The risks and benefits of estrogen replacement therapy: Leisure World.

A women spends about one-third of her life in her postmenopausal years. Some women supplement this period of decreased estrogen production with estrogen replacement therapy (ERT). Many epidemiologic studies have examined the long-term effect of postmenopausal estrogen deprivation and of ERT. Since the 1970s, we have evaluated the risks and benefits of ERT in one population of older women in the California retirement community of Leisure World. ERT is the most effective method for preventing osteoporotic bone loss and fractures in postmenopausal women. In Leisure World, ERT reduced the risk of hip fractures by about 50%. The effect is greatest in longterm users, but may be lost after discontinuation. Postmenopausal osteoporosis affects the bones of the jaws as well as other skeletal bones. Bone loss in the jaws may result in tooth loss. In Leisure World, estrogen users have retained more natural teeth than nonusers. Cardiovascular disease is the leading cause of hospitalization and death in women. In Leisure World, ERT reduced the risk of fatal and nonfatal myocardial infarction, ischemic heart disease, other heart disease, and stroke by 20-40%. The reduction is greatest in long-term and/or current users. ERT is effective in women with and without cardiovascular disease risk factors. One of the most feared aspects of aging is Alzheimer's disease. In Leisure World, women who had used ERT had a reduced risk of Alzheimer's disease. Risk decreased with increasing duration of use. Estrogen use, however, is not without risk. Unopposed estrogen increases risk of endometrial cancer. Risk increases with increasing years of use and remains high after discontinuation.(ABSTRACT TRUNCATED AT 250 WORDS)