Vitamin D With Calcium—But Not Vitamin D Alone—Reduces the Overall Risk of Fracture
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Data from 68,517 adult men and women (mean age 69.6 years) indicates that vitamin D given alone in doses of 10 to 20 µg (400 to 800 IU) is not effective in preventing fractures. In contrast, the combination of vitamin D and calcium reduces hip fractures and total fractures—and probably vertebral fractures—irrespective of age, sex, or previous fractures.
The authors used individual patient data methods to perform a meta-analysis of seven major randomized trials of (1) vitamin D with calcium or (2) vitamin D alone. The analysis covered 7,202 fractures over 177,203 person years. Trials of vitamin D with calcium showed a significantly reduced overall risk of fracture (hazard ratio 0.92; 95% CI, 0.86 to 0.99); trials that used vitamin D 10 µg with calcium also showed a significantly reduced risk of hip fracture (hazard ratio 0.74; 95% CI, 0.60 to 0.91). (The authors noted that trials of vitamin D 20 µg with calcium attempted to provide fracture prevention at a threefold higher risk level for hip fractures than did studies using the lower dose.) No significant effects were found for vitamin D alone in daily doses of 10 µg or 20 µg. No interaction was found between fracture history and treatment response, nor any interaction with age, sex, or hormone replacement therapy.
The authors recommend a vitamin D dose of at least 400 IU daily combined with 1,000 mg of calcium. In high-risk patients, this should be supplemented by bisphosphonates or other antiosteoporotic agents in accordance with national and international guidelines.
Br Med J. 2010;340:b5463.