But they had fewer heart attacks later, and the effects balanced out over four years. The study's lead author, Dr. Stephen B. Hulley, chairman of epidemiology and biostatistics at the University of California at San Francisco, cautioned that the findings are directly applicable only to women who already have heart disease. He said more research is needed to determine whether the findings also hold true among women who do not yet have heart disease. For now, Hulley said, a woman's decision about whether to take hormone supplements should be made with her doctor, based on her individual traits, preferences and the evidence available. Estrogen alone is no longer prescribed to most postmenopausal women because it can promote uterine cancer.
Progestin offsets the cancer-causing effect.
But progestin also may diminish the heart protective effect associated with estrogen alone, Manson said. The previous studies on estrogen and the heart involved women who were taking hormones even before they were enrolled in the research. People who opt for preventive therapy tend to have healthy habits generally. That may explain most of the heart advantages attributed to estrogen, experts said. It is too soon to say whether the risks associated with estrogen-containing supplements, including the increased risk of breast cancer, are outweighed by the benefits, experts agreed.