DALLAS (AP) _ The influential American Heart Association is changing course and recommending that women not be prescribed estrogen solely to prevent strokes and heart disease, because of growing evidence that the supplements might cause harm.
Doctors long believed that hormone supplements are good for women's hearts. But the heart association _ one of the most authoritative organizations in the field of heart disease prevention _ cited conflicting evidence that has come out over the past few years.
Hormone supplements combining estrogen and progesterone are prescribed to about 20 million American women, mostly to treat hot flashes and other post-menopausal symptoms and to lower the risk of brittle bones.
The heart association said that women taking hormones for the non-cardiac benefits do not need to stop. But women should not start taking hormones simply to prevent heart trouble.
The new guidelines were published in Tuesday's issue of Circulation, a journal of the American Heart Association. They represent a shift from 1999, when the organization said that doctors may consider the use of hormones to help prevent heart disease.
The lead author of the guidelines, Dr. Lori Mosca, director of preventive cardiology at New York Presbyterian Hospital of Columbia and Cornell universities, said the widely held assumption that estrogen offers a protective effect is based on the fact that women generally have their first heart attack 10 years later than men.
But a review of research on the topic found no clear evidence that hormone replacement therapy reduces the risk of heart disease in women, and actually found that in some cases, women had a higher risk of heart problems, Mosca said.
For example, a study published earlier this month in the Annals of Internal Medicine concluded that postmenopausal women who have had a heart attack or diagnosis of heart disease and are on hormone supplements for less than one year have an increased risk of another heart attack or dying from heart disease than those who are not on hormones.
While hormone treatment does benefit the heart by raising good cholesterol, reducing bad cholesterol and relaxing blood vessels, doctors know it also can have negative side effects, such as inflammation of blood vessels and blood clotting.
``The thing we thought was giving a benefit may cause problems in some women,'' Mosca said. ``I think that a woman should be aware as to why she is taking hormone replacement therapy. Is she taking it because she thinks it's protecting her heart? I think women need to reflect upon why they are on it and consult with their doctor.''
Dr. JoAnn E. Manson, chief of preventive medicine at Harvard's Brigham and Women's Hospital, estimated that 20 percent of women taking hormone replacement therapy are doing so expressly to prevent heart disease.
Manson, co-author of a recent New England Journal of Medicine article that advised doctors not to prescribe hormones just to prevent heart disease, said the figure was once twice as high, but fell in recent years as more studies questioned the benefits and suggested negative effects.
``I think it has dropped but not enough,'' Manson said. ``There are still many clinicians out there who are prescribing hormone replacement therapy for the express purpose of preventing heart disease.''
A National Institutes of Health study of 27,500 women is looking at whether hormone replacement therapy should be used solely to prevent cardiovascular disease. But the results are not expected for five years.
``We have a long time to wait. In the interim, this is an attempt to form reasonable recommendations in the face of less than perfect science,'' Mosca said.
Dr. Nieca Goldberg, chief of the women's heart program at Lenox Hill Hospital in New York City, said the new guidelines are important because they pull together a body of evidence that suggests traditional heart disease treatments, including stopping smoking, diet changes and exercise, are the best ways to prevent cardiovascular disease.
``Obviously that's a lot harder than taking a pill,'' Goldberg said.