Calcium supplements not associated with increased risk of cardiovascular disease in women

Calcium supplements are widely taken by women for bone health. Previous studies have suggested that calcium supplements may increase risk of cardiovascular disease, but the data has been inconsistent. A new study by researchers at Brigham and Women's Hospital (BWH) did not find that calcium supplement intake increases risk of cardiovascular disease in women.

The study is published online May, 2014 in Osteoporosis International.

Researchers examined supplemental calcium use and incident cardiovascular disease in a prospective cohort study of 74,245 women in the Nurses' Health Study. The women did not have cardiovascular disease or cancer at the start of the study. They were followed for 24 years to document risk of developing heart attack and stroke. Calcium supplement intake was assessed every four years.

"Our study has several distinct strengths compared to prior studies including the large number of participants, long-term follow-up, large number of cardiovascular events that were confirmed by medical record review, detailed information about diet and other cardiovascular disease risk factors, and repeated assessment of calcium supplement use over the 24-year follow up period," said Julie Paik, MD, MPH, BWH Channing Division of Network Medicine, Department of Medicine, lead study author.

The researchers found that at the start of the study, women who took calcium supplements had higher levels of physical activity, smoked less, and had lower trans fat intake compared to women who did not take calcium supplements. During the 24 years of follow-up, there were 2,709 heart attacks and 1,856 strokes.

"Based on our findings, additional prospective cohort studies examining potential cardiovascular disease risk associated with calcium supplement use are needed," said Paik. "Future randomized trials of calcium supplementation, if conducted, should be designed to optimize assessment of cardiovascular events."