Calcium supplements linked to heart risk
Friday July 30th, 2010
Taking calcium supplements may be linked to an increased risk of heart attack, according to an analysis published today.
Many osteoporosis patients are given calcium supplements to reduce the risk of fracture. Previous studies had suggested that high calcium intake might protect against diseases of the blood vessels.
But a 2008 study found an increased risk of heart attack in women taking calcium.
Professor Ian Reid of the University of Auckland, New Zealand, and colleagues analysed 15 trials, testing the impact of daily calcium supplements in patients followed for a median of 3.6 years.
Experts from the British Heart Foundation today urged caution on the findings - pointing out that no direct research had been reported on the effects of supplements.
In the research, the rate of heart attack was 27 to 31 per cent higher on calcium, depending on the type of trial, and was independent of age, sex, and type of supplement.
On the website of the British Medical Journal, the team conclude: "Calcium supplements are associated with an increased risk of myocardial infarction. As calcium supplements are widely used, these modest increases in risk of cardiovascular disease might translate into a large burden of disease in the population."
They add that the risk did not apply to higher calcium intake in the diet, and call for a reassessment of calcium tablets in the management of osteoporosis.
In an editorial, Professor John Cleland and colleagues at Hull University, UK, write: "Calcium supplements, given alone, improve bone mineral density, but they are ineffective in reducing the risk of fractures and might even increase risk.
"On the basis of the limited evidence available, patients with osteoporosis should generally not be treated with calcium supplements. Research on whether such supplements are needed as an adjunct to effective agents is urgently required."
But Judy O’Sullivan, of the British Heart Foundation, said: "We need to be cautious about the results of this analysis because none of the studies involved were designed to look specifically at the relationship between calcium supplements and the risk of heart attack.
"However, the research should not be completely ignored. Any new
guidelines on the prevention of fractures in those most vulnerable to
them should take this type of analysis into account.
"Anyone who has been advised by their doctor to take calcium supplements shouldn’t stop because of this research alone."
Cleland, J. G. F., Witte, K. and Steel, S. Calcium supplements in people with osteoporosis. The British Medical Journal, 2010;341:c3856.
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