Abstract
Over the past two decades, multiple observational studies have suggested that postmenopausal hormone therapy reduces the risks of osteoporotic fractures and coronary heart disease. On the basis of this evidence, hormone therapy was often recommended for women who were at high risk for fractures and coronary disease. But these recommendations were based entirely on observational evidence, which can sometimes be misleading if the groups being compared have different risk patterns and lifestyles. In the early to mid-1990s, several large, randomized trials were initiated to provide definitive evidence concerning the risks and benefits of hormone therapy for the prevention of disease. . . .