High calcium supplementation may cause CVD death in men

A high intake of supplemental calcium appears to be associated with an increased risk of cardiovascular disease (CVD) death in men but not in women, according to a study published online Monday in JAMA Internal Medicine. Qian Xiao, of the U.S. National Cancer Institute, and colleagues examined whether the intake of dietary and supplemental calcium was associated with mortality from total CVD, heart disease and cerebrovascular diseases. Calcium supplementation has become widely used, especially among the elderly population, because of its proposed bone health benefits. However, beyond calcium's 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 write in the study background. The study participants were 388,229 men and women, aged 50 to 71, from the National Institutes of Health-AARP (American Association of Retired Persons) Diet and Health Study in six states and two metropolitan areas from 1995 through 1996. During an average 12 years of follow-up, 7,904 CVD deaths in men and 3,874 CVD deaths in women were identified and supplements containing calcium were used by 51 percent of men and 70 percent 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 deaths linked specifically with heart disease. For women, supplemental calcium intake was not associated with CVD death, heart disease death or cerebrovascular disease death. Dietary calcium intake also 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. Given the extensive use of calcium supplement in the population, it is of great importance to assess the effect of supplemental calcium use beyond bone health," the authors conclude.