Epidemiological overview of oestrogen replacement and cardiovascular disease

In contrast to numerous epidemiological studies of prevention in men, there has been limited research into the prevention of cardiovascular disease in women. Nevertheless, sufficient data have accumulated showing that OeRT does protect against circulatory disease in women, although evidence regarding the true magnitude of that protection remains incomplete. The best estimates of the relationship between OeRT and CVD come from population-based prospective studies which are remarkably consistent: overall they indicate a 40% reduction in CVD with use of OeRT. However, because of the underlying better health of the postmenopausal women who use hormone replacement therapy, this result probably overestimates the benefit of OeRT by an unknown degree. Furthermore, details of OeRT formulation (especially the influence of regimens with an added progestin), dose, duration, and route of administration have not been adequately studied, and the evidence regarding the effect of OeRT on rates of stroke is equivocal and requires clarification. Oestrogen's cardioprotection appears to derive from favourable effects on serum lipoprotein profiles. There may also be a direct effect on the arterial system. Detrimental influences of OeRT on haemostatic function seem unlikely. Definitive information about the actual size of effects of commonly-used regimens of OeRT on cardiovascular disease and intermediate endpoints such as serum lipid concentrations can only be obtained through large-scale randomized controlled trials. Even if the reduction in CVD were modest, the mortality rates of CVD in our society are still so high that widespread use of oestrogen replacement therapy would result in substantial numbers of women's lives being saved.