REDUCED MORTALITY ASSOCIATED WITH LONG-TERM POSTMENOPAUSAL ESTROGEN THERAPY

Objective: To compare all-cause and specific-cause mortality rates in women who had or had not used long-term postmenopausal estrogen replac ement therapy (ERT). Methods: We identified women who used long-term p ostmenopausal ERT and compared them with a sample of age-matched postm enopausal nonusers. Through linking of these subjects' medical record numbers to various data bases, we examined survivorship and cause of d eath among estrogen users and nonusers. The risk of death in 232 postm enopausal women who began ERT within 3 years of menopause and used it for at least 5 years was compared with that of 222 age-matched postmen opausal nonusers. In the users, the mean length of estrogen use was 17 .1 years. Results: Statistically significant reductions in all-cause m ortality were found in users compared with nonusers. For death from an y cause, the age-adjusted relative risk (RR) and associated 95% confid ence interval (CI) in estrogen users was 0.54 (0.38-0.76). The reducti on in all-cause mortality was largely due to reductions in coronary he art disease (RR 0.40, CI 0.16-1.02) and other cardiovascular disease ( RR 0.27, CI 0.10-0.71). Overall cancer mortality was similar in the tw o groups (RR 0.85, CI 0.46-1.58), although estrogen users had a higher risk of death from breast cancer (RR 1.89, CI 0.43-8.36) and lower ri sk of death from lung cancer (RR 0.22 CI 0.04-1.15). Conclusion: Long- term ERT use is associated with lower all-cause mortality and confers this apparent protection primarily through reduction in cardiovascular disease.