Calcium intake may increase CVD risk in men, but not women

Calcium from supplements was not related to death from cardiovascular disease in women, but may increase the risk in men, according to a study published recently in JAMA Internal Medicine.

Calcium intake has been promoted due to its proposed benefit on bone health, particularly among the older population. However, concerns have been raised about the potential adverse effect of high calcium intake on cardiovascular health.

Qian Xiao, PhD, of the National Cancer Institute, Bethesda, Md., and colleagues investigated whether calcium intake-from dietary sources and supplements-is related to risk of death from cardiovascular diseases. The researchers used data from the NIH-AARP Diet and Health Study, a large, long-term follow-up study of Americans aged 50 to 71 years. Information on calcium intake from diet and supplements was collected via questionnaire completed at study entry. Participants were then followed for an average of 12 years.

“To carry out the analysis we categorized men and women based on their total intake of calcium from dietary sources and supplements including calcium, and compared their risk of death from cardiovascular diseases,” Xiao said. “In our analysis we took into account other known risk factors from cardiovascular diseases, such as BMI and smoking history. 

“We found that compared to men who did not report taking calcium supplements, men who reported taking 1,000 mg per day were 20% more likely to die of cardiovascular diseases,” she continued. “Among women, we did not observe a relationship between calcium supplement intake and risk of death from cardiovascular diseases.”

Xiao pointed out that the study is based on observation-and not designed to determine cause and effect. “Although we observed an increased risk of death from heart disease in men, we cannot say for sure that it was a result of using supplements containing calcium,” she said. “We need more studies to clarify this possible relationship and the underlying mechanism.”