Stroke risks fade when women stop taking estrogen

[April 06, 2011]  CHICAGO (AP) -- Strokes and other health problems linked with estrogen pills appear to fade when women quit taking them after menopause, the first long-term follow-up of a landmark study found. It's reassuring news for women who take the hormone in their 50s when menopause usually begins.

The latest study bolsters previous evidence that concerns about breast cancer and heart attacks are largely unfounded for those who take the hormone for a short period of time to relieve hot flashes and other menopause symptoms.

Estrogen-only pills are recommended just for women who have had a hysterectomy, and the study focused only on that group. About 25 percent of women in menopause have had hysterectomies. Other women are prescribed a combination pill of estrogen and progestin because for them, estrogen alone can raise the risk for cancer of the uterus.

The study results don't really change the advice doctors have been giving for several years now: Take hormones to relieve menopause symptoms in the lowest possible dose for the shortest possible time.

The women in the study took estrogen for about six years and were evaluated for about four years after stopping. Slightly increased risks for strokes and blood clots that were found while they took the pills disappeared during the follow-up. Unfortunately, the bone-strengthening benefit of estrogen disappeared, too. Once women ended it, they had just as many hip fractures during the follow-up as women who'd taken dummy pills.

The research also found that women who started taking estrogen-only pills in their 50s fared better after stopping than women who'd started in their 70s -- an age when hormones are generally no longer recommended.

"Our results emphasize the need to counsel women about hormone therapy differently depending on their age and hysterectomy status," the researchers said in reporting the study to be published in Wednesday's Journal of the American Medical Association.

The new results are from 10,739 participants in the estrogen-only part of the federal government's Women's Health Initiative study -- research which shook up conventional wisdom about health benefits of hormones for menopausal women. Study of the estrogen-progestin group was halted in 2002 when risks for heart attacks and breast cancer were linked with the combination hormone pills. The estrogen-only study was halted in 2004 after stroke risks were seen in that group.

The troubling findings prompted many doctors to stop prescribing the pills to prevent chronic health problems and led millions of women to quit taking them.

Doctors now generally recommend hormones only to relieve hot flashes, night sweats that disrupt sleep and vaginal dryness in the lowest possible dose for the shortest possible time. Dr. Jacques Rossouw, who directed the initial research at the National Institutes of Health, said the estrogen follow-up results reinforce guidance "that women can use it shortly after the menopause for a limited period of time and then stop."

When the research began in the 1990s, doctors were still prescribing hormones after menopause, based on the belief the pills were good for bones, the heart and had other benefits beyond relieving menopause symptoms. So the women in the WHI study were taking hormones after menopause, rather than using them to relieve symptoms.

The women in the new study were in their 60s on average, nearly a decade past the age when most women enter menopause. So the overall results don't necessarily apply to the average U.S. woman now weighing the pros and cons of taking hormones.

One surprising twist in the results: The younger estrogen-takers actually had a lower risk for heart problems, breast cancer and death than those taking dummy pills. Researchers don't know why and say women should not use that as a reason to take hormones. They hope answers may be found in further research.

The results suggest that for every 10,000 women in their 50s taking estrogen for a year, there would be 12 fewer heart attacks and 13 fewer deaths than among women not on estrogen, said Dr. JoAnn Manson, a study co-author and chief of preventive medicine at Harvard's Brigham and Women's Hospital.

However, using the same comparison for women in their 70s, there would be 16 extra heart attacks and 19 extra deaths for those on estrogen versus those not taking the pills, she said.

"It's really powerful and compelling evidence," Manson said.

Breast cancer also appeared to be less common in women who'd taken estrogen than among those on dummy pills. An editorial accompanying the study notes that those findings contrast with many studies linking estrogen pills with an increased breast cancer risk.

Andrea LaCroix, the study's lead author and a researcher at the Fred Hutchinson Cancer Research Center in Seattle, said it's possible that estrogen didn't have a harmful effect on breast tissue in women studied because they were taken well after menopause when women's naturally occurring estrogen levels have declined.

Dr. Graham Colditz, a Washington University researcher who co-wrote the editorial, noted that duration of estrogen use as directed was pretty short during the study, averaging about 3 1/2 years, and most women started taking the hormone years after a hysterectomy or after menstrual periods ended.

"The results really don't directly translate to how we see women getting hormone therapy in the real world of current American medicine," Colditz said.

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Online:

JAMA: http://jama.ama-assn.org/

Women's Health Initiative:
http://www.nhlbi.nih.gov/whi/

[Associated Press; By LINDSEY TANNER]

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