Does not protect against CHD: WHI quantifies risks, benefits of estrogen therapy; Reports hazard rations of 1.39 for nonfatal stroke and 0.70 for osteoporotic fractures.(News)

Recently released data from the estrogen-only arm of the Women's Health Initiative, which was halted prematurely in February, shows that estrogen therapy is associated with a significantly increased risk of stroke and venous thromboembolic disease, compared with placebo, and it does not protect against coronary heart disease.

The data also show that estrogen therapy is associated with a significant reduction in fracture risk.

Aside from its short-term use to relieve menopausal symptoms, estrogen therapy has no overall benefit, reported Garnet L. Anderson, Ph.D., of the Fred Hutchinson Cancer Research Center, Seattle, and associates (JAMA 291[14]:1701-12, 2004).

"These findings reinforce the recommendations that estrogenalone therapy should not be used for the prevention of chronic disease. NIH continues to advise women to follow current FDA guidance, which says that hormone therapy should be used to treat menopausal symptoms and that it should be used at the smallest effective dose for the shortest period of time," Dr. Barbara Alving, director of the Women's Health Initiative (WHI), said in a telephone press briefing.

The estrogen-only arm of the WHI was stopped 1 year early, after 6.8 years of follow-up, because of the increased stroke risk. Investigators did not release any of the data until now.

The recently published study shows an increased risk (hazard ratio 1.39) of nonfatal stroke among estrogen users, compared with women taking placebo. This stroke risk translates into 12 additional nonfatal strokes per 10,000 person-years among estrogen users.

An estrogen user's risk of nonfatal stroke therefore was increased to 0.44% annually, a 0.12% rise, Dr. Jacques Rossouw. WHI Project Officer at the National Heart, Lung, and Blood Institute, said in an interview; the NHLBI in Bethesda, Md., sponsored the study.