Calcium supplements linked to heart attack risk

30^th July 2010 - Calciumsupplements are linked with an increased heart attack risk, according to researchers. Calcium is commonly taken by older people for osteoporosis, and a reassessment is being called for over managing the bone condition.

The National Osteoporosis Society says nearly three million people in the UK are estimated to have the condition. One in two women and one in five men over the age of 50 in the UK will break a bone mainly because of poor bone health.

New study

To further investigate this important issue, an international team of researchers from the Health Services Research Unit at the University of Aberdeen, and colleagues from the US and Australia, analysed the results of 11 randomised controlled trials of calcium supplements (without  vitamin D given at the same time) involving 12,000 patients.

They found that calcium supplements were associated with about a 30% increased risk of heart attack and smaller increases in the risk of stroke and mortality.

The findings were similar across trials and were independent of age, sex and type of supplement.

Risks

Because of the widespread use of calcium supplements, the researcher say that even a small increase in risk could translate into large numbers in the wider population.

Previous studies have found no increased heart risks with higher calcium intake from diet, suggesting that the risks are restricted to supplements.

Writing at bmj.com, the study team say that calcium supplements give only modest benefits to bone density and preventing fractures, so a reassessment of the use of calcium supplements for osteoporosis is needed.

In an editorial to go with the article, Professor John Cleland of Hull York Medical School, University of Hull, and colleagues suggests that, while uncertainty exists about whether the increase in heart attack and stroke is real, there are also doubts about the benefit  of calcium supplements in reducing fractures. They say that, 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. 

They also believe that research on whether such supplements are needed as an adjunct to effective agents is urgently required.