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NIH Research Matters

October 28, 2013

More Guidance For Hormone Replacement Therapy

Hormone therapy may be a reasonable option for younger women to manage menopausal symptoms for a limited period of time, according to a new analysis. However, the therapy isnít recommended for chronic disease prevention.

Three mature women walking on a windy beach.

The Women’s Health Initiative (WHI) was established to study several aspects of women’s health, including the effects of postmenopausal hormone therapy. This long-term, national health study is sponsored by NIH’s National Heart, Lung, and Blood Institute (NHLBI).

Women, ages 50 to 79, enrolled at centers across the country between 1993 and 1998. Almost 17,000 women with an intact uterus participated in an estrogen plus progestin therapy trial. About 10,700 women who’d had a hysterectomy (surgical removal of the uterus) participated in an estrogen-alone therapy trial. About 81% continued follow-up after the planned end of the trials. Findings from a comprehensive analysis of 13 years of cumulative data were published on October 2, 2013, in the Journal of the American Medical Association.

Women who took estrogen plus progestin had rates of overall illness (such as coronary heart disease, stroke, breast cancer, blood clots in the lungs, colorectal cancer, endometrial cancer, and hip fracture) and death that were 12% higher than women who took placebo pills. In absolute terms, there were 20 more major illnesses or deaths per year for every 10,000 women taking the hormone therapy than for those taking placebo. After the women stopped taking the hormone therapy, there were no lasting effects on overall illness and death.

Women who took estrogen alone had overall rates of illness and death similar to those for women who took placebo pills. The results, however, differed by age. Women who took estrogen in their 50s had a 16% reduced risk of overall illness and death. In absolute terms, there were 19 fewer major illnesses or deaths per year for every 10,000 women in this age group compared to the same number taking a placebo. Those who took estrogen in their 70s had a 17% increased risk of overall illness and death, with 51 more major illnesses or deaths per 10,000 women per year compared to placebo.

Overall, the investigators found that menopausal hormone therapy had a complex pattern of benefits and risks. For example, both regimens decreased the risk of diabetes by 14-19%, but increased the risks of gallbladder disease and urinary incontinence by 50-60%. These changes in risks lessened after the drugs were stopped.

“Decisions about hormone therapy are not easy, but these findings provide an evidence base for finding a way forward,” says Dr. Jacques Rossouw, chief of NHLBI's Women’s Health Initiative Branch. “Hormone therapy affects many organ systems in the body and changes the risks of many diseases—some in good ways, others in bad ways. Depending on hysterectomy status, age, and other individual factors, the consequences can vary dramatically. The WHI emphasizes the need for women to talk about their risk factors with their doctors before making any decisions regarding hormone therapy.”

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Reference: Menopausal hormone therapy and health outcomes during the intervention and extended poststopping phases of the Women's Health Initiative randomized trials. JAMA. 2013 Oct 2;310(13):1353-68. doi: 10.1001/jama.2013.278040. PMID: 24084921.

Funding: NIHís National Heart, Lung, and Blood Institute (NHLBI).

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Editor: Harrison Wein, Ph.D.
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NIH Research Matters is a weekly update of NIH research highlights from the Office of Communications and Public Liaison, Office of the Director, National Institutes of Health.

This page last reviewed on March 31, 2014

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