[Changes in bone mineral content and bone metabolism related to menopause]

Although the phenomenon of postmenopausal osteoporosis has attracted attention, there have been no parameter-matched studies of pre- and postmenopausal difference in metacarpal bone mineral status and bone metabolism. Therefore the authors compared metacarpal bone loss in a group of 41 postmenopausal volunteers (average postmenopausal duration: 39.3 months) and 28 age- and body size-matched controls (age 50-54), using the MD method. Perimenopausal changes in bone metabolism were also examined in these groups. The result revealed that the reduction in the metacarpal bone mineral status due to menopause occurs mainly in the bone mineral density such as GSmin and sigma GS/D. The reduction rate was the highest for the index of GSmin, corresponding to 5.1% per year. Serum levels of Alp and osteocalcin were significantly higher and the U-Ca/cr ratio tended to be higher in the postmenopausal subjects than in controls. The serum levels of calcium regulating hormones such as PTH and calcitonin in these two groups did not differ significantly. However the estrone and the estradiol levels, were significantly lower in postmenopausal subjects. Significant correlations were found between Alp and the postmenopausal period (r = 0.4684), and between the U-Hpr/cr ratio and postmenopausal period (r = -0.5332). It therefore appeared that estradiol is mainly related to postmenopausal bone metabolism causing insufficient suppression of bone resorption. However, calcium regulating hormones appeared to be not directly related to the postmenopausal bone loss mechanism. Bone turnover decreased with the postmenopausal period.