Obese middle-aged women face a higher risk of stroke compared to healthy women of their age, a new study revealed.

Strokes, which occur when blood flow to the brain is blocked, can kill brain tissue and are one of the worldwide leading causes of death and permanent disability. Treatments include blood thinning drugs and attempts to lower cholesterol.

Experts from the University of South Carolina led by Dr. Amytis Twofighi, a neurology specialist, compared data from two federal health studies: National Health and Nutrition Surveys 1988-1994 (NHANES III) and NHANES 1999-2004.

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%.

The researchers blame the weight gain, especially around the waist, for this problem.

"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,” Dr. Towfighi said in the study presented at the American Stroke Association's International Stroke Conference.

The researchers found that the portion of women with abdominal obesity rose from 47 percent in the earlier survey to 59 percent in the recent years.

The study also found that the waistline of women involved in the 1999-2004 study had an average of 5 centimeters more than those in the 1988- 1994-study.

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.

Moreover, women in the second study showed signs of poorer blood sugar control than in the past, the study say.

The results of the study are meant to trigger an alarm signal for women who should keep their weight down through a healthy diet and regular exercise. They always seem to work when it comes to a better life.

"This study highlights the need to intensify efforts in curbing the obesity epidemic in the United States," said Dr. Towfighi.

Statistics show that stroke is the third leading cause of death and a major cause of long-term disability in the United States.