Confirming what a growing number of studies has shown, the U.S. Preventive Services Task Force (USPSTF), a government panel that periodically reviews the evidence on screening and other preventive treatments, recommended this week that postmenopausal women should not take hormone replacement therapy to prevent conditions such as heart disease, cancer or dementia.
Before 2002, doctors recommended that women use supplemental hormone treatments to restore levels of estrogen and progestin, which naturally wane during and after menopause. The thinking was that the hormone supplements would lower women’s risk of cancer and heart disease: because women tend to experience heart attacks about a decade later than men, it was thought that women’s hormones must provide some sort of protective effect.
(MORE: Making Sense of Hormone Therapy After Menopause)
But in 2002, the Women’s Health Initiative (WHI), the first long-term study of hormone replacement therapy, which involved 160,000 women followed for 15 years, found little difference in heart disease rates among hormone users and non-users. In fact, the data showed slightly higher rates of heart disease and breast cancer among those who relied on hormone therapy.
Based on the data, thousands of women abandoned hormone therapy. Indeed, since the WHI findings were released, breast cancer and heart disease rates among postmenopausal women have dipped, possibly due to the drop in use of hormone therapy.
But over the past decade, scientists have continued to study the long-term effects of supplemental hormone treatments, including the use of estrogen alone, on women’s health outcomes. Some data have suggested that some postmenopausal women taking hormone therapy may reduce their risks of bone fractures, dementia and even heart disease.
If the back-and-forth seems confusing, that’s because it is, thanks to the piecemeal way in which study results, each focused on a specific outcome — such as osteoporosis or heart disease — have been released. So the government panel reviewed all the latest gold-standard evidence and weighed the potential benefits of hormone therapy to its risks in context
(MORE: U.S. Panel Recommends Delaying Regular Mammograms Until Age 50)
While the hormone treatments do provide relief of menopausal symptoms like hot flashes and night sweats, the panel found that the hormones’ risks don’t justify long-term use for the prevention of other diseases. Here’s what the task force found:
- Women taking estrogen and progestin in combination, or estrogen alone, had up to a 30% lower risk of having a bone fracture compared with women taking placebo; however, this benefit doesn’t outweigh the increased risks of developing heart disease, blood clots or breast cancer, and there are other medications on the market to treat thinning bones
- Hormone therapy does nothing to reduce women’s heart disease risk
- Women taking hormone therapy increased their risk of having a stroke, gall bladder disease or urinary incontinence by 35% to 79%
- Women taking hormone therapy had twice the risk of developing potentially dangerous blood clots as women taking placebo
- Women taking both estrogen and progestin were more likely to develop breast and colon cancer
- Taking estrogen and progestin did not protect against dementia
The task force also found that postmenopausal taking estrogen alone — which is appropriate only for women who have had a hysterectomy (estrogen has been linked to uterine cancer) — had a slightly lower risk of breast cancer.
(MORE: Estrogen After Menopause Lowers Breast Cancer Risk for Some Women)
The panel’s advice doesn’t necessarily apply to women who are going through menopause and are suffering from intense hot flashes or night sweats. Doctors still advise hormone therapy to relieve the worst of these symptoms, but don’t recommend that women stay on the treatment for longer than several months.
Alice Park is a writer at TIME. Find her on Twitter at @aliceparkny. You can also continue the discussion on TIME’s Facebook page and on Twitter at @TIME.