Calcium plus vitamin D supplementation and the risk of fractures.

Study answer

What this study found

Calcium plus vitamin D did not significantly reduce hip fracture or total fractures, although it produced a small improvement in hip bone density. Hip fracture occurred in 175 women in the calcium plus vitamin D group versus 199 in placebo (hazard ratio 0.88, 95% CI 0.72-1.08), and total fractures occurred in 2102 versus 2158 (hazard ratio 0.96, 95% CI 0.91-1.02). Hip bone density was 1.06 percent higher in the calcium plus vitamin D group (P<0.01), and the adherence-adjusted hip fracture hazard ratio was 0.71 (0.52-0.97). The regimen increased renal calculi risk (hazard ratio 1.17, 95% CI…

Study & population

Randomized, placebo-controlled trial in healthy postmenopausal women aged 50 to 79 years enrolled at 40 Women's Health Initiative clinical centers in the United States.

Intervention

The active regimen was oral calcium carbonate plus vitamin D3: each tablet contained 500 mg elemental calcium and 200 IU vitamin D3, taken as two tablets per day in divided doses with meals.

Key limitation

Fracture outcomes were not significantly improved in the intention-to-treat analysis despite a bone density benefit, and adherence influenced the apparent hip-fracture reduction.

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Original abstract