The government on Tuesday announced that it has ended its last major study of estrogen replacement therapy, noting that taking estrogen alone isn't as bad as using it with the hormone progestin but that it still carries significant health risks. Women who took estrogen alone after menopause had a significantly increased risk of stroke and a possibly higher risk of dementia, the National Institutes of Health announced Tuesday. That doesn't mean that women who just started using estrogen to relieve menopausal symptoms, such as hot flashes, should panic, cautioned Barbara Alving, director of the NIH's Women's Health Initiative. "This isn't an emergency," she said. But there are women who have used estrogen for many years, even decades, and "this provides them with an opportunity to say, 'Do I really need to be on this still?' " Alving added. For now the government's advice is that if you use hormones for menopausal symptoms, use the lowest effective dose for the shortest possible duration, Alving stressed. Women now taking hormone therapy or considering it should discuss their individual risk factors with their doctors, cautions the American Society for Reproductive Medicine.
Although hormone replacement therapy was once widely recommended for menopausal women, recent studies have shown that the treatment can raise the risks of heart attack and breast cancer. Still, some doctors may prescribe hormones temporarily to women with severe symptoms. Doctors long thought that using estrogen, alone or together with progestin, would keep women healthier after menopause in such ways as reducing heart attacks and keeping the brain sharp. But studies have shown hormone therapy significantly raises the risks for breast cancer, heart attacks, strokes, and other ailments. Millions of women have quit using the estrogen-progestin combination since 2002, when the first studies suggested hormone therapy was dangerous.
Scientists weren't sure whether estrogen alone was as risky as combination therapy including estrogen and progestin. Now the NIH is shutting down its study of estrogen-only use a year early, telling the 11,000 women enrolled to quit their pills--essentially ending hope that estrogen alone would have some usefulness that the hormone combination did not. Among the specific results of the study released Tuesday were evidence that estrogen alone increased the risk for strokes as much as estrogen-progestin combination therapy, boosting the risk eightfold over women not taking the hormones; that estrogen alone had no effect, good or bad, on heart disease, while combination therapy has been shown to boost heart risks by 29%; and that estrogen alone didn't increase the risk of breast cancer but didn't lower it either, compared with evidence that combination hormone replacement therapy raises breast cancer risks by 26%.