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Estrogen No Help for Stroke

Women who've had one attack not protected against another

TUESDAY, Oct. 30, 2001 (HealthDayNews) -- Older women with heart disease should not count on estrogen to stave off strokes, reports a new study.

"Unfortunately, the news is that estrogen is not effective for secondary prevention of stroke, and taking estrogen did not reduce the risk of stroke or death," says study author Catherine Viscoli, a research scientist at Yale University's Internal Medicine Department in New Haven, Conn. "We cannot recommend therapy with estrogen for secondary prevention of stroke."

Results of the Yale study, funded by the National Institute of Neurological Disorders, echo those reported in 1998 from one of the largest studies of hormone replacement therapy ever conducted, called the Heart and Estrogen/Progestin Replacement study (HERS). It examined 2,700 women with heart disease at 18 sites nationwide.

"Their population was with postmenopausal women who had cardiac disease, [and] their trial was negative also," Viscoli says.

Studies have shown that the loss of natural estrogen as women age may contribute to a higher risk of cardiovascular disease after menopause, leading researchers to surmise that estrogen plays some kind of role, says the American Heart Association. If menopause is caused by surgery to remove the uterus and ovaries, for instance, the risk rises sharply. If menopause occurs naturally, the risk rises more slowly. Also, women who have had a stroke are at much higher risk for another one, the association reports.

More than 97,000 American women died from strokes in 1998.

Having a "mini-stroke," medically known as a transient ischemic attack (TIA), is considered both a predictor and a risk factor for another stroke. Caused by the temporary reduction of blood flow to the brain as a result of tiny blood clots, a TIA can cause numbness or tingling, speech and balance difficulties as well as vision changes. Symptoms begin suddenly, last only a short time and disappear completely, usually within 24 hours.

"What we were interested in was if estrogen could be a prevention for secondary stroke or TIA," Viscoli says. "The data, early in the '90s suggested potential benefit of estrogen for cardiovascular and cerebellar vascular disease, but none of these were randomized, placebo-controlled studies, and that's considered the gold standard in determining the efficacy of a treatment."

The Yale study followed 664 women, with an average age of 71, who had had a stroke or a TIA in the previous 90 days. The women were divided into two groups, with one group receiving a placebo and the other a standard replacement course of estrogen.

Nearly three years later, doctors had recorded 99 strokes or deaths among the women taking estrogen, compared with 93 among those who'd been given a placebo.

In addition, the women taking estrogen were more prone to vaginal bleeding, cancer of the lining of the uterus and a more frequent need for hysterectomy. Findings appear in the current issue of the New England Journal of Medicine.

The results are disappointing, but not totally unexpected, says Dr. Rose Marie Robertson, professor of medicine at Vanderbilt University in Nashville, Tenn., and immediate past president of the heart association.

"Because the HERS trial suggested a lack of benefit in coronary heart disease, and there have been a number of studies that show there have been a small and insignificant increase in stroke from the use of estrogen, the results here are not entirely surprising," Robertson says.

But she says don't discount estrogen replacement entirely.

"Estrogen replacement therapy has many important benefits for women, including prevention of osteoporosis, treatment of hot flashes and treatment and prevention of vaginal atrophy," she says.

What To Do

The best defense against stroke is a good offense, Robertson says.

"What you need are lifestyle changes and aggressive treatment of all the modifiable risk factors for cardiovascular disease," she says. "Get your high blood pressure, high cholesterol under control. And for stroke in particular, it's very important that the presence of atrial fibrillation, a particular heart rhythm associated with stroke, be recognized and controlled."

To learn more about cardiovascular disease and estrogen, visit the American Heart Association Web site. And for more on stroke, try the National Stroke Association.

SOURCES: Interviews with Catherine Viscoli, Ph.D., research scientist, internal medicine department, Yale University, New Haven, Conn., and Rose Marie Robertson, M.D., professor of medicine, Vanderbilt University, Nashville, Tenn; Oct. 25, 2001, New England Journal of Medicine
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