Feb. 20, 2008 (New Orleans) -- Bulging waistlines may be to blame for a rise in strokes among middle-aged women, researchers report.
In a large national study, weight gain, especially around the waist, was linked to an increase in strokes among women aged 35 to 54.
"Women ages 35 to 54 have higher stroke rates than men of those ages, and this is likely due to increasing rates of abdominal obesity," says researcher Amytis Towfighi, MD, an assistant professor of neurology at the University of Southern California in Los Angeles.
That gives weight to their hefty hypothesis, says Ralph Sacco, MD. Sacco, an American Stroke Association (ASA) spokesman and head of neurology at the University of Miami, was not involved with the research.
The findings are "alarming," he tells WebMD.
The study was presented at the ASA's International Stroke Conference.
Stroke Rates Higher in Women Than in Men
The new work builds on previous research that showed that between 1999 and 2004, women aged 45 to 54 were more than twice as likely as their male counterparts to report having had a stroke.
To determine if the gender gap was a real phenomenon or a fluke, the researchers analyzed data from the National Health and Nutrition Examination Survey done from 1988 to 1994 and from 1999 to 2004.
It was real, Towfighi says. The stroke rates among women aged 35 to 54 tripled from the earlier time period to the later period: from 0.6% to 1.8%. The stroke rate among middle-aged men remained stable, at about 1%.
"We did not find significant differences in presence of conventional cardiovascular risk factors," Towfighi says.
Obesity on the Rise
But the percentage of women who had abdominal obesity -- a waist circumference of 35 inches or more -- jumped from 47% in the first study to 59% in the later study. Among men, it increased from 29% to 41%.
Looked at another way, women in the latter survey had an average waist circumference of nearly 1.6 inches more than women in the earlier study.
Towfighi says that for reasons that are not yet understood, "abdominal obesity is a stronger risk factor for stroke in women."
Body mass index (BMI), a measure of obesity, also rose slightly more in women than in men. The average BMI for women in the later study was 28.7, compared with 27.1 in the earlier study. The corresponding figures for men were 28.4 and 27.2. A BMI of 25.0 to 29.9 is considered overweight, while a BMI of 30 or more is considered obese.
In addition, women in the second study showed signs of poorer blood sugar control than in the past, Towfighi says.
The findings reinforce advice to keep your weight down, through a healthy diet and regular exercise, she tells WebMD. People who are overweight or who are told by their doctors that they have poor blood sugar control should avoid a lot of starches and sugars, she adds.