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29-07-2010 | General practice | Article

Calcium supplements may raise heart risk


Free abstract

Research suggests that calcium supplements may increase the risk of myocardial infarction (MI).

Analyses of 11 placebo-controlled trials, including over 12,000 participants, revealed a 30% increased relative risk of MI over 4 years among people taking calcium supplements for treatment or prevention of osteoporosis.

Reporting their findings in the British Medical Journal, Professor Ian Reid (University of Auckland, New Zealand) and co-workers say: "Given the modest benefits of calcium supplements on bone density and fracture prevention, a reassessment of [their] role… is warranted."

The researchers emphasise that they excluded studies on co-administered calcium and vitamin D, so the findings may not apply to people taking a combination of these supplements.

Professor John Cleland (University of Hull) and colleagues comment in a related editorial that there are no conclusive data to show that calcium and vitamin D supplements, either alone or in combination, reduce fracture risk.

However, among other treatments for osteoporosis, bisphosphonates and raloxifene have generally been given in addition to calcium and vitamin D, they note.

And Dr Claire Bowring, of the National Osteoporosis Society, said: "In the studies looking at the effect of osteoporosis treatments on reducing the rate of fractures, it was ensured that the people recruited into the trials had enough calcium. Therefore, it cannot be assumed that the osteoporosis treatments will be effective without ensuring that people have sufficient levels of calcium."

Professor Cleland and team conclude: "On the basis of the limited evidence available, patients with osteoporosis should generally not be treated with calcium supplements, either alone or combined with vitamin D, unless they are also receiving an effective treatment for osteoporosis for a recognised indication."

GP News is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2010

By Caroline Price