UNANSWERED QUESTIONS IN HORMONAL REPLACEMENT THERAPY

This review addresses many of the unanswered questions existing relati ve to the use of exogenous estrogens and progestins in postmenopausal women (PMW). The literature in the field is reviewed and summarized, w ith a particular effort to identify key questions of major concern. Th e effect of selection bias on conclusions reached from retrospective s tudies involving hormone replacement therapy (HRT) has not been examin ed. Less is actually known about the effects of progestins than estrog ens. Many of the endocrine changes that occur with aging remain poorly defined. Effects of estrogens and progestins on the breast and on bre ast cancer are unclear. Estrogens have recognized beneficial effects a nd progestins have detrimental effects on lipoprotein metabolism. Estr ogens also have direct effects on the vasculature and may impact on ca rdiovascular risk in other ways. Although estrogens are the only agent s known to eliminate hot flushes, the mechanism by which flushes arise is not known. Estrogens may have ameliorating effects on mood and beh avior and may improve dementia, but research in this area has been lim ited to date. Lastly, the preferred estrogens and progestins, their do sages and routes of administration, remain to be more completely defin ed.