[Effects of estrogen therapy on bone mass in postmenopausal women with osteopenia].

Estrogen treatment prevents early postmenopausal bone loss. The aim of this study was to evaluate the effects of estrogen-progestogen therapy on bone mass in elderly osteopenic postmenopausal women. Fifteen women with a mean age of 58 +/- 6 (mean +/- SD) years and 12 +/- 7 (5-31) years from menopause were evaluated. Bone mineral density (BMD) was assessed by dual X-ray absoptiometry (DXA) with 1.7% variation coefficient at lumbar spine (L2-4) and 1.9% at femur neck. Measurements were done at both sites before and after a 12 month treatment. At the beginning of the study lumbar spine BMD (LS BMD) was low: < 0.9 grs/cm2; z-score: -1.4 +/- 0.17 (mean +/- SEM). Treatment consisted in transdermal 17 beta estradiol (50 micrograms/day) (n = 10) or an equivalent natural estrogen oral dose (n = 5). Variable doses of medroxiprogesterone acetate were added on an individualized basis to women with an intact uterus (n = 12). Calcium intake was increased up to a median of 1200 mg/day (800-1600). After a one year treatment LS BMD was increased by 8.4 +/- 1.1% (mean +/- SEM) (95% CI: 6-10.8), from 0.748 +/- 0.02 to 0.810 +/- 0.02 gr/cm2 (p < 0.0001). A less marked gain in femur neck bone mineral density (FN BMD) was also noticed: 3.9 +/- 1.5% (95% CI: 0.6-7.2); 0.671 +/- 0.02 vs 0.697 +/- 0.02 gr/cm2 (p < 0.05). Patients treated with transdermal and oral routes showed similar results. Percentage variations in LS BMD and FN BMD were positively correlated (r: 0.53; p < 0.05). Six patients were treated for 2 years; LS BMD continued to rise, the additional gain being 5.1 +/- 2.2% (p < 0.05), while a non significant increase in FN BMD was observed (7.5 +/- 3.5%; p = 0.06). In the early postmenopausal period, hormonal replacement therapy (HRT) produces either a stabilization or a slight increase (2-4%) in BMD. In contrast, a significant augmentation of bone mass (especially at the spine) seems to occur in osteopenic women when THR is administered in the late postmenopausal period. This suggests that HRT could be used for the prevention as well as for the treatment of postmenopausal osteoporosis. Further studies should be done to evaluate whether HRT reduces the incidence of osteoporotic fractures in elderly osteopenic women.