Comparison of effects of estriol on bone mineral density of vertebrae between elderly and postmenopausal women

To compare the efficacy of estriol (E₃) for postmenopausal and senile osteoporosis, we administered orally 1 g/day calcium lactate alone (control groups) or with 2 mg/day estriol (E₃ groups) to 20 postmenopausal women aged 50–65 years and 29 elderly women aged 70–84 years, and determined their bone mineral density (BMD) of the lumbar vertebrae AP scan by dual-energy X-ray absorptiometory. Of 41 subjects who completed 10 months of treatment, 8 postmenopausal women and 12 elderly women in the E₃ groups showed a significant (P < .05) increase in BMD, 5.59% ± 4.79% and 3.83% ± 7.90% of the respective basal values, while 10 postmenopausal women and 11 elderly women in the control groups showed a decrease in BMD, −4.02% ± 7.00% and −3.26% ± 4.60% of the respective basal values, after 10 months. On the other hand, genital bleeding as a side effect of E₃ occurred in 6 elderly subjects at this dose. Moreover, decrease in serum level of corrected calcium was seen only in the elderly women receiving E₃. Although a lower dosage of E₃ may be recommended for elderly subjects, these observations suggest, first, that hormone replacement therapy with E₃ has efficacy for involutional osteoporosis, and, second, that the bones in elderly women also maintain responsiveness to E₃. Received: May 19, 1997 / Accepted: July 7, 1997