Estrogen therapy arrests bone loss in elderly women.

Although osteoporosis is an age-related disorder, the accelerated bone loss observed in postmenopausal women may be preventable with early diagnosis and adequate estrogen replacement. In a prospective study, we investigated the effect of oral estrogen replacement using conjugated estrogens (Premarin, 0.625 mg) or micronized 17 beta-estradiol (Estrace, 1 mg) versus no estrogen in sequential single-photon bone density measurements over 3-year intervals in 397 postmenopausal women. Estradiol, 1 mg, and conjugated estrogens, 0.625 mg, were equally effective in regarding bone loss. The rate of bone loss was about the same for estrogen users regardless of age (51 to 80 years) and was approximately one third that of nonusers. Among nonusers a uniform accelerated rate of bone loss of 2.5% per year was noted between 56 and 70 years old, whereas between the ages of 51 and 55 years and after age 70 years, the rate of bone loss was significantly less. Ever users over age 65 years showed continued protection from bone loss as long as estrogen therapy was continued. Previous estrogen users who stopped estrogen after age 65 years lost bone more rapidly than women of similar age who had never taken estrogen. Thus to prevent accelerated bone loss in postmenopausal women, we recommend early and continued hormone replacement for life. Estrogen nonusers should be monitored at regular intervals to minimize accelerated bone loss.