Obesity Epidemic Driving Stroke Surge in Middle-Aged Women

Caroline Cassels

February 21, 2008

February 21, 2008 (New Orleans, Louisiana) — A new study shows a surge in stroke prevalence among women in the United States is a new phenomenon that is driven primarily by the obesity epidemic.

In a presentation here at the American Stroke Association's International Stroke Conference 2008, investigators at the University of Southern California Stroke Center and University of California, Los Angeles (UCLA) Stroke Center found women between the ages of 35 to 54 years who participated in the National Health and Nutrition Examination Study from 1999 to 2004 (NHANES IV) had significantly greater mean body-mass index (BMI) and waist circumference than their counterparts who participated in NHANES III a decade earlier.

"When we compared prevalence data among men and women in NHANES III and NHANES IV, we found women's stroke prevalence had increased significantly, whereas men's remained stable. However, other than abdominal obesity, we found no significant differences [between the 2 studies] in terms of other factors, including cholesterol and blood pressure levels, that might account for this finding," principal investigator Amytis Towfighi, MD, told Medscape Neurology & Neurosurgery.

Midlife Stroke Surge

"In fact, in the NHANES IV study, more people were taking cholesterol-lowering and blood pressure medications, suggesting these risk factors were better controlled than in the earlier study," she added.

Early last year, Dr. Towfighi's group was the first to report an increase in stroke among women in mid-life compared with men.

The purpose of the current study, said Dr. Towfighi, was 3-fold. "We wanted to determine whether the higher stroke prevalence among women in mid-life was a new phenomenon, whether it was due to increasing stroke rates among women or decreasing stroke rates among men, and, if it was due to an increased prevalence among women, what was contributing to it," she said.

A total of 5112 and 4594 individuals participated in the NHANES III and IV studies, respectively. All of these individuals had answered a question about whether a physician ever told them they had had a stroke.

Historical vascular risk factors, clinical exam variables, and medication usage were compared, and participants were stratified by age and sex.

Recognizing At-Risk Patients

According to Dr. Towfighi the study found no significant difference in stroke prevalence among men and women aged 35 to 54 years between 1988 and 1994. However, this changed during the NHANES IV study period, when stroke prevalence among women in this age group was 1.8% vs 1% in men.

Abdominal obesity increased among both sexes. In NHANES III, 47% of women had a waist circumference of 35 inches or greater, vs 58.6% of women in NHANES IV. The percentage of men in NHANES III with abdominal obesity was 29.4%, vs 40.9% in the more recent study.

According to Dr. Towfighi, these results corroborate those of other studies showing the prevalence of abdominal obesity is greater among women. In addition, the study confirms previous findings that abdominal obesity has a greater impact on stroke risk among women than among men.

Potential pathophysiologic explanations for this are not clear and require further study, she said.

In the meantime, it is important that clinicians recognize the increased stroke risk assumed by young and middle-aged females with abdominal obesity and provide them with the support they need to effectively manage their weight.

The study was supported by a grant from the Iris Cantor-UCLA Women's Health Center. The authors report no disclosures related to the study.

International Stroke Conference 2008: Abstract P241. Presented February 20, 2008.

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