Race- and sex-specific associations of obesity measures with ischemic stroke incidence in the Atherosclerosis Risk in Communities (ARIC) study.
OBJECTIVE
Studies have suggested differences in the association between obesity and ischemic stroke in black versus white populations. In this study, we explored ischemic stroke risk in relation to a variety of obesity measures by sex and race.


METHODS
Using data from the Atherosclerosis Risk in Communities Study, we obtained information on body mass index, waist circumference, and waist-to-hip ratio from 13 549 black and white participants who were aged 45 to 65 years between 1987 and 1989. All were free of cardiovascular disease and cancer at baseline. Incident strokes over a median follow-up of 16.9 years were ascertained from hospital records.


RESULTS
Although crude incidence rates of ischemic stroke varied more than 3-fold by race and sex, the relationship between higher measures of obesity and ischemic stroke risk was positive and linear across all groups. The crude incidence of ischemic stroke was 1.2 per 1000 person-years for white women with the lowest body mass index, ranging up to 8.0 per 1000 person-years for black men with the highest body mass index. Hazard ratios for the highest versus lowest quintile of body mass index, waist circumference, and waist-to-hip ratio ranged from 1.43 to 3.19, indicating increased stroke risk associated with obesity, however it was measured, even after adjustment for potential confounders. Additional adjustment for factors that may mediate the relationship, such as diabetes and hypertension, significantly attenuated the associations, suggesting that these factors may explain much of the stroke risk associated with obesity.


CONCLUSIONS
Degree of obesity, defined by body mass index, waist circumference, or waist-to-hip ratio, was a significant risk factor for ischemic stroke regardless of sex or race.
Yatsuya
Hiroshi
H
Division of Epidemiology & Community Health, School of Public Health, University of Minnesota, 1300 South 2nd Street, Suite 300, Minneapolis, Minn 55454, USA. yatsu002@umn.edu
Folsom
Aaron R
AR
Yamagishi
Kazumasa
K
North
Kari E
KE
Brancati
Frederick L
FL
Stevens
June
J
D050197:Atherosclerosis / Q000208:ethnology* / Q000235:genetics / Q000503:physiopathology; D015992:Body Mass Index; D001837:Body Weights and Measures / Q000592:standards; D002545:Brain Ischemia / Q000208:ethnology* / Q000235:genetics / Q000503:physiopathology; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000208:ethnology* / Q000235:genetics / Q000503:physiopathology; D044469:Racial Groups / Q000208:ethnology* / Q000235:genetics; D012111:Residence Characteristics; D012307:Risk Factors; D012727:Sex Characteristics; D055105:Waist Circumference / Q000502:physiology; D049629:Waist-Hip Ratio