A closer look at WHI study on calcium and fractures

Despite all the negative reports in the lay press claiming the latest WHI study proved that calcium/vitamin D supplements do not prevent fractures in postmenopausal women, a closer look at the results clearly shows that they do.

A recent New York Times headline that shouted, "Big study finds no clear benefit of calcium pills," was attempting to summarize a New England Journal of Medicine trial that found 1,000 mg of calcium carbonate and 400 IU of vitamin D, given to more than 36,000 women for about 7 years, reduced the risk of hip fracture by a mere 12% (and the threat of spine fracture by only 10%). But when investigators excluded those women in the trial whose adherence to the supplement regimen dropped below 80%, the risk of hip fracture was almost 30%. So it's probably more accurate to conclude that women who don't take their calcium regularly can't expect any protection from hip fractures.

Jackson RD, LaCroix AZ, Gass M, et al. Calcium plus vitamin D supplementation and risk of fractures. N Engl J Med. 2006; 354:669-683.