John Bilesikian (professor of Medicine – College of Physicians and Surgeons, Columbia University, New York, USA)
Estrogen replacement has always been an important therapy for endocrinologists to consider in postmenopausal women because of a wealth of epidemiological and cross-sections data that argue, in a rather compelling manner, for its efficacy. Until recently, however, there was little evidence in well designed, prospective studies that estrogen therapy prevents osteoporotic fracture. Ironically, the Women’s Health Initiative (WHI), a mammoth study conducted in the United States over the past decade, has provided unequivocal evidence for the efficacy of estrogen to reduce fracture incidence. Fractures were reduced at vertebral and non-vertebral sites.
Even the incidence of hip fracture was reduced. It is important to note, however, that the population studied in the mildly osteoponic range. The demonstrated efficacy of estrogen is even more remarkable considering theses mild reductions in bone density. the point is made that such important fracture studies with estrogen therapy are still lacking in frankly osteoporotic subjects. Is seems likely, however, that if fracture efficacy is clearly demonstrate osteoporotic population. The real problem with the WHI is that the adverse event profile clearly exceeded the predetermined stopping point both for the combination therapy arm (estrogen and progesterone) and monotherapy with estrogen alone. The "official" endocrinological view therefore is that estrogen should not be used as a primary therapy to prevent or to treat osteoporosis. This directive has led many postmenopausal women to stop their estrogen replacement regimen and, in some cases, to recapitulate the accelerated bone loss that is typical of the early postmenopausal state. These women should be identified early and, if at risk, should be offered alternative preventive regimens. The WHI also called attention to the possibility that lower doses of estrogen and other routes of administration than were used in that study might not only be safer but also effective. These points as well as the usage of estrogen preparations are all being considered by endocrinologist and otlher specilist as we seek to determine how best to prevent posmenopausal bone loss.