Could too much calcium give you a heart attack?
Many men and women take calcium as a dietary supplement, often to promote bone health. However, a new study has found that a high intake of calcium may increase the risk of heart disease. In addition, a gender discrepancy was found. The study was published online on January 4 in the journal JAMA Internal Medicine.
The researchers noted that in Western nations, significant emphasis has been placed on calcium intake because of its proposed benefit for bone health. Calcium supplementation has become widely used, especially among the senior population. A recent study reported that more than 50% of older men and almost 70% of older women in the US take calcium supplements. However, beyond calcium’s established role in prevention and treatment of osteoporosis, its health effect on nonskeletal outcomes, including cardiovascular health, remains largely unknown and has become an increasingly controversial subject. Therefore, they conducted a study to investigate whether intake of dietary and supplemental calcium is associated with mortality from total cardiovascular disease, heart disease, and cerebrovascular diseases.
The prospective study was conducted from 1995 through 1996 in California, Florida, Louisiana, New Jersey, North Carolina, and Pennsylvania; in addition, it included the two metropolitan areas of Atlanta, Georgia, and Detroit, Michigan. The study group comprised 388,229 men and women aged 50 to 71 years from the National Institutes of Health–AARP Diet and Health Study.
Dietary and supplemental calcium intake was assessed at baseline (1995-1996). Supplemental calcium intake included calcium from multivitamins and individual calcium supplements. Cardiovascular disease deaths were determined using the National Death Index. Multivariate Cox proportional hazards regression models adjusted for demographic, lifestyle, and dietary variables were used to estimate relative risks (RRs).
The investigators found that during a mean of 12 years of follow-up, 7,904 cardiovascular disease deaths occurred in men and 3,874 cardiovascular disease deaths occurred in women. Supplements containing calcium were used by 51% of men and 70% of women. In men, supplemental calcium intake was associated with an elevated risk of cardiovascular death, more specifically with heart disease death but not significantly with cerebrovascular disease death. In women, supplemental calcium intake was not associated with cardiovascular disease death, heart disease death, or cerebrovascular disease death.
The researchers concluded that their findings suggest that high intake of supplemental calcium is associated with an excess risk of cardiovascular disease death in men but not in women. They recommended that additional studies are needed to investigate the effect of supplemental calcium use beyond bone health.
Take home message:
This study should be reassuring to older women who take calcium supplements with the goal of reducing the risk of osteoporosis. Older men are less susceptible to osteoporosis; however, many older men develop osteoporosis.
Reference: JAMA Internal Medicine