New thoughts about estrogen therapy from the Women's Health Initiative.

Since the introduction of hormone replacement therapy (HRT) in 1942, the availability of scientific information regarding the physiologic action of estrogen alone and in combination with progesterone has grown substantially. The specific physiology of changes in endogenous estrogen as a causal factor in bone loss that occurs as the result of menopause is now better understood. Accumulating evidence regarding the benefit of estrogen in protecting against bone loss at the time of menopause made it the first choice for prevention and treatment of osteoporosis, until the findings of the Women's Health Initiative (WHI) were announced in 2002. Fortunately, the availability of multiple alternative agents for prevention and treatment of osteoporosis in menopausal women has provided clinicians with other options. There remain a small number of patients who cannot tolerate or afford these alternative therapies. Recent publications resulting from the WHI should be understood by practicing physicians who are faced with this dilemma and may need to consider HRT in treating patients with osteoporosis.