Overweight and Obesity:
Prevalence and Health
Risks
Dr. David L. Gee
FCSN/PE 446
Overweight vs. Obese

Traditional Definitions
– Obese:
Body
fatness above population norm
– Overweight:
Body

weight above population norm
Current NIH Definition
– Obese is a more severe form of
overweight
Body Mass Index
 BMI
= BW /
 where:
2
H
–BW = kilograms
–H = meters
Body Mass Index

Example:
– BW = 165 lbs / 2.2 lbs/kg

= 75 kg
– H = 70 in x 2.54 cm/in



= 178 cm = 1.78 m
BMI = 75 / 1.782 = 24
BMI is not a direct measure of body
fatness
1998 NIH-NHLBI Clinical
Guidelines





Expert Panel (24 members)
Systematic Literature Review (19801997)
394 randomized controlled trials
Executive summary 1998
Arch Int Med (Sept ‘98), JADA (Oct
‘98), NHLBI Web page
1998 NIH-NHLBI Guidelines
 Overweight:
BMI 25 - 29.9
 Obese: BMI > 30
–Obesity Class I: 30 - 34.9
–Obesity Class II: 35 - 39.9
–Extreme Obesity: >40
Prevalence of Overweight and Obesity
in the United States, 1999-2004
JAMA 295: 1549-1555 (2006)

2003-2004 NHANES
Overweight
All adults
Males
Females
66%
71%
62%
32%
31%
33%
5%
3%
7%
BMI > 25
Obese
BMI > 30
Severely
Obese
BMI > 40
Obesity Trends Among U.S. Adults
between 1985 and 2005

Source of the data:
CDC’s Behavioral Risk Factor Surveillance
System (BRFSS).
– state health departments
– monthly telephone interviews with U.S. adults.
Is being overweight really that
dangerous?
Excess Deaths Associated with Underweight,
Overweight, and Obesity
JAMA 2005:293:1861-1867



“Underweight and obesity… were
associated with increased mortality…”
“Overweight was not associated with
excess mortality.”
“Study finds government overstated danger
of obesity” – USA Today – 4/19/05
– http://www.usatoday.com/news/health/2005-0419-obesity-danger_x.htm
For adults ages 25-59, increased mortality
in underweight and obese categories, but
not overweight category.
Is being overweight really that
dangerous?
Other interpretations:

While risk of mortality may not be greater in
overweight subjects, risk of chronic disease is
greater in overweight and obese subjects
– Improved detection and treatment of risk factors result
in reduced mortality in overweight subjects
Hypertension, diabetes, dyslipidemia
 Quality of life


Overweight is a temporary state
– Most/many overweight become obese
– Obese state is clearly a health risk
Prevalence and Trends in Obesity Among US
Adults, 1999-2000
JAMA 288(14)1723-1727 (2002)
Childhood Obesity
Overweight Prevalence in
Children & Adolescents:
Definitions
Criteria based on NHANES
1976-1980
 Higher BMI criteria

– >95th percentile = overweight, medical
follow-up (~BMI=30 in adults)
– 85-95th pct = risk of overweight (~BMI=25
adults)
American children are getting fatter…
Prevalence of Overweight* Among U.S. Children and Adolescents (Aged 2 –19 Years)
National Health and Nutrition Examination Surveys
American boys of all ethnicities are
getting fatter
Adolescent Boys Prevalence of Overweight* by Race/Ethnicity (Aged 12–19 Years)
National Health and Nutrition Examination Surveys
American girls, especially AfricanAmerican girls, are getting fatter
Adolescent Girls Prevalence of Overweight* by Race/Ethnicity (Aged 12–19 Years)
National Health and Nutrition Examination Surveys
The Spread of the Obesity
Epidemic in the US, 1991-1998





JAMA 282: 1519-1522 (1999)
cross sectional random telephone
survey
>100,000 subjects
obesity = BMI > 30
self-reported data
– probable underestimation of obesity
Changes of Obesity Prevalence:
Gender
1991
1998
%
increase
men 11.7% 17.7% 51.5%
women
12.2% 18.1% 47.1%
Although the prevalence of obesity is higher in women than in men,
The rate of increase in obesity is greater in men than in women.
Changes of Obesity Prevalence:
Age
Age
18-29
30-39
40-49
50-59
60-69
> 70
1991
7.1%
11.3%
15.8%
16.1%
14.7%
11.4%
1998
12.1%
16.9%
21.2%
23.8%
21.3%
14.6%
% increase
69.9%
49.5%
34.3%
47.9%
44.9%
28.6%
Although the prevalence of obesity is greater in older Americans,
The rate of increase in obesity is rising faster among younger Americans
Changes of Obesity Prevalence:
Ethnicity
Ethnicity
1991
1998
% increase
White
11.3%
16.6%
47.3%
Black
19.3%
26.9%
39.2%
Hispanic
11.6%
20.8%
80.0%
Other
7.3%
11.9%
62.0%
Prevalence of obesity is highest among African-Americans,
The rate of obesity rising fastest in the Hispanic population.
Changes of Obesity Prevalence:
Education Level
Education
Level
1991
1998
< High
school
High
school
Some
college
>
College
16.5%
24.1%
%
increase
46.0%
13.3%
19.4%
46.1%
10.6%
17.8%
67.5%
8.0%
13.1%
62.9%
Prevalence of obesity is higher in less educated Americans, but
The rate of obesity is faster among more educated Americans.
Obesity is growing worldwide
Science: 7 January 2005: vol. 307. no. 5706, p. 38
Obesity and Health

Contributes to over half of
Western chronic diseases.
– Coronary heart disease
– All major cancers
except
lung cancer
– Diabetes
– Stroke
Obesity and Mortality Rate
 Lowest
mortality
–BMI = 19-25
–10% to 20% under average BW
 Mortality
rate increases
exponentially above BMI of 25
–CDC 2005 study, above 30
Overweight and Coronary
Heart Disease
70% of CHD cases are
overweight
 Being overweight

– increases CHD mortality risk
– increases Total Cholesterol & LDL-C
– decreases HDL-C
– increases VLDL-TG
BMI and Prevalence of Hypercholesterolemia
NHANES III
BMI and Prevalence of Low HDL
NHANES III
Obesity and Diabetes Mellitus
80% of diabetics are overweight
 Prevalence

– 7th most frequent cause of death
– 11 million cases in US
Diabetes Prevalence
1994 & 2002
Millions of Cases of Diabetes in 2000 and Projections for 2030, with
Projected Percent Changes. NEJM 356:213-215(2007)
Obesity and Diabetes Mellitus

Type 1 DM (IDDM) (10-15%)
– absolute deficiency of insulin
– not associated with obesity

Type 2 DM (NIDDM) (80%)
– peripheral insulin resistance
– highly associated with overweight
– weight loss cornerstone of treatment
Complications of Diabetes

Micro-angiopathies
– blindness
– renal failure
– amputations
 uncontrolled
infections,
numbness

Macro-angiopathies
– coronary heart disease
Diagnostic Criteria for Diabetes
(2005)

Fasting blood glucose > 126 mg/dl
– 110-125mg/dl impaired glucose tolerance


Testing for all adults over 45 years every 3
years
Testing earlier or more frequently
– if BMI > 25 plus
 CVD
risk factors
 At risk ethnicity
 Family history
 Chronic inactivity
 History of gestational diabetes
Obesity and Stroke
Hypertension and Stroke
 Obesity and Hypertension
Prevalence

– 35% of obese have hpt
– 17% of desirable BMI have hpt

Diagnostic Criteria
– systolic BP > 140 or
– diastolic BP > 90
BMI and Prevalence of Hypertension
Prevalence of the Metabolic Syndrome
Among US Adults
JAMA, 287: 356-359 (2002)

Definition
– Cluster of risk factors resulting in substantial increased
risk for developing diabetes and cardiovascular disease
(NCEP-ATP III)

Criteria: three or more of the following
–
–
–
–
–
Abdominal obesity (m>40”, f>35”)
Hypertriglyceridemia (>150mg/dl)
Low HDL-C (m<40mg/dl, f<50mg/dl)
Hi blood pressure (>130/85)
Hi fasting blood glucose (>110 mg/dl)
Prevalence of the Metabolic Syndrome
Among US Adults
JAMA, 287: 356-359 (2002)

NHANES III (1988-1994)
– 8814 adults

Results:
–
–
–
–
Age adjusted prevalence: 24%
Prevalence increased with age
Prevalence increased in Hispanic-Americans
Prevalence similar in white males & females
 Higher
in black and Hispanic females than males
Obesity and Cancer

Positive association with:
– Breast Cancer (post menopause)
– Colon Cancer
– Prostate Cancer
– Endometrial Cancer

Essentially all except lung
cancer
Overweight, Obesity, and Mortality from Cancer in a Prospectively
Studied Cohort of U.S. Adults
NEJM 348:1625(April 2003)

900,000 adults
– Prospective study, free of cancer
 Self
reported height/body weight in beginning
– 16 year follow up
– ~57,000 cancer deaths
Obesity and Mortality from Cancer
NEJM April 2003
Under Fitness vs Over Fatness?

Association of Physical Activity and Body Mass
Index With Novel and Traditional
Cardiovascular Biomarkers in Women Samia Mora,
MD, MHS; I-Min Lee, MBBS, ScD; Julie E. Buring, ScD; Paul M Ridker,
MD, MPH JAMA. 2006;295:1412-1419.

Women’s Health Study
– 27,158 healthy women (mean age = 55yrs)
– Randomized, placebo controlled for low-dose asprin
and vitamin E in primary prevention of CVD and
Cancer.
– Main outcome measures of this study:

Association of physical activity and BMI on CVD risk factors
Adjusted Odds Ratios for the Association of Quintiles of Physical Activity and
Quintiles of Body Mass Index With Elevated Biomarker Levels*
Mora, S. et al. JAMA 2006;295:1412-1419.
After adjusting for age, race, smoking, systolic blood pressure, diabetes, menopausal status, hormone use, and either
BMI or physical activity, both physical activity and BMI remained significantly associated in a linear manner with
Copyright restrictions may apply. most biomarker levels, with greater odds ratios (ORs) for BMI compared with physical activity
Association of Physical Activity and Body Mass Index Categories With
Cardiovascular Biomarkers
Mora, S. et al. JAMA 2006;295:1412-1419.
High BMI showed stronger associations with these biomarkers than physical inactivity,
but within BMI categories, physical activity was generally associated with more favorable
cardiovascular biomarker levels than inactivity.
Copyright restrictions may apply.
Association of Physical Activity and Body Mass
Index With Novel and Traditional Cardiovascular
Biomarkers in Women
Samia Mora, MD, MHS; I-Min Lee, MBBS, ScD; Julie E. Buring,
ScD; Paul M Ridker, MD, MPH JAMA. 2006;295:1412-1419.





Conclusions:
Both lower levels of physical activity and higher levels of
BMI were strongly and independently associated with
adverse inflammatory and lipid biomarker levels.
BMI showed greater magnitude of association with the
biomarkers
A modest level of physical activity was significantly
associated with more favorable biomarker profiles, even in
overweight or obese individuals.
The most favorable inflammatory and lipid levels were
found in women who had at least moderate physical
activity levels and were normal weight.
Another view:
Cardiorespiratory Fitness, Macronutrient Intake,
and the Metabolic Syndrome: The Aerobics Center
Longitudinal Study
JADA 2006; 106:673-679


~12,000 adult men and women enrolled in
prospective trial at the Cooper Clinic,
Dallas, TX
Cross-sectional epidemiological study
Odds of prevalent metabolic syndrome by fitness groups and BMI categories
1.2
1
Odds Ratio
0.8
Low fitness
0.6
Moderate fitness
High fitness
0.4
0.2
0
Normal w eight
Overw eight
Fitness was significantly and inversely associated with
prevalent metabolic syndrome in both normal and
overweight subjects. (however, researchers did not
report absolute risk of normal and overweight subjects)
The Cost of Obesity
Health Affairs, Aug 2006
Year
% of Medicare % of Medicare
Patients with
spending on
obesity
obese patients
1987
11.7%
9.4%
2002
22.5%
24.8%
$336 billion 2005 total Medicare expenses
Effects of Weight Loss on Health
The good news!
 Reduces
overall mortality
 Reduces risk factors
–
–
–
–
decreases plasma TG
decreases blood pressure
increases HDL-C, decreases LDL-C
decreases fasting blood glucose
The Effect of Weight Loss on Left
Ventricular Mass
NEJM 314: 334-339 (1986)
21 week, randomized control trial, n=41, young overweight patients
Hypertension and Weight Loss
in Men
Conclusion:
– modest weight loss results in
lowering of blood pressure in obese
men.
– effect of weight loss is comparable
if not better than with medication
Women, Weight Change, &
Hypertension
Ann. Internal Med. 128: 81-88
(1998)
 Nurse’s Health Study

– 1976 – 1992 (16 yr)
– 82,473 healthy females
– 16,395 new cases of hypertension
Women, Weight Change, & Hypertension
6
5.21
5
4
RR 3
1.74
2
1
0
1
no change
0.85
mod wt loss
0.74
sig wt loss
mod wt gain
severe wt gain
Long-term effects of modest weight loss in
Type II diabetic patients.
Arch. Int. Med. 147:1749-1753 (1987)
1 year,
Behavioral
weight control
program,
N=114 type 2
diabetics
Long-term effects of modest
weight loss in Type II diabetic
patients.

Conclusions:
–Modest weight loss results in
improved
glucose control
improved insulin sensitivity
reduced triglycerides
increased HDL-C
Prevention of Type 2 Diabetes Mellitus by
Changes in Lifestyle among Subjects with
Impaired Glucose Tolerance
 NEJM - May 2001
 522 middle age males
– BMI = 31
– w/ impaired glucose tolerance

3.2 year follow-up
– Intervention group
 individualized
wt. loss counseling
– Control group
 standard
advice
Prevention of Type 2 Diabetes Mellitus by
Changes in Lifestyle among Subjects with
Impaired Glucose Tolerance
 Weight Loss
– Intervention = 4.2 kg
– Control = 0.8 kg


Diabetes Incidence @ 3 years
– Intervention = 11%
– Control = 23%
“The reduction in the incidence of diabetes was
directly associated with changes in lifestyle”
Weight Cycling - Risk Factor?

Significant and deliberate fluctuations in
body weight
– Yo-yo dieting

Framingham Studies (1991)
– individuals with greatest weight fluctuations
had highest risk of overall mortality and
mortality & morbidity to coronary heart
disease.
Variability of body weight and health
outcomes in the Framingham population.
NEJM 324: 1839-1844 (1991)
Weight Cycling and
Cholecystectomy in Women


Ann. Internal Med. (Mar 1999)
Nurse’s Health Study
– (47,153 women, 30-55yr, w/o gall bladder
disease, 1972-1988)

Weight cycling history (1 episode
intentional)
– light = 5-9 lbs (20.1% of subjects)
– moderate = 10-19 lbs (18.8%)
– severe = >20 lbs (16%)
Weight Cycling and
Cholecystectomy in Women

Adjusted relative risk for cholecystectomy
compared to women who maintained their
weight:
– 1.20 for light cyclers
– 1.31 for moderate cyclers
– 1.68 for severe cyclers

Caused by:
– weight cycling?
– severity of obesity?
Intentional vs Unintentional
Weight Loss and Mortality in
Older Women.

Iowa Women’s Health Study
– 25,897 women (55-69 yrs)
– questionnaire regarding wt loss
since 18 yrs old
– followed 4 years
Intentional vs Unintentional
Weight Loss and Mortality in
Older Women.

Intentional wt loss (> 20 lbs):
– risk of total or CHD mortality not
affected

Unintentional wt loss:
– 26-57% greater mortality risk,
– 51-114% greater CHD risk

Increased mortality due to wt loss due
to pre-existing disease.
Weight Cycling: Health Risk
Factor?
NIH/NIDDK/WIN statements
 risk of remaining obese vs.
risk(?) of weight cycling
 underscores importance of lifelong changes in behaviors to attain
a healthy weight.

A Prospective Study of Weight Change
and Health-Related Quality of Life in
Women
 JAMA Dec. 1999
 Nurse’s Health Study
– 40,098 women, 4 yr longitudinal study
– Weight changes
– Quality of life questionnaire
Physical
function
Vitality
Freedom
from bodily pain
Mental health
The effect of weight gain/loss on:
Vitality Score

Weight gain:
– associated with
declines in
vitality scores in
all BMI
categories

Weight loss
– associated with
improved
vitality scores
only in women
with BMI>25
The effect of weight gain/loss on:
Mental Health Score

Weight gain
– associated with a
decline in mental
health scores in
all weight
categories

Weight loss
– associated with
improved mental
health scores only
in obese class I
women and
declined in
normal weight
women.
A Prospective Study of Weight Change and
Health-Related Quality of Life in Women.
Conclusions:
 For women at all BMI categories:
– Don’t gain weight
– Reduced quality of life

For overweight and obese women:
– Weight loss is generally associated with
improved quality of life

For normal weight women
– Weight loss does not improve quality of life
 May
actually reduce quality of life

Lose weight to improve health
– Optimal health attained at BMI = 18,5-25

Avoid trying to lose weight to look like a
media star
– Media stars often may
 Be
genetically thin
 Lose weight in unhealthy ways
 Actually not be all that thin
Jamie Lee Curtis
Before and after work with 13 experts & 3 hours
“True Thighs” More magazine, August 2002
"The retouching is excessive.
I do not look like that and
more importantly I don't
desire to look like that," she
said. "I actually have a
Polaroid that the
photographer gave me on the
day of the shoot… I can
tell you they've reduced the
size of my legs by about a
third. For my money it looks
pretty good the way it was
taken."