The more obese people are, the higher their risk of stroke—regardless of race, gender, and how obesity is measured, according to a study published in Stroke: Journal of the American Heart Association.
Lead author and University of Minnesota visiting associate professor Hiroshi Yatsuya, M.D., Ph.D., and colleagues evaluated the health of 13,549 middle-aged black and white men and women in four American communities (including one in Minnesota) from 1987 through 2005 as part of the Atherosclerosis Risk in Communities Study, sponsored by the National Heart, Lung, and Blood Institute.
At the start of the study, participants were free of cancer and cardiovascular disease. During the follow-up period, 598 ischemic strokes—which are caused by blockages of blood flow to the brain—occurred.
Yatsuya and colleagues examined stroke rates in groups of people based on different indicators of obesity, including body mass index (BMI), waist circumference, and waist-to-hip ratio. But any way they measured overweight, they reached a similar conclusion.
People who had the highest BMIs were 1.43 to 2.12 times more likely to have a stroke compared with people with the lowest BMIs, varying modestly by race and sex. When waist circumference was used as a measure of obesity, the most overweight group was 1.65 to 3.19 times more likely to suffer a stroke, and the highest waist-to-hip ratio group was 1.69 to 2.55 times more likely to have a stroke.
Because more obese people tended to have higher blood pressure and more cases of diabetes, Yatsuya’s group further examined the relationship between obesity and ischemic stroke by statistically adjusting for these factors.
“That significantly weakened the associations, suggesting these major risk factors explain much of the obesity-stroke association,” Yatsuya says.
The study results re-emphasize the need to prevent obesity in general, he says. But a more controlled study such as a clinical trial would be needed to determine whether obesity prevention or control could actually decrease stroke incidence, he adds.