[Usefulness of estriol for the treatment of bone loss in postmenopausal women].

To assess the effect of estriol (E3) on bone loss in Japanese postmenopausal women, twenty-five women within 10 years after menopause received 2 mg/day of E3 and 2 g/day of calcium lactate (Ca) daily (n = 17; Group-E3 + Ca) or 2 g/day of Ca daily (n = 8; Group-Ca) for one year. Bone mineral density (BMD) at the lumbar spine L2 - L4 was evaluated by dual energy X-ray absorptiometry (DXA). In Group-Ca, BMD was significantly reduced (p < 0.05 vs. pretreatment) at the end of the study period. In contrast, in Group-E3 + Ca, the mean percent increase in BMD was 1.66%, which was significantly higher than that of Group-Ca (-3.08%; p < 0.001). As for the biochemical markers of bone metabolism, bone specific alkaline phosphatase (ALPIII) reflecting bone formation, and pyridinoline (Pyr) and deoxypyridinoline (D-Pyr) reflecting bone resorption, were significantly decreased (p < 0.001) in Group-E3 + Ca after six months of treatment. These data indicate that the acceleration of bone turnover usually observed after menopause was prevented by treatment with E3. As to the side effects of E3, only one of the 17 patients experienced a slight increase in vaginal discharge, but no other side effects were observed. Accordingly, reasonable compliance can be expected among postmenopausal women treated with E3 to prevent bone loss.