The Women’s Health Initiative (WHI), begun in 1991 by the National Institutes of Health, is one of the largest studies of women’s health ever undertaken. More than 160,000 post-menopausal women ages 50 to 79 were recruited into a variety of trials designed to find the best ways to prevent heart disease, breast and colorectal cancers, and osteoporosis.
Thanks to the study’s rigid design, most doctors view the WHI as the definitive word on women’s health. Final results were due out—and eagerly awaited—in 2005. But one part of the study, involving more than 16,000 women, was halted last week. These women were taking a combination of estrogen and progestin called hormone-replacement therapy (HRT).
Researchers concluded that the risks of HRT clearly outweighed the benefits. Though HRT may still be appropriate as a short-term therapy for menopausal distress, women cannot expect it to protect them in the long term against aging-related diseases. Other parts of the giant WHI study, including a trial that looks at the effects of estrogen alone, continue.