POSTMENOPAUSAL ESTROGEN AND PROGESTIN USE AND THE RISK OF CARDIOVASCULAR-DISEASE

Background Estrogen therapy in postmenopausal women has been associate d with a decreased risk of heart disease. There is little information, however, about the effect of combined estrogen and progestin therapy on the risk of cardiovascular disease. Methods We examined the relatio n between cardiovascular disease and postmenopausal hormone therapy du ring up to 16 years of follow-up in 59,337 women from the Nurses' Heal th Study, who were 30 to 55 years of age at base line. Information on hormone use was ascertained with biennial questionnaires. From 1976 to 1992, we documented 770 cases of myocardial infarction or death from coronary disease in this group and 572 strokes. Proportional-hazards m odels were used to calculate relative risks and 95 percent confidence intervals, adjusted for confounding variables. Results We observed a m arked decrease in the risk of major coronary heart disease among women who took estrogen with progestin, as compared with the risk among wom en who did not use hormones (multivariate adjusted relative risk, 0.39 ; 95 percent confidence interval, 0.19 to 0.78) or estrogen alone (rel ative risk, 0.60; 95 percent confidence interval, 0.43 to 0.83). Howev er, there was no significant association between stroke and use of com bined hormones (multivariate adjusted relative risk, 1.09; 95 percent confidence interval, 0.66 to 1.80) or estrogen alone (relative risk, 1 .27; 95 percent confidence interval, 0.95 to 1.69). Conclusions The ad dition of progestin does not appear to attenuate the cardioprotective effects of postmenopausal estrogen therapy. (C) 1996, Massachusetts Me dical Society.