Calcitriol and alendronate combination treatment in menopausal women with low bone mass

Serum calcitriol levels decrease with advancing age in relation to reduced dietary intake or poor intestinal absorption of vitamin D. These decreased levels affect the development of senile osteopenia, which can be effectively prevented by the administration of alendronate and calcium. To evaluate the effect of a combined treatment with alendronate and calcitriol on bone mineral density (BMD), we followed 152 osteopenic postmenopausal women, aged 55-75 years, for 9 months. They were divided into three groups. The first group was treated every other day with 0.25 microgram of synthetic 1,25-dihydroxyvitamin D3 plus 10 mg alendronate. The second group received the same dose of alendronate plus calcium (500 mg/day). The third group received only calcium (500 mg/day). BMD measurements were made at the level of the lumbar spine and the femoral neck. At the beginning and at the end of the period of treatment the same biochemical analyses of bone metabolism were made. There were no significant differences in the baseline values of the three groups in the biological parameters. Alendronate plus calcium treatment led to a significant reduction in total alkaline phosphatase and hydroxy prolinuria as well as to a significant increase in lumbar and femoral bone density. The same changes were observed in the group treated with alendronate plus calcitriol except that femoral BMD did not significantly improve. These results show that continuous treatment for 9 months with calcitriol or calcium in combination with alendronate significantly increases both vertebral and femoral neck density (from 3.8% to 4.5% and from 0.61% to 2.36% respectively) in osteopenic postmenopausal women. The effects of both combinations on bone mass are clearly greater than those achieved by calcium monotherapy.