WASHINGTON — A study is raising new questions about the safety of calcium, which many women take to protect their bones.
An analysis of data collected about more than 16,000 women who participated in the landmark 2002 Women’s Health Initiative found that those who started taking calcium as part of the study were at increased risk for heart attacks and strokes.
The new analysis from 16,718 women, led by Ian Reid of the University of Auckland, of data published in the British medical journal known as BMJ, found that the women who were not taking calcium when the study started but began taking it when they got into the research project were at 13 to 22 percent increased risk.
The researchers speculate that suddenly starting calcium may boost the risk, perhaps by hardening the arteries.
An editorial accompanying the analysis states that further studies are needed.