Use of calcium or calcium in combination with vitamin D supplementation to prevent fractures and bone loss in people aged 50 years and older: a meta-analysis

Background Whether calcium supplementation can reduce osteoporotic fractures is uncertain. We did a meta-analysis to include all the randomised trials in which calcium, or calcium in combination with vitamin D, was used to prevent fracture and osteoporotic bone loss. Methods We identified 29 randomised trials (n=63897) using electronic databases, supplemented by a hand-search of reference lists, review articles, and conference abstracts. All randomised trials that recruited people aged 50 years or older were eligible. The main outcomes were fractures of all types and percentage change of bone-mineral density from baseline. Data were pooled by use of a random-effect model. Findings In trials that reported fracture as an outcome (17 trials, n=52625), treatment was associated with a 12% risk reduction in fractures of all types (risk ratio 0 center dot 88, 95% CI 0 center dot 83 center dot 0 center dot 95; p=O center dot 0004). In trials that reported bone-mineral density as an outcome (23 trials, n=41 419), the treatment was associated with a reduced rate of bone loss of 0 center dot 54% (0 center dot 3 5-0 center dot 73; p < O center dot 0001) at the hip and 1 center dot 19% (0 center dot 76-1 center dot 61%; p < O center dot 0001) in the spine. The fracture risk reduction was significantly greater (24%) in trials in which the compliance rate was high (p < O center dot 0001). The treatment effect was better with calcium doses of 1200 mg or more than with doses less than 1200 mg (0 center dot 80 vs 0 center dot 94; p=O.006), and with vitamin D doses of 800 IU or more than with doses less than 800 IU (0 center dot 84 vs 0 center dot 87; p=O.03). Interpretation Evidence supports the use of calcium, or calcium in combination with vitamin D supplementation, in the preventive treatment of osteoporosis in people aged 50 years or older. For best therapeutic effect, we recommend minimum doses of 1200 mg of calcium, and 800 IU of vitamin D (for combined calcium plus vitamin D supplementation).