Estrogen therapy in the prevention and management of osteoporosis.

Many studies have shown that bone loss accelerates after oophorectomy or the menopause. If estrogen replacement therapy is instituted soon after the onset of these changes, much of this bone loss, and subsequent fractures, can be prevented. Most investigations have evaluated the effects of oral estrogens, but other routes of administration may be equally beneficial. The use of estrogens natural to the human also seems preferential. Several theories have been advanced regarding the mechanism of action of estrogen in this population. The most popular concept holds that estrogen stimulates calcitonin production, but other theories also must be considered since this is controversial and far from proven. A local action of estrogen on the skeleton cannot be ruled out. In addition to estrogen, calcium supplementation and exercise may have roles to play in the prevention and management of osteoporosis.