A high intake of supplemental calcium appeared to be associated with an increased risk of death from cardiovascular disease in men, but not in women, in a study of more than 388,000 participants between ages 50 to 71.
Calcium supplementation has become widely used, especially among the elderly population, because of its proposed bone health benefits, according to background information in the study, which is scheduled for publication in the Archives of Internal Medicine.
However, beyond calciums established role in the prevention and treatment of osteoporosis, its health effect on nonskeletal outcomes, including cardiovascular health, remains largely unknown and has become “increasingly contentious,” the authors wrote.
Qian Xiao, PhD, of the National Cancer Institute in Bethesda, Md., and colleagues examined whether the intake of dietary and supplemental calcium was associated with mortality from total CVD, heart disease and cerebrovascular diseases. The study participants were 388,229 men and women ages 50 to 71 from the National Institutes of Health-AARP Diet and Health Study in six states and two metropolitan areas from 1995 through 1996.
The researchers found that supplemental — but not dietary — calcium intake was associated with increased CVD mortality in men.
During an average 12 years of follow-up, 7,904 CVD deaths in men and 3,874 CVD deaths in women were identified, while supplements containing calcium were used by 51% of men and 70% of women. Compared with non-supplement users, men with an intake of supplemental calcium of more than 1,000 mg/day had an increased risk of total CVD death — linked specifically with heart disease, but not significantly with cerebrovascular disease death.
For women, supplemental calcium intake was not associated with CVD death, heart disease death or cerebrovascular disease death. Dietary calcium intake was not associated with CVD death in men or women.
“Whether there is a sex difference in the cardiovascular effect of calcium supplement warrants further investigation,” the researchers concluded. “Given the extensive use of calcium supplements in the population, it is of great importance to assess the effect of supplemental calcium use beyond bone health.”
In a related commentary, Susanna C. Larsson, PhD of the Karolinska Institutet in Sweden, wrote: “More large studies are needed to further assess the potential health risks or benefits of calcium supplement use on CVD morbidity and mortality.
“Meanwhile, a safe alternative to calcium supplements is to consume calcium-rich foods, such as low-fat dairy foods, beans and green leafy vegetables, which contain not only calcium but also a cocktail of essential minerals and vitamins.”