Nocturnal Blood Pressure
Dipping, Acculturation, and
the Metabolic Syndrome in
Hispanic Women
Smriti Shivpuri, M.S.
Linda C. Gallo, Ph.D.
San Diego State University/
University of California San Diego
Joint Doctoral Program in Clinical Psychology
Nocturnal Blood Pressure (NBP)
Dipping

NBP dipping defined as difference between diurnal and nocturnal
levels of BP

Typical NBP dipping in adults 10-20%

Classification
 “Non-dippers”
<10%
 “Dippers”
>/= 10%
 “Extreme Dippers”
>20%
 “Reverse Dippers”
higher nocturnal BP
NBP Dipping and Cardiovascular
Disease (CVD) Outcomes

Non-dipping linked to increased risk of a variety of CVD outcomes:
 Heart failure, Myocardial Infarction1
 Stroke2
 Sudden Death1
 Target Organ damage3
 Carotid IMT4
 Left ventricular hypertrophy5

Mediating physiological mechanisms poorly understood
Metabolic Syndrome (MetSyn)

Syndrome characterized by constellation of risk factors of metabolic
origin

Defined by NCEP ATPIIIa as 3 of following (women):
El eva te d B P
A bdo m in al O b esity
At h er o ge n ic Dysl ip id em ia
In su li n Resist an ce
aNational
Syst o lic B P (S B P )  130 OR D ia st o lic BP (D B P)  85
Wa ist Circ u m fere n ce > 88 cm (> 35 in )
HDL C ho lester o l < 50 m g /d L, T riglyceri d es  1 50 m g /d L
F a sting g lu co se  110 m g/d L
Cholesterol Education Program Adult Treatment Panel III
Metabolic Syndrome

MetSyn may be mediating mechanism between NBP dipping and
CVD

Associated with almost three-fold increased risk of CVD6

Research addressing association between NBP dipping and the
MetSyn is limited

Linked to NBP Dipping in some studies
 Greater prevalence of MetSyn in non-dippers versus dippers7,8, 9
 Higher mean score of MetSyn (when measured continuously) in
non-dippers than dippers10
 No association in other studies11
NBP Dipping in Hispanics

Evidence exists that NBP Dipping differs by race
 African-Americans more likely to have “blunted” NBP Dipping
than non-Hispanic Whites, and be classified as non-dippers12,13

Little to no work to date on NBP Dipping and CVD outcomes in
Hispanics
 Some evidence that Hispanic men may be more likely to be
non-dippers than non-Hispanic Whites, but not true for Hispanic
women14
 One study found greater odds of stroke in nondippers versus
dippers for African-Americans and non-Hispanic Whites, but not
in Caribbean Hispanics15
NBP Dipping and MetSyn in
Hispanics

Among ethnic minority groups
in U.S., Mexican-Americans
have one of highest rates of
MetSyn16

No studies have looked at link
between NBP Dipping and
MetSyn in Hispanics or nondiseased populations, or
examined whether
acculturation, which has been
shown to affect the
relationship between risk
factors and CVD outcomes,
moderates relationship
Note. Image courtesy http://img.medscape.com/slide/migrated/editorial/cmecircle/2006/5186/images/caballero/slide032.gif
Current Study

Purpose: To examine relationship between NBP dipping and
MetSyn in Mexican-American women and explore whether
association is modified by acculturation level

Sample: 277 middle-aged (M=49.56yrs) healthy Mexican-American
women, recruited from South San Diego border community


Inclusion criteria: age between 40-65 years, Mexican-American
ethnicity, literate in English or Spanish, and free of major health
conditions (e.g., CVD, cancer) and medications with autonomic effects
Methods: Completed battery of questionnaires assessing
sociodemographic, health history/behavior, and psychosocial
factors, and next day underwent assessment of MetSyn
components and completed 36hr ambulatory BP (AmBP) protocol
Assessment

NBP Dipping




Acculturation



AmBP monitor recorded participants’ BP every half hour during day, every hour
during night
Resulted in an average of 60 BP readings per person over 36 hours
Calculated as : (average diurnal BP - average NBP)/ average diurnal BP*100
Measured using preferred language version of survey (commonly used proxy)
Low Acculturated (Spanish) = 0; High Acculturated (English) = 1
MetSyn (defined using NCEP ATP III criteria)



Waist circumference, height, weight measured by trained assessors
Average SBP, DBP recorded as mean of 3 measurements while seated
Glucose, HDL, triglycerides obtained through fasting blood draw
Analyses

Hierarchical Linear Modeling (HLM) used to obtain average diurnal
and nocturnal BP levels across repeated measurements while
accounting for nesting of measurements within individuals

Logistic Regression used to test effects of NBP dipping (SBP and
DBP), acculturation, and their interaction on probability of MetSyn

Covariates (identified from prior research) included:




Average daytime BP
Age
Body Mass Index
Socioeconomic status (measured by educational attainment)
Results

No significant association between Diastolic BP dipping or Diastolic
NBP dipping*Acculturation interaction and MetSyn

Significant Systolic NBP (NSBP) dipping*Acculturation interaction
B
Age
Educat ion
Avg Da y SBP
BMI
NSBP D ipp ing
Accu lturat ion
Constant
NSBP
D ipp ing *
Accu lturat ion
S.E.
0.0 3 7
-0.0 5 1
0.0 3 5
0.1 8 7
0.0 1 2
0.0 4 7
-12. 4 71
0.1 6 3
0.0
0.0
0.0
0.0
0.0
0.3
2.3
Wald
df
Sig.
95% C.I. for
EXP(B)
Lower
Upper
Exp(B)
27
44
15
34
29
95
81
1.9 3 1
1.3 0 4
5.0 6 7
29. 7 69
0.1 7 7
0.0 1 4
27. 4 32
1
1
1
1
1
1
1
0.1
0.2
0.0
0.0
0.6
0.9
65
54
24
00
74
05
0
0.0 6 3
6.8 4 1
1
0.0 0 9
1.0
0.9
1.0
1.2
1.0
1.0
38
51
35
06
12
48
0
1.1 7 8
0.9
0.8
1.0
1.1
0.9
0.4
85
72
04
28
56
83
1.0 9 3
1.0 3 7
1.0 6 7
1.29
1.0 7 2
2.2 7 5
1.0 4 2
1.3 3 1
Results

Decreased NSBP dipping associated with increased risk for MetSyn (i.e.,
increased NSBP dipping protective), but only for high acculturated women
Association between Gradations of Systolic NBP (NSBP)
Dipping and Odds of MetSyn in High Acculturated women
§
*
*
* p < .05
§
Odds Ratios
p<.10
Conclusions

Systolic NBP dipping associated with MetSyn in high-acculturated
but not low-acculturated Mexican-American women


Each 10% decrease in dipping associated with 3.67 increased odds of
MetSyn
Trend for non-dippers having three fold greater odds of MetSyn as
compared to dippers (p=.06)

Diastolic NBP dipping not associated with MetSyn

Finding suggests mechanisms by which NBP dipping relate to
MetSyn may differ by acculturation

Less acculturated, more traditional women may be buffered
against harmful metabolic effects of increased blood pressure load
Potential Buffering Mechanisms

Sociodemographic Factors


Psychosocial Factors


Marital Status, Income
Social support, Anger, Hostility, Chronic Stress, Racism
Behavioral Factors

Smoking, alcohol consumption, physical activity

Addition of these factors in exploratory follow-up analyses
attenuated interaction effect, but it remained statistically significant

Interestingly, for high-acculturated women NSBP dipping
associated with DBP, waist circumference and HDL components of
MetSyn; for low-acculturated, only waist circumference
Limitations/Future Directions

Limitations




Cross-sectional study
Ambulatory BP measurement for dipping only 36 hour cycle
No gender or ethnic comparisons possible
Future directions



Explore whether NBP dipping association with CVD outcomes varies
by acculturation status in Hispanics
Determine whether NBP dipping is related to other, non-metabolic
factors in low-acculturated Hispanics (e.g., serum uric acid levels,
hyperthyroidism, hyperaldosteronism)17
Cross-gender and cross-ethnic comparisons with Hispanics on
association between NBP dipping and CVD outcomes
References
1.
Staessen, J., Thijs, L., Fagard, R., O'Brien, E., Clement, D., de Leeuw, P., & …Webster, J.
(1999). Predicting cardiovascular risk using conventional vs ambulatory blood pressure in
older patients with systolic hypertension. Systolic Hypertension in Europe Trial Investigators.
JAMA: The Journal Of The American Medical Association, 282(6), 539-546
2.
Kabutoya, T., Hoshide, S., Ishikawa, J., Eguchi, K., Shimada, K., & Kario, K. (2010). The
effect of pulse rate and blood pressure dipping status on the risk of stroke and cardiovascular
disease in Japanese hypertensive patients. American Journal Of Hypertension, 23(7), 749755
3.
Sega, R., Facchetti, R., Bombelli, M., Cesana, G., Corrao, G., Grassi, G., & Mancia, G.
(2005). Prognostic value of ambulatory and home blood pressures compared with office blood
pressure in the general population: follow-up results from the Pressioni Arteriose Monitorate e
Loro Associazioni (PAMELA) study. Circulation, 111(14), 1777-1783
4.
Alioglu, E., Turk, U., Bicak, F., Tengiz, I., Atila, D., Barisik, V., & ... Akin, M. (2008). Vascular
endothelial functions, carotid intima-media thickness, and soluble CD40 ligand levels in dipper
and nondipper essential hypertensive patients. Clinical Research In Cardiology: Official
Journal Of The German Cardiac Society, 97(7), 457-462
References
5.
Cuspidi, C., Giudici, V., Negri, F., & Sala, C. (2010). Nocturnal nondipping and left ventricular
hypertrophy in hypertension: an updated review. Expert Review Of Cardiovascular Therapy,
8(6), 781-792.
6.
Wilson, P., D'Agostino, R., Parise, H., Sullivan, L., & Meigs, J. (2005). Metabolic syndrome as
a precursor of cardiovascular disease and type 2 diabetes mellitus. Circulation, 112(20),
3066-3072.
7.
Ayala, D., Hermida, R., Chayan, L., Mojón, A., Fontao, M., & Fernández, J. (2009). Circadian
pattern of ambulatory blood pressure in untreated hypertensive patients with and without
metabolic syndrome. Chronobiology International, 26(6), 1189-1205.
8.
Hassan, M., Jaju, D., Albarwani, S., Al-Yahyaee, S., Al-Hadabi, S., Lopez-Alvarenga, J., & ...
Bayoumi, R. (2007). Non-dipping blood pressure in the metabolic syndrome among Arabs of
the Oman family study. Obesity (Silver Spring, Md.), 15(10), 2445-2453.
9.
Hermida, R., Chayán, L., Ayala, D., Mojón, A., Domínguez, M., Fontao, M., & ... Fernández, J. (2009).
Association of metabolic syndrome and blood pressure nondipping profile in untreated hypertension.
American Journal Of Hypertension, 22(3), 307-313.
References
10.
Tartan, Z., Uyarel, H., Kasikcioglu, H., Alper, A., Ozay, B., Bilsel, T., & ... Cam, N. (2006).
Metabolic syndrome as a predictor of non-dipping hypertension. The Tohoku Journal Of
Experimental Medicine, 210(1), 57-66.
11.
Cuspidi, C., Meani, S., Fusi, V., Severgnini, B., Valerio, C., Catini, E., & ... Zanchetti, A.
(2004). Is the nocturnal fall in blood pressure reduced in essential hypertensive patients with
metabolic syndrome?. Blood Pressure, 13(4), 230-235.
12.
Ancoli-Israel, S., Stepnowsky, C., Dimsdale, J., Marler, M., Cohen-Zion, M., & Johnson, S.
(2002). The effect of race and sleep-disordered breathing on nocturnal BP "dipping": analysis
in an older population. Chest, 122(4), 1148-1155
13.
Sherwood, A., Thurston, R., Steffen, P., Blumenthal, J., Waugh, R., & Hinderliter, A. (2001).
Blunted nighttime blood pressure dipping in postmenopausal women. American Journal Of
Hypertension, 14(8 Pt 1), 749-754.
14.
Hyman, D., Ogbonnaya, K., Taylor, A., Ho, K., & Pavlik, V. (2000). Ethnic differences in
nocturnal blood pressure decline in treated hypertensives. American Journal Of Hypertension,
13(8), 884-891
References
15.
Phillips, R., Sheinart, K., Godbold, J., Mahboob, R., & Tuhrim, S. (2000). The association of
blunted nocturnal blood pressure dip and stroke in a multiethnic population. American Journal
Of Hypertension, 13(12), 1250-1255.
16.
Ford, E., Giles, W., & Dietz, W. (2002). Prevalence of the metabolic syndrome among US
adults: findings from the third National Health and Nutrition Examination Survey. JAMA: The
Journal Of The American Medical Association, 287(3), 356-359.
17.
Kanbay, M., Turgut, F., Uyar, M., Akcay, A., & Covic, A. (2008). Causes and mechanisms of
nondipping hypertension. Clinical And Experimental Hypertension (New York, N.Y.: 1993),
30(7), 585-597