Vitamin D supplementation and bone mineral density in early postmenopausal women

Background: Increased vitamin D intake may preserve or increase bone mineral density (BMD) in older persons. Objective: A 2-y double-blind study was undertaken to determine whether weekly administration of 10 000 units of vitamin D-2 maintained or increased BMD in younger postmenopausal women more efficiently than did calcium supplements alone. Design: One hundred eighty-seven women who were greater than or equal to 1 y postmenopausal were randomly assigned to take either 1000 mg Ca/d after the evening meal or 1000 mg Ca/d plus 10 000 U vitamin D-2/wk in a double-blind, placebo-controlled format. The BMD of the proximal forearm, lumbar spine, femoral neck, Ward's triangle, and femoral trochanter was measured at 6-mo intervals by osteodensitometry. Results: During the 2-y period, there was no significant difference in the change in BMD at any site between the subjects taking calcium supplements and those taking calcium plus vitamin D2. Both groups significantly (P < 0.005) gained BMD in Ward's triangle and the femoral trochanter but significantly (P < 0.005) lost bone in the proximal radius. There was no significant change in the lumbar spine or femoral neck BMD. Conclusion: In younger postmenopausal women ((x) over bar age: 56 y) whose average baseline serum 25-hydroxyvitamin D concentration was well within the normal range, the addition of 10 000 U vitamin D2/wk to calcium supplementation at 1000 mg/d did not confer benefits on BMD beyond those achieved with calcium supplementation alone.