Study: Estrogen's Effect May Depend on Age

Jun 21, 05:00 AM

Current Headlines: By Rita Rubin

Estrogen pills reduce the amount of calcified plaque in the coronary arteries of postmenopausal women in their 50s, a finding that should reassure women who need to take the hormone for relief of moderate to severe hot flashes, say the authors of a study out today.

The amount of calcified plaque foreshadows future risk of heart attacks. Still, no postmenopausal woman should take estrogen solely to protect her heart, the authors say.

"There are other known risks" of estrogen therapy, says lead author JoAnn Manson, chief of preventive medicine at Boston's Brigham and Women's Hospital. "It's unclear that the benefits would outweigh the risks" in women who aren't bothered by hot flashes.

Manson's team studied a subset of women in the Women's Health Initiative, a government-sponsored trial that randomly assigned more than 16,000 postmenopausal women ages 50 to 79 to hormone pills or sugar pills. The initiative was designed to look at whether estrogen really protected older women's hearts, as many doctors presumed.

The 1,064 women in the subgroup study had been randomly assigned to take Premarin, which contains only estrogen, or a placebo. They had all had hysterectomies, so they didn't need progestin, taken to protect the uterus against estrogen's cancer-causing effect.

Computerized tomography, or CT, was used to assess the women's coronary-artery calcium score. Women with no calcified plaque scored zero. Among women who took at least 80% of their study pills, those on estrogen were 60% less likely to score above 300.

The new study, in The New England Journal of Medicine, contributes to a better understanding of how age and time since menopause influence hormone therapy's effects, Manson says. An analysis of Women's Health Initiative data out in April found that the older a woman is, the more likely hormone therapy will increase heart disease risk.

In 2002, one arm of the Women's Health Initiative stopped earlier than planned because Prempro, a combination of estrogen and progestin, raised women's risk for heart attack, stroke, blood clots and breast cancer after an average of four years of treatment.

Less than two years later, a parallel study of Premarin stopped early because it showed that the hormone raised stroke risk after five years of treatment on average. Publicity about the Women's Health Initiative's initial findings scared many women out of taking hormones for symptom relief, says Columbia University endocrinologist Michelle Warren, who spoke at a press conference sponsored by Wyeth, maker of Prempro and Premarin.

"I have a big menopause practice, and no one wants to take hormones anymore," Warren, who was not involved with the Women's Health Initiative, said in an interview. "I hate to see patients suffer unnecessarily."

To see whether taking estrogen in early menopause protects against heart attacks when women are older, Manson says, researchers would probably have to follow 30,000 women for a decade -- a prohibitively expensive study. (c) Copyright 2005 USA TODAY, a division of Gannett Co. Inc.