CHICAGO, April 28 (Reuters) - Middle-aged women who take hormone replacement therapy to ease menopausal symptoms increase their risk of stroke, researchers said on Monday.
But the overall risk of stroke is low for women in their early 50s just entering menopause and the heightened risk may be minimal if they follow recommendations to take lower doses of the hormones for the shortest possible time.
Using data from 121,700 female nurses participating in the Nurses' Health Study, which began in 1976, researchers found women taking estrogen had a 39 percent increased risk of stroke compared to women who did not take the hormone.
Women taking an estrogen-progestin combination to protect against ovarian cancer had a 27 percent higher risk of stroke.
There were 360 strokes among women who did not take hormone therapy and 414 strokes among those who did.
The percentage increase in stroke risk was similar for women regardless of whether they were in their early 50s and newly menopausal, or older. But because the starting point for stroke risk among the younger women was lower -- 3.8 strokes per 10,000 women per year -- the percentage increase represented fewer additional cases of stroke.
"It added to up to two more cases of stroke per 10,000 women per year taking hormone therapy," Dr. JoAnn Manson of Harvard Medical School, who worked on the study, said in a telephone interview.
"And the risk could be further minimized by using lower doses of estrogen and limiting duration to only a few years," she said.
"If a woman is going to seek hormone therapy for treatment of hot flashes, night sweats, she's likely to do so soon after menopause. They tend to improve over time and to be worse early in menopause."
Manson and colleagues at Brigham and Women's Hospital and Harvard in Boston presented their findings in the Archives of Internal Medicine.
Taking hormone therapy to relieve hot flashes, night sweats and other symptoms has been controversial since 2002, when another study, the Women's Health Initiative, found it raises rates of breast cancer, heart attacks, blood clots and strokes.
But researchers have since honed the findings and made new recommendations that suggest hormone therapy remains an option for some menopausal women, if they need it.
"The key point is the risk of stroke with hormone therapy in recently menopausal women can be minimized by limiting the duration of treatment and using lower doses. That's the really key finding," Manson said.
Current guidelines call for a lower daily dose, 0.3 milligrams of oral conjugated estrogen, compared to the previous 0.625 milligram dose. The lower dose was found in the study to significantly lower stroke risk, she said.
Manson said an earlier finding about younger menopausal women suggested hormone therapy may actually protect them from heart disease. But that finding was inconclusive, and Manson said women should only take hormones if they need them. (Editing by Maggie Fox and Bill Trott)
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