Middle-Aged Women Gaining Weight,
Raising Their Stroke Risk

ED EDELSON / HealthDay News 20feb2008

image source: 21feb2008

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 Dr. Amytis Towfighi, an assistant professor of neurology at the University of Southern California, who was expected to report the findings Wednesday at an American Stroke Association's International Stroke Conference in New Orleans.

Most stroke studies focus on older people, but the incidence of stroke in women aged 35 to 54 is twice as high as in men of the same age, 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.

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

"In women, waist circumference increased significantly, as did the prevalence of obesity," 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, a measure of obesity, rose from 27.11 in the earlier study to 28.67 in the later study. And 14.8 percent of the women in the later study reported using medications to lower blood pressure, up from 8.9 percent in the earlier study. Almost 4 percent of women in the later study said they were taking medication to lower cholesterol, compared to 1.4 percent in the earlier study.

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

The relationship makes sense, said Daniel T. Lackland, a professor of epidemiology at the University of South Carolina, and a spokesman 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.

But it's difficult to disentangle the various risk factors that circle around obesity, 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 high cholesterol levels. "Is obesity an independent risk factor for stroke? The study was not designed to show that."

The study does reinforce the standing advice to avoid obesity, as well as other stroke risk factors, 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.

A recent national study found that uncontrolled hypertension rates are increasing among American women of all ages, with 22 percent of women having high blood pressure in the early 2000s, compared to 17 percent in the 1990s. The incidence among American men dropped from 19 percent to 17 percent during that same period, but the rate of decline among men has slowed, the study found.

More information

Stroke and its causes are described by the American Heart Association.

SOURCES: Amytis Towfighi, M.D., assistant professor, neurology, University of Southern California, Los Angeles; Daniel T. Lackland, Ph.D., professor, epidemiology, University of South Carolina, Charleston; Feb. 20, 2008, presentation, American Stroke Association's International Stroke Conference, New Orleans

source: 21feb2008

Obesity Linked To Stroke Increase
Among Middle-aged Women

ScienceDaily 21feb2008

Middle-aged women's waists aren't the only thing that increased in the last decade. So did their chance of stroke. In a new study reported at the American Stroke Association's International Stroke Conference 2008, rising obesity rates have been linked to more strokes among women aged 35 to 54.

A previous analysis of stroke prevalence rates in the United States from 1999 to 2004 revealed that women in their midlife years were more than twice as likely as men of similar age to report having had a stroke, said Amytis Towfighi, M.D., an assistant professor in the Neurology Department at the University of Southern California in Los Angeles, Ca.

To determine if this was a new phenomenon and to explore the potential contributions of vascular risk factors to stroke prevalence rates, researchers analyzed data from the National Health and Nutrition Surveys 1988--1994 (NHANES III) and 1999--2004. Researchers found that while 1.79 percent of women ages 35 to 54 who participated in NHANES reported having stroke, only 0.63 percent of women the same ages who participated in the earlier survey (NHANES III), reported stroke.

The analysis compared medical history variables (including smoking, diabetes mellitus, heart attack, high blood pressure), medication usage, and clinical markers among women in NHANES III and 1999--2004. Clinical markers evaluated included waist circumference, body mass index (BMI), total cholesterol, low density lipoprotein cholesterol (LDL), also known as bad cholesterol), and blood pressure.

"We did not find significant differences in presence of conventional cardiovascular risk factors, such as blood pressure, total cholesterol, LDL, smoking, heart disease, high blood pressure or diabetes, when we compared the two groups," said Towfighi, lead author of the study. Instead, women in the more recent survey were more likely to be using medications to control blood pressure and cholesterol. In fact, 14.8 percent of women in NHANES 1999--2004 reported using medications to lower blood pressure, compared to 8.9 percent in the earlier survey. Nearly 4 percent of women in NHANES 1999--2004 used medications to lower cholesterol, versus 1.4 percent in NHANES III.

"Women in NHANES 1999--2004 were significantly more obese than women a decade prior, with an average BMI of 28.67 kg/m2 versus 27.11 kg/m2 the decade prior," Towfighi said. BMI of 25.0 to 30.0 is considered overweight, while BMI of 30.1 or more is considered obese.

"In addition, women in NHANES 1999--2004 had an average waist circumference of nearly 4 centimeters more than women in the earlier study," Towfighi said. Women in NHANES 1999--2004 also had higher average glycated hemoglobin (an indicator of poor blood sugar control).

The researchers concluded that although key traditional risk factors, such as high blood pressure, may not be higher today than in the '90s, obesity and blood sugar markers are on the increase. "Abdominal obesity is a known predictor of stroke in women and may be a key factor in the midlife stroke surge in women," Towfighi said. "This study highlights the need to intensify efforts in curbing the obesity epidemic in the United States."

Co-authors are Rita Engelhardt, Dr.PH., and Bruce Ovbiagele, M.D., from the University of California at Los Angeles.

Adapted from materials provided by American Heart Association, via EurekAlert!, a service of AAAS.

source: 21feb2008