Middle-aged American women are gaining weight, especially around the waist, while their risk of stroke has increased significantly, a new study finds.

"In this study, we can't determine exact cause and effect, but it suggests there might be a relationship," said Amytis Towfighi, MD, an assistant professor of neurology at the University of Southern California, who reported the findings at the American Stroke Association's International Stroke Conference in New Orleans.


Most stroke studies focus on older people, but the incidence of stroke in women ages 35 to 54 is twice as high as in men of the same age, Dr. Towfighi said. Using data from the National Health and Nutrition Studies done in 1988-1994 and 1999-2004, she and her colleagues looked at whether the risk of stroke in middle-aged women has increased and what the causes of such an increase might be.

Study Results

The increase is real, the study found. In the earlier study, 0.6% of women in the age group reported strokes, but that rose to 1.8% in the later study. Stroke incidence among men of the same age remained stable, with an incidence of about 1%.

"In women, waist circumference increased significantly, as did the prevalence of obesity," Dr. Towfighi noted. "There was no difference in the percentage of women who had diabetes, were smokers or who had hypertension."

Women in the later study had an average waist circumference that was 4 centimeters wider than women in the earlier study. Average body-mass index (or BMI, a measure of body fat based on height and weight) rose from 27.11 in the earlier study to 28.67 in the later study. (A BMI of 25 to 299 is considered overweight, 30 or above is obese.) And 14.8% of the women in the later study reported using medications to lower blood pressure, up from 89% in the earlier study. Almost 4% of women in the later study said they were taking medication to lower cholesterol, compared to 1.4% in the earlier study.

Possible Explanation

"Abdominal obesity is a known predictor of stroke in women and may be a key factor in the midlife stroke surge in women," said Dr. Towfighi.

The relationship makes sense, said Daniel T. Lackland, PhD, a professor of epidemiology at the University of South Carolina, and a spokesperson for the American Stroke Association. "People have shown that obesity does make a big difference in increasing the risk of stroke and cardiovascular disease," he said.

Other Risk Factors

But it's difficult to disentangle the various risk factors that circle around obesity, Dr. Lackland said. "What many have shown is that if you increase obesity, you increase the risk of high blood pressure, diabetes and also lipid abnormalities," he said, a reference to unhealthy cholesterol and triglyceride levels. "Is obesity an independent risk factor for stroke? The study was not designed to show that."

Reducing Stroke Risk

The study does reinforce the standing advice to avoid obesity, as well as other stroke risk factors, Dr. Lackland noted. "By losing weight, you lose abdominal circumference, you reduce the risk of diabetes and lipid abnormalities, all of which are known risk factors for cardiovascular disease," he said.

Migraines Raise Stroke Risk

In a study of 1,000 women, those who had migraine headaches at least twice a year preceded by visual auras (bright flashing dots, blind spots or distorted vision had a 50% greater risk for ischemic stroke (caused by a blood clot than women who did not have migraines.

If you suffer migraines with aura: Ask your doctor to monitor your stroke risk.

Minor Leg Injuries Increase Blood Clot Risk

Injuries that are not serious enough to be treated by a doctor, such as ankle sprains and pulled muscles, cause about 8% of all thromboses—serious clots that form inside the veins of the legs. The risk is low, but be aware of the potential danger. If you have a minor leg injury and pain and swelling increase over time or if you experience pain or difficulty breathing (possibly a sign of a pulmonary embolism, which is a blockage of the blood vessels to the lung caused by one or more blood clots, often originating in the leg), seek medical attention.

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