Hormone Replacement Therapy: What's Science and What's Speculation? What More do we Need to Know?

Abstract

Whether or not to use hormone replacement therapy for postmenopausal women is a complex issue. While most physicians recommend it for the stabilization of accelerated bone loss resulting from declining estrogen levels and for protection against coronary artery disease, many women are reluctant to comply. One reason to urge women to do so is the growing realization that ovarian steroids have a diverse and important effect on many bodily systems besides the reproductive tract. Estrogen's role in the central nervous system, for example, is not as widely appreciated as its actions on bone, the cardiovascular system, and the reproductive and urinary tracts. The hormone's action on neuronal and glial cells ensures the plasticity and continuing effective function of the brain. Indeed, adequate estrogen levels are associated with a significantly lowered incidence of Alzheimer's disease in female patients. Nevertheless, important questions remain to be answered about the advisability of hormone replacement therapy: we lack precise and complete information about the physiology of normal menopause; the sites and mechanisms of action of ovarian steroids; optimal therapeutic regimens; and the long-term, deleterious effects of hormone replacement therapy.