Degree of obesity raises risk of stroke, regardless of gender, race

Jan 21, 2010

The higher a person's degree of obesity, the higher their risk of stroke -- regardless of race, gender and how obesity is measured, according to a new study published in Stroke: Journal of the American Heart Association.

"It has not been clear whether overweight and are risk factors for , especially among blacks," said Hiroshi Yatsuya, M.D., Ph.D., study lead author and visiting associate professor at the University of Minnesota in Minneapolis. "There are also questions about which measure of ( [BMI], or waist-to-hip ratio) is most closely associated with disease risk."

Analyzing the ARIC Study database in which subjects' BMI, waist circumference and waist-to-hip ratio were measured at the study's start, Yatsuya and colleagues followed 13,549 middle-aged black and white men and women in four U.S. communities from 1987 through 2005. Participants started the study free of cancer and cardiovascular disease.

During the follow-up period of about 19 years, 598 ischemic strokes occurred. The researchers calculated incidence rate -- the number of new cases per 1,000 people per year -- according to groups representing different degrees of obesity, using each obesity measure.

They found that incidence rates differed substantially between whites and blacks. For example, the stroke rate in the lowest BMI category was 1.2 per 1,000 person-years for white women and 4.3 per 1,000 person-years for black women. The rate in the highest BMI category was 2.2 for white women and 8.0 for black men.

"Black women had about three times higher incidence of stroke than in the lowest as well as in the highest BMI categories," Yatsuya said. "But the correlation between increasing stroke incidence and increasing degree of obesity was apparent in both races and genders."

Individuals in the highest BMI category had 1.43 to 2.12 times higher risk of stroke (varying modestly by race and sex) compared to the lowest BMI category. When waist circumference was used as a measure of obesity instead of BMI, those risk ratios ranged from 1.65 to 3.19; and 1.69 to 2.55 when waist-to-hip ratio was used. Thus, for any obesity measure, individuals in the highest category had approximately two times higher risk of stroke compared to the lowest category in each race-sex group.

"Since individuals with higher degrees of obesity tended to have higher blood pressure levels or higher diabetes prevalence, we further examined the relationship between the degree of obesity and incidence by statistically adjusting for difference in blood pressure of diabetes status attributed to the degree of obesity," Yatsuya said. "That significantly weakened the associations, suggesting these major risk factors explain much of the obesity-stroke association."

The study re-emphasizes the need to prevent obesity in general, Yatsuya said. But, he said, clinical trials would be needed to determine whether obesity prevention or control would actually decrease stroke incidence.

Explore further: Harmful drinkers would be affected 200 times more than low risk drinkers with an MUP

add to favorites email to friend print save as pdf

Related Stories

Obesity linked to stroke increase among middle-aged women

Feb 21, 2008

Middle-aged women’s waists aren’t the only thing that increased in the last decade. So did their chance of stroke. In a new study reported at the American Stroke Association’s International Stroke Conference 2008, ...

BMI and waist circumference

Dec 08, 2009

Body mass index (BMI) and waist circumference are well known risk factors for cardiovascular diseases (CVD), but a new study reported in the European Journal of Cardiovascular Prevention and Rehabilitation today now conclu ...

Recommended for you

Research looks to combat US Latina immigrant obesity

5 hours ago

According to the U.S. Census Bureau, Latinos are the largest minority group in the United States, comprising 16.7% of the population. Approximately one-third of Latinos are obese and are 1.2 times as likely to be obese compared ...

User comments : 0