MENOPAUSE-RELATED CHANGES IN BONE-MINERAL DENSITY IN JAPANESE WOMEN -A LONGITUDINAL-STUDY ON LUMBAR SPINE AND PROXIMAL FEMUR

We investigated 2-year longitudinal changes of bone mineral density (B MD) in lumbar spine and proximal femur in 64 Japanese women aged 38-67 . Forty subjects were premenopausal (mean age 44.9) and 24 postmenopau sal (mean age 54.6) at enrollment of the study. Six subjects experienc ed menopause during the 2-year study period and were defined as the pe rimenopausal group. Measurements of BMD were performed using dual-ener gy X-ray absorptiometry at L2-4, femoral neck, greater trochanter, and Ward's triangle. Paired t test revealed no significant decrease in BM D at any site in the premenopausal group. Significant annual decrease in BMD was observed in the perimenopausal group at L2-4, femoral neck, and greater trochanter. A similar tendency was observed in Ward's tri angle, but did not reach statistical significance. In the postmenopaus al group, significant decrease in BMD was found at the proximal femur, but not at L2-4. Significant inverse correlation between age and chan ge rate of BMD was found at L2-4, but not at the proximal femur, in pr emenopausal women. In postmenopausal women, there was a significant as sociation between body weight (BW) change and change rate in BMD at L2 -4, femoral neck, or greater trochanter. This association was not foun d in the premenopausal group. These results suggest that effect of men opause on BMD may be different in individuals and sites of the skeleto n. BW change may affect change in BMD in postmenopausal women. However , the limited variability in both BW and BMD changes among premenopaus al women in this study may explain the poor association between change in BW and change in BMD in the premenopausal group. As individual dif ferences in each group is considerably large, annual measurements of B MD may be necessary to find possible candidates for early intervention .