POSTMENOPAUSAL HORMONE-THERAPY AND MORTALITY

Background Postmenopausal hormone therapy has both benefits and hazard s, including decreased risks of osteoporosis and cardiovascular diseas e and an increased risk of breast cancer. Methods We examined the rela tion between the use of postmenopausal hormones and mortality among pa rticipants in the Nurses' Health Study, who were 30 to 55 years of age at base line in 1976. Data were collected by biennial questionnaires beginning in 1976 and continuing th rough 1992. We documented 3637 dea ths from 1976 to 1994. Each participant who died was matched with 10 c ontrols alive at the time of her death. For each death, we defined the subject's hormone status according to the last biennial questionnaire before her death or before the diagnosis of the fatal disease; this r educed bias caused by the discontinuation of hormone use between the t ime of diagnosis of a potentially fatal disease and death. Results Aft er adjustment for confounding variables, current hormone users had a l ower risk-of death (relative risk, 0.63; 95 percent confidence interva l, 0.56 to 0.70) than subjects who had never taken hormones; however, the apparent benefit decreased with long-term use (relative risk, 0.80 ; 0.67 to 0.96, after 10 or more years) because of an increase in mort ality from breast cancer among long-term hormone users. Current hormon e users with coronary risk factors (69 percent of the women) had the l argest reduction in mortality (relative risk, 0.51; 95 percent confide nce interval, 0.45 to 0.57), with substantially less benefit for those at low risk (13 percent of the women; relative risk, 0.89; 95 percent confidence interval, 0.62 to 1.28). Conclusions On average, mortality among women who use postmenopausal hormones is lower than among nonus ers; however, the survival benefit diminishes with longer duration of use and is lower for women at low risk for coronary disease. (C)1997, Massachusetts Medical Society.