Strokes have tripled in recent years among middle-aged women in the United States, an alarming trend doctors blame on the obesity epidemic.
Nearly 2 percent of women ages 35 to 54 reported suffering a stroke in the most recent federal health survey, from 1999 to 2004. Only about half a percent did in the previous survey, from 1988 to 1994.
The percentage is small because most strokes occur in older people. But the sudden spike in middle age and the reasons behind it are ominous, doctors said in research presented Wednesday at a medical conference. It happened even though more women in the recent survey were on medicines to control their cholesterol and blood pressure - steps that lower the risk of stroke.
Women's waistlines are nearly 2 inches bigger than they were a decade earlier, and that bulge corresponds with the increase in strokes, researchers said. In addition, women's average body mass index, a commonly used measure of obesity, rose from 27 in the earlier survey to 29. A BMI of 25 to 29.9 is considered overweight; BMI of 30 or greater is considered obese. The women also had higher blood sugar levels.
No other traditional risk factors like smoking, heart disease or diabetes changed enough between the two surveys to account for the increase in strokes.
In a prestroke population of middle-aged women, a tripling of cases is "an alarming increase," said Dr. Ralph Sacco, neurology chief at the University of Miami Miller School of Medicine.
The study was led by Dr. Amytis Towfighi, a neurology specialist at the University of Southern California in Los Angeles, and presented at the International Stroke Conference in New Orleans.
She used the National Health and Nutrition Surveys, a federally funded project that gives periodic health checkups and questionnaires to a wide sample of Americans.
Participants are routinely asked whether a doctor had ever told them they had had a stroke, and about 5,000 middle-aged people answered that question in each survey.
Researchers saw that the stroke rate had spiked in middle-aged women but stayed about the same - around 1 percent - in middle-aged men. So they looked deeper at the responses to see if they could learn why. Belly fat stood out, Towfighi said. The portion of women with abdominal obesity rose from 47 percent in the earlier survey to 59 percent in the recent one.
BY THE NUMBERS
Bulging waists, more strokes?
59 Percentage of women ages 35 to 54 with abdominal obesity in most recent federal survey (1999 to 2004).
47 Percentage with abdominal obesity in the previous survey (1988 to 1994).
2 inches. Approximate increase in middle-aged women's waistlines from a decade ago.