by Martha Kerr

Last Updated: 2008-02-26 11:23:41 -0400 (Reuters Health)

NEW ORLEANS (Reuters Health) – The rapidly rising incidence of stroke among Americans is primarily due to the increasing numbers of middle-aged women with stroke, and is associated with abdominal obesity, investigators told attendees at the American Stroke Association’s International Stroke Conference 2008.

"The incidence of stroke is two times higher in women than men between the ages of 35 and 54," announced Dr. Amytis Towfighi of the University of Southern California, Los Angeles.

Dr. Towfighi and colleagues analyzed data from the National Health and Nutrition Surveys (NHANES) conducted in 1988-1994 (5,112 participants) and in 1999-2004 (4,594 participants).

Dr. Towfighi said that women aged 35 to 54 years who reported a history of stroke accounted for 1.79% of the 1999-2004 study population but only 0.63% of women in the same age bracket in the 1988-1994 survey. "The number of middle-aged women with stroke tripled," she pointed out.

"Traditional biomarkers and risk factors such as diabetes, cardiovascular disease and hypertension didn’t change" between the two surveys, Dr. Towfighi said. "However, waist circumference and body mass index increased significantly."

Waist circumference and BMI also increased among men in the same age bracket, but not as sharply as in women.

She said that 47% of women in the earlier survey qualified as having abdominal obesity, with a waist circumference of 88 cm or greater, while 59% of women had abdominal obesity in the later survey. The proportion of men with abdominal obesity increased from 29% to 41%.

"There is no good explanation for why abdominal obesity has a greater impact on stroke in women, except that it is one of the defining features of the metabolic syndrome, and the metabolic syndrome has a significantly greater effect on women than men," Dr. Towfighi told Reuters Health. Stroke may be one of those effects that women experience, she added.

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