Key findings of estrogen plus progestin compared to the placebo for every 10,000 women each year were: more strokes (8 more cases); an increased risk of breast cancer (8 more breast cancers); an increase in heart attacks (7 more heart attacks); a higher risk of blood clots (8 more women with blood clots in the lungs and 18 more with blood clots in the legs or lungs); a reduction in hip fractures (5 fewer hip fractures); and a drop in the risk of colorectal cancer (6 fewer colorectal cancers).
Rossouw cautioned that the findings for the two hormone therapy studies should not be compared directly. At baseline, the women in the estrogen-alone study had a higher risk of cardiovascular disease than those in the estrogen-plus-progestin trial. Those in the estrogen-alone study were more likely to have such heart disease risk factors as high blood pressure, high blood cholesterol, diabetes, and obesity.
Women in both hormone trials are now in a followup phase, due to last until 2007, during which their health will be closely monitored.
WHI was launched in 1991 and consists of a set of clinical trials to test the preventive effects of postmenopausal hormone therapy, diet modification, and calcium and vitamin D supplements on heart disease, fractures, breast and colorectal cancer, as well as an observational study, which is looking for predictors and biological markers for disease. The diet modification trial involves nearly 49,000 women, the calcium/vitamin D trial about 36,000 women, and the observational study about 94,000 womenall three studies are continuing.
NHLBI collaborates on the WHI with the National Cancer Institute, the National Institute of Arthritis and Musculoskeletal and Skin Diseases, and the National Institute on Aging, and the
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Contact: NHLBI Communications Office
301-496-4236
NIH/National Heart, Lung, and Blood Institute
13-Apr-2004