Detailed results of the "estrogen-alone" study within the Women's Health Initiative (WHI), which was terminated in early March 2004, are providing some of the first answers to questions about the efficacy of estrogen alone to prevent chronic disease in healthy, postmenopausal women who have had a hysterectomy.
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| Researcher JoAnn Mason (Staff photo Kris Snibbe/Harvard News Office) |
WHI researchers, including investigators at Brigham and Women's Hospital (BWH), have shown that after 6.8 years of study on more than 10,000 women nationwide, estrogen-alone hormone replacement therapy (HRT) in postmenopausal women increased the risk of stroke, reduced the risk of hip fracture, and had minimal effect on the risk of heart disease and breast cancer. In addition, the research suggests that women who start estrogen earlier in life may receive more heart health benefits than those who start later in life. These findings are published in the April 14 issue of the Journal of the American Medical Association.
According to JoAnn Manson, chief of preventive medicine and principal investigator of the WHI at BWH, "These results suggest that the risks and benefits of estrogen therapy are fairly balanced, but these hormones should not be taken to prevent cardiovascular disease. More research is needed to understand if the benefits outweigh the risks in younger women beginning estrogen shortly after menopause. Estrogen therapy still has a role in the short-term treatment of menopausal symptoms, but the lowest dose should be used for the shortest duration of time possible."
The estrogen-alone study involved 10,739 women ages 50 to 79 years who were studied for 6.8 years. Study participants were randomly assigned either a daily dose of hormone replacement therapy (HRT) - 0.625 mg/day conjugated equine estrogen (CEE) - or a placebo. The study's main goal was to determine the impact estrogen alone has on coronary heart disease risk, but like the "estrogen plus progestin" study, which was stopped in 2002, an increased risk of stroke was found. Specific findings related to estrogen-alone HRT include: