[The preventive effect of estrogen and vitamin D on postmenopausal bone loss]

In order to evaluate the preventive effect of estrogen and vitamin D3 on postmenopausal bone loss, either estrogen (Premarin 0.625 mg/day) or vitamin D3 (Onealfa 1.0 micrograms/day) was administered to postmenopausal women. Changes in lumbar bone mineral density (BMD) were monitored by dual energy X-ray absorptiometry (DEXA). The lumbar BMD of women given estrogen showed a significant increase at 6 months after treatment. The highest response to estrogen was demonstrated within a year after treatment, and thereafter the effect was diminished but still prevented further bone loss. On the other hand, the effect of vitamin D was heterogeneous. Half of the women receiving vitamin D showed a remarkable increase at a year later, but in the remainder there was a decrease and the overall there was little change from the pretreatment value. These results indicate that estrogen can be used as a first choice for the prevention of postmenopausal bone loss, but further studies on the preventive effect of vitamin D are needed.