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Boning Up On Calcium

Extra calcium in the diet produces a sustained reduction in the rate of loss of bone density in healthy post-menopausal women, according to an Auckland School of Medicine study.

Research leader Dr Ian Reid says while controversy continues regarding the role of calcium in the prevention of osteoporosis, previous studies have indicated a short-term effect on bone density of around two years.

"We found the benefit from calcium supplementation on the rates of bone loss and the reduction in fractures throughout the skeleton, was sustained over the four years of treatment," he says.

In general, differences in bone density are associated with differences in fracture risk. In the present population, Reid says, it is possible to project what change in fracture risk might result from the reductions in bone loss.

"With continued use of calcium supplements over 30 years of post-menopausal life, that person could expect a 50% reduction in fracture risk."

Osteoporosis affects 40% of post-menopausal New Zealand women and leads to 2,500 hip fractures annually.

With just 78 subjects in the study, it can't be regarded as a definitive demonstration of the fracture-prevention efficacy of calcium supplementation, but it does provide evidence to support the use of calcium as an effective measure against bone loss.