table5.Sensitivityandspecificityoftheregistrationofoverweightand
hypertensioninthreegeneralpractises(Datafromascreeningin1978
andfromthemorbidityregisterjustpriortothescreening)
Disorder
Sex
n
Age
%withhypertension
atscreening
Hypertension
Men
16.7
98.5
96.8
13.0
66.0
93.7
50.6
96.4
349
350
397
7.4
4.3
3.7
33.3
99.4
76.9
96.4
40-
50
29
39
50
17.6
89.9
95.4
20-
50 1086
9.0
74.5
97.3
29 343
30- 39 333
40- 50 363
12.9
59.1
95.3
27.9
68.8
94.2
31.4
77.2
88.0
20-
50 1039
24.2
70.9
92.6
20-
9.17
93.8
89.9
18.00
92.1
87.7
40-
29 349
39 350
50 397
39.04
87.7
85.5
20-
50 1086
23.02
89.6
87.9
202030-
Men
Women
%
29.2
40-
Overweight
Specificity
%
1.8
7.2
2030-
Women
Sensitivity
29 343
39 333
50 363
1039
20-
30-
Note(forTable5):
Sensitivity=percentageofthosewiththedisorderatthescreeningthathad
beenregisteredashavingthatdisorder.
Specificity=percentageofthosewithoutthedisorderatthescreeningandwho
hadnotbeenregisteredashavingthatdisorder.
Personswhoatthetimeofthescreeningwereundergoingtreatmentforhypertensionwereregardedashypertensiveregardlessoftheirbloodpressure
-64-
Resultsfroma screening inthreepractises in1978showthat theprevalenceof
bothhypertensionandoverweight increasewithage.Thepercentageof subjects
ashypertensive atthescreeningwhohadbeen registered inthemorbidity
registerbecauseofoverweight increasedwithage.Theaccuracyofthe
registrationofhypertensionappeared tobemuchbetter forwomenthanformen.
The samewas trueforthe registrationofoverweight, registeredwasgceater
thanthepercentageofcorrectly registeredhypertensives (table5 ) .
Calculationsof theodds ratios forthepresenceofhypertension inoverweight
subjectscomparedwithnon-overweight subjects (using thescreeningdata)
indicated thatthestrengthofthecorrelationbetweenoverweightand
hypertensiondecreaseswithage.Theodds ratioscalculated fromthe
registrationdatashowedthatthistrendwaslessclearinmen,whileinwomen,
an increase inodds ratioswithagewasobserved.Our resultsshowthatusing
the registrationdatatocalculatethecorrelationbetweenoverweightand
hypertensionwould resultsinunderestimate forwomenaged20- 29yearsand an
overestimate formenaged 40- 50years.
Table6.Odds ratiosforpresenceorabsenceofhypertension inoverweight
subjects comparedwithnon-overweight subjects.Calculationsusing
data frommorbidity register anddata froma screening in1978
Men
Women
Age
Registration
Screening
Registration
Screening
Odds 95%CI
Odds 95%CI
Odds 95%CI
Odds 95%CI
ratio
ratio
ratio
ratio
29 1.88 0.36-9.92
39 2.34 0.94-5.84
40- 50 3.94 2.27-6.82
20-
7.90 2.61-23
30-
1.82 0.55-5
20- 50 3.28 2.09-5.16
2.93 1.71-4
4.52 2.96-6.90
91
99
98
8,05 1.57-41
2.36 1.16-8
2.73 1.50-4
37 7.3 1.76-30
40 4.94 2-08-11
99 1.28 0.67-2
3.11 1.90-5.08 2.89 1.81- 4.64
45
73
49
DISCUSSIONAND CONCLUSIONS
Inthisstudy itwas shownthatpatientsfromfourgeneralpractiseswhowere
registered asbeingoverweightbytheir general practitioner displayed more new
spellsof illnessduring sixyearsof follow-up thanpatientswhowere not
registered asoverweight.Thesedifferenceswere alsoapparentwithinageand
social classgroups.The registration inthese fourpractises is continually
monitored andevaluated and isdoneaccording tostandardized criteria. Itis
thereforevery likely thatthesedifferences are real.Nevertheless,itisnot
possible toinfer acausal relationship betweenoverweightand the incidence of
common illness.Personal characteristics notmeasured inthisstudycouldbe
responsible forbothoverweight and illness.
Some of theassociations between overweight and illness thatwereobserved in
thisstudy (Table2)havebeenobservedbefore.Theassociation between
overweight andmusculo-skeletaldisorders [3,13,14],skinafflictions[15],
distortions andminor injuries [16,17]andmenstrual abnormalities [18,19]have
been reported.Theassociation betweenoverweight andpsychoneurotic complaints
isoften citedbut isdifficult tointerpret. Itisknownthatbeing overweight
may causemuchdistress,especially inwomen [20,21,22].Thishasbeen confirmed
intheNetherlands,where ithasbeen shownthatadultoverweightwomen reported
that theyused sleepingpills,sedatives or tranquilizersmore often than
non-overweightwomendid [3].Youngoverweight adultwomen reported having
headaches andnervousbreakdownsmoreoftenthannon-overweightwomen [4].On
theother hand, itisknownthatmood and certainmental statesmay contribute
totheonset ofoverweight [23,24].Our finding thatthis relationshipwasmore
pronounced inmen than inwomen isnotconfirmed intheliterature. Itmust be
noted,however,thatmost researchonoverweight in relation to psychosocial
problemshasbeencarried out inwomen.Huygenandhis colleagues [25]
demonstrated that subjectswith recurrent psychosocial complaintsvisited their
general practitioner more oftenbutwerealsomoreoftenoverweight.Overweight,
psychoneurotic complaintsand other illnessesmay thusbe interrelated and it is
notpossible to interpret theassociations between these intermsofcausality .
Franksandhis colleagues [6]havepointed outaproblem thatmayarise from the
use ofdataderived fromdiagnoses.They found that frequency ofvisits tothe
general practitioner andpercentagewithpsychosocial complaints differed
between obesepatients according towhether their obesityhadbeendiagnosed. In
their study itwasclear thatthe registered obeseand thenot registered obese
groupsdiffered inage (menandwomen)and social class (men). Inourdata,age
-66andsocialclassvrereshowntobe importantassociatesof registered morbidity
andmight thereforeexplain,atleastpartly,the findingsofFranksandhis
colleagues.A relatedargumentwasputforwardbyGarrow [26],whoproposed that
practitionersmayexamineoverweightsubjectsmorethoroughly fordisorders they
suspecttobe related tooverweightthantheyexaminesubjectswhoarenot
overweight.Onedisordermostlikelytobeaffectedbysuch informationbias is
hypertension.Fromourcomparisonofdata fromascreeninganddata fr<3mthe
morbidity register justprior tothescreening itwasevident thattherewas
misclassificationofoverweightandhypertension,butnoconsistentpattern
through theageand sexgroupscouldbe found.Theaccuracyofthe registration
ofhypertensionandoverweight increasedwithage,andtherebywith the
prevalenceofhypertensionandoverweight,andwasmoreaccurate inwomenthan
inmen.This findingprobably reflectsthatwith increasingagepatients receive
more routineexaminations (includingbloodpressuremeasurements)andcontact
theirphysicianmoreoften.Thesameistrueforwomencompared tomen.
Comparingtheodds ratioscalculated fromthescreeningdata tothose calculated
fromthe registerdata revealed thatinsomeagegroupstheassociationbetween
overweightandhypertension issomewhatunderestimated and inothers somewhat
overestimated.Conclusionsbasedontheregistrationdatawoulddiffer fromthe
screeningdata inwomenaged 20-29yearsandinmenaged 40-50years.Inthe
other sexandagegroupstheassociationswerequite similar.Informationbias
due todifferentialmisclassification ofhypertension inoverweightand
non-overweight groups ispresentonlytoalimitedextent.Of coursethese
comparisonsareonlyacrudewaytodetectaconsistentbiasandarebased on
datameasuredononeparticular occasion.Itisverylikelythat,duetothis
screening in1977-1978 theaccuracyofthe registrationofbothhypertension and
overweight inthemorbidity registrationhasimproved considerably. Inaddition,
hypertension isoneofthedisordersthat ismostlikelytosuffer frombias,
and itisevenlesslikelythatasimilarbiasispresent inother associations
observed inthisstudysuchastheassociationbetweenoverweightand common
coldand influenza,anassociation that isprobablynotanticipatedbygeneral
practitioners.
It remainstobeestablishedwhether theassociationsobserved inthisstudyare
causedbyoverweightorwhetheroverweightsubjectsaremerelymore
hypochondriacal thannon-overweight subjects.Furtherevidence foracausal
relationshipmaybeobtained fromstudiesinwhichtheeffectsofpreventionand
treatmentofoverweight ingeneralpractisesontheuseofmedical careare
studied.Suchevidencemaycontribute toaneventual reductionofutilizationof
primaryhealthcare inpractises inwhichphysicianspaymuchattentiontothe
reductionoftheprevalenceofoverweightamongtheirpatients.
ACKNOWLEDGEMENTS
Theauthorswould liketothank J.Burema forstatisticaladvice,P.Hoppener
for computerassistance,J.Burrough forassistance inthepreparationofthe
manuscript,personnel fromtheDept.ofGeneralPractiseoftheUniversityof
Nijmegenforcollecting thedata,andtheDutchPraeventiefonds for financial
support.
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1.National InstitutesofHealthconsensusdevelopment conference
statement.Healthimplicationsofobesity.Ann InternMed1985,-103:1073.
2. SeidellJC,BakxJC,DeurenbergP,HoogenHJMvanden,HautvastJGAJ,
StijnenT.Overweightandchronic illness-a retrospectivecohortstudy
withafollow-upof6-17 yearsinmenandwomen initially20-50yearsof
age.JChronDis1986,inpress.
3.SeidellJC,DeGrootCPGM,VanSonsbeekJLA,Deurenberg P,Hautvast
JGAJ.Associationsofmoderateand severeoverweightwith self-reported
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4.DeurenbergP,vanPoppelG,HautvastJGAJ.Morbiditeitensubjectief
welbevindenbijjongevolwassenenmetovergewicht.NedTijdschrGeneeskd
1984;128:940.
5.VandenBergJ.Memorybiasinreportingthenumberofconsultations
withaGP.MndberGezondheid (CBS)1983;5:24.
6. FranksP,Culpepper L,DickinsonJ. Psychosocialbias inthediagnosis
ofobesity.J FamPract1982;14:745.
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1970-71.London.HerMajesty'sStationaryOffice,1974.
8.NijmeegsUniversitairHuisartsen Instituut.Epidemiologic inde
huisartsenpraktijk.Gewone ziekten.Eenaantalmorbiditeitsgegevensuit
eenviertal huisartsenpraktijken.Nijmegen:NUHI,1980.
9.Hunyor SN,FlynnJM,CochineasC.Comparisonofperformanceofvarious
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1978;2:159.
10.VanReeJW.HetNijmeegsInterventieproject (thesis)Nijmegen,1981.
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-6811.KleinbaumDG,KupperLL,MorgensternH.EpidemiologicResearch
Priciplesandquantitativemethods.LifetimelearningPublications,
BelmontCA,1982.
12.SnedecorGW,CochranWG.StatisticalMethods.TheIowaStateUniversity
Press,Ames,1980.
13.AroS,LemoP.Overweightandmusculoskeletalmorbidity:atenyear
follow-up.IntJObes1985;9:267.
14.SilberbergR.Obesityandosteoarthritis.InMedicalcomplicationsof
obesity(editedbyManciniMetal):301.AcadPress,London,1979.
15.HanzlickovaL,KrizekV,StepanekP.Dermatologischebefundebei
fettleibigkeit.MunchMedWschr1967,-199:586.
16.SeidellJC,BakxJC,DeurenbergP,BuremaJ,HautvastJGAJ,HuygenFJA.
Therelationbetweenoverweightandsubjectivehealthindutchadults.
AmJPublicHealth1968,inpress.
17.HenschelA.Obesityasanoccupationalhazard.CanadJPublic
Health1967;58:491.
18.HartzAJ,BarboriakPN,WangA,KatayamaKP,RimmAA.Theassociation
ofobesitywithinfertilityandrelatedmenstrualabnormalitiesinwomen.
IntJObes1979;3:57.
19.FriedlKE,PlymateSR.Effectofobesityonreproductioninthefemale.
JObesityandWeightRegulation1985;4:129.
20.StewartA,BrookRH.Effecrtsofbeingoverweight.AmJPublicHealth
1983;73:171.
21.RodinJ,SilbersteinL,Striegel-MooreR.Womenandweight:anormative
discontent.NebraskaSymposiumonMotivation.LincolnNE,Universityof
NebraskaPress,1985.
22.AllonN.Thestigmaofoverweightineverydaylife.In:Psychological
aspectsofobesity:ahandbook (editedbyWolmanBBetal).VanNostrand
ReinholdCompany,1982.
23.LoweMR,FisherEB.Emotionalreactivity,emotionaleatingandobesity:
anaturalisticstudy.JBehavioralMedicine1983;6:135.
24.VanStrienT.Eatingbehaviour,personalitytraitsandbodymass.Swets
NorthAmericaInc.Berwin,1986.
25.HuygenFJA,HoogenHJMvanden,LogtATHvande,SmitsAJA.Nerveus
functioneleklachtenindehuisartsenpraktijk.NedTijdschrGeneeskd
1984,-128:1321.
26.GarrowJS.Howtotreatandwhentotreat.In:Thetreatmentofobesity
(editedbyMunroJF).MTPPress,London,1979.
-69-
Appendix I.Descriptionofcodesandgroupsofcodesused inanalysis
Code
Description
111
Irondeficiency anemiaandotherhypochronic anemia,excl.anaemia in
135
Emotional disorderswithorwithout somatic symptoms (or
pregnancy.
reactions),('Nervous-functional complaints'),incl.nervous reactions,
psychogenic reactions,functional reactions,hypochondriasis,
neurasthenia,overwork.
182
Otitisexterna,excl.thatasa resultofperforation.
240
Coryza,commoncold,incl.rhinitis,sore throatwithout temerature,
241
Febrile commoncoldand influenza-like illness,influenza,pharyngitis.
242
Tonsillitis,including lymphadenitis colly,tonsillar abcess,excl.
243
Sinusitis,acute.
excl.allergic rhinitisandglueear.
acute lymphadenitis.
245
Epidemic influenza.
313
Urinary infection,acute (acute cystitis),excl.pyelitisand acute
325
Dysmenorrhoea,excluding premenstrual symptoms.
327
Irregular menstruation, incl.amenorrhoeanotduringpregnancy and less
328
Menorraghia.
329
Menopausal and climacterialsymptoms.
381
Dermatitis,incl.diaper rash,intertrigo,allergic eczema,contact
pyelonephritis.
than 4months,excl.amenorrhoea more than 4months.
dermatitis,varicose eczema,nickeleczema, rhagades,seborrhoeic
dermatitis inadults,dermatitisdue tothe sun.Excl.dermatitisdue to
occupation ordrugs,urticaria,insectbites,pigmented naevus,scabies,
erysipelas,dystrichotic eczema,strophulus,sunburn,allergic sun
reaction,herpeticdermatitis.
370
Furuncle,carbuncle (boil).
377
Skin infections:pyoderma,folliculitis,secondary impetigoof theskin,
372
Cellulitisandabscesseswithout lynphadenitis, incl.sebaceouscyst,
excl.dermatophytosis,pilonidalsinus.
pompholyx,sweatglanddisease,para-anal abscess,erysipeloid,excl.
cellulitis of fingerand toeandnon-infected cellulitis.
407
Acute lumbago,excl.prolapsed intervertebral d i s c , sciatica.
408
Fibrositis,incl.myositis,myalgia,tenditisaround shoulder,stiff
neck,lowback pain,overstrained muscle;excl.tenosynovitis.
480
Sprainsand strains,incl.effusionafter injury.
495
Small superficial injuriesorcontusions,blisters,excl.non-traumatic
epistaxis.
* Illnesseslooked atbut toofewforanalysis:infectiousdiseases,allergies,
thyroiddisfunction,metabolicdisturbances,diseasesofblood and
bloodforming organs,psychiatric diseases,addiction,illnessesofnervous
systemand senses,digestive tract complaints
**Chronicdiseases studiedwith longer follow-up:neoplasmata,diabetes
mellitus,gout,cardiovascular disease,arthrosis
-71-
Appendix II.Morbidity subdivided intolevelsofseverity
Levelof severity
Complaint
Codesof complaints
inE-list
lower
skininfections
anemia
021
111
psychoneurotic complaints
135
otitisexterna
102
varicoseveins
224
hemorrhoids
commoncoldwithout fever
gastroenteritis
225
240
289
cystitisacuta
313
menstrualdisorders
325-9
eczema
middle
379-81
acnevulgaris
385
minor injuries
495
herpessimplex
diabetesmellitis
014
091
gout
commoncoldwith fever,influenza
093
241-5
bronchitis
247-8
prolapseduterus
324
skindisorders
370
psoriasis
skeletalproblems
382
406-8
distortions
higher
allmalignanttumors
cerebrovascular accident
coronaryheartdisease
vascular complaints
480
050-69
155
211-3
221-3
all fractures (excludingwristandcollarbone) 410-77
-72-
CHAPTER4
OVERWEIGHTANDCHRONIC ILLNESS-A RETROSPECTIVECOHORTSTUDY,WITHA FOLLOW-UP
OF 6-17YEARS,INMENANDWOMENOF INITIALLY20- 50YEARSOFAGE
J.C.Seidell,K.C.Bakx,P.Deurenberg,H.J.M.vandeHoogen,J.G.A.J.Hautvast,
T.Stijnen
J ChronDis1986 (inpress)
ABSTRACT
A retrospective cohort-studywitha follow-upof6-17yearswas carriedoutin
fourgeneralpractices inTheNetherlands intheperiod 1967-1983.Intotal
317overweightmenand 565overweightwomenwere followed ina continuous
morbidity registration,startingintheyear theywerediagnosed asoverweight
(atage20- 50years). Incidenceof illnessesinthisgroupwascompared to
that inacontrol group (444menand627womenwithout registered overweight),
matched onsex,ageandcalendar-year atstartoffollow-up.
The incidenceof registeredmorbidity intheoverweightgroupwashigher for
diabetes,gout,arterioscleroticdisease,arthrosis formenandwomen,andalso
forvaricoseveins forwomen.IncreasingBMIatstartof follow-upwas
associatedwith increased risk formost illnessesunder study.Forgoutand
arterioscleroticdisease inmen,overweightappeared tobea risk factorat
lower levelsofBMI thaninwomen.
INTRODUCTION
Recent reportsofexpertcommitteeshave stressed thatoverweightandobesity
are importanthealthhazardsinaffluent societies [1,2,3].Manyprospective
studieshave shownthattheoverweightandtheobese tendtohave shorter life
spans [3],andanexcess risk formorbidity.Fromthe reportsor reviewsonthe
risksofoverweight itisclear thatobesity isconsidered tobea risk factor
formany illnesses,butthatthese riskshave rarelybeenstudied intermsof
2
BodyMass Index (BMIinkg/m )inafollow-upsituationoflongduration.In
thisstudya retrospective cohortanalysiswascarriedout,usinga continuous
morbidity registrationwith standardized criteria fordiagnosesofdiseases in
fourgeneralpractices.The incidence insubjects,registered asoverweight
-73-
duringafollow-upperiodof6-17years,wascomparedtothatinacontrolgroup
withoutregisteredoverweight.Withtheuseofweightandheightdataof
overweightsubjects,measuredbythegeneralpractitioners,animpressionofthe
risksindifferentcategoriesofBMIcouldbeevaluated.
METHODS
Forthisstudy,informationwasobtainedfromtheContinuousMorbidity
RegistrationoftheDepartmentofGeneralPracticeoftheUniversityof
Nijmegen.Infourpractices,alldiagnosesareregisteredonadaytodaybasis.
Thesemorbiditydatacanbelinkedtoacomputerizedcontinuousregistrationof
thepatientfiles(whichincludesup-to-dateinformationondemographic
variables).Twopracticesstartedtheregistrationin1967,twoothersjoinedin
1971.Thetotalpopulationofthefourpracticestogethercomprisesabout12,000
patientsandisconsideredtoberepresentativeoftheDutchpopulation,with
respecttothedistributionofageandsex.Onepracticeissituatedinan
industrialtown(approximately180,000inhabitants),oneinamiddlesizedmixed
industrial/ruraltown(approximately10,000inhabitants)andthetwoother
practicesaresituatedinruralareas.Diagnosesareregisteredaccordingtothe
E-list [4],whichisaversionofthe'InternationalStatisticalClassification
ofDiseasesandCausesofDeath'adaptedforuseinTheNetherlands.A
descriptionofthediagnosticcriteriafordiseasesstudiedinthispapercanbe
foundintheAppendix.Twogroupsofpatients,anoverweightgroupandanonoverweightgroup,wereretrospectivelyfollowedup.Theoverweightgroup
comprisedofallpatientswhowereregisteredasoverweightbytheirgeneral
practitionersintheperiod1967-1978.Thethresholdcriteriafordiagnosisof
overweight(relativeweight>115%)correspondstoaBMIbetween25.0-26.0
2
2
kg/m (forwomen)orbetween26.0-27.0kg/m (formen).Overweightwasonly
registeredwheninitialdiagnosedoverweightpersistedinthesubsequentyear.
Overweightsubjectswerefollowed-upinthemorbidityregistration,startingin
theyeartheiroverweightstatusappearedforthefasttimeintheregistration
(t0forthesepersons).
Theoverweightpopulationwasrestrictedtopatientsforwhomoverweightwas
registeredforthefirsttimebetweenages20-50years,andwhocouldbe
followedforatleast6yearsintheregistration.
Dataonheightandweightwereobtainedfromindividualpatientrecords.Dueto
omissionsofgeneralpractitionersontheirpatientrecordsorrecordsmissing
wasperformedwithregardtoageatstartoffollow-up(in5yearagegroups),
-74sexandgeneralpractice.The ratioof thecell frequencies inthe576
(6*2*4*12)cellsofthecontrolgroupcompared tothecell frequenciesof the
overweightgroupwasalwaysbetween1.0 and 1.5 (average1.3).Toobtainavalid
control group,informationonnon-overweightstatusinthemorbidity
registration throughoutthecompleteobservationperiod 1967- 1983wasused.
Therefore,theoratically,thecontrolgroupcouldnotbecontaminatedwithnon
overweight subjectswhosubsequentlybecameoverweight.
Boththeoverweightandthecontrolgroupwere restricted,beforematching,to
persons stillpresent inthegeneralpractices.Theywere senta questionnaire
(response:70%;detailsaredescribedelsewhere) [7a].Thosewhowere candidates
forthestudypopulation,butdiedbefore theendoftheobservationperiodwere
firstanalysed separatelyandwerelateradded tothestudypopulation.Social
classwasdefinedastheprofessionoftheheadofthehousehold and ratedas
low (unskilledand skilledworkers);middle (lowerandmiddleemployees)orhigh
(highemployees).
Statistical analysis
Since lengthof follow-updifferedbetweenindividuals,statistical techniques
foranalysing survivaldatawereapplied tostudytheincidenceof registrations
ofchronicdiseases fortheoverweightand thecontrolgroup [8].Using these
techniques itwaspossible touse informationonthecompleteobservationperiod
ofupto17years (1967- 1983).Endpoints intheanalysiswereeither the first
occurrenceoftheparticulardiseaseunder studyor theendof theobservation
period (1/1/1984).Onlypersonswhowere,according tothe registration,freeof
thediseaseunder studyatthetimethefollow-upstarted,wereused for
follow-up.
Analysiswasperformed formenandwomen separately,and foragegroups (based
onageatstartoffollow-up)separatelyaswellasforallagestogether.
Kaplan-Meier estimatesofthe 'disease-free'proportionof thepopulationwere
calculated foreachyearof follow-up,usingtheSAS-programPHGLM [9].
The logrank statistic [10]wasused totestdifferences,onayear-to-year
basis,betweencumulative incidencesofthediseasesunder studyofthe
overweightand thecontrolgroups.TheproportionalhazardsmodelofCox [11]
wasapplied toestimatethe riskofoverweightand tocontrol for potentially
confoundingeffectsofsex,age,socialclassandpractice,usingdummy
variables forcategorically scaledvariables.Relative riskswere calculated as
the ratioof the incidencedensities (incidencedividedbynumber ofperson
yearsobserved)intheoverweightand thecontrolgroup.Itappeared that32men
-75-
(11.9%)and23women(5.9%)belongingtothecontrolgroupcouldnowbe
consideredoverweight.Analyseswererepeateddeletingthese'falsenegative'
subjectsfromthecontrolgroup.Endpointswerefirstregistrationsofthe
followingchronicdisorders:anginapectorisormyocardialinfarction;gout,
diabetesmellitus,varicoseveins;arthrosis;stroke;chronicalbronchitisand
myodegeneratiocordis.Norelationbetweenoverweightandthelatterthree
diseaseswasfound.Resultsoftheanalysesofthesediseasesareomitted.
RESULTS
InTable1somecharacteristicsofthestudypopulationareshown.The
differencesbetweentheoverweightandthecontrolgroupindistributionover
thesocialclassesreflectaninverserelationshipbetweenlevelofprofession
andbodyfatness.
Tablela.Ageandnumberofyearsoffollow-upofthestudypopulation
Men
Overweight
group
37.6 8.0
Overweight
group
mean SD
Ageatstartof
Women
Control
group
mean SD
37.4 8.1
Control
group
mean SD
36.8 8.6
mean SD
36.1 8.7
follow-up
Yearsoffollow-up 10.6 3.1
10.4 3.0
12.0 3.1
11.3 3.1
Tablelb.Distributionofpersonsinthestudypopulationoversocialclasses
Socialclass
n
%
n
low
203 64.0
210 47.3 361 63.9
297 47.7
middle
101 31.9
179 40.3 175 31.0
260 41.5
high
13
4.1
317 100.0
55 12.4 29
5.1
70 11.2
444 100.0 565 100.0
627 100.0
IT
-76-
BMI'satstartoffollow-upcouldbecalculated for83.3%ofoverweightmenand
2
88.3%ofoverweightwomen.MeanBMIofoverweightmen (28.7kg/m ;SD2.0)was
2
lower (p<0.05) thanthemeanBMIofoverweightwomen (29.3kg/m ;SD3.4).
BMI'softheoverweight incidentcaseswerecalculated.Thedistributionsover
categoriesofBMI fortheoverweight casesofvariousdiseasesand ofall
overweightpersonsareshowninTable2.
Table 2indicatesthat,forwomen,there isanincrease inrisk foralldiseases
shown,except forgout,withhigher levelsofbody fatness.Theproportionof
female casesisclearlyelevated,compared tothecontrolgroup,andcompared to
2
lower levelsofBMI,whentheBMI ishigher than30.0kg/m .A similartrend is
seen fordiabetesandarthrosis inmen.The incidenceofgoutand
arteriosclerotic disease,however,wasparticularlyhighforoverweightmen in
theBMIcategory27.0- 29.9kg/m2.
InTable 3thelogrank statistics fordifferences inthecumulative proportions
ofpersonswith thediseaseunder studybetweentheoverweightand control
groupsaregiven (foragegroupsseparatelyandallagescombined).Differences
weregreater foragegroupsabove 30years.
Adding thepersonswhodied intheperiod 1967- 1983tothestudypopulation in
the retrospective cohortanalysisdidnotalteranyoftheconclusionsdrawn
fromtheanalysisexcludingdeaths.Cox's regressionmodelwasused tocontrol
for thepotential confoundingeffectsofsocialclassorgeneralpractice.
Neither social classnordifferences inpracticenoraddingthesmallgroupof
deceasedpersons tothestudypopulation,significantly influenced the
relationshipbetweenoverweightandtheincidenceof registereddiseases.To
giveanimpressionoftheBMI'softhesubjectsintheoverweightandthe
control groupstheBMI'sbased onself-reported heightandweightsattheendof
theobservationperiod (spring1984)areshown (Table4 ) .
-77-
tx> T
r-i m
o> <& m
o
m rH eo
o
eo i—
co in ^o o \o
•H <N -tr .-* vo
H IN H
«) m 01
m r-J m
m o
-H
i£> vo
I m
m
o c
• 5
o o
r- o o T c
o
I
I
-73-
Table 3.RelativeRisks andlogrank statistics fortestingdifferences inincidencebetweenoverweight and
control groupduring17yearsoffollow-upinacontinuousmorbidity registration
ageatt
disease freepopulation
numberofincidentcases
Relative
p-value
overweight:control
overweight:control
Risk
forlogre
observed
statistic
expected
0.24
20-29
64 : 93
0.4
0.6
30-39
113 :161
2.5
3.3
7.1
0.036
40-50
139 :187
3.4
4.6
4.0
0.063*
20-50
316
6.2
8.7
5.6
0.003**
20-29
140 :168
0.9
1.1
1.2
0.91
30-39
182 :210
2.0
2.0
3.5
0.32
40-50
237 :247
7.1
6.9
13.5
0.002**
20-50
559 :625
6.3
0.001**
441
**
Arteriosclerotic
20
29
64 : 93
disease
30
39
112 :162
0
4
2.1
3.0
5.8
0.076*
40
50
136 :185
15
8.3
11.7
4.1
0.002**
4.5
14.7
312 :440
20
29
140
168
30
39
183
210
5: 0
2.4
2.7
0.017**
40
50
240
248
16 : 4
10.1
9.9
0.008**
0: 0
21 : 4
men
women
Varicose veins
women
29
64
93
5: 3
3.3 : 4.7
(2.4)
0.23
30-
39
113
160
11 : 5
6.6 : 9.5
(3.1)
0.024**
40-
50
139
187
25 :23
19.9 :28.5
1.5
20-
50
316
440
41
p <0.10
31
29.7 :42.3
0.14
1.8
0.007**
20-
29
140
168
2: 3
2.4
2.7
0.8
0.76
30-
39
183
210
19 : 9
13.8
14.2
2.4
0.049**
40-
50
238
248
52 :44
47.7
48.3
1.2
0.38
73 :56
62.6
66.4
20-29
64 : 93
1.4
1.6
30-39
113 :163
0.4
0.6
40-50
149 :187
1.7
2.3
50
4.6
1.5
0.066*
0.057*
0.23
3.8
9.5
0.19
0.010**
317
444
20 - -29
138
168
0
30 - -39
183
210
1.0
1.0
0.15
40 - -50
241
248
1.0
1.0
0.17
20 - -50
562
626
20 - -29
135
167
17
17
15.5
18.5
1.2
0.60
30 - -39
176
202
30
24
25.0
29.0
1.2
0.18
40 - -50
230
257
47
35
40.4
41.6
1.5
0.15
80.2
89.8
1.4
0.034*
626
p <0.05
0.0005**
20-
20
women
0.0004**
0
0.046*
-79Table4.DistributionovercategoriesofBMIbasedonself-reportedweightand
heightin1984*
BMI
Overweight group
Controlgroup
category
men
n (%)
men
n (%)
(kg/m2)
<25.0
25.0-26.9
27.0-29.9
>,30.0
27
48
64
43
(14.8)
(26.4)
(35.2)
(23.6)
women
n
55
96
117
102
(%)
(14.8)
(25.9)
(31.6)
(27.6)
181
56
30
2
women
n
313
53
17
6
(67.3)
(20.8)
(11.2)
( 0.7)
(%)
(80.5)
(13.6)
( 4.4)
( 1.5)
182 (100.0)
370 (100.0)
269 (100.0)
389 (100.0)
Unknown
135
192
175
238
Total
317
562
444
627
*Actualmeasuredweight(withoutclothes)andheight(withoutshoes)were
requested.70%returnedthequestionnaire,ofthese95.2%gavebothweightand
height
Table4showsthatabout15%oftheoverweightpopulationcannolongerbe
2
consideredoverweight(BMI<25.0kg/m).Thismayhavebeentheresultof
weightreducingeffortsresultingin,atleasttemporarily,normalweightorthe
consequenceofchronicillness.Aneffectofageingorofunderreportingof
weightcannotbeexcluded.Inthecontrolgroup,12%ofthemenand6%ofthe
2
womenhaveaBMI>27kg/m.Thesepersonscanbeconsideredasfalsenegative
controlsubjects,whohaveneverbeenregisteredbytheirgeneralpractitioner
asoverweightinthemorbidityregistration.Astheseimpropercontrolsubjects
mightinfluenceestimatesofrelativeriskaspresentedintable2,analysis
wererepeatedafterdeletingthesepersonsfromthecontrolgroup.Table5shows
therelativerisksandp-valuesofthelogrankstatisticsafterremovalofthese
subjects.
-80Table5.Relativeriskscalculatedastheratioofincidencedensitiesofsome
chronicillnessesintheoverweightgroupandinthecontrolgroup,
afterexclusionofsubjectsinthecontrolgroupwho,accordingto
2
selfreporteddata,hadaBMI>27.0kg/m inthespringof1984
Illness
Sex
Relative Risk
p-value for
logrank statistic
DiabetesMellitis
men
5.2
5.6
0.004
4.2
5.1
0.0009
1.9
1.3
0.006
0.013
women
9.0
_
0.05
women
1.4
0.04
women
Arteriosclerotic
men
Disease
women
Arthrosis
men
women
Gout
Varicoseveins
men
0.002
0.0008
0.10
DISCUSSION
Thisstudydemonstratesthatoverweightpatientsingeneralpracticeareat
higherriskfordevelopingarterioscleroticdisease,diabetesmellitus,
arthrosis,goutandvaricoseveins(thelatteronlyforwomen).Itshouldbe
notedthattheoverweightgroupandthecontrolgroupdifferedinfrequencyof
illnessatthebeginningofthestudy,becausepersonsintheoverweightgroup,
butnotinthecontrolgroup,wereselectedatthestartoffollow-uponthe
basisofavisittothegeneralpractitioner (onwhichoccasiontheir
overweightstatuswasdiagnosed.
Manyinvestigatorshavestudiedtheassociationsbetweenoverweightand
disease.Mostofthesestudies,however,havecross-sectionalorcase-control
designs.Causalinferencefromthesestudiesisoftenproblematic,especially
whendiseasessuchasarthrosis,gout,varicoseveinsandnon-fatal
-81arterioscleroticdiseaseareunder study,becausethesediseasesmight
contribute toweightchange.Thiscouldleadtomisleadingassociations.The
prospective studiesthathavebeenundertakenhavegenerallyconsidered causes
ofdeath.Onlyveryfewinvestigatorshave studied theincidenceofdisease in
relationtooverweight [12].Inthisstudy,casesofparticulardiseasesunder
studyatthestartoffollow-upwereexcluded,sotime-relationships between
theonsetofoverweightandtheonsetofdiseasesarelikely.Foroverweight
cases,theweightchangebetweenthestartofthefollow-upandtheendofthe
observation-periodwereanalyzed.There isnoindicationthatanyofthe
diseasesunder studycaused significantweightgainorweight loss.
As ineveryotherobservational studyinwhichoverweightisthe independent
variable,thetimebetweenthestartoffollow-upandtheoccurrenceofdisease
shouldbe interpretedwithcaution,becausetheexact 'exposure time',i.e.the
ageofonsetofoverweight israrelyknown.Inthisstudy,theuseofa
continuousmorbidity registrationimpliesthat,especially inthefirstyears
of the registration,manyoverweightpersonshadbeenoverweight fora
considerablenumberofyearsbeforethestartoffollow-up.Thisexposure-time,
which isnotaccounted for intheanalysis,probably increaseswith increasing
ageatthestartof follow-up.Thismightexplain,notonlythe increasing
incidenceofchronical illnesswithadvancingage,butalsothe stronger
associationsof illnesswithoverweight intheolderagegroups.Thefinding in
Table 4thatmorementhanwomenfromthecontrolgroupcanbe considered
overweight,probably reflectstheselectiveattentionofgeneral practitioners
with regard tooverweight inwomen.Comparingthe resultsfromTable 3with
those inTable 5suggeststhattheinclusionofthefalsenegative controls
introduceda slightbiasawayfromthenull.Thiscouldmeanthatundiagnosed
overweightsubjectshave relativelylower incidenceofillnessescompared to
diagnosedoverweight subjects.Suchselectionbiashasbeen reported ingeneral
practices intheUnited States [13].The relationshipswithchronic illnesses
demonstrated inthisstudyarediscussedbelow.
Arterioscleroticdisease
Bothmyocardial infarctionandanginapectorisarecommonmanifestationsof
arteriosclerotic disease,themostcommoncauseofdeath inTheNetherlands
[14].Bothhaveoneunderlying functionalabnormality: ischemiaor insufficient
oxygen supplytothetissuesoftheheart.Inlong-term follow-upstudies,
overweighthasbeenassociatedwitharterioscleroticdisease inmultivariate
analysisasan independentpredictor [15].A largeproportionofcaseswith
clinicalmanifestationsofarteriosclerotic diseasedosurvive,probablywith
severe impairmentoftheirqualityoflife.Thisstudyshowsthat
arteriosclerotic disease,includingandexcluding fatalcases,isclearly
related tooverweight.An important finding isthatapronounced increase in
risk inmenwasobservedatlowerlevelsofBMI inmenthaninwomen.Thismay
bedue tosexdifferences infatdistribution,whichare related to
hypertension [16,17]andcardiovascularmortality [18].Itmustbenoted that
bodyweight isclearly related tomajor risk factors forcardiovascular disease
likeserumcholesterol levelandbloodpressure.Adjustments forthese factors
arelikely toyieldlowerestimatesofthe relative risksassociatedwith
overweight,ashasbeendemonstrated intheFraminghamHeartStudy [12].No
baselinedataofthesepossibleconfounding factorswerepresent inthe
morbidity registrationonwhichwebasedouranalysis,norweremeasuresof fat
distribution.Theselimitationsshouldbekeptinmindintheinterpretationof
ourresults.
Diabetesmellitus
Manystudies,prospective [19,20]aswellascross-sectional [21,22,23],have
demonstrated theassociationbetweenoverweightanddiabetes (TypeII).This
studyconfirmsthatthere isanincrease inriskwithhigher levelsofBMI.
Gout
IntheFramingham study itwasshownthatthe risk forgoutinmen increased
appreciablyonlywhenweightsexceeded 130%oftheappropriateweight for
height [24].Althoughgoutwasnotacommondisorder inthisstudy,itis
striking thatvirtuallyallcasesbelonged totheoverweightpopulation.Most
of thecasesofgouthadaBMI,atthestartoffollow-up inthecategory 27.0
2
- 29.9kg/m ,which isclearlylower than130%oftheappropriateweight,as
found intheFramingham study.
Arthrosis
TheRoyal CollegeofPhysicianshasemphasized thepossibility thatthe
associationbetweenoverweightandarthrosismightbe the resultof reduced
physicalactivity,leadingtoweightgain [1].Comparing theBMI'sofcasesof
arthrosisatthestartoffollow-upwithBMI'sbasedonweightsmeasured bythe
generalpractitioner anaverageof11yearslater,revealed thatonly 18%were
inahigher categoryofBMIthanatthestartof follow-up.FromTable?4and 5
itcanbe seenthatanincrease inrisk forarthrosisbecomesapparentwhen the
-83-
BMI is27.0orhigherandthat30- 39yearoldoverweightwomenwere
particularlyat risk fordevelopingarthrosis.The individualpatient records
were studied fortheaffected sitesofarthrosis.Inabout35%ofthecasesin
both theoverweightandthecontrolgroup,theaffected siteswere
weight-bearing joints (kneesand hips).Also forother sites,nodifferencewas
foundbetweentheoverweightandthecontrolgroup.Thefactthatarthrosis
associatedwithoverweight isnot restricted toweightbearing jointshasbeen
observed inprevious studies[25].
Varicoseveins
Varicoseveinsweremuchmorecommoninwomenthaninmen.Ithasbeenobserved
thatwomenwithvaricoseveinsareheavier thancontrolsofthesameage
[26,27].Results fromtheBasle study [28]demonstrated thatparity isan
important risk factorforvaricoseveinsinwomen.
Inourpopulation,parity intheoverweightgroup (nulliparous:6%, one
pregnancy:10%,twopregnancies:33%,threepregnancies:23%,fourormore
pregnancies:28%)wasvery similar toparity inthecontrolgroup (nulliparous:
7%, onepregnancy:9%),(twopregnancies:31%,threepregnancies25%,fouror
morepregnancies:28%).Comparing incidenceofvaricoseveinsbetweenthe
overweightandcontrolgroupincategoriesofparity showedno confounding
effectofparityontheestimatesof relativerisk.
Intheanalysisnoadjustmentscouldbemade forthepossible confounding
effectofsmoking,underweightortypeof fatdistribution.Since smokersare
generallylessobese thannon-smokers,andalsohavehighermorbidity,taking
smoking intoaccountwouldprobablyyieldhigherestimatesof relative risk.
Fatdistribution,wasonlyassessed inasubpopulationoftheoverweight
subjects intwogeneralpractices.Thewaist:thighcircumference ratiowas
shown tobe related toarthrosis inmen,hypertension inmenandwomen,
diabetesorgoutinwomen,andvaricoseveinsinwomen.Theseassociationswere
independentofthedegreeofoverweight[17].
CONCLUSIONS
Overweight leadstoanincreased frequencyofchronic illnesses,registered in
generalpractice.Formen,thiselevated riskwasapparentatlower levelsof
BMIthan forwomen.Thisisinagreementwith findingsofstudiesonfat
distribution,whichhave shownthat,forthesamedegreeofoverweight,menare
-84-
athigher riskofvariousdisordersthanwomen[29].
Atpresent,overweight ingeneralpractice isacondition forwhich relatively
morewomenare treated thanmen.Howeveroverweightasahealthhazard inmen
shouldnotbeneglected.Thisstudydoesnotallowfordetectinga
dose-response relationship,butitisapparent fromTable2thatoverweight in
men isassociatedwithchronic illnessatlower levelsofBMIthan inwomen.
Thediseasesthatwere foundtobeassociatedwithoverweightmightleadto
important functional limitationsanddiminished subjectivehealth.ItShouldbe
emphasized thatselectionbiasmighthave influenced the resultsofthe
analysisand thattheelevated risksassociatedwithoverweightmightatleast
partlybeattributedtoconfoundingeffectsoffactorslikeserumcholesterol
andbloodpressure.Levelsofthese risk factorsforarterioscleroticdisease
usuallytendtonormalizeandconditionslikediabetesmellitus,goutand
arthrosisarelikelytoimprovewhenasubstantialweight reduction isachieved
andmaintained [30].
Thus, treatmentofthosewhoarealreadyoverweightand,perhapsmore
importantly,preventionofoverweight inthosewhoareat risk,deserves
attention ingeneralpractice.Thegeneralpractitioner isable tomonitor
weight changesona regularbasis.Whenpersons,especiallyyoungadults,who
2
arealreadymoderatelyoverweight (BMI>25kg/m )gainweight,attention
shouldbepaid totheirnutritionalhabitsandotheraspectsoftheir
lifestyles,inordertopreventthemfrombecomingseverelyoverweight,which
would increase theirchancesofdevelopingachronicdisease.
ACKNOWLEDGEMENTS
Theauthorsaregrateful toF.J.A.Huygenand staffofthedepartmentof
General Practice inNijmegenforgenerouslyproviding themorbiditydata;J.
BuremaandS.Ward forhelpfulcomments;P.Hoppener forcomputer assistance
andA.Zijlmans fortypingthefinaldraftofthemanuscript.
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!
APPEM)IX
Diagnosticcriteria forchronicdiseasesinthecontinuousmorbidity
registration.
Diabetesmellitus
A singleblood-glucoselevel >10mmol/1wasusedasthecriterion.Indoubtful
cases,thiswasconfirmedbyanabnormalOralGlucoseToleranceTestaccording
toWHOcriteria.
Gout
Goutwas registeredwhentheusualclinical symptomswereobserved,ifnecessary
confirmedbylaboratoryinvestigation.
Arthrosis
Arthrosisdeformanswas registeredwhentherewere clear clinical signsof
arthrosis (e.g.,pain,stiffnessand inflammation),confirmedbyanX-ray.
Varicoseveins
Varicoseveinsof lower limbswere registeredwhenclearlyvisiblevaricose
veinswerepresented,observedeitherat routineexaminationor following
specific complaints fromthepatient.
Myocardial infarction
Myocardial infarctionwas registeredwhenaclinical suspectionofamyocardial
infarctioncouldbeconfirmedbyanabnormalECGand/orbymeasurementsof the
concentrationsoftheenzymesCPK,SGOT,LDH (exceptionsweremade forpatients
whodiedbefore such investigationswere possible).
Anginapectoris
Anginapectoriswasdiagnosedwhenaclinicalexaminationprovided sufficient
evidence foranginapectoris (notnecessarilyconfirmedbylaboratory-orECGtest).
CHAPTER5
THERELATIONBETWEENOVERWEIGHTANDSUBJECTIVEHEALTH-WITHATTENTIONTOTHE
EFFECTSOFAGE,SOCIALCLASS,SLIMMINGBEHAVIORANDSMOKINGHABITSONTHIS
RELATION
J.C.Seidell,K.C.Bakx,P.Deurenberg,J.Burema,J.G.A.J.Hautvast,
F.J.A.Huygen
AmJPublicHealth1986;76:(inpress)
ABSTRACT
Subjectivehealthstatuswasassessed,inrelationtooverweight,by
administeringalistof51healthcomplaintstoadultmenandwomenwhowere
eitherchronicallyoverweightasdefinedbyBodyMassIndex(BMI)ornot
overweight,inacontinuousmorbidityregistrationinfourgeneralpractices
duringtheperiod1967-1983.Responseswerereceivedfrom455men(182
overweight)and790women(386overweight),age26-66years.Responserate
(71%)andagedistribution(meanage48)wereequalinoverweightand
non-overweightgroupsofbothsexes.BMIwascorrelatedwiththetotalnumberof
complaintsinwomen(r=0.15)butnotinmen(r=0.07).Multipleregression
analysisrevealed,however,thatagewasaneffectmodifierinthisrelation,
therebeinganegativeassociationbetweenBMIandsubjectivehealthinyounger
menandapositiveassociationinoldermen,whereas,inwomen,theassociation
betweenBMIandsubjectivehealthwasmuchmorepronouncedatyoungeragesthan
atolderages.Inaddition,currentsmokinghabitsandsocialclass(inmenand
women)andreportedslimmingbehavior (inwomen)hadanindependentrelationto
thetotalnumberofhealthcomplaints.BMIwasalsorelatedtospecific
complaintsandgroupsofcomplaints,particularlyinwomen.
INTRODUCTION
Overweightisariskfactorforthedevelopmentofvariousdiseases' andis
12
verycommoninaffluentcountriesincludingTheNetherlands.Wehaveshownthat
overweightisaccompaniedbyanexcessofbothobjectivelyregisteredmorbidity
andsubjectivereportedillness,increaseduseofmedicalcareforparticular
reasons,andtheuseofcertaindrugs.Thesubjectivehealthstatusof
-89overweightpersonscouldbemediatedthroughtheassociationbetweenoverweight
andmorbidity.Ontheotherhand,intheabsenceofillness,overweightperse
mayberelatedtoadiminishedfeelingofwellbeing.Deviationsfromacultural
45
idealofslimmnessmaybeinvolvedinsucharelation' aswellasfunctional
limitationsduetoexcessweight.
Theassociationofoverweightwithstatesofmentalhealthhasbeenthesubject
ofmanystudies,buttheassociationwithsubjectivehealthcomplaintshasbeen
asomewhatneglectedsubject.ResearchintheU.S.A. indicatedthatoverweight
wasrelatedtofunctionallimitations,pain,worryandrestrictedactivities.In
Sweden,associationsbetweenoverweightandindicesofhealthwerefoundtobe
78
lesspronouncedinmiddleagedmenthaninwomen'.
InthisstudyweinvestigatedtheassociationbetweentheBodyMassIndex(BMI=
2
weight/height)andresponsestoalistof51subjectivehealthcomplaints.The
relationsofBMIwiththetotalnumberofcomplaintsaswellaswithgroupsof
complaintswerestudied,adjustingforthepossibleconfoundingeffectsof
slimmingbehavior,smokinghabits,age,andsocialclass.
METHODS
Samplecharacteristics
Thedatapresentedinthispaperwereobtainedfromaquestionnairethatwas
administeredinthespringof1984tomembersofastudypopulationthathad
q
beenfollowed-upinacontinuousmorbidityregistration .Fortheoverweight
group,personswereselectedonthebasisofdiagnosisofoverweightatage2050yearsbygeneralpractitionersfromfourgeneralpracticesinamixed
rural/urbanarea.Thecontrolgroupcomprisedarandomsampleofadultswhohad
neverbeendiagnosedasoverweight;thisgroupwasmatchedtotheoverweight
groupinage,sex,practiceandcalendar-yearatstartoffollow-up.Detailsof
q
thefollow-upstudyandsamplingmethodshavebeendescribedelsewhere.
Thetotalpopulationinthefourgeneralpracticescomprisesabout12.000
individuals,andisrepresentativefortheDutchpopulationwithrespecttothe
distributionofageandsex.AllpersonssampledwereCaucasianandofDutch
nationality.
Personswhoseaddresseswereknown(93%)weresentaquestionnaire,whichwas
returnedby1241persons(71%response).Theresponsewasnotselectivewith
regardtooverweightstatus,sex,ageorsocialclass.Table1showssome
characteristicsofthestudygroup.
-90-
Descriptionofmeasures
1.Overweightwasdiagnosedintheperiod1967-1978bygeneralpractitioners
accordingtocriteriathatcorrespondtoaBodyMassIndex(BMI=
2
2
2
weight/height)ofatleast26.0kg/m (forwomen)or27.0kg/m (formen).
Heightandweightweremeasuredbythegeneralpractionersatthetimeofthe
diagnosisofoverweight.Onaverage,thiswas12yearspriortothe
administrationofthequestionnaire (range6 - 1 7 years).Aspartofthe
follow-upquestionnairein1984,subjectswereaskedtoweighthemselvesin
themorningwithoutshoesandclothesandmeasuretheiractualheightwithout
shoes.Virtuallyallsubjectsindicated,whenaskedinthequestionnaire,
thattheyhadbeenabletofollowtheseinstructionsforweighingthemselves
andmeasuringheight.Inaddition,self-reportedheightsandweightswere
foundtobeaccuratewhencomparedtomeasuredheightsandweightsina
25
sampleof305oftheoverweightsubjects .Unlessotherwisespecified,BMI
whenusedinthispaperreferstocurrentBMI.
2.Socialclasswasdefinedaslower(unskilledandskilledmanualworkers),
middle(loweremployees)orupper (higheremployees),accordingtothe
professionoftheheadofthehousehold.
3.Smokingbehaviorwasclassifiedfromquestionnaireintofourcategories
(neversmoked,stoppedsmoking,smokinglessthan10cigarettesperday,and
10cigarettesormoreperday).Inmultipleregressionanalysesdummy
variablesforthecategories"stoppedsmoking",and"smoking"wereused,
while"neversmoked"wasthereferencecategory.
4.Slimmingbehaviorwasclassifiedintofivecategories("never","seldom",
"regularly","often",or"(almost)always",tryingtoreduceweight).Inthe
multipleregressionanalyses,"regularly"and"often"slimmingwerecombined
intoonecategory.Dummyvariableswereused,with"neverslimming"asthe
referencecategory.
5.Subjectivehealthwasmeasuredbyratedhealthona7-pointscaleandbythe
answerstoalistof53healthcomplaints .ThislistisoftenusedinThe
Netherlandstoassesssubjectivehealthstatus .AppendixIgivesashort
descriptionofsomesingleitemsand,itemsandclustersidentified:using
12
factoranalysis .Allitemsweredichotomous;twoitems("do youfeeltoo
thin?"and"doyoufeeloverweight?")wereexcludedfromtheanalysissince
theseitemscouldseriouslyconfoundtherelationbetweenoverweightandthe
totalnumberofcomplaints.Thesquarerootofthetotalnumberofcomplaints
(fromtheremaining51items)hadacloseapproximationtothenormal
distributionandshowedtheclearestlinearrelationshipwithBMIandother
-91-
variables;itwasthereforeused intheanalysisasanindex forgeneral
subjectivehealth.Inlogistic regression,scoresonsubscaleswere
consideredaswellassomesingle items.These itemswere selectedwhen,in
analysisofcontingencytables,afteradjustments forsex,socialclassin
theperiod 1967-1978andage,theanswersonthese itemswerediffered
betweentheoverweightandthecontrolgroupataprobabilitylevelof 0.05.
6. Statisticalmethods.Multiplelinearandlogistic regressionanalyseswere
performedwiththeuseofthestatisticalpackageprogramsBMDP2Rand
BMDPLR .Presenceof interactionwasassessedbyaddingcross-product terms
ofvariablestoamodel thatcontainedallthemaineffects.Whenthe
F-to-enter ofan interactiontermhadaprobabilityvalue lessthan0.10,the
cross-product termwas included inthestraight regressionanalysiswhose
resultsarepresented inthetables.Thedependentvariable inmultiple
linear regression (table4)wasthesquare rootofthetotalnumberof
complaints. IndependentvariableswereBMI,age (andacross-product termof
BMIandage,reflectingstatistical interactionofBMIandageinthe
analysis), socialclass,smokinghabitsandslimmingbehavior.For categories
of smokinghabitsandslimmingbehavior,dummyvariableswereused (using
never-smokingandnever-slimmingas reference categories). Inmultiple
logistic regression (table6)thesame independentvariableswereused.The
dependentvariablewasdichotomous:presenceorabsenceofa complaint
(single items)orpresenceorabsenceofatleastonecomplaint (groupsof
items).
RESULTS
Table 1showsthedistributionofsubjectsinBMI categoriesandcategoriesof
possible confoundingvariables.At thetimeofthestudy,about27%ofthe
originally registeredoverweightwomenand41%of theoriginally registered
overweightmencouldnotbeconsidered overweightanylonger,whileabout6% of
thewomenand 12%ofthemen inthecontrolgroupwouldbeconsidered overweight,according tothesamecriteriausedearlierbytheirgeneral
practitioners. InTable 1,currentoverweight isinversely related tosocial
class;ageand smokingmorethanwomen;subjects intheoverweightgroups
reported slimmingmoreoftenthanthoseinthecontrolgroup,thisbeingmore
pronounced inwomen thaninmen.Subjectivehealth,ratedona7-pointscale,
washighlycorrelatedwith thesquare rootofthenumberofcomplaints (men:r=
0.61,95%CI= 0.55 -0.66;women:r= 0.65,95%CI=0.61 - 0.69)
-92-
Table1.BodyMass Index,socialclass,age,smokinghabits,andslimming
behaviourofthose respondingtothequestionnaire,classified
accordingtooverweight status (registeredin1967-1978)andsex
Men
Women
Overweight
n
A. BodyMassIndex
Control
n
%
%
Overweight
Control
n
%
n
%
(kg/m2)
181 67.3
<25.0
55
14.8
313 80.5
27
14.8
25.0-26.9
96
25.9
53 13.6
48
26.4
56
27.0-29.9
117
31.6
17
4.4
64
35.2
30 11.2
>30.0
102
27.6
6
1.5
43
23.6
2
0.7
16
-
15
0
-
4
-
Lower
248
64.2
186
46.1
117
64.3
124
45.4
Middle
118
30.6
177 43.8
59
32.4
117
42.9
Upper
20
5.2
41 10.1
6
3.3
26-39
82
21.2
35
19.2
62
22.7
40-49
98
25.4
131
32.4
64
35.2
78
28.6
50-66
205
53.1
184 45.5
74
40.7
130
47.6
163
42.2
156
38.6
22
12.1
40 14.7
85
22.0
99
24.5
59
32.4
79
smoking<10cigs/day
43
11.1
59 14.6
41
22.5
smoking>10cigs/day
95
24.6
90 22.3
60
32.0
108
39.6
52
13.6
207
55
31.1
190
69.6
108
55 20.1
16
5.9
unknown
-
20.8
B. SocialClass
32 11.7
C. Age(years)
87 21.5
D. Smokinghabits
neversmoked
stoppedsmoking
28.9
46 16.8
E. Slimmingbehaviour
never
51.6
seldom
83
21.8
26.9
59
33.3
regular
119
31.2
56 14.0
34
19.2
often
48
12.6
12
3.0
15
8.5
0
0.0
(almost)always
79
20.7
18
4.5
14
7.9
12
4.4
unknown
Total
5
386
z
100
3
404
100
5
-
0
_z_
182
100
273
100
-93-
InwomenBMIwascorrelatedwiththenumberofcomplaints (r= 0.15;95%CI:
0.08 - 0.21),butinmenthecorrelationwasvery slight (r= 0.07;95%CI:
-0.03- 0.17). Intable2theaverageofthesquare rootofthetotalnumber of
complaints invariouscategoriesofBMIareshown.Itcanbe seenthat inall
categoriesofBMImore complaintswere reported intheoverweight groupthan in
thecontrol group.Overweight statusinthistablewasbasedonthe
classificationbythegeneralpractitioners.Insubsequentanalysiswedidnot
use thegeneralpractitioner classificationasthiswouldprobablywould have
led toanoverestimationoftheassociationbetweencurrentoverweightand
current subjectivehealth.
Table2.Square rootofthetotalnumberofcomplaintspercategoryofcurrent
BodyMass Indexbyoverweight statusbasedonthediagnosisoftheir general
practitioners 6-17 yearsearlier
Women
A. BodyMass Index (kg/m)
<25.0
25.0-26.9
27.0-29.9
>,30.0
Men
Overweight
Control
Overweight
Control
mean
mean
mean
mean
3.3
3.2
3.4
3.5
3.0
2.9
2.8
3.0
3.1
3.3
3.2
3.2
2.8
2.5
2.8
3.0
2
Theaveragenumberofcomplaints incategoriesofothervariablesthatwereused
inthisstudyare shown inTable 3.Thenumberofcomplaintsgenerally increased
withage,withheavier smoking (inmenandwomen)andwithmore frequent
slimming inwomen.A clear inverse relationbetweensocialclassand thenumber
of complaintswas found inmenandwomen.
As thevariables intable3areknowntobe related tobothoverweightand to
subjectivehealthweperformed amultiple regressionanalysis inwhichall these
variableswere takenintoaccount.Intheevaluationof thedataaclear
interactionbetweenageandBMIwasobserved inbothmenandwomen.Therefore
this interactionwas included inthemultiple regressionmodel.The resultsare
presented intable4.
-94-
Table3.SquarerootofthetotalnumberofcomplaintsaccordingtocurrentBMI,
socialclass,age,smokinghabits,andslimmingbehaviorformenand
women
Women
n=790
BodyMassIndex(kg/m)
<25.0
25.0-26.9
27.0-29.9
>30.0
2
Men
n=451
mean
mean
3.0
3.1
3.3
3.5
2.8
3.3
3.0
2.7
3.1
2.9
3.1
3.1
Socialclass
Low
Middle
High
2.6
2.4
Age(years)
26-39
40-49
50-66
3.0
3.2
3.3
2.7
3.0
3.2
3.1
3.4
2.7
2.9
3.0
Smokinghabits
neversmoked
stoppedsmoking
smoking<10cigs/day
smoking>10cigs/day
2.6
3.0
3.1
Slimmingbehavior
Never
Seldom
Regular
Often
(Almost)always
2.9
3.0
3.3
3.4
3.5
2.9
2.8
2.8
3.9
2.9
-95-
Table4.RelationofBMI,age,socialclass,smokinghabits,andslimming
behavior tothesquare rootofthetotalnumberofcomplaints(51
items).Resultsofmultiplelinear regressionanalysis
Sex
Variable
Regression
StandardError
coefficient ofregr.coeff.
Women BMI(kg/m2)
Age (years)
BMIx (Age-48)
+
Social class
0.022
0.014
0.078*
0.032
-0.002*
0.001
-0.272*
0.081
Smoking*
0.326*
0.117
Ex-smoking*
0.278*
0.131
Slimming (seldomP
0.233*
0.118
Slimming (often/regular)*
0.352
0.220
Slimming (almostalways)*
0.438*
0.179
0.020
0.021
-0.092*
0.051
0.004*
0.002
-0.344*
0.099
0.376*
0.189
2
TotalR *100=7.6
Men
BMI(kg/m2)
Age (years)
BMIx (Age-48)+
Social class
Smoking"
Ex-smoking'
1
Slimming (seldom)" '
-0.199
0.207
-0.003
0.145
Slimming (often/regular)?
0.832*
0.422
Slimming (almostalways)^
0.228
0.284
TotalR 2*100=10
Notes:*p<0.05
+ Cross-product termofBMIandageindicating statistical interaction
betweenBMIandageintheirassociationwith subjectivehealth(48
yearsistheaverageageinmenandwomen)
+ Dummyvariablesforcategoriesofsmokinghabits ("neversmoked"is
the reference category)
vDummyvariablesforcategoriesofslimminghabits ("neverslimming"is
the reference category
The resultsinTable4areinagreementwiththesimpleanalysisinthat social
classwasfoundtobenegatively relatedtosubjectivehealth,that smokershad
-96-
morehealthcomplaintsthanthosewhoreportedtheyneversmoked.Menwho
stoppedsmokinghadlesscomplaintsandwomenwhostoppedhadmorecomplaints
thanthosewhoneversmoked.Inmostcategoriesofslimmingfrequencythenumber
ofcomplaintswashigherthaninthecategoryof"neverslimming"alsoafter
adjustmentforBMIandtheothervariablesandthiswasmorepronouncedinwomen
thaninmen.Thepresenceofaninteractionterminmultipleregressionintable
4complicatestheinterpretationoftheregressioncoefficientsofBMIandage.
Forinterpretationpurposeswecalculatedthepredictedaveragenumberof
complaintsaccordingtotheregressionmodelsintable4fordifferentvaluesof
BMIandage(correctedforthetransformationofthepredictedsquareroot
valuestoactualnumberofcomplaints).
TheresultsareshowninTable5.Inmen,ahigherBMIwasassociatedwithmore
healthcomplaintsattheageof55butwithlesscomplaintsat35.Inwomena
higherBMIwasassociatedwithmorecomplaintsattheageof35butnotatthe
ageof55.Anincreaseinnumberofcomplaintswithagewasclearerin
overweightmenthaninleanmen,andclearerinleanwomenthaninoverweight
women.
Table5.Averagenumberofcomplaints,predictedbyregressioncoefficientsof
theregressionmodelfromtable4,attwodifferentagesandfortwo
differentlevelsofBodyMassIndex
Sex
Age
BodyMass
2
23kg/m
Women
Men
35years
Index
28kg/m2
9.6
11.1
55years
12.3
12.4
35years
9.2
9.8
11.3
55years
8.3
Note:estimatescorrectedfortransformingthepredictedsquarerootof
complaintstotheaveragenumberofcomplaints(byaddingtheresidual
varianceofthenumberofcomplaintsinthesquarerootscale)
AstheBMImightberelatedtospecificcomplaintsbutnottoothers,westudied
therelationofBMItoabsenceorpresenceofspecificcomplaintsandabsences
orpresenceofatleastonecomplaintoutofgroupsofcomplaints.The
-97-
complaintsthatwere foundtobe relatedtoBMI,independentofage,social
class,and smokinghabitsareshowninTable 6.
Table6.Groupsofcomplaints (clusters)and singlecomplaints related tothe
BodyMass Index,adjusting forage,socialclass,slimmingbehavior,
andsmoking habits.Resultsfrommultiplelogistic regression
analysis
Sex
Description
ofcomplaints
i
Women Stomach/digestion
Skeleto/muscular
Nervousness
Tiredness
Nose/throat
Shortnessofbreath
Painchest/heart
Oftenhavingmishaps
Tight inchest
Men
Partial logistic regression
ternsin
% reporting
1 complaints
cluster
fromcluster
b
SE(b)
No.of
Stomach/digestion
Skeleto/muscular
Shortnessofbreath
coefficientofBMI
5
30.6
0.0422
0.0194
5
4
5
3
1
1
1
1
67.2
0.0703
0.0244
48.3
0.0570
0.0196
50.0
0.0432
0.0194
22.6
0.0371
0.0208
18.0
0.115
0.0228
13.8
0.0390
0.0230
0.115
0.0309
12.4
0.0584
0.0250
27.5
0.0760
0.0344
59.3
0.0767 0.0359
12.8
0.0898
5
5
1
6.8
0.0368
Note:all regressioncoefficientssignificantlydifferent fromzero (p< 0.05).
Thedependentvariable intheanalysiswasdichotomous:presenceor
absenceofaparticular complaint (singleitems)orpresenceorabsence
ofatleastonecomplaintoutofagroup (cluster)ofcomplaints
Complaintsofthedigestive tract,theskeleto-muscularsystemand shortnessof
breathwereassociatedwithBMIinmenandwomen.Inaddition,inwomenan
associationwas foundbetweenBMIandcomplaintsofnervousness,tiredness,nose
and throat,pain inthechestandheart region,oftenhavingmishaps,andoften
feeling tightinthechest.Slimmingbehaviorwasindependently relatedto
complaintsoftirednessandoftenhavingmishaps (notshowninthe tables).
-98DISCUSSION
Ourdata showthat increasedBodyMass Indexisassociatedwithmore subjective
healthcomplaintsbutthatageisaneffectmodifier inthisassociation.Inmen
a positiveassociationcouldbedemonstrated inolderagesandanegative
association inyounger ages. Inwomen,ontheotherhand,thepositive
correlationbetweenBMIandnumberofcomplaintsdiminishedwithage.Inmost
studiesthathave reportedanassociationbetweenoverweightand subjective
healthapossible interactionbetweenageandBMIwasnottakeninto
account 6,7 ' 8 .
Theeffectmodificationofage inmencannotbeeasilyexplained.Itmaybe that
a longperiodofoverweight isneededbeforeaneffectofoverweighton
subjectivehealthbecomesapparent inmen.The reasonwhy inyoungerwomena
muchstronger relationbetweenoverweightandcomplaintswas foundthaninolder
womenmaybethatyoungerwomenworrymoreandaremoreconcernedaboutbeing
overweight,hence,exhibitmorehealthcomplaints.Someofthespecifichealth
complaintsassociatedwithBMIarepsychosomatic (e.g.nervousness,titedness,
oftenhavingmishaps). Inthese relationsnosignificant interactionwas
observedbutitmustbenoted that inlogisticanalysis,interaction is
evaluated onamultiplicative scalewhereas inmultiple linear regression
14
analysis interaction isassessedonanadditive scale
Inour study itwasnotpossibletodeterminewhetherpsychosomatic complaints
were thecauseor the resultofoverweight ' .Theeffectsofthestigmaof
45
obesity,especially inwomen,havebeen reviewed recently ' and ithasbeen
suggested thatsociety'sdiscriminationagainsttheobeseandthepressuresfor
thinnessareenoughtoaccount formanypsychological complaints inthe
17
overweight .Ontheotherhand,ithasbeenshownthatpsychosocial problems
18
maycontribute toweightgain and thatweightchangesareaccompanied by
1920
changes inmood ' .Inwomen,ahigher frequencyof slimmingbehaviorwas
related tomorehealthcomplaints,independentlyofthedegreeofoverweight;
only 15%ofthewomen,however,reported thathealth reasonswere importantas
motives forslimming,whereas the reasons 'problemswithclothes'and 'my
figure'wereeachendorsedby65%ofthewomenwhohadever tried tolose
weight.Therefore,itisnotlikelythatthe relationbetween slimmingand
subjectivehealthcomplaintscanbeexplainedbythefactthatmostwomentryto
loseweightbecauseofhealthproblems.Perhapsslimmingbehavior initself is
associatedwith increaseddistress.Whenwe stratified theoverweightgroup (as
classifiedby thegeneralpractitioners)intopersonswhoshifted outofthe
-99overweightcategory (basedcurrentBMI)and thosewho remained inthe overweight
category itwas surprising tofindthat thesetwogroupshadanequal average
number of complaintsandbothgroupshadmore complaints thanthegroup thathad
remained non-overweight.Thus, successful slimming cannotaccount for improved
subjectivehealth status.Only 10%or lessofthevariance inthenumber of
complaints couldbeexplained byallthevariables inthe regression analysis
(Table 4 ) .Thus theremustbeotherunmeasured determinants,thataccount for
theunexplained partof thevariance.
Although subjects received instructions formeasuring heightsandweights,the
useof self-reported measurements has itslimitations.Forexample,evenwhen
all subjectswould have followed the instructions carefully, insystematicerrors
mayhaveoccurred becauseof thepoorqualityof somehomeweighing-scales.
Wemay conclude that theassociation ofoverweightandpoorer subjective health
statusdiffersbetweenmenandwomenand thatthisassociation isdependent on
age. Inyoungerwomen,thisassociation isprobably related toan increased
concernof thesewomenabout theirweightor figure.Inthisparticular age
group itmaybe important toinvestigatewhether the 'legitimization'of being
overweight (assuggested byStewartandher colleagues )mayhaveapositive
effect onsubjective health. Incaseof increased health risk it remains
necessary totreat thosewhoareoverweight.Publichealthmeasures should be
directed towards theprevention ofoverweightand increasing awarenessabout the
health risksassociatedwithoverweightwhenaccompanied byanabdominal fat
22
distribution ,a familyhistoryofcardiovascular disease ordiabetes,elevated
23
levelsof risk factors forcardiovascular disease and inthose caseswhen
subjects suffer fromafflictions thatmaybenefit fromweight reduction .In
our opinion,public healthmeasures should,besides informing thepublic about
thehealthhazardsofoverweight,payattention totheunwarranted social
pressures forthinnessespecially inthose inwhomoverweight ispredominantly a
24
cosmeticproblem .
ACKNOWLEDGEMENTS
Theauthors like tothank thePraeventiefonds inTheNetherlands for financial
support for the studyand theheadand staffof theDepartment ofGeneral
Practice of theUniversity ofNijmegenfor their cooperation and generously
providing of the information fromtheir ContinuousMorbidity Registration.
Theyparticularly like tothank P.Hoppener,H.vandenHoogen,S.Ward ,W.
Knuiman-HijlandA.M. Zijlmansfor technical assistancewith the study.
21
-100-
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-102-
AppendixI
A.Descriptionofclustersofcomplaints (identifiedusingfactoranalysis
(Philipsenetal.1983)
Nameofcluster
Item
Women Men
Stomach/digestion 1.Doesyourstomachoftenfeelfulland
bloated?
+
+
+
+
+
2.Doyouoftenhavepainsinthestomach
region?
3.Doyouoftenhaveanupsetstomach?
4.Doyouoftenhavestomachcomplaints?
5.Doyouoftenhaveindigestion?
-Skeleto-muscular
1.Doyouoftenhaveunpleasantlycoldfingers,
handsorfeet?
2.Doyourbonesormusclesoftenache?
3.Areyoubotheredbyweakorachingfeet?
4.Areyouoftentroubledbybackache?
+
+
+
5.Doyourarmsandlegsoftengodeador
tingle?
-Nervousness
1.Doyouoftengetupset?
2.Doyouoftenfeelnervous?
+
3.Areyouoftenirritable?
+
4.Doyourhandsoftenshake?
-Tiredness
1.Doyouoftenfeeltired
2.Doyouoftenfeelsleepishorsluggish?
3.Doyouoftenfeellistless?
+
+
+
4.Doyougenerallygetupfeelingtiredand
notrestedinthemorning?
5.Doyoufeeltiredsoonerthanyouthinkis
normal?
+
-103-
-Noseandthroat
1.Areyouregularlybotheredbycoughing?
+
2.Doyouoftenhavetoclearyourthroat?
+
3.Isyournoseoftenblocked?
+
B.Othercomplaints,forwhichtheanswerswerefoundtodifferbetweenthe
overweightandcontrolgroups(p<0.05,afteradjustmentforsocialclass).
Onlycomplaintsthatarenotincludedintheclustersofcomplaintslisted
abovearepresented.
-Complaint
1.Doyougetshortofbreatheasily?
+
+
2.Doyoufallasleepeasilyanddoyousleep
well?
+
3.Doyousometimessweatheavilyevenwhenit
isnothot?
+
4.Doyouoftenhavelittlemishaps?
5.Doyouoftenfeeltightinthechest?
+
+
+=Stratifiedanalysis(withadjustmentforsocialclass)revealeda
differencebetweenoverweightandcontrolgroup(p<0.05)(usingthe
14
chi-squaredtestofMantelHaenszel )
Note:clusters(factors)identifiedwhen,afterrotation,thefactorloadingof
theitemsononlyoneofthefactoreswasatleast0.40.Moreinformation
abouttheclusteranalysisisavailableonrequesttotheauthors.
..-.
.
-104-
I ,T
'
CHAPTER6
FATDISTRIBUTIONOFOVERWEIGHTPERSONSINRELATIONTOMORBIDITYAND SUBJECTIVE
HEALTH
J.C.Seidell,J.C.Bakx,E.deBoer,P.Deurenberg,J.G.A.J.Hautvast
IntJObesity 1985;9:363-374
ABSTRACT
Theassociationbetween fatdistribution,morbidityand subjectivehealthwas
studied in95overweightadultmenand210overweightadultwomen.Retrospective
morbiditydataweretakenfromacontinuousmorbidity registrationmadeby
generalpractitionersoveraperiodofmaximally 17years.Inaddition
informationabout subjectivehealthandweighthistorywasobtained froma selfadministeredquestionnaire.Anthropometricmeasurementswere takenand,onthe
basisofwaist-hipandwaist-thighcircumference ratios,subjectswere
classified intoupperbodysegmentobesity,intermediateobesity,and lower body
segmentobesity.
Itwas found that,adjusted forageandbodymass index,ahighwaist-thigh
circumference ratiowasa risk factor forhypertensionand forgoutor diabetes
inwomenandarthrosis inmen.A lowwaist-thigh ratiowasassociatedwith a
highprevalenceofvaricoseveins inwomen.
Theassociationsofwaist-hipscircumference ratiowithmorbiditywere less
pronounced,with theexceptionofhypertension formen.Information frontthe
questionnaire revealedthatpersonswithupperbody segmentobesity (especially
men)feltlesshealthyandhadmorehealth complaints.These findingsweremore
pronounced for subjectsyounger than50yearsofage thanfor thoseof 50years
andolder.
Theweighthistoriessuggestthatwomenwith lowerbodysegmentobesityhad a
longerhistoryofobesitythanwomenwithupperbodysegmentobesity.Thiswas
not found inmen.Itisconcluded thatclassificationofobesityonthebasisof
circumference ratiosisuseful fortheevaluationofhealthhazardsof
overweightsubjects.
-105-
INTRODUCTION
Thedistributionof fatover thebodyisimportant intheassociationofobesity
and somemetabolicdisturbancesinlipidandcarbohydratemetabolism.
A relativepredominanceof fatintheupperpartofthebody,or,more
specifically,intheabdominal region,isrelatedtometabolicdisturbancesas
wellastotheprevalenceofvariousdisorders,suchasdiabetes
,,.. 9,15,16,18,21,29,31,
. . 3,16,18,21
16 ,and
nlK1 ,, ,.
mellitus
• > • • • >
hypertension
' ' ' gallbladder
disease
menstrualdisorders .Fatdistributionhasalsobeenshowntobean important
predictor ofdeathduetocardiovasculardiseaseor stroke,andofdeathsfrom
IT
j
21a
all
causesin.men 22
andwomen
Usefulmeasuresfortheclassificationofdifferenttypesof fatdistributionin
epidemiological studies includethecircumference ratioofwaistand
i iR 1ft y \ y?
1
hips > • • i an( jthe ratioofwaistandthighdiameters.
Bothwaist-hipsandwaist-thighcircumference ratioswereused inthisstudyto
describe the fatdistribution inagroupofoverweightDutchmenandwomen.The
aimofthestudywastodeterminewhetherassociationsoffatdistributionwith
diseasecouldbeconfirmedorestablished,andwhether fatdistributionwas
relatedtosubjectivewell-beingandweighthistory.The resultsofthestudy
confirmthatfatdistribution isanimportantindicator forboth registered
disordersand subjectivehealth status (thelatterespecially inmen).
SUBJECTSANDMETHODS
Subjects
Subjectswerepatientsoftwogeneralpracticestakingpart intheContinuous
MorbidityRegistrationattheDepartmentofGeneralPracticeoftheUniversity
ofNijmegen.Personswhohadbeendiagnosed,bythegeneralpractitioner as
'obese' (criterium:Broca Index >115%)atanagebetween20and 50years,and
were stillobeseatthetimeofthisinvestigation,receivedamailed
questionnaire.Thosewhocompleted thequestionnaire,fromwhich information
about subjectivehealthandweighthistorywasobtained,wereaskedto
participate inananthropometric study.548Personswere sentaquestionnaire,
401 (73%)returned thequestionnaireand,ofthese,305 (56%;95men,210women)
agreed toparticipate intheanthropometricstudy.
Measurements
The subjectsweremeasuredeitherathomeor inthedoctor'sofficebyatrained
-106-
assistant.Height instandingposition (tothenearest0.1 cm)andweight (to
thenearest0.5 kg,onacalibratedbalance)weremeasuredofsubjectswithout
shoes,wearingonlyunderwear orlight indoorclothing.Measurementsofthe
circumferencesofsubjectswere takeninastandingposition,breathing
normally.Theminimal circumference ofthewaist,themaximalhips
circumferencesandthehighesthorizontal circumferenceoftheleftupper thigh
weremeasured (tothenearest0.1 cm)usingametaltapemeasure.
Calculations
The ratiosofwaisttothighcircumference ratio (waist-thigh ratio)andwaist
tohipscircumference (waist-hips ratio)werecalculated.Waist-hips ratiohas
been showntobeausefulmeasure forclassificationof fatdistribution in
9 "71R 1ft 91 99
relationtometabolicassociatesofobesity ' < > < <
mTherewere
indications fromtheliterature thatthewaist-thigh ratiocouldbeatleastan
equallygood indicatorof fatdistribution .Thereforebothcircumference ratios
wereused intheanalysis.As inother studies.UpperBodySegmentObesity
(UBSO)wasdefinedastheupper tertileofthecircumference ratios,when these
wereusedascategorically scaledvariables,andLowerBodySegmentObesity
9 22
(LBSO)asthelower tertileofthe ratios'
9
BodyMass Index (BMIinkg/m )wascalculatedusingweightandheightas
measuredbythegeneralpractitionersatthetimeofwhichobesitywasdiagnosed
(t Q )andusingweightandheightattimeoftheanthropometric studyin1984.In
analysis,withcategorically scaledvariables,twoclassesofobesitywere
distinguished,according totheclassificationofGarrow :BMI25.0-29.9
(GradeIormoderateobesity)andBMI >30.0 (GradeIIorsevere obesity).
Morbidityanalysis
Forallpersonsthattookpartinthestudy,wewere informed aboutthe
diagnosesmadebythegeneralpractitionersduring theprevious17years(i.e.
since thestartoftheContinuousMorbidityRegistration)ofanyofthe
following chronicdisorders:diabetesmellitus,gout,anginapectoris,
hypertension,varicoseveins,non-fatal ischaemicheartdisease,arthrosis,
eczemaandprolapsuteri.
Thediagnosesweremadeusingaclassification systembasedonthe International
ClassificationofDiseases (ICDversion6)using standardized procedures
shortdescriptionofdiagnostic criteria isincluded inAppendix I.The
a
24
-107-
prevalence of somepossibly relevantdisorders for thisstudywas toolow for
analysise.g. cancer,stroke,gallstones,myodegeneratiocordisand periferal
arterial heartdisease.
Combinations of somedisorderswerealso studied (e.g.diabetesand/or gout,and
a combination of seriousdisorders:diabetes,gout,anginapectoris, ischaemic
heartdisease and arthrosis).
Questionnaire
The subjectswere asked to ratetheir subjective health statusona7-point
scale (1-verygood,7«very bad). Thequestionnaire included alistof 53
items (subjective health complaints)oftenused tomeasure subjective health in
4
epidemiologic surveys inTheNetherlands .For thispaper,a 39-item
abbreviationwasused,inanalysis since these itemshadbeenpublished in
26
English .The totalnumber ofcomplaints onthis39-item listwas calculated
foreach subject.Thedistribution of thesecumulative scoreswas markedly
skewed tothe left.The square rootwasapproximately normallydistributed and
wasthereforeused inanalysis.Subscoresofsomeclustersofcomplaintswere
calculated.These clustershadbeen indentified using factoranalysisondata
25
from largeepidemiologic surveys .
Information aboutweight history,about smokinghabitsandabout slimming
frequencywasalsoobtained fromthequestionnaire.Age and socio-economic
status,based ontheprofession ofthehead ofthehousehold,were registered in
24
themorbidity registration .
Statistical methodsmorbidity analysis
Ina forward stepwise multiple logistic regression analysis,using the computer
package programme BHPLR ,the following continuousvariableswere candidates for
inclusion inthelogistic modelasindependentvariables:age,BMI,
circumference ratiosand,categorically scaled, socio-economic status (lower,
24
middle,upper class)
Analysisusing age (<50;> 10 years in 1984),BMI (<30;>30kg/in in 1984)
and circumference values (lower,middleandupper tertile)as categorically
scaledvariables produced comparable results.Thelatter procedure yielded
multiple regression coefficients intervals oftheodds ratiosaccording to
23
LemeshowandHosmen (1984) capaing theupper tertileof the circumference
ratios tothe lower tertile.Analysiswereperformed separately formenand
-108-
womenandforthetwocircumferenceratios.
Questionnaireanalysis
Fortheanalysisoftheinformationobtainedfromthequestionnaire,t^testsor
chi-squaredtestswereperformedtocomparesubjectsintheuppertertile(upper
bodysegmentobesity)withthoseinthelowertertile(lowerbodysegment
obesity)ofthewaist-thighratio.Multiplelinearregressionanalyseswere
performedusingtheprogramBMDPLR.
RESULTS
SomecharacteristicsofthestudypopulationaregiveninTable1.
Table1.Meanandstandarddeviationofageandsomeanthropometric
measurementsofthestudypopulation
Men (n=9S)
Women (n=210)
Mean
Age
years
Weight
kg
cm
Height
2
BMI
kg/m
Waist-circumference
cm
cm
cm
Hips-circumference
Thigh-circumference
S.D.
Mean
S.D.
49.2
9.2
11.9
90.3
11.8
89.6
6.1
4.1
9.7
177.4
109.9
10.0
105.0
60.1
5.0
59.2
6.1
3.1
8.8
5.8
4.0
49.9
9.7
78.7
163.4
29.5
28.7
101.6
Waist-hipsratio
0.82
0.05
0.97
0.06
Waist-thighratio
1.42
0.16
1.72
0.15
InTable2theclassificationofmenandwomenintypesoffatdistribution
(upperbodysegmentobesity,intermediateobesityorlowerbodysegment
obesity)isshown.Whenclassifyingaccordingtobothwaist-hipsratiosand
waist-thighratiosnoexactlyequalgroupscouldbeformed(especiallyinthe
caseofthewaist-hipsratiodistribution).Thereforeonlyapproximationsof
thetertilesoftheratioswereused.Theratioswerehighlycorrelated (r=
0.76;p<0.001)andonlyafewsubjectsappearindifferentextremetertiles
ofthedifferentratios.
-109-
Table2.Numberofsubjectsinvariousclassesofwaist-hipscircumference
ratioandwaist-thighcircumferenceratio*
Women
Waist-thigh ratio
Waist-hipsratio
<0.78
(LBSO)**
<1.34
(LBSO)**
1.35-1.49
(Intermediate)
> 1.50
(UBSO)
allwomen
0.79-0.84
(Intermediate)
>0.85
all women
(UBSO)
45
9
3
24
44
19
2
14
49
71
67
71
57
87
65
209
Men
Waist-thigh ratio
Waist-hipsratio
<0.94
<1.65
(LBSO)**
1.66-1.78 (Intermediate)
>1.79
allmen
(UBSO)
0.95-0.99
>1.00
allmen
(LBSO)**
(Intermediate)
26
4
1
4
15
8
2
13
22
32
31
27
37
95
(UBSO)
Cut-offvaluesweresettoobtainapproximatetertilesofthe
distributionofthecircumferenceratios.Becauseofthedistributionof
thecircumferenceratiosexactlyequalgroupscouldnotbeformed
** LBSO(LowerBodySegmentObesity)wasdefinedasthecategorywithlow
valuesofthecircumferenceratios.Intermediatewasdefinedasthemiddle
categoryofthecircumferenceratios.
UBSO(Upperbodysegmentobesity)wasdefinedasthecategorywithhigh
valuesofthecircumferenceratios
FromTable3itcanbeseenthatwomenwithupperbodysegmentobesitywere
heavieratthetimeofinvestigation(1984)thanattimeofdiagnosisofobesity
(t Q ).Upperbodysegmentobesewomengained2.7+7.6kg(mean+standard
deviation).Therewasnosignificantchangeofweightinsubjectsinanyofthe
othercategoriesofwaist-thighratio.
32
31
-noTable3.AgeandBodyMassIndex(BMI)ofthestudypopulationattimeof
investigation(1984)andattimeofdiagnosis(t0)indifferentclasses
offatdistribution
Number
LBSO**
ofsubjects
Mean
SD
Intermediate
Mean
UBSO**
SD
Mean
SD
Women
71
Numberofsubjects
71
67
Ageatt Q
34.03
8.91
38.27
9.08
41.04
8.41
Agein1984
46.24
9.65
50.49
9.83
53.15
8.51
BMIatt Q
28.15
2.04
29.15
3.56
29.74
3.23***
BMIin1984
27.84
2.99
29.20
3.75
31.05
4.34***
Men
32
Numberofsubjects
32
31
Ageatt„
35.52
8.69
37.83
7.54
41.04
6.95
Agein1984
45.34
9.65
48.59
7.74
53.65
8.32
BMIatt Q
28.43
1.54
28.76
1.38
29.60
2.70
BMIin1984
27.74
2.31
28.77
2.49
29.46
4.02
*t Q=1967-1983.Subjectswereselectedonthegroundsthattheyhadbeen
diagnosedbytheirgeneralpractitionaratage20-50years
**
LBSO(LowerBodySegmentObesity),IntermediateandUBSO(UpperBody
SegmentObesity)weredefinedasthelower,middleanduppertertileof
waist-thighratiorespectively (seeTable1)
***
DifferenceinBMIbetweentimetQand1984statisticallysignificant,
(p<0.05)
Theindependentvariablesincludedinthestepwiselogisticregressionanalysis,
themultiplelogisticregressioncoefficientsandtheirstandarderrors:,using
age,BMIandcircumferenceratiosascontinuousvariablesareshowninTable4.
Thenumberofcasesforeachdisorderorcombinationofdisordersisalpogiven.
TheresultsshowninTable4wereessentiallythesamewhencategoricallyscaled
variablesforage,BMIandcircumferenceratioswereused.
Theodds'ratios(showninTable5,withtheirconfidenceintervals)are
estimatesofrelativeriskforhavingadisorderforsubjectswithupperbody
segmentobesitycomparedtopersonswithlowerbodysegmentobesity.Theodds
-111-
able 4.Multiple regression coefficients obtained instepwisemultivariate logistic regressionanalysis,using disorders
asdependent variables andBMI,ageandcircumferences ratios asindependent continuous variables
ender
Dependent variable
(Disorder)
onen
Hypertension
Gout ordiabetes
Circum-
Number
Regression coefficients
ference
circum-
SES
ratio
ference
high/low middle/low
wr
9.45
0.10
WH
8.28
0.10
wr
9.43
4.58
WH
15.80
11.50
ofcases
SES
-
0.07
0.12
62
62
13
13
Arthrosis
wr/WH*
8.10
Varicose veins
wr
1.19
2.70
WH
4.26
6.44
myocardial infarction
WT/WH*
8.88
0.12
-
13
Prolapsuteri
WT/WH*
8.64
0.13
0.97
22
0.12
0.03
36
55
55
Angina pectorisor
Serious disorders
combined**
Hypertension
WT
- 8.17
3.96
-
0.87
0.97
16
WH
- 12.60
19.10
0.26
0.51
0.39
16
WT
- 8.86
7.49
0.25
-
-
12
WH
- 7.50
-
-
1.56
- 1.25
12
myocardial infarction
WT/WH
- 8.11
-
Serious disorders
WT
- 3.54
5.86
26
combined**
WH
- 4.79
-
26
Serious disorderor
WT
- 3.06
4.67
32
hypertension
WH
- 3.21
-
32
Arthrosis
Angina pectorisor
NeitherWTnorWHwere included inthestepwise regression analysisandthereforeproduced thesame
Oneormore ofthe following disorders:gout,diabetes,arthrosis,anginapectoris,myocardial infarction,
prolapsuter
LIregression coefficients were statistically significant from zero (b/SE(b)greaterthan 2)
-112ratiosarederived from regressioncoefficientsofthecategorically scaled
circumference ratiosandareadjusted forothervariables inthemodel.The
resultsindicateahigherprevalenceofhypertension,goutordiabetes inwomen
intheupper tertileofthewaist-thigh ratiotheninwomen inthelower
tertile,andalowerprevalenceofvaricoseveins inwomen intheupper;tertile
ofbothcircumferenceratios.
Table 5.Odds ratiosand95%Confidence intervalsofOdds ratiosfordisorders,
comparing theupper tertiletothelower tertileofthecircumference
ratiosofwaist-hipsandwaist-thigh
Circum-
95% Confidence Interval
of theOdds Ratio
Disorder
Odds ratio
Hypertension
2.44
1.09 -
5.56
ference
Ratio
Women WT
WH
Men
WT
Goutordiabetes
4.68
2.10 -
10.44
VaricoseVeins
0.37
0.27 -
0.60
Goutordiabetes
2.66
0.68 -
10.38
VaricoseVeins
0.40
0.16 -
0.86
Hypertension
3.69
1.74 -
5.64
Arthrosis
Seriousdisorders
WH
Hypertension
11.88
1.38 -
35.40
5.58
2.86 -
10.89
54.98
4.02 - 752.00*
Note:
Seriousdisorders:oneormoreofthefollowingdisorders:anginapectoris,
Ischemicheartdisease,gout,diabetes,arthrosis
- Oddsadjusted forothervariables inthelogistic regressionmodel
-WT=waist-thigh ratio
WH=waist-hips ratio
* Themagnitudeof theodds ratioand itswide confidence interval canbe
explainedby thelargenumberofvariables inthemodel (4)while therewere
only 16malecasesofhypertension
Formen,ahighprevalenceofarthrosis,orofat leastone seriousdisorder,
was found intheupper tertileof thewaist-thigh ratio.Using thewaist-hips
ratioasindicator of fatdistribution,hypertensionwasmore frequent in
-113-
subjects intheupper tertile ofboth ratios.
Upper body segmentobesemenandwomen,asdefined as theupper tertile of the
waist-thigh ratio, reported a lower subjective health status than lower body
segment obesemenandwomen (p<0.05).When stratified intotwoage groups(
< 50years; >,50years), thisdifference disappeared inthegroup ofwomen of 50
years and older.
Themeans and standard deviation of the square rootof thenumber of complaints
are given inTable 6.Without taking age intoaccount,a statistically
significantdifferencewas foundbetween the results forupper body segment
obesemenand lower body segment obesemen.When subjectswere stratified into
twoage groups,a significantdifference (p<0.05)was found only for men
younger than 50yearsofage.
Table 6. Crude and age-specific estimates of the square root*ofthe total
number ofhealth complaints ona listof 39complaints (meanand
standard deviations) inmenandwomenwithUBSOand LBSO**
LBSO**
age
n
mean score*
LBSO**
n
st.dev.
Women< 50yrs
> 50yrs
all ages
Men <50yrs
>,50yrs
all ages
42
19
61
2.88 - 0.83
17
11
28
2.25 - 1.32
2.94 - 1.26
2.90 - 0.97
2.48 - 1.01
2.34 - 1.19
mean score
p-value for difference
st.dev.
in mean score
17
44
61
3.37 - 1.05
0.1314
3.02 - 1.39
0.8873
3.11 - 1.31
0.2384
6
16
22
3.63 - 0.80
0.0214
3.08 -1.13
0.2184
3.23 - 1.06
0.0124
* Square rootwas takenbecause itsdistributionwas approximately normal
(ahigher value indicatesmorehealth complaints)
** LBSO and UBSO Lower andUpper Body SegmentObesity,defined as the lower and
upper tertile of thewaist-thigh distribution, respectively
Multiple linear regressionwasperformed,with the square rootof the total
number of complaints asa continuousdependentvariable and the waist-thigh
ratio,age,BMI in1984 (all three continuous), socio-economic status, slimming
frequency,and smokinghabits (allthreeascategorical variables) as
independent variables.
-114-
Formen,12.0%ofthevariancewasexplainedbythefullmodel,withthe
2
waist-thighratioastheonlysignificantindependentvariable(r =6.7%).For
women10.2%ofthevarianceinthenumberofcomplaintswasexplainedbyallsix
variablesinthemodel,withslimmingfrequencyastheonlysignificant
2
independentvariable (r =5.6%).
Whenclustersoforgan-specificcomplaintswereanalysed,upperbodysegment
obesemenwerefoundtosuffermorefromheartandchestpains,complaintsof
bonesandextremitiesandshortnessofbreaththanlowerbodysegmentobesemen.
Thesedifferenceswerestillsignificant(p<0.05)alsowhenadjustedforage.
Formenyoungerthan50years,stomachcomplaintsandindigestionwerealso
significantlymorefrequentinupperbodysegmentobesesubjects(p<0.05)(see
AppendixIIforalistingoftheitemsoftheclustersofcomplaints).
Amultiplelineairregressionwasperformedwithwaist-thighratioasa
continuousdependentvariableandsixindependentvariables:age,BMIatt Q ,BMI
in1984ascontinuousvariables,andsmokinghabits,slimmingfrequencyand
socio-economicstatusascategoricallyscaledvariables.Formenthefullmodel
explained30.1%ofthevariationinthewaist-thighratio.Thesinglevariables
2
withsignificantpredictivepowerwereage(r =16.5%)andsocio-economic
2
status(r =3.3%). Forwomenthefullmodelexplained22.0%ofthevariationin
thewaist-thighratio,withtheBMIin1984(r =15.9%)andage(r =9.0%)as
significantpredictors.Ahighwaist-thighratio(upperbodysegmentobesity)is
thusassociatedwitholderageinmenandwitholderageandhigherdegreeof
obesityinwomen.
Womenwithupperbodysegmentobesityreportedlessoftenthattheyhadbeen
"toofat"atbirth(p<0.05),inchildhoodorinadolescence (p<0.10)than
lowerbodysegmentobesewomen.Mendidnotconsiderthemselvestohavebeen
overweightbefore20yearsofage.Whenthesubjectswereaskedaboutthe
maximalweighttheyrememberedfromactualmeasurementsduringsixageintervals
1 5 - 1 9 , 2 0 - 2 9 , 3 0 - 3 9 , 4 0 - 4 9 , 5 0 - 5 9 , 60yearsorolder)theaverageBMI
inallageintervals,except15-19and20-29years,wasfoundtobehigher
forwomenwithupperbodysegmentobesitythanforwomenwithlowerbodysegment
obesity.TheaverageBMIofmenwithupperbodysegmentobesitywas
significantlylowerthanthatofmenwithlowerbodysegmentobesityintheage
interval20-29years.Inotherageintervalstherewasnodifferencebetween
theaverageBMIofupperandlowerbodysegmentobesemen.Nodifferenceswere
foundbetweenupperbodysegmentobesesubjectsandlowerbodysegmentobese
subjectsinslimmingfrequency,smokinghabitsorsocio-economicstatus.
-115DISCUSSION
The studypopulationwasagroupofobese subjects intwogeneral practices in
twomedium sizedmixed rural/industrial towns inTheNetherlands (near
Nijmegen).Thepopulationwasprobablynot representative fortheentire obese
population inTheNetherlandsbutwithin thepopulation ofobese subjects of
thepractices the studypopulationwasnotselected onthebasisofBMIand
morbidity.Nevertheless,extrapolation toother overweight populations should be
donewithcaution.
Obesity hadbeendiagnosed by thegeneral practitionarswithin the last 5 - 1 7
yearsbefore thisstudy.From theweight histories inthequestionnaire itwas
clear that the subjects included inthe studypopulationhadbeenobeseat least
since thetimeofdiagnosisof obesity.
There isevidence that fatdistribution isa relatively permanent charactistic
of subjects,evenwhen therearemajorweight changes '' ' ' . I t was
considered appropriate therefore,tolinkpresent fatdistribution tothe
retrospective morbiditydata.
Upper bodysegmentobesityandlowerbodysegmentobesitywere arbitrarily
defined astheupper tertileand lower tertileof thecircumference ratios,an
9 22
approachused alsobyother investigators ' .Both circumference ratios
probablymeasure approximately thesameconcept:the fatstored inthe abdominal
region relative tothat inthegluteal (hips)and femoral (thighs) regions.Both
gluteal and femoral regionsprobablyhave similar physiological
characteristics .
The results from themorbidity analysis confirm that fatdistribution, as
measured bycircumference ratios,isassociated with theprevalence of some
chronic disorders inseriously ormoderately obese subjects.Theassociations of
a relatively central deposition of fatwithdiabetes,glucose tolerance and
hyperinsulinemiaarewell k n o w n 9 ' 1 0 ' 1 1 ' 1 5 ' 1 6 ' 1 7 ' 1 8 - 2 5 ' 2 9 ' 3 1 .T h e possible
mechanismsof this relationshiphave recentlybeen studiedbyEvanset
al. '' .Diabeteswas significantly related tothewaist-thigh ratio forwomen
inunvariate analysisbutnotafter adjustments forageandBMI.Both diabetes
and goutare known tobe the resultofmetabolic aberrations associated with
1928
obesity ' andVague reported thatall ofhisgout-afflicted subjectswere
29
hyperandroid .
Diabetes (11 female cases)andgout (2female cases)werenotvery common inthe
studypopulation but the combinationwas independently related to fat
distribution.
-116-
We founda strongassociationbetweenhypertensionandboththewaist-hips ratio
formen,andamoremoderateassociationbetweenhypertensionandthe
waist-thigh ratioforbothmenandwomen.Other studieshavealsofoundthatfat
distribution,independentlyofdegreeofobesity,isrelated to
3 1Rfi
1 1ft?1?Q
hypertension > > ' • ' , sincehypertension isa risk factor for
cardiovascular diseaseand stroke,thisobserved relationmaypartlyexplain the
21a22
findings fromGothenburg ' inwhich itwasdemonstrated that,formen,the
waist-hips ratioisaprognostic factor fordeath fromcardiovascular disease or
strokeand fordeathofallcauses.
Wearenotawareofanystudy reportinganassociationbetweenfatdistribution
andarthrosis.Itistemptingtosuggestthattheassociationobservedhere
indicates thatmetabolicdisturbancemayplayagreater rolethanweight induced
wearand tear intheetiologyofarthrosis.Infact,afteradjustment forthe
waistthighratio,anegativemultiple regressioncoefficient forBMIwasfound
27
(Table 4). Silberberg hasreviewednumerousstudiesontheassociationof
obesityandarthrosis,andhasconcluded thatthere isno reasontoassumea
direct causal relationshipbetweenjointdiseaseandthemechanical overload
causedbyobesity.An injuriousmetaboliceffectoffatorcomponentsof faton
weightbearingaswell asnon-weightbearing jointswashypothesized .Itcould
27
be importanttonotethatanassociationbetweenfatdistributionandblood
8 921
lipidslevelshasbeenobserved '' .Univariateanalysis revealed thatfat
distribution inwomenwasassociatedwitharthrosis (resultsnotshown)but this
associationdisappearedwhenadjustments forBMIandageweremade.The reason
for thissexdifference inrisk isnotclear,although itshouldbenoted that
ingeneralmenhavehigher circumference ratiosthanwomen (Table 2).
Thenegativeassociationbetweencircumference ratiosandvaricoseveinshasnot
been reported inanyother studieson fatdistributionanddisease,although it
hasbeensuggestedbyVague thatinsufficientvenouscirculation isoneofthe
29
characteristicsofgynoidobesity .Upperbody segmentobesityandandroid
obesityare thoughttooverlapconsiderablyasarelowerbody segment Obesity
1 21
andgynoidobesity'
Theanalysisof theinformationobtained fromthequestionnaire revealedthat,
formenalsootherdisorders,notmeasured inthemorbidity registration,were
associatedwith fatdistribution.A highwaist-thigh ratiowasassociatedwith
stomachcomplaintsand indigestion,heartandchestpains,skeletalcomplaints,
problems intheextremities,and shortnessofbreath.
Forwomena relativepredominanceof fatstorage intheabdominal region (upper
bodysegmentobesity)wasassociatedwithdegreeofobesity,andprobably also
-117-
witharelativelylateonsetofobesity.Thisisinagreementwiththeresults
ofstudiesdemonstratingtherelationbetweenadultonsetofobesityoradult
weightgainandvariousmetabolicassociatesofobesity.Theserelationsare
essentiallythesameasthosefoundbetweenfatdistributionandmetabolic
aberrations.
Wemayconcludethatintheevaluationoftheriskprofileofmoderatelyand
seriouslyobesesubjectsitisimportanttoassesstheirfatdistribution.
Circumferenceratiosmaybeusefulforthispurpose.Theyareeasytomeasure
andcanbeappliedinepidemiologicresearchaswellasingeneralpractice.The
waist-thighratiocouldbeconsidered,aswellasthewaist-hipsratio,because
theformerratiomightbeatleastequallysensitiveasanindicatorofchronic
disordersasthelatterratio.Furtherresearch,preferablylarge-prospective
studies,shouldrelatetheincidenceofdisordersnotonlytobaselinefat
distributionandBMIbutalsotochangesinthesecharacteristics,totakeinto
accountindividuals'weighthistoryandfamilyhistoryofobesityandmorbidity.
TheeffectsofweightreductionOnbothfatdistributionandhealthshouldalso
becarefullystudied.
Untilmoreprecisecriteriaaredeveloped,thetertilesofthewaist-thighratio
andwaist-hipsratiocanbeusedasaroughmeasureforclassificationinto
extremetypesoffatdistribution.
ACKNOWLEDGEMENTS
TheauthorsliketothankthePraeventiefondsinTheNetherlandsforfinancial
supportforthestudyandtheheadandstaffoftheDepartmentofGeneral
PracticeoftheUniversityofNijmegen(Director:prof.F.J.A.Huygen)fortheir
cooperationandgenerouslyprovidingoftheinformationfromtheirContinuous
MorbidityRegistration.TheyalsoliketothankW.vandenBosch,P.Hoppener,
H.vandenHoogen,D.Kaayk,T.Kempener,S.WardandA.M.Zijlmansfor
technicalassistancewiththestudy.
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3.BlairD,HabichtJ,SimsEAH,SylvesterD,AbrahamS.Evidenceforan
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regionalbodyfatdistributiontoglucosetoleranceandresponsetodietin
premenopausalwomen.Proc.NorthAm.Assoc.StudyObesity,Poughkeepsie,New
York (Abstr),1982.
8.EvansDJ,HoffmannRG,KalkhoffRK,KissebahAH.Relationshipofandrogenic
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304-310.
9.EvansDJ,HoffmanRG,KalkhoffRK,KissebahAH.Relationofbodyfat
topographytoinsulinsensitivityandmetabolicprofilesinpremenopausal
women.Metabolism1984;59:68-75.
10.EvansDJ,MurrayR,KissebahAH.Relationshipbetweenskeletalmuscle
insulinresistance,insulin-mediatedglucosedisposalandinsulinbinding:
effectsofobesityandbodyfattopography.JClinInvest1984;74:1515-1525.
11.FeldmanR,SenderAJ,SiegelaubAB,OaklandMS.Differenceindiabeticand
non-diabeticfatdistributionpatternsbyskinfoldmeasurements.Diabetes
1969;18:478-486.
12.G a m SM.Relativefatpatterning:anindividualcharacteristic.HumBiol
1955;26:75-89.
13.GarrowJS.Treatobesityseriously.Aclinicalmanual.Churchill
Livingstone,London,1981.
14.GraigLS,BayerLM.Androgenicphenotypesinobesewomen.AmJPhysiol.
Anthropol1967;26:23-33.
15.HartzAJ,RupleyDC,KalkhoffRD,RimmAA.Relationshipbetweenobesityand
diabetes:influenceofobesitylevelandbodyfatdistribution.PrevMed
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16.HartzAJ,RupleyDC,RimmAA.Theassociationofgirthmeasurementswith
diseasein32.856women.AmJEpidemiol1984;119:71-80.
-11917.JoosSK,MuellerWH,HanisCL,SchullWJ.Diabetesalertstudy:weight
historyandupperbodyobesityindiabeticandnon-diabeticmexican-american
adults.AnnHumBiol1984;11:167-171.
18.KalkhoffRK,HartzAJ,RupleyDC,KissebahAH,KelberS.Relationshipof
bodyfatdistributiontobloodpressure,carbohydratetoleranceandplasma
lipidsinhealthyobesewomen.JLabClinMed1983;102:621-627.
19.KannelWB.Healthandobesity:anoverview.In:Healthandobesityed. Conn
LH,deFeliceEA, KuoP.RavenPress,NewYork.
20.KissebahAH,VydelingumN,MurrayR,EvansDJ,HartzAJ,KalkhoffRK,Adams
RW.Relationofbodyfatdistributiontometaboliccomplicationsofobesity.
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21.KrotkiewskiM,BjorntorpP,SjostromL,SmithU.Impactofobesityon
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21a.LapidusL,BengtssonC,LarssonB,PennertK,RyboE,SjostromL
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23.LemeshowS,HosmerDW.Estimatingoddsratioswithcategoricallyscaled
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24.NijmeegsUniversitairHuisartsenInstituut.GewoneZiekten.Nijmegen,1980
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26.vanReekJ,DiederiksJ,PhilipsenH,vanZutphenW,SeelenT.Subjective
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27.RoyalCollegeofPhysicians.Obesity.JRoyCollPhysLondon1983;17:1-58.
28.SilberbergR.Obesityandosteoarthrosis.In:Medicalcomplicationsof
obesity,ManciniM,LewisB,ContaldoFeds.:301-315,AcadPress,London,
1979.
29.VagueJ.Thedegreeofmasculinedifferentiationofobesity;afactor
determiningpredispositiontodiabetes,atherosclerosis,goutanduric
calculus.Am J ClinNutr1956;4:20-34.
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ofadiposemass:histometricandanthropometric aspects.In:The regulation
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AmericanElsevier,Amsterdam,NewYork,1974.
31.VagueJ, CombesR,TranciniM,Angeletti S,RubinP.Thediabetogenic
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Contaldo Feds.:45-51,AcadPress,London,1979.
-121-
AppendixI
Diagnostic criteria forchronicdiseasesinthecontinuousmorbidity
registration.
Hypertension
Hypertensionwas registratedwhendiastolicbloodpressure (measured inlying
position)washigher than100mmHgatatleastthreedifferentoccasions.
Diabetesmellitus
A singlebloodglucose-level >10mmol/1wasusedasthecriterion.Indoubt
(6-10mmol/1)confirmedbyglucosetolerancetest.
Gout
Goutwas registeredwhen severalclinical symptomsclearly indicatedgout (e.g.
painand swelling inalargetoe,unilateral arthritis infeetor toes,
hyperuricarmia,manifestationorsuspectionoftophus,presenceofurale
crystals injointsetc.)
Arthrosis
Arthrosisdeformanswas registeredwhentherewere clearclinical signsof
arthrosis (likepain,stiffnessand inflammation)were found,inmost cases
confirmedbyanX-ray.
Varicoseveins
Varicoseveinsoflower limbswere registeredwhenclearlyvisiblevaricose
veinswerepresented,observedeitherat routineexaminationor following
specific complaintsofthepatient.
Myocardial infarction
Myocardial infarctionwas registeredwhenaclinical suspectionofamyocardial
infarctioncouldbeverifiedbyabnormal ECGand/orofconcentrationsof
enzymesCPK,SGOT,LDH (exceptionsweremade forpatientswhodiedbefore such
investigationswere possible).
Anginapectoris
Anginapectoriswasdiagnosedwhenaclinicalexaminationprovided sufficient
evidence foranginapectoris (notnecessarilyconfirmedbylaboratory-orECG
- test).
-122-
AppendixII
Clustersofcomplaintstakenfromalistof53healthcomplaints' .subjects
wereaskedtocircle'yes'or'no'foreachitem
-Digestivetractcomplaints
-Doesyourstomachfeelfullandbloated?
-Doyouoftenhavepainsinthestomachregion?
-Doyouoftenhavestomachtrouble?
-Doyouhaveunspecificstomachcomplaints?
-Doyouoftenhaveindigestion?
-Skeletalcomplaints
-Doyouregularlyhaveunpleasantcoldfingers,handsorfeet?
-Doyourbonesormusclesoftenache?
-Areyoubotheredbyweakorachingfeet?
-Areyouoftentroubledbybackache?
-Doyourarmsandlegsoftengodeadortingle?
-Heartandchestcomplaints
-Doyouoftenhavepainsinthechestorheartregion?
-Doyouoftenhavepalpitationsoftheheartorthrobbinginyourheart
region?
-Doyouhavefeelthightinthechest?
-Shortofbreath
-Doyougetshortofbreatheasily?
425
-123-
CHAPTER7
ASSESSMENTOF INTRA-ABDOMINALANDSUBCUTANEOUSABDOMINAL FAT-RELATION
ANTHROPOMETRYANDCOMPUTEDTOMOGRAPHY
J.C.Seidell,A.Oosterlee,M.A.O.Thijssen,J.Burema,P.Deurenberg,
J.G.A.J.Hautvast,J.H.J.Ruijs
AmJClinNutr (inpress)
ABSTRACT
Theabilitytodistinguishbetween intra-abdominal andsubcutaneousabdominal
fatmaybeimportant inepidemiologicandclinical research.Inthisstudy
anthropometricmeasurementsweretakenfrom71menand 34womenpresenting for
routinecomputed tomography (CT).Areasofabdominal fatwerecalculated fromCT
scansmadeattheleveloftheL4vertebra.Theamountsofintra-abdominal and
subcutaneousabdominal fatcouldbeaccuratelypredicted fromseveral
2
circumferences,skinfoldmeasurements,bodymass indexandage (R ranged from
0.79 to 0.84). Inaddition,itwas foundthattheareaof intra-abdominal faton
theCTscanwas related tothewaist/hipcircumference ratio (r=0.75 inmen,r
=0.55 inwomen)andtothewaist/thigh circumference ratio (r= 0.55 inmen,r
• 0.70 inwomen). Thecorrelationsofthecircumference ratioswith theareasof
subcutaneous fatwere invariablylower.
INTRODUCTION
Itisnowgenerally recognized thatfatdistribution,asascertained fromthe
ratioofwaist circumference tohipcircumference,isan importantprognostic
indicatorof theoccurrenceofmetabolicabnormalities,diabetesmellitus (type
II), hypertension,cardiovasculardisease,strokeanddeath inmenandwomen
(1). This relationshipmightdependontheincreasedaccumulationof
intra-abdominal fat (2).Ithasbeenshownthatsubcutaneous fat isless
responsivethanomentaladiposetissue tothelipolyticeffectsofepinephrine
andnor-epinephrine (3)andtotheantilipolyticeffectof insulin (4).Free
fattyacidsare therefore releasedata rapid rateanddraindirectly intothe
portalvein.Long-termexposureofthelivertohighconcentrationsof fatty
acidsmay resultinmetabolicderangements (5,6).
-124-
Ashwelletal(7)recentlycomparedinformationfromcomputedtomographyscans
madeattheleveloftheumbilicuswithcircumferenceratiosof28adultwomen
andshowedthatthesecircumferenceratioswererelatedtotheamountof
intra-abdominalfatandtheratioofintra-abdominalfattosubcutaneous
abdominalfat.
Kissebahandhiscollegues(8)showedthatinwomen,thelatterratiocorrelates
strongly(r»0.8approximately)withincreasedglucoseresponsetooralglucose
challengeandtoinsulinlevels.
Inourstudyoftheserelationshipsweincludedbothmenandwomen.Furthermore,
wemeasuredcircumferencesatmorelevelsandincludedskinfoldmeasurements
takenattheleveloftheumbilicus.Wedevelopedmultipleregressionmodelsto
predicttheamountandproportionsofintra-abdominalfatandsubcutaneous
abdominalfatfromthesesimpledataonanthropometryandage.Although
extrapolationoftheresultingregressionequationstootherpopulationsmustbe
donewithgreatcautiontheyprovideinsightintotheindependentcontribution
oftheindependentvariablestothevariationinfatareasontheCTscans.
PATIENTSANDMETHODS
Patients
Westudiedpatientswho,duringaperiodofthreemonths,werereferredtothe
RadiodiagnosticInstituteoftheUniversityHospitalinNijmegenforaCTscan
oftheabdomen.Theycomprisedin-patientsaswellasout-patientsand^inmost
cases,theycamefordiagnosisortherapeuticevaluationofcancerorother
malignancies.Weexcludedpatientsundertheageof19andallthosewhoseCT
scansrevealedabnormalfeaturesthatcouldinfluencethemeasurementsoffator
anthropometricmeasurements.Thus,patientswithlargelocalabnormalities,
enlargedliverorspleen,andthosewithastomaatthelevelatwhichthe
measurementsweretakenwereexcluded.Menopausalstatuswasassessed,andin
onecasewherethiswasuncertainbecauseofillnessandtherapy,awomanwas
excluded.Thefinalpopulationcomprised71malesand34females.Theprocedures
followedwereinaccordwiththeethicalstandardsoftheCommitteeonHuman
ExperimentationoftheInstituteofRadiodiagnostics.
ComputedTomography
TheCTscanningwasdonewithaSiemensSomatomDR3(SiemensUBMed,
Henkestrasse127,8520ErlangenGFR).Radiographicfactorswere125KVand350
mAs.Withalateralcomputedradiographindexedtothescannertableposition,
-125-
theCT-scanthroughthethefourthlumbarvertebra(L4wasobtained.The
resultingscanwasofalayer8mmthick .TheL4levelcorrespondstothe
umbilicuslevel,atwhichwaistcircumferenceisusuallymeasured (7,9).As
describedinotherstudies(10)theamountoffatattheumbilicuslevelis
representativeofthetotalabdominalfatandithasbeensuggestedthatyoucan
bestdistinguishthesexesonthebasisoffatattheumbilicus(11).Thedata
fromthescanswereanalysedusingahistogram-basedvolumetricanalysis
techniquebywhichtissueareaonaCTscanimagecanbemeasuredusinga
certainrangeofHounsfieldUnits(10,12).Wedeterminedtherangefor
measurementsoffattobe-150to-50Hounsfieldunits,whichisinaccordance
withrangesdescribedinsimilarstudies (7,9,10).
Weusedarangeof-700to3071Hounsfieldunits(therebyexcludingsmall
amountsofairpresentonthescan)forthetotalareaofthecross-section.The
areaofintra-abdominalfatwasdiscernedfromtheareaofsubcutaneousfatby
tracingalinewithalightpencursorthroughthem.rectusabdominus,m.
obliquusinternus,m.quadratuslumbarumandthelongbackmuscles.Thetotal
areaoffatwithinthislinewasdefinedastheintra-abdominalfat.Theamount
ofsubcutaneousfatwasascertainedasthedifferencebetweenthetotalareaof
fatshownonthescanandtheareaofintra-abdominalfat.Thismethodhasbeen
provedtobeveryaccurateandreproducibleashasbeenreviewedbyGraueret
al(12).Theratioofintra-abdominalfattosubcutaneousabdominalfatwas
calculated.Fatpercentagewascalculatedastheratiooftotalareaoffatto
totalareaofthecross-section.
Anthropometricmeasurements
Allpatientswereaskedaseriesofquestions.Theirresponsestogetherwiththe
patientfilesandtheevaluationoftheradiologists,providedinformationabout
currenthealthstatusandpastillness,typeoftreatmentoruseofdrugs,
menopausalstatus,long-termbedrest,weightchangesintheyearprecedingthe
examination,andage.
Wemeasuredtheheighttothenearest0.1cmandbodyweighttothenearest0.5
kgonacalibratedweighingscaleofthesubjectswhentheywerenotwearing
shoesandwerecladonlyinunderwearorlightindoorclothing.BodyMassIndex
(BMIinkg/m2)wascalculatedasweightdividedbyheightsquared.
Circumferencesweremeasuredatthefollowinglevels,usingaplastictape
measure:smallestcircumferenceatthewaist,waistattheumbilicuslevel,
widesthipcircumference,hipsattheleveloftheanteriorsuperioriliacspine
oftheiliaccrest,andthighcircumferenceatthehighestlevel.
-126Most resultspresented inthispaperwereobtainedusingthe ratioofwaist
circumference:hipcircumference (WHR)andthe ratioofthewaistcircumference:
thighcircumference (WTR)basedonwaistattheumbilicuslevel,hipsatthe
iliaccrestandthehighestthighcircumference.
Twoskinfoldmeasurements (Harpender skinfold caliper,CMSWeighing Equipment
Ltd,London)were takenonthehorizontal linefromtheumbilicus tothe
mid-axillary line:onehorizontally,atone-thirdofthedistance fromthe
umbilicus (para-umbilicalis),andtheotherobliquely,onthemid-axillary line
itself (whichinmostcasescorrespondswiththesupra-iliac skinfold).All
measurementsweretakenwiththesubjectstandinguprightandbreathinglightly.
Statisticalanalysis
The relationsbetweenanthropometricmeasurements,weightchangesinthe
precedingyear,menopausal status,andage,andofvarious fatareasand
proportionsof fatareasasobtained fromtheCTscanswereanalysed by
calculatingproduct-moment correlationcoefficientsandbyusingmultiple linear
regressionanalysis (13).Comparinguntransformedvariableswithlog
transformationsand square roottransformationsofthevariables revealed that
the square rootsofall theCTscanmeasurementsgaveamuchbetter
approximation tothenormaldistributionandtolinear relationsinthe
regressionanalysis.Therefore,inour statisticalanalysisweused thesquare
rootsofthesevariables.
RESULTS
Table1showssomecharacteristicsofthe sample.Onaverage,inthisstudythe
BodyMass Index (BMI)ofthewomenwashigher thanthatofthemenbut,
nevertheless,inwomen the ratiosofwaistcircumference tohip circumference
andwaist circumference tothighcircumferencewere lower.When theWHRbasedon
minimumwaistgirthandmaximumhipgirthwasused,thedifference betweenmen
andwomenwasevenmorepronounced (average ratioformen:0.93,forwomen:
0.87).CT-scanmeasurementsattheleveloftheL4showthat,onaverage,women
hadalarger totalareaofbody fatthanmen:thiscouldlargelybeattributed
todifferences inamountsofsubcutaneous fatandwasalso reflected inthe
proportionsof intra-abdominal fatinmenandwomen.
-127-
Table1.Details of71menand34womenattendingforcomputedtomography
Men
Women
mean
SD
rang s
Age (years)
51.5
17.2
19
BodyMass Index (kg/m)
23.4
3.1
17.8 -
mean
SD
range
85
52.4
13.4
19
72
31.6
26.0
5.0
19.4 -
38.3
Waist:hip ratio
0.96
0.05
0.80 -
1.10
0.94
0.08
0.79 -
1.09
Waist:thigh ratio
1.75
0.18
1.41 -
2.10
1.68
0.22
1.28 -
2.08
CTscandata;
Totalareaoffat (cm)
Area ofintra-abdominal fat (cm)
2
Areaofsubcutaneous fat (cm}
Ratioof intra-abdominal tosubcutaneous fat
20.2
112.9
24.2 -
487.1
347.9
169.5
90.8 -
691.0
89.9
53.0
12.7 -
247.0
91.8
52.7
18.8 -
221.0
30.3
70.9
11.4 -
319.1
256.2
129.9
71.5 -
567.5
0.77
0.39
0.11-
2.42
0.38
0.19
InTables2and3thecorrelationsbetween someoftherelevantvariablesare
presented.InmenandinwomentheWHRcorrelated positivelywiththetotal area
of fat,areaofintra-abdominalfatand areaofsubcutaneousfat.Inwomen,but
notinmen,theWHRiscorrelatedwiththeratioofintra-abdominal fatto
subcutaneousfat.Inwomen,thecorrelationsbetweentheWTRandareasoffat
are consistentlyhigher thanthosebetweentheWHRandareasoffat.Inmen,the
reverseistrue,thecorrelationsoftheWHRwithareasoffatbeinghigher than
thoseoftheWTRwiththeexceptionofthecorrelationswith theratioof
intra-abdominal fatandsubcutaneousfat.
Inmostepidemiologic studiestheeffectsoffatdistributionareestimated
after adjustingforBMIandage.Table4showsthesignificanceofthepartial
correlationsofWHRandWTRwiththeareasoffat,adjustedforageandBMI.The
partial correlationswithintra-abdominalfatwere invariablyhigher thanthose
with subcutaneousfat.Thestatistical associationbetweenWHRinmenandareas
offatwassimilartothatofWTRinwomenandareasoffat.Thesameholdsfor
theWTRinmenandtheWHRinwomen.
0.08 -
1.04
-128-
Table 2.Correlationmatrix ofvariables inmen
1.Age
2.BodyMassIndex
0.15
0.24
0.76
(weight/height )
3.Waist:hipratio
4.Waist:thigh ratio
1.00
0.68
0.14
1.00
0.47
5.Total areaoffat
0.81**
0.33*
(CTscan)
6.Totalareaofintra-
0.54
abdominal fat (CTscan)
**
0.75
0.76
**
0.75
1.00
**
**
0.35*
1.00
0.55**
0.90
0.16
0.95**
**
1.00
7.Areaof subcutaneous
0.76**
0.14
fat (CTscan)
0.68**
0.72
8.Ratioof intra-abdominal
tosubcutaneous fat
0.53**
0.02
0.13
0.56**
-0.03
0.37** -0.33
1.00
9.Ratiooftotal fattototal
body area
0.29
0.67
0.66
0.29
0.96
0.83
0.93
-0.10
0.70**
0.59**
0.05
0.77**
0.57**
0.83** -0.33*
1.00
10.Sum skinfolds (para-umbilical
andsupra-iliac)
-0.09
0.73
1.00
Table 3.Correlationmatrixofvariables inwomen
1.Age
2.BodyMass Index
1.00
0.51
1.00
3.Waist:hip ratio
0.40
0.47
1.00
4.Waist:thigh ratio
0.60
0.55
0.77
2
(weight/height}
5.Total areaoffat (CTscan) 0.54
6.Area ofintra-abdominal
0.91
0.62
0.47
0.82
1.00
0.65
0.55
1.00
0.70
0.86
1.00
fat (CTscan)
7.Area ofsubcutaneous fat
(CTscan)
0.46
0.87
0.39
0.57
0.98
0.73
0.42
0.16
0.34
0.42
0.14
0.61
0.47*
0.78**
0.47*
0.63**
0.95**
0.78**
0.56
0.89
0.73
1.00)
8.Ratioof intra-abdominalto
subcutaneous fat
-0.07
1.00
9.Ratiooftotalfatto
totalbodyarea
0.94
0.08
1.00
10.Sumof skinfolds
(para-umbilical and
supra-iliac)
<0.05;
<0.001
0.43
0.83
0.73
0.88
0.05
0.36
1.00
-129Table4.T-valuesforthepartial correlation coefficientsofwaist:hip ratioand
waist:thigh ratiowithfat areasontheumbilical CTscan;adjusted forageandBMI
Men
Dependent variable
4.33
Area oftotalfat
Area of intra-abdominal
Area of subcutaneous
Women
Waist:hip
Eat
fat
Ratioof intra-abdominal
4.86
2.96
to
0.64
**
**
*
Waist thigh
Waist hip
Waist:thigh
1.79
0.53
2.73*
3.38*
1.66
2.63
0.66
0.22
1.66
2.10*
1.41
1.48
*
subcutaneous fat
Percentage fat
p-values:
<0.05 ;
<0.001
InTables5and6theresultsofstepwisemultiple regression analysis
arepresented,usingtheareasoffatcalculated fromtheCTscansasdependent
variablesandanthropometricdataandageasindependentvariables.Most (79.4%
to90.5%)ofthevarianceintotalareaoffataswellasinareasofwiththe
results fromtable4,theresultsinTables5and6showthat,inmen,theWHRis
a better indexofcharacteristicsoftheareasoffatthantheWTR,whereasin
womentheWTRisthemoreappropriate index.Note that,inwomen,menopausal
statewasmorecloselyassociatedwiththeareaofintra-abdominal fatthanage.
Menopausal statehadnorelationwithtotalfatorsubcutaneous fat.Tolearn
moreaboutwhytheWHRandWTRbehaveddifferentlyinthestatistical analysis
we repeatedtheanalysisusing separatecircumferencemeasurements rather than
ratiosofcircumferences.
inmen,thehipcircumference,afteradjustmentforalltheothervariables,
correlatednegativelywiththeintra-abdominalandsubcutaneousareasoffaton
theCTscan,whereaswaistandthighcircumferenceshadpositive partial
correlationcoefficients.Inwomen,thethighcircumferencehadanegative
partialcorrelationcoefficientwithbothfatareas,whereasthehip
circumference correlatedpositivelywithtotalandsubcutaneousfatand
negativelywith intra-abdominal fat. Waist,inwomen,remained positively
correlatedwithbothareasoffat.
TT
-130-
Table 5.Multiple regressionmodels linkingfatmeasurementstakenfromCTscansto
anthropometric variables andage
Men
Dependent
Independent
Regression
variable
variable
coe fficients of regr.coeff.
Total areaoffat (cm
BMI
0.404
Skinfolds
1.480
0.243
34.122
10.284
0.060
0.012
WHR
Age
Intercept:-
Standarderror
0.108
39 953
Area of intra-abdominal
BMI
0.350
0.084
fat (cm >:I
Skinfolds
0.405
0.189
WHR
33.118
8.032
Age
0.068
0.009
0.108
Intercept:-
37 322
Areaof subcutaneous
BMI
0.157
fat (cm ): s
Skinfolds
1.630
0.227
29.159
11.397
Age
0.051
0.018
WTR
-10.694
5.060
0.029
0.009
WHR
Intercept:Ratio of I:S
18 798
BMI
Skinfolds
- 0.109
WTR
1.583
Intercept:-
0.021
0.272
1 323
Table 6.Multiple regressionmodelslinking fatmeasurementstakenfromCTscans (atthelevelofthe
umbilicus)toanthropometricvariables andage
Women
Dependent
Independent
Regression
variable
variable
coefficientsof
St*
ndarderror
Total areaoffat (cm
BMI
0.508
0.097
Skinfolds
1.044
0.297
WTR
9.958
3.871
regr.coeff.
Intercept:-15.282
Area of intra-abdominal
BMI
0.367
0.061
fat (cm ): I
WTR
10.911
3.660
Menopausal state
0.994
0.497
(1=post;0=pre)
Intercept:-15.083
Area of subcutaneous
fat (cm 2 ): S
BMI
0.373
0.105
Skinfolds
1.301
0.313
Intercept:-3.327
Ratioof I:S
-0.036
0.017
WTR
0.870
0.369
Age
0.0026
0.0019
Skinfolds
Intercept:-0.4105
Note (table 5&6)thesquare rootsweretakenofthedependent variablesandofwaist:hip ratio (WHR),
waist:thigh ratio (WTR)andsumofskinfolds (Skinfolds);variableswereselectedbymeans
ofstepwisemultiple regressionanalysis (pvalueforF-to-enter lessthan0.10);other candidates
for regressionwere:height,weightchange intheyearpreceding theexamination andall
cross-products ofvariablesofthe independent variables
All other regressioncoefficients statistically significant different fromzero (p<0.05)
-131-
DISCUSSION
WHRandWTRareoftenusedinepidemiologicandclinicalinvestigationsas
indicesoffatdistribution.TheresultsofourstudyindicatethatWHRandWTR
inmenandwomenareassociatedmorecloselywithintra-abdominalfatthanwith
subcutaneousabdominalfatatthelevelofthefourthlumbarvertebra.
Wealsodemonstrated (Tables5and6)thatamountsofintra-abdominaland
subcutaneousfatcanbepredictedaccuratelybymeansofeasy-to-measure
anthropometricvariablesandage.Thesepredictionsmaybeimportantinfuture
researchbecausetheyenablethespecificeffectsofthesefatdepotson
morbidityandmortalitytobeestimated.Recently,Sjostrometal.(11)
presentedpreliminaryresultsthatindicatethatevenhighercorrelationsof
anthropometricvariableswithtotalvolumeofvisceraladiposetissuemaybe
obtainedbyassessingthetotalcross-sectionalbodyareabymeansoftransverse
andsagittaldiametersofthebody(inmen,correctedforsubcutaneousfat).
Althoughtheirapproachwasdifferent,theaimoftheirstudywassimilarto
ours.Thereforeitwillbeimportanttocomparetheresultswhenalldetailsof
theirstudybecomeavailable.
AscanbeseenfromTable1,menhaveagreaterproportionofintra-abdominal
fatthanwomen.Thismaypartlyexplainwhy,whenequallyobese,menhavea
greaterriskforcardiovasculardiseasethanwomen.Thisdifferencebetweenmen
andwomenagreeswithresultsfromotherstudies(9,12)andprobablyreflects
theimportanceofhormonesand/orgeneticinfluencesonfatdistributioninthe
abdomen.
Borkanetal.(14)suggestedthatinmen,ageisanimportantdeterminantfor
theproportionofintra-abdominalfat.Thisobservationisconfirmedbyour
data,aswefoundthat,inmen,agecorrelatedwiththeamountof
intra-abdominalfat(r=0.54)butnotwiththeamountofsubcutaneousfat(r=
0.14).Inwomenthiswaslessclear (Table3).
OurresultsconfirmthefindingsreportedbyAshwelletal.(7)whosestudyof
theCTscansof28womenshowedthatcircumferenceratioswererelatedmore
stronglytointra-abdominalfatthantosubcutaneousfat.Wehavenowshownthat
thisisalsotrueinmen.Wewereunabletoconfirm,however,thatafter
adjustmentsforageandBMI,circumferenceratiosarecorrelatednegativelywith
subcutaneousfat.AlthoughourstudywassimilartothestudydonebyAshwellet
al,weusedWHRbasedonwaistgirthattheleveloftheumbilicusratherthan
theminimumwaistcircumference,andthehipcircumferenceatthelevelofthe
anterioriliaccrestratherthanthewidesthipcircumference.Werepeatedour
-132-
analysisusingthesame ratiosasAswellandhercolleguesbut,inconttastto
their findingswe foundevenpoorer correlationswiththe ratioof
intra-abdominal fatandsubcutaneous fat,bothinmenand inwomen.Not*that
WHRscalculated fromthedifferentcircumferences correlated strongly ifimen (r
= 0.90)butlesswell inwomen (r= 0.77).Thisindicatesthat,especially in
women, itisimportant tostandardizethesemeasurements.
The resultspresented inTables5and6indicate thattheWHRandWTRdiffer
betweenmenandwomenasindicesof fatdistribution.WHR inmen resemblesWTR
inwomen inthestatistical analysiswhereasWTR inmen resemblesWHR inwomen.
Thenegativepartial correlationcoefficients forareaofabdominal fatand the
hipcircumference inmenand thethighcircumference inwomen indicate that
thesecircumferencesprovideadditional informationonnon-fattissue,i.e. that
atagivenwaistandthighcircumferencealargerhipcircumferenceindicates,
inmen,ahigherproportionofleanbodymassintheabdomen,whereas inwomen
withagivenwaistandhipscircumference,alargerthigh circumference
indicatesmore leanbodymassintheabdomen.
Analysisof residuals indicated thattherewerenodeviations fromlinearity in
themultiple regressionanalysespresented inTables5and6.Whenthedatawere
stratified into10-year agegroupsandcategoriesofBMI,theanalysis revealed
similarassociations throughout the rangeofageandBMI.
Itshouldbenoted that,aswedescribed inthePatientsandMethodssection,
thesampleofpeoplewe studied cannotbe regardedas representative ofithe
totalpopulationofthesameage range.Wecarefullyexcludedallpatielntsin
whom illnesscouldhavedistorted ourmeasurements.We cannotbecertain,
however,that illnessortherapydidnot influence theamountordistribution of
fat intheabdomen.Alteredmenopausal statusandweight lossarethemost
likely causesforsuchchanges.We repeatedtheanalysis,includingweight
change intheyearprecedingtheexaminationbutwe foundno independent
relationofthisvariablewithanyofthedependentvariablesweused.Thus,
although thesizeofareasof fatontheCTscanmayhavebeen influencedby
factors thatwedidnotmeasure,itseemslikelythatanysuchfactorwould have
produced corresponding changes incircumferences,skinfoldsandweight.
Summarizingour results,wecanconfirmthat,inourstudypopulation,inboth
menandwomen,theWHR andWTR are relatedmore strongly totheamountof
intra-abdominal fatthantotheamountofsubcutaneousabdominal fat.This
findingmightbe important forexplaining theconsistent relationsbetweenWHR
andWTRandmetabolicaberrations,manifest illnessanddeath.
The regressionmodelswepresent inthispaperarebasedonobservationsonmen
-133-
andwomencoveringawide rangeofageanddegreeofobesity.Giventhefairly
restrictednumberof subjects,especiallyinwomen,theextrapolationofthe
regressionmodelstootherpopulationsmustbedonewithgreatcaution.The
multiple regressionanalysisshows,however,that,inthestudiedgroups,the
variation inthe fatareasontheCTscansareexplained toahighdegreeby the
simpleanthropometricvariables,age,andmenopausal state.Inaddition,the
multiple regressionmodelsprovideinformationaboutthe independent
contributionsofeachoftheindependentvariablestotheexplanationof the
variance ofintra-abdominal and subcutaneousabdominal fatareasontheCTscans
attheL4level.
ACKNCWLEDGEMENTS
Theauthorswould liketothank the radiologistsandtechnical staffof the
DepartmentofRadiologyoftheUniversityHospital inNijmegenfor invaluable
assistance intheCTmeasurements,M.Rookus forhelpfuldiscussionsand J.
Burrough forhelpwiththepreparationofthemanuscript.The financial support
of theDutchPraeventiefonds isgratefullyacknowledged.
REFERENCES
1.BjorntorpP.Adiposetissueinobesity (Willendorflecture). In:Recent
advances inobesity research IV:163-170.HirschJ,Van ItallieTB
(eds). JohnLibbey,London,Paris,1985.
2. LarssonB,Svardsudd K,WelinL,WilhelmsenL,BjorntorpP,TibblinG.
Abdominaladiposetissuedistribution,obesity,and riskof cardiovascular
diseaseanddeath:a13year followupofparticipants inthe studyofmen
born in1913.BritMedJ1984;288:1401-4.
3.Goldrick RB,McLouglinGM.Lipolysisandlipogenesis fromglucose inhuman
fatcellsofdifferentsizes.JClinInvest1970;49:1213-1223.
4. Bolinder J, KagerL,OstmanJ,Arner P.Differencesatthe receptorand
postreceptor levelsbetweenhumanomentaland subcutaneousadipose tissue in
theactionof insulinonlipolysis.Diabetes1983;32:117-23.
5.SmithU.Regionaldifferences inadipocytemetabolismandpossible
consequences invivo.In:HirschJ,VanitallieTB (eds).Recentadvances in
obesity research IV:33-36.JohnLibbey,London,Paris1985.
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6.BjomtorpP.Obesityandtheriskofcardiovasculardisease.AnnClinRes
1985;17:3-9.
7.AshwellM,ColeTJ,DixonAK.Obesity:newinsightintotheanthropometric
classificationoffatdistributionshownbycomputedtomography.BritMedJ
1985;290:1692-1694.
8.KissebahAH,EvansDJ,PeirisA,WilsonCR.Endocrinecharacteristicsin
regionalobesities:roleofsexsteroids.In:VagueJetal.(eds)
Metaboliccomplicationsofhumanobesities:115-130.ElsevierScience
PublishersBV,Amsterdam,1985.
9.DixonAK.Abdominalfatassessedbycomputedtomography:sexdifferences
indistribution.ClinRadiol1983;14:189-191.
10.BorkanGA,GerzofSG,RobbinsAH,HultsDE,SilbertCK,SilbertJE.
Assessmentofabdominalfatcontentbycomputedtomography.AmJClinNutr
1982;36:172-177.
11.SjostromL,KvistH,TylenK.Methodologicalaspectsofmeasurementsof
adiposetissuedistribution.InVagueJetal.(eds).Metabolic
complicationsofhumanobesities:13-19.ElsevierSciencePublishersBV,
Amsterdam,1985.
12.GrauerWO,MossAA,CannCE,GoldbergHI.Quantificationofbodyfat
distributionintheabdomenusingcomputedtomography.AmJClinNutr
1984;39:631-7.
13.DixonWJ.BMDPstatisticalsoftware.BerkelyCA.UniversityofCalifornia
Press,1983.
14.BorkanGA,HultsDE,GerzofSG,RobbinsAH,SilbertCK.Agechangesin
bodycompositionrevealedbycomputedtomography.JGerontology1983;
38:673-677.
i
-135-
GENERALDISCUSSION
This thesis reportsontheassociationsbetweenoverweightandseveralaspects
ofmorbidity.Thelasttwochaptersprovide someinsight inthe roleof fat
distribution intheseassociations.Inthestudiesdescribed inthisthesis
overweightandobesity (orsevereoverweight)aredefined intermsoftheBody
2
Mass Index (BMI=weight/height ).Although itisknown thatinindividuals the
BMIcanbeanunreliableestimateofbodyfatness,inepidemiologic research it
isconsidered tobe themost satisfactorymeasureofobesity (1,2,3).Themost
seriousmisclassificationofobesity statusonthebasisoftheBMIoccursin
theveryold,theverymuscularandthosewhohavenot reached theendof
puberty (4).The treshold levelsofBMI forthedefinitionof (moderate)
overweightandobesity (orsevereoverweight)arestillarbitraryalthough itis
2
nowgenerallyagreed thatwhen theBMIexceeds30kg/m aperson isobesewith
clearlyassociated increased risksforprematuredeath,cardiovasculardisease,
diabetesmellitusandseveralothermoreorlessseriousmetabolicabberations.
Mostoftheseassociationswereconfirmedbytheresultsofthestudies
2
presented inthisthesis.BelowaBMIof 30kg/m increasedmorbidity risksare
lessclearandprobablyconfinedtosubgroups:thosewithanabdominal typeof
fatdistribution,thosewhowerealreadyoverweightasyoungadults,and those
whohavea familyhistoryofchronicdisordersor increasedlevelson
cardiovascular riskfactors.
Fromcross-sectional studies (Chapters2and 5)aswellasfrom longitudinal
studies (Chapters 3and4)itisnotdirectlypossible tomake inferencesabout
thecausal relationshipsbetweenoverweightandmorbidity. Forsomeofthe
observed associations (e.g.thoseofBMIwithhypertension,cardiovascular
disease,diabetesmellitus,arthrosis,menstrualabnormalities)there isnow
muchevidence fromtheliterature thatthedisordersarethe resultof increased
body fatness.An importantaspectoftheevidence,with implications forthe
treatmentofoverweight is,thatwhenoverweightpersonssucceed inlosing
weight,bloodpressure,glucose toleranceandlevelsofblood lipidsgenerally
tend tonormalize.Overweight subjectswho suffer fromjointdisorders,
menstrual abnormalities,shortnessofbreathetc.normally find reliefoftheir
symptomswhentheyloseweight(5). Insomeoverweight subjects,especially in
women,mental state improveswhentheysucceed inmaintaining substantialweight
loss.Although thebenefitsof reducingweightareclear,itmustbenoted that
slimming initselfmaycauseunwanted sideeffects.For instance,ithasbeen
argued that slimmingwill increasethelithogenityofthebile,thereby
-136-
increasingtheriskofgallstones.Unsuccessfulslimmingattemptsmaylftadto
increaseddepression.Thus,slimmingshould,ideally,besupervisedbymedical
professionalists.
TheassociationofBMIandpsychosomaticcomplaintsisanexampleofth$complex
interrelationsbetweenthetwovariables.Itmaybethatpsychosomatic
complaintsaretheresultofbeingoverweightbutsomepsychologicalstudies
haveshownthatpsycho-socialproblemsmaycontributetoweightgain(6K In
addition,thepossibilitythatpersonalcharacteristicscauseoverweightaswell
aspsycho-somaticcomplaintscannotbeexcluded.Inthepopulationfromfour
generalpractices,describedinChapters3-6itwasfoundthatespecially
womenweremuchconcernedabouttheirweightandthatinthosewhoconsidered
themselvesoverweight,cosmeticproblemsdominatedandwerefarmoreimportant
thanconcernsabouthealth(7).Whenlookingattheregistersofgeneral
physiciansonewouldtendtoconcludethatoverweightispredominantlyaproblem
inwomen.InChapter4,however,itwasshownthatinmenanincreasedriskfor
cardiovasculardiseasebecomesapparentatlowerlevelsofBMIthaninwomen.
Thus,asGarrowhasstated (8),manypeopledonotcorrectlyappreciatethe
hazardsofobesity.Somepeople,whodonotneedto,worryabouttheirweight.
Others,whodoneedtoworryabouttheirweight,donot.
Thefindingthatmenseemtobemorevulnerabletotheeffectsofobesityon
cardiovasculardiseaseriskfactorsthanwomencan,atleastpartly,be!
explainedbysexdifferencesinfatdistribution (9).Thisbringsustothe
topicoffatdistributionwhichisthesubjectofChapters6and7.Ithasbeen
shownintheseandotherstudies(reviewedinChapter1)thatthewaistj/hip
circumferenceratioandthewaist/thighcircumferenceratioareconvenient
indicatorsoffatdistribution.TheresultspresentedinChapter6confirmthat
thesecircumferenceratiosare,independentofthedegreeofoverweightandage,
relatedtotheprevalenceofcertaindisorders.Thefindingthat,inwomen,a
highwaist/thighratiowasassociatedwithareportedonsetofoverweightat
lateragethaninthosewithalowwaist/thighratiomightgiveanindicationof
oneaspectoffatdistributionthathasreceivedlittleattention (Fig).Levels
ofsex-hormonesthatchangewithageingareprobablythemostlikelyexplanation
forthisobservation.
Hormonalfactorsareprobablyofprimaryimportanceindeterminingan
individual'sfatdistribution.Thetypicalfemaleadiposetissueinthe
femoral-glutealregionisthoughttohaveaspecificfemalefunction:energy
storageforlactationpurposes(10). Theinfluenceofmenopausalstate,the
administrationofsexhormonesandthelevelsofsex-hormonesinobesewomen
-137-
withdifferenttypesoffatdistribution(11)demonstratetheimportanceof
hormonalinfluences.Thefindingthatanabdominaltypeoffatdistributionis
associatedwithcomplicatingdisordersisshownunanimouslyinnumerousstudies.
Yetitremainstobeproventhattheseassociationsareindependentofhormonal
factors.Probably,sexhormoneshavebothadirecteffectonglucoseandlipid
metabolismaswellasanindirecteffectviatheirrelationtofatdistribution
(11).Theassociationofmenopausalstatewithintra-abdominalfatbutnotwith
subcutaneousabdominalfat(describedinChapter7)indicatesthatahighwaist
thighratioinpost-menopausalwomenmaybemoredeletorioustohealththanin
pre-menopausalwomen.This,however,requiresfurtherinvestigation.
Circumferencemeasurementsshouldbeincorporatedinthesetofanthropometric
measurementsinanyepidemiologicandclinicalresearch.Studiesinwhichthe
independenteffectsofbothintra-abdominalandsubcutaneousabdominalamounts
offattometabolicdisordersandclinicalillnesscanbeestablishedare
urgentlyneeded.Suchstudieswouldbeimportantforfurthercharacterizationof
subgroupsofoverweightsubjectsthathaveincreasedhealthrisks.Theeffects
oftreatmentinthesesubgroupsshouldbestudiedcarefullyinwellcontrolled
interventionstudieswithlongfollow-up.Detailedclassification,onthebasis
ofthefatdistributionoverandwithinthebodyofoverweightsubjectswillbe
importantforthediagnosisandtreatmentofoverweightandobesity.
9
•
l.b.o.
u.b.o.
FIGURE-Percentageofwomenwhoindicatedtohavebeen 'toofat'at
differentstagesoflife.
1=atbirth;2=childhood «12yrs);3=adolescence (12-20yrs);4=young
adult (20-30yrs);5=after30yearsofage.
l.b.o.=lowertertileofwaist-thighcircumferenceratio
u.b.o.=uppertertileofwaist-thighcircumferenceratio
(Chapter6)
-138-
REFERENCES
1.Gezondheidsraad.Adviesinzakeadipositas.StaatsuitgeverijDenHaag,1984.
2.RoyalCollegeofPhysicians.Obesity.JRoyCollPhys1983;17:1-65.
3.BurtonBT,FosterWR,HirschJ,vanItaalieTB.Healthimplicationsiof
obesity:AnNIHconsensusdevelopmentconference.IntJObesity
1985;9:155-159.
4.GarrowJS.Treatobesityseriously.Aclinicalmanual.Edinburg:Churchill
Livingstone,1981.
5.BlackburnGL,ReadJL.Benefitsofreducingrevisited.PostgradMedJ
1984;60(suppl.3):13-18.
6.VanStrienT.Eatingbehaviour,personalitytraitsandbodymass(thesis),
Wageningen,TheNetherlands,1986.
7.SeidellJC,BakxJC,vandenHoogenHJM,DeurenbergP.Overgewichtin
relatietotmorbiditeltensubjectiefwelbevindeninvierhuisartsen
praktijken.In:Deeerstelijnonderzocht(BoermaWGW,HingstmanLreds):
225-36.Deventer,VanLoghumSlaterus,1985.
8.GarrowJS.Whyarewefat?NutrFdSci1986;22:21-2.
9.Bjorntorpp.Obesityandtheriskofcardiovasculardisease.AnnClinRes
1985;17:3-9.
10.Rebuffe-ScriveM.Regionaldifferencesinadiposetissuemetabolismin
relationtosexsteroidhormones(Thesis),Goteborg,Sweden,1986.
11.KissebahAH,EvansDJ,PeirisA,WilsonCR.Endocrinecharacteristicsin
regionalobesities:roleofsexsteroids.In:Metaboliccomplicationsof
humanobesities(VagueJetal.eds):115-30.Amsterdam,ElsevierScience
Publishers,1985.
-139SAMENVATTING
Inditproefschriftwordenonderzoekenbeschreven naardeverbanden tussen
overgewicht envetverdeling enerzijdsenaspectenvangezondheid anderzijds.
De idealeproefopzet omdezeverbanden teonderzoeken ismetbehulpvan
prospectieve cohort studieswaarin groteaantallen individuen, liefstvan enkele
generaties,vanafhungeboorte tothundood zoudenmoetenworden gevolgd.
Gedurende deobservatieperiode zouvandeonderzoekspopulatie zowelde
gewichtsontwikkeling, devetverdeling alswelhetoptredenvan ziektenenhet
subjectiefwelbevindenmoetenwordenbijgehouden. Inzo'n ideale onderzoeksopzet
zoudenook sociale kenmerken,familiairekenmerkenenleefgewoonten moeten
wordenbetrokken endeniveausvan risicofactoren voor chronische aandoeningen
herhaaldelijk moetenworden bepaald.
De inditproefschrift beschreven onderzoeken zijn,inhetlichtvande
hierbovengeschetste onderzoeksopzet,noodzakelijkerwijszeerbeperkt en
hierdoor kunnen slechtsenkeleaspectenvandeverbanden tussenovergewicht en
vetverdeling endeobjectieve ensubjectieve gezondheidstoestand wordenbelicht.
Er zijngoede redenenomdezeverbanden teonderzoeken.Nietalleenkomt
overgewicht veelvoor inlandenzoalsNederland meteengeindustrialiseerde
samenlevingmaarer zijn tevensveelaanwijzingen datdeprevalentie van
overgewicht indie landen toeneemt.Bovendienmaakteengrootdeelvande
Nederlandse volwassenen zich,omuiteenlopende redenen,zorgenover het
lichaamsgewicht.Opdevraag ofdeze zorgen,vanuit gezondheidskundig oogpunt,
terecht zijnkanditproefschrift geendirectantwoord geven.De beschreven
onderzoeken geven,opzijnbest,een schattingvanhet relatieve risicodat
personenmeteenbepaaldematevanovergewicht ofeenbepaalde vetverdeling
hebben tenopzichte vanpersonen zonderovergewicht ofmeteen 'gunstige'
vetverdeling.Het relatieve risicogeefteenindrukvandeverhoudingvan kansen
ophethebbenofkrijgenvanbepaalde aandoeningen indegroependie worden
vergeleken.
Of eenindividu zich zorgen zoumoetenmakenover eenverhoogde kansophet
krijgenvaneenaandoening iseenzuiverpersoonlijke aangelegenheid. Of een
samenleving zichdaarover zorgenmaakt iseenpolitieke enethische kwestie.
Inhoofdstuk 1wordteenoverzicht gegevenvandehuidige inzichten inde
verbanden tussenovergewicht,vetverdeling enhetoptredenvanstoornissenin
hetmetabolismeen,eventueel daaruitvoortkomende,aandoeningen.
-140-
Inhoofdstuk 2wordteenindruk gegevenvandeprevalentievanmatig (QI25- 30
2
2
kg/m )enernstig (QI>30kg/m )overgewichtbijNederlandsevolwassenen,
gebaseerdopdegewichtenenlengteszoalsongeveer 19000Nederlanders,ouder
dan20jaar,zeopgavenaanenquetricesvanhetC.B.S.Bepaalde aandoeningen
werdenvakergenoemddoorpersonenmetovergewichtdandoorpersonen zonder
overgewicht (o.m.hypertensie,suikerziekte,spataderen,asthma/brochitigen
aambeienbijvrouwen,hypertensiebijmannen).Ookblekenpersonenmet '
overgewicht,omsommige redenen,vakerbijdehuisartsofeenspecialistte
komenenwerdenbepaaldemedicijnenvakergebruikt.
Dezeverschillenwarenvooralduidelijkwanneerpersonenmeternstigovergewicht
werdenvergelekenmetpersonenzonderovergewicht;bijpersonenmetmatig
overgewichtwarendeverschillenveelminder grootenmaar inenkelegevallen
statistischsignificant.
Hoofdstukken3totenmet6hebbenbetrekkingopeen retrospectief cohort
onderzoek datwerdverrichtmetbehulpvandegegevensverzameld indeContinue
MorbiditeitsRegistratievanhetNijmeegsUniversitairHuisartsen Instituut.
AllepersonenbijwieovergewichtdoordehuisartsenwerdgeregistreerdVan20
tot 50-jarige leeftijd indeperiode 1967- 1978endienogbereikbaarwaren in
1983,werdenvergelekenmeteengroeppersonenbijwienooitovergewichtwas
vastgesteld.Degroepenwaren,watbetreftleeftijd,geslachten
huisartsenpraktijk, zogoedmogelijk aanelkaargelijk gemaakt.
Allepersonenwaren6jaartevolgenindeContinueMorbiditeitsRegistratie.
Hetbleekdat,gedurendedie6jaar,zoweldemannenalsvrouwenmetovergewicht
meerverkoudheid/griep,nerveus-functionele klachten,huidproblemen,myalgieen
lumbagoendistorsiesvoorkwamendanindegroepzonderovergewicht.Bijvrouwen
wasdatbovendienooknoghetgevalvoormenstruatiestoornissen,enbijmannen
voor kleineongevallen (Hoofdstuk 3 ) .De follow-upwerduitgebreid totniaximaal
17jaren (Hoofdstuk 4)ende incidentiesvanverschillende chronische
aandoeningenwerdenbestudeerdenvergelekenmetbehulpvan 'survival-arialyse'
technieken.De incidentievandiabetesmellitus, jicht,myocard infarct/angina
pectorisenartrosewashoger indegroepmetovergewicht (zowelbijmannenals
bijvrouwen).Bijdevrouwenwasdithetgevalvoor spataderen.De incidentie
vanhypertensiewasookverhoogd indegroepmetovergewicht (nietbeschrevenin
ditproefschrift).
In1983werddepersonenuitdegevolgde cohorteneenvragenlijstgestuurd.Deze
werd ingevuld teruggestuurd door71%.
Enkeleanalysesvandezeenquete zijnvermeld inhoofdstuk 5.Veel andere
o
gegevenszijneldersgepubliceerd .Indevragenlijstwasondermeereenlijst
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opgenomenvan 51klachten (dezgn.VOEG-lijstvanDirken)entevenswerd
gevraagd naarhethuidige gewicht,delengte,rookgewoonten ende frequentie van
vermageren.De somscorevande 51klachtenbleekgecorreleerd aandeQI bij
vrouwenmaarnietbijmannen.Inmultipelelineaire regressiebleek echter dat
leeftijd een interactievertoondemetdeQI innunrelatiemetdeklachtenscore.
Bij jongemannenwasereennegatiefverband tussendeQIende klachtenscore,
bijouderemanneneenpositiefverband.Bijvrouwenbleek deassociatie tussen
deQI endeklachtenscore veelduidelijker bijjongevrouwendanbijoudere
vrouwen.
DeQIbleek, inmultipele logistische regressie analyse,ook gerelateerd aan
afzonderlijke klachten ofgroepjesvanklachten.Bijmannenenvrouwenwaren
deze klachten:klachtenaanhetmaagdarmkanaal,spier-engewrichtsklachten en
kortademigheidenbijvrouwen:nervositeit,moeheid,neus-enkeelklachten, pijn
indehart-enborststreek,benauwdheid opdeborstenhetvaak hebbenvan
kleineongevalletjes.
InHoofdstuk 6iseenonderzoek beschrevenwaarbijbij 305personenuitde groep
metovergewicht devetverdelingwerdbepaald aandehandvandemiddel/heup
omtrekverhouding (middel/heupratio)endemiddel/dijomtrek verhouding
(middel/dij ratio).Demiddel/dij ratiobleek,ookna correctievoor leeftijd en
QI, positief geassocieerd metdeprevalentie vanhypertensie bijmannen en
vrouwen, jichtofdiabetesbijvrouwen,arthrose bijmannenen negatief
geassocieerd metdeprevalentie van spataderenbijvrouwen.Deassociaties van
demiddel/heupratiometdezeaandoeningen blekenminder sterk (met uitzondering
vanhypertensie bijmannen).Deklachtenscore (ziehoofdstuk 5)bleek bijmannen
positief gecorreleerd metdemiddel/dij ratio.Groepenvanklachten die
geassocieerd warenmetdemiddel/dij ratiowaren:pijn indehart-en
borststreek, gewrichtsklachten enkortademigheid.Vrouwenmeteenhoge
middel/dij ratiogavenaanpasopoudere leeftijd 'tedik'tezijngeworden dan
devrouwenmeteenlagemiddel/dij ratio.Ditwerdbevestigd doornun
gerapporteerde gewichtsontwikkeling.
Hoofdstuk 7beschrijft eenonderzoek waarbijmetbehulpvan 'Computed
Tomography'de relatiewerd onderzocht tussendeomtrekverhoudingenende
hoeveelheid endeverhouding van intra-abdominaalveten subcutaan abdominaal
vet terhoogtevandeL4 (meestalopnavelhoogte).Hetbleek datde correlaties
tussendeomtrekverhoudingen endehoeveelheid intra-abdominaal vet significant
waren,ookna correctie voorde leeftijd endeQI.De correlaties tussende
omtrekverhoudingen endehoeveelheid subcutaanvetwaren steeds lager.Er bleken
opvallende verschillen tebestaan tussenmannenenvrouwen.Bijmannenwas
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relatiefeenveelgroterdeelvanhetabdominalevet indebuikholteop^eslagen.
Ditaandeelnamtoemetdeleeftijden,bijvrouwen,nademenopauze.
Devoornaamsteconclusiesvandeonderzoeken zijndaternstigovergewicht,enin
minderemateookmatigovergewicht,samengaanmetmeermorbiditeitenm£t
verminderdsubjectiefwelbevinden.Vanuitgezondheidskundig oogpunt zouj
rten
bij
deevaluatievanpersonenmetzowelmatigalsernstigovergewichtrekenirig
moetenhoudenmetdevetverdeling.
REFERENTIES
1.BakxJC,SeidellJC,DeurenbergP,vandenHoogenHJM.Thedevelopmentof
hypertensionofoverweightpatients seeningeneralpractice.J Family
Practice 1987 (in press).
2. SeidellJC,BakxJC,vandenHoogenHJM,DeurenbergP.Overgewicht ihrelatie
totmorbiditeitensubjectiefwelbevinden invierhuisartsenpraktijken.In:
BoermaWG*J,HingstmanL (red.). Deeerstelijnonderzocht.Deventer:Van
LoghumSlaterus,1985:225-236.
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SUHHARY
Thisthesis reportsontheassociationbetweenoverweightand fatdistribution
withaspectsofmorbidity inDutchadults.
The idealstudydesign for investigating theseassociationswouldhavebeen to
carryoutalargeprospectivecohortstudyinwhichalargenumberof
individuals,preferably fromseveralgenerations,couldbe followedup from
birth todeath.Throughout theobservationperiod thedevelopmentofweightand
fatdistributionwouldhave tobe registeredaswellastheoccurrenceofall
diseasesandlevelandchangeofwell-being.Suchanidealstudywould involve
measuresoffamiliarity,elementsoflife-styleandthelevelsofknownrisk
factorsfordisease.
Itshouldbenoted thatthestudiesdescribed inthisthesisare,compared to
thedescribed studydesign,severelylimitedanditmayverywellbethat
associationsobserved inthestudiescanbe,atleastinpart,explainedby
variablesthathavenotbeenmeasured inthestudies.
Thereareseveralgood reasonsforstudyingtheassociationsbetweenoverweight
andaspectsofhealth.Notonlyistheprevalenceofoverweight inindustrial
societies,likeinTheNetherlands,considered tobehighbut,moreover,there
aremany indications thattheprevalenceofoverweighthasbeen increasingover
thepastdecades.Inaddition,alargeproportionofDutchadultsare,because
ofvarious reasons,concernedabouttheirweight.Whetherornotthisconcernis
justifiedonmedical groundsisnotthedirectsubjectofthisthesis.The
investigationspresentedherecan,atbest,giveanestimationofthe relative
risksforcertaindisorderscomparingseveraldegreesofoverweight.Whether or
notan individualworriesaboutacertainincrease inhealth risksisapersonal
matter.Societiesconcernaboutoverweightand itspossibleconsequences isa
politicalandethicalmatter.Itisnotthetaskofepidemiologists totell
individualsandgouvernmentshowtofeelandact.
Chapter 1ofthisthesis isaliterature review,givinganoverviewof current
insights intheassociationsbetweenoverweight,fatdistributionandthe
occurrenceofmetabolicdisturbancesand,possibly resulting,complicating
disorders.
Chapter 2givestheprevalenceofmoderateoverweight (BMI25- 30kg/m )and
2
severeoverweight (BMI>30kg/m )in19,000Dutchadults (self-reported data).
Itcouldbeshownthat,afteradjustmentsforageandeducational level,certain
chronicdisorderswere reportedmoreoften inoverweightsubjectsthanin
subjectswithoutoverweight (i.e.hypertension,diabetesmellitus,varicose
2
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veins,asthma/bronchitisandhemorroidsinwomen,hypertensioninmen). In
addition,itappeared thatmoreoftheoverweightsubjectsconsulted their
generalpractitioner oramedical specialist forparticular reasonsandjahigher
use ofseveralmedicinsthanthosewhowerenotoverweight.These differences
weremorepronouncedwhencomparing severelyoverweight subjectsto
non-overwight subjectsand lessclearorabsentformoderately overweight
subjects.
i
Chapters 3 - 6 consider retrospective cohortstudiesthatwereperformedondata
collected inacontinuousmorbidity registration infourgeneral practices
(source:DepartmentofGeneral Practice,UniversityofNijmegen).All subjects
whowere registered asoverweightattheageof20- 50years intheperiod 1967
- 1978were followed inthe registration.Themorbiditydatawerecompared to
those inacontrol groupfrequencymatchedonage,sex,generalpracticeand
durationof follow-up.All subjectswere selectedonthebasisthattheycould
be followed foratleast6years.During these sixyears (Chapter 3)itwas
shownthatmoreoverweightmenandwomenwere seenbytheirGP'sforcommoncold
& influenza,psychosocial problems,skinafflictions,myalgyandlumbago,
distortions,menstrualabnormalities (womenonly),andsmallinjuries (menonly)
thanmenandwomen inthenon-overweightgroup.The follow-upperiodwas
extended tomaximal 17years (Chapter 4)and theincidencesof severalChronic
diseaseswere comparedbetweentheoverweightandthenon-overweightgroupwith
theuseof 'survivalanalysis'techniques.The incidenceofdiabetesmellitus,
gout,arteriosclerotic disease,artrosis,varicoseveins (womenonly),ftnd
hypertension (presented elsewhere )was increased intheoverweightgroup.In
Chapter 5some resultsarepresentedofthe relationbetweenBMIand complaints
listed inaquestionnaire thatwasadministered tothestudypopulation (spring
1984). The response ratewas71%.Manyother resultswere reportedelsewhere .
Thequestionnaire included,besidesthelistof 51subjectivehealthcomplaints,
questionsaboutcurrentweightandheight,smokinghabitsand slimming,
frequency. Inmultiple linear regressionanalysisthesumofcomplaintswas
correlatedwiththeBMIinwomen (especiallyyoungwomen),positively inolder
menandnegatively inyoungermen.Inaddition,itcouldbe shownthat,in
multiple logistic regressionanalysis,thepresence ofparticular complaintsor
groupsofcomplaintswas related totheBMI (inmenandwomen:digestive tract
complaints,muscleand jointcomplaints,shortnessofbreath;inwomenonly:
nervousness,tiredness,nose-andthroatcomplaints,painintheheart-or chest
region,tightnessatthechestandoftenhavinglittlemishaps).
InChapter 6,a studyisdescribed relatingthefatdistribution (in310
2
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subjectsoftheoverweightstudygroup)toregisteredmorbidity.Thewaist/hip
circumferenceratio(WHR)andwaist/thighcircumferenceratio(WTR)weretaken
asmeasuresoffatdistribution.TheWTRwas,afteradjustmentsforageandBMI,
positivelyrelatedtotheprevalenceofhypertension(inmenandwomen),goutor
diabetes(inwomen),artrosis(inmen),andnegativelyrelatedtotheprevalence
ofvaricoseveinsinwomen.TheassociationsoftheWHRwiththesedisorders
wereequalorlessstrong(withtheexceptionofhypertensioninmen).Thetotal
numberofsubjectivehealthcomplaints(seealsoChapter5)waspositively
relatedwiththeWTRinmen.WomenwithahighWTRreportedtohavebeen'too
fat'atolderagesthanwomenwithalowWTR.Thiswasconfirmedbytheirweight
history.InChapter7,therelationofcircumferenceratiostofatareason
ComputedTomographyscansattheL4levelwasstudied.Itwasfoundthatthe
correlationofthecircumferenceratioswerehigherwiththeamountof
intra-abdominalfatthanwithsubcutaneousabdominalfat.Therewerepronounced
differencesintheabdominalfatdistributionbetweenmenandwomen.Inmen,a
relativelylargerproportionoffatwasstoredintheabdominalcavity.This
proportionincreasedwithageand,inwomen,aftermenopause.
Itisconcludedthat,fromamedicalpointofview,itisnecessarytoinclude
measuresoffatdistributionintheevaluationofoverweightandobesesubjects.
REFERENCES
1.BakxJC,SeidellJC,DeurenbergP,vandenHoogenHJM.Thedevelopmentof
hypertensionofoverweightpatientsseeningeneralpractice.JFamily
Practice1987(inpress)
2.SeidellJC,BakxJC,vandenHoogenHJM,DeurenbergP.Overgewichtinrelatie
totmorbiditeitensubjectiefwelbevindeninvierhuisartsenpraktijken.In:
BoermaWGW,HingstmanL (red.).Deeerstelijnonderzocht:225-236.Deventer:
VanLoghumSlaterus,1985.
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CURRICULUMVITAE
JacobCaesar Seidellwerdop 3november 1957geborenteWeert.HetAthejieum-B
diplomawerdbehaald in1976aanhetEckartCollege teEindhoven.Inhetzelfde
jaarwerd zijnstudieaandeLandbouwhogeschoolteWageningenaangevang*n.
Tijdens zijnpraktijktijd deedhijonderzoek ophet 'DunnClinicalNutrition
Centre' teCambridge,Engeland. Injuli1983slaagdehijvoorhetdoctoraial
examen (metlof)metalshoofdvakkenHumaneVoedingenToxicologie.Per1
September 1983tradhijindienstbijdeVakgroepHumaneVoeding teWageningen
alswetenschappelijkassistentalwaar,met financiele steunvanhet
Praeventiefonds,hetinditproefschriftbeschrevenonderzoekwerdverricht.Per
1 januari 1987zalhij,metbehulpvaneenstipendiumvanZWO,gedurendeeen
jaarverder onderzoek naaraspectenvanvetverdelingverrichtenaande
UniversiteitvanGoteborg teZweden.