Calcium Supplements Useless in Averting Hip Fracture

A new study has found that calcium from food as well as from supplements does not prevent hip fractures in men and women, and that supplements may even increase the fracture risk.

Researchers at the University Hospital Zurich (Switzerland) conducted a meta-analysis in which they combined results from 12 double blind, randomized, placebo-controlled trials, as well as observational cohort studies of calcium intake and hip fractures. The meta-analysis included seven prospective cohort studies of 170,991 women with 2,954 hip fractures and five that included 68,606 men with 214 hip fractures. Studies in which calcium supplements were combined with other nutrients, such as vitamin D, were excluded.

The researchers found that among women, there was no association between total calcium intake and hip fracture risk. Among men, the pooled risk ratio per 300 mg of total calcium a day was 0.92. On the basis of five clinical trials (including 5,666 women, primarily postmenopausal, and 1,074 men) with 814 nonvertebral fractures, the pooled relative risk for nonvertebral fractures between calcium supplementation (800-1600 mg/d) and placebo was 0.92. On the other hand, they found that in four clinical trials with separate results for hip fracture (6,504 individuals with 139 fractures), the pooled relative risk showed a 64% increased hip fracture risk between calcium (800 and 1200 mg/d) and placebo. The study was published in the December 2007 issue of the American Journal of Clinical Nutrition.

"This meta-analysis highlights the importance of not segmenting nutrition into heterogeneous populations and isolated nutrients. Bone is not just calcium, and calcium does not function in isolation,” concluded lead author Heike A. Bischoff-Ferrari, M.D., and colleagues.

The researchers explained that calcium supplementation or the consumption of calcium-rich foods is commonly recommended for the prevention of osteoporosis and fractures, based on controlled trials with bone density as the outcome. However, normal serum levels of 25-hydroxyvitamin D are necessary for optimal calcium absorption from the gastrointestinal tract.


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University Hospital Zurich