1-α-Hydroxyvitamin D3 treatment decreases bone turnover and modulates calcium-regulating hormones in early postmenopausal women

50 Japanese women within 10 years after menopause (mean age 52.5 years) were studied to determine the effects of 0.75 μg of 1-α-hydroxyvitamin D3 [1-α-(OH)D3] with calcium (150 mg/day) (treated group: N = 25) and calcium only (control group: N = 25) for 12 months on bone mass and metabolism. Their L2-4 BMD measurements were 1.5 SD below the mean value of Japanese young, normal women. L2-4 BMDs increased significantly in the treated group (+2.1%; p< 0.01), but decreased significantly in controls (−2.1%; p< 0.01). Although serum calcium and creatinine remained unchanged in both groups, phosphorus levels increased significantly in the treated group (p< 0.01). Urinary calcium/creatinine (Cr) increased in both groups. Urinary pyridinoline/Cr and deoxypyridinoline/Cr decreased significantly in the treated group (p< 0.05), but not in the control group. Serum osteocalcin levels remained unchanged in both groups. Intact parathyroid hormone levels decreased significantly (p< 0.05) and calcitonin levels significantly increased in the treated group (p< 0.05), but these changes were not observed in the control group. These data clearly demonstrate that 0.75 μg of 1-α-(OH)D3 maintained bone mass by reducing bone resorption by modulation of calcium-regulating hormones. Temporarily increased urinary calcium excretion was observed in control group, but did not appear to be effective in modulating bone turnover.