In this case, women who were randomized to take calcium and vitamin D as part of the study protocol had a modest 13 to 22 percent increased risk of cardiovascular problems, particularly heart attacks. Women in the control arm had no change in risk.
The case against calcium became stronger when researchers added in data from 13 other, unpublished trials involving almost 30,000 women. Now the increased risk for heart attack was 25 to 30 percent and, for a stroke, 15 to 20 percent.
While the authors speculate that an increased risk could be biologically plausible given that calcium is connected with hardening of the arteries, another expert thinks not.
While calcium does tend to be a marker of inflammation, explained Dr. Philip Houck, assistant professor of internal medicine at Texas A&M Health Science Center College of Medicine, "lesions with calcium are actually more stable so there's less of a chance of having a heart attack than in vessels that are less calcified."
Moreover, the results may have been statistically significant but that doesn't mean they're clinically significant, he added. "If women have good reason to take calcium because their bones are thin, then they should not be afraid of taking the calcium," said Houck, who is also a cardiologist with Scott & White in Temple, Texas.
Dr. Susan V. Bukata, associate professor of orthopaedic surgery at the University of Rochester Medical Center, said that the study really doesn't provide enough information to make a definitive conclusion.
Nevertheless, accumulating evidence has her urging patients to get their calcium from their diet, rather than reflexively telling them to take 1,200 milligrams of calcium a day. "With diet plus a supplement combined, women should be getting 1,000- to 1,500-milligrams a day," she said.
And in an accompanyi
All rights reserved