Dietary and Supplemental Calcium Intake and Cardiovascular Disease Mortality: The National Institutes of Health–AARP Diet and Health Study

Study Questions:

What is the impact of dietary and supplemental calcium intake on mortality from total cardiovascular disease (CVD), heart disease, and cerebrovascular diseases?

Methods:

This was a prospective study from 1995 through 1996 in California, Florida, Louisiana, New Jersey, North Carolina, and Pennsylvania and the two metropolitan areas of Atlanta, Georgia, and Detroit, Michigan. A total of 388,229 men and women, ages 50-71 years, from the National Institutes of Health–AARP Diet and Health Study were included. Dietary and supplemental calcium intake was assessed at baseline (1995-1996). Supplemental calcium intake included calcium from multivitamins and individual calcium supplements. Multivariate Cox proportional hazards regression models adjusted for demographic, lifestyle, and dietary variables were used to estimate relative risks (RRs) and 95% confidence intervals (CIs).

Results:

During a mean of 12 years of follow-up, 7,904 and 3,874 CVD deaths in men and women, respectively, were identified. 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 CVD death (RR >1000 vs. 0 mg/d, 1.20; 95% CI, 1.05-1.36), more specifically with heart disease death (RR, 1.19; 95% CI, 1.03-1.37), but not significantly with cerebrovascular disease death (RR,1.14; 95% CI, 0.81-1.61). In women, supplemental calcium intake was not associated with CVD death (RR, 1.06; 95% CI, 0.96-1.18), heart disease death (RR, 1.05; 0.93-1.18), or cerebrovascular disease death (RR, 1.08; 0.87-1.33). Dietary calcium intake was unrelated to CVD death in either men or women.

Conclusions:

The authors concluded that high intake of supplemental calcium is associated with an excess risk of CVD death in men, but not in women.

Perspective:

This large, prospective study concludes that supplemental but not dietary calcium intake was associated with an increased CVD mortality in men, but not in women. The lack of association between dietary calcium and CVD mortality reported here is consistent with previous observational studies. The observed gender interaction in the CV effect of calcium supplement warrants further investigation, particularly given the extensive use of calcium supplements in women.

Clinical Topics: Prevention, Vascular Medicine, Diet

Keywords: Michigan, Follow-Up Studies, New Jersey, Georgia, Calcium, Pennsylvania, Proportional Hazards Models, Cerebrovascular Disorders, California, Florida, Cardiovascular Diseases, Louisiana, Confidence Intervals, Diet, North Carolina


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