CAUSE-SPECIFIC MORTALITY IN WOMEN RECEIVING HORMONE REPLACEMENT THERAPY

To assess the risks and benefits of menopausal hormone replacement the rapy, we followed a 23,246-member, population-based cohort of Swedish women who were prescribed menopausal estrogens for an average of 8.6 y ears for mortality. Compared with the general population, the standard ized mortality ratio for all cause mortality in this cohort was 0.77 ( 95% confidence limits = 0.73, 0.81). Deaths in each of the 12 major ca tegories of causes of death except for injuries occurred 12% to 86% le ss frequently than expected. We examined in detail four specific cause s of death according to the type of hormone prescribed, namely weak es trogens (primarily estriol), more potent estrogens (primarily estradio l and conjugated estrogens) in combination with a progestin, and more potent estrogens without a progestin. Mortality from endometrial cance r was not related to the prescription of weak estrogens or an estrogen progestin combination, but mortality was 40% higher in women prescrib ed more potent estrogens without a progestin. Women prescribed weak es trogens, more potent estrogens, and the combined estrogen-progestin re gimen were at reduced risk of death from ischemic heart disease (stand ardized mortality ratios of 0.7, 0.6, and 0.4, respectively). The more potent estrogens and the estrogen-progestin combination were associat ed with a marked reduction in risk of intracerebral hemorrhage (standa rdized mortality ratios of 0.4 and 0.6, respectively) and ''other'' ce rebrovascular disease, but not other types of stroke. The concern that use of progestins would lead to psychic disorders related to suicide received no support from our results. Breast cancer results are descri bed elsewhere. These data provide little evidence of an adverse effect of the combined estrogen-progestin regimen as compared with estrogens alone on mortality. They do indicate, however, that both selection fa ctors and biology may contribute to the almost across-the-board reduct ion in mortality associated with hormone replacement therapy.