February 13, 2013
Too Much Calcium Supplementation Linked to Heart Disease Deaths in Men

Bethesda, MD— A new study arms pharmacists with some critical information to share with older men inquiring about the benefits of using calcium supplements for bone health: Too much supplemental calcium may be associated with increased risk of dying from cardiovascular disease (CVD) in men, although not women.

That’s according to a study of more 388,000 participants between the ages of 50 and 71 years, which was published online by JAMA Internal Medicine.

The authors, led by Qian Xiao, PhD, of the National Cancer Institute, note that calcium supplementation is widely used in an effort to promote bone health, especially among the elderly population in Western countries. The study cites recent research suggesting that more than 50% of older men and 70% of older women in the United States use calcium supplements.

The authors point out, however, that beyond calcium’s usefulness in prevention and treatment of osteoporosis, “its health effect on nonskeletal outcomes, including cardiovascular health, remains largely unknown and has become increasingly contentious.”

To examine whether the intake of dietary and supplemental calcium was associated with mortality from total CVD, heart disease, and cerebrovascular diseases, the study looked at 388,229 subjects ages 50 to 71 years from the National Institutes of Health-AARP Diet and Health Study in California, Florida, Louisiana, New Jersey, North Carolina, and Pennsylvania as well as two metropolitan areas—Atlanta and Detroit—from 1995 through 1996. Slightly more than half of the male subjects, 51%, and 70% of the females used calcium supplements.

During an average 12 years of follow-up, researchers identified 7,904 CVD deaths in men and 3,874 CVD deaths in women. They found that men with an intake of more than 1,000 mg/day of supplemental calcium were at an increased risk of total CVD death (risk ratio [RR], 1.20)—more specifically with heart disease death but not significantly with cerebrovascular disease death. None of those risks were elevated in women who used calcium supplements.

“In this large, prospective study we found that supplemental but not dietary calcium intake was associated with an increased CVD mortality in men but not in women,” according to the authors, who add, “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.”

In an accompanying commentary, Susanna C. Larsson, PhD, of the Karolinska Institutet in Stockholm, Sweden, calls for more large studies “to further assess the potential health risks or benefits of calcium supplement use on CVD morbidity and mortality.”

As a safe alternative, Larsson suggests that health providers recommend increased intake of calcium-rich food 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.”

"These non-dairy food sources of calcium have the added health benefits and have recently been reported to improve glycemic control in persons with diabetes. The paradigm ‘the more the better’ is invalid for calcium supplementation,” Larsson writes.

U.S. Pharmacist Social Connect