Effects of 1?-hydroxyvitamin D3 on lumbar bone mineral density and vertebral fractures in patients with postmenopausal osteoporosis

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Abstract
The effects of 1α-hydroxyvitamin D3 [1α(OH)D3] on bone mineral density, fracture incidence, and bone metabolism were evaluated by a double-blind, placebo-controlled study. Eighty postmenopausal osteoporotic Japanese women (71.9±7.3 years, mean±SD) were randomly assigned to 1 μg of 1α(OH)D3 daily or inactive placebo for 1 year. All patients were given supplemental calcium (300 mg of elemental calcium daily). Lumbar (L2–L4) bone mineral density (BMD) determined by dual energy X-ray absorptiometry increased 0.65% with 1α(OH)D3 treatment and decreased 1.14% with placebo (P=0.037). BMD in both the femoral neck and Ward's triangle did not yield any significant differences between the two groups, whereas trochanter BMD in the 1α(OH)D3-treated group increased 4.20% and decreased 2.37% with placebo (P=0.055). X-ray analysis demonstrated that new vertebral fractures occurred in two patients with 1α(OH)D3 and in seven patients with placebo. The vertebral fracture rate in the treated group was significantly less (75/1000 patient years) than in the control group (277/1000 patient years; P=0.029). Hypercalcemia (12.1 mg/100 ml) occurred in one patient receiving 1α(OH)D3; however, the serum calcium level in this patient promptly decreased to the reference range after cessation of the treatment. There were no significant changes in serum creatinine level in either group. A significant increase in urinary excretion of calcium was found but there was no significant change in urinary excretion of hydroxyproline in the treated group. The serum level of bone-derived alkaline phosphatase activity significantly decreased by−26±26 (mU/ml) after the treatment (P=0.003). These results indicate that 1α(OH)D3 treatment is effective for maintaining trabecular bone mass and prevents further vertebral fractures without any serious adverse effects in postmenopausal osteoporosis.