Calcium intake from foods or supplements at levels within recommended ranges is not associated with increased risk of cardiovascular disease among healthy adults.

Cover: Calcium Intake and Cardiovascular Disease Risk

Calcium Intake and Cardiovascular Disease Risk

An Updated Systematic Review and Meta-Analysis

Published in: Annals of Internal Medicine, 2016

Posted on RAND.org on November 17, 2016

by Mei Chung, Alice M. Tang, Zhuxuan Fu, Ding D. Wang, Sydne J. Newberry

Research Question

  1. How does calcium intake affect the risk of cardiovascular disease in healthy adults?

Background

Conflicting evidence exists regarding potential cardiovascular risks associated with high levels of calcium intake.

Purpose

To update and reanalyze 2 systematic reviews to examine the effects of calcium intake on cardiovascular disease (CVD) among generally healthy adults.

Data Sources

MEDLINE; Cochrane Central Register of Controlled Trials; Scopus, including EMBASE; and previous evidence reports from English-language publications from 1966 to July 2016.

Study Selection

Randomized trials and prospective cohort and nested case–control studies with data on dietary or supplemental intake of calcium, with or without vitamin D, and cardiovascular outcomes.

Data Extraction

Study characteristics and results extracted by 1 reviewer were confirmed by a second reviewer. Two raters independently assessed risk of bias.

Data Synthesis

Overall risk of bias was low for the 4 randomized trials (in 10 publications) and moderate for the 27 observational studies included. The trials did not find statistically significant differences in risk for CVD events or mortality between groups receiving supplements of calcium or calcium plus vitamin D and those receiving placebo. Cohort studies showed no consistent dose–response relationships between total, dietary, or supplemental calcium intake levels and cardiovascular mortality and highly inconsistent dose–response relationships between calcium intake and risks for total stroke or stroke mortality.

Limitations

CVD disease outcomes were secondary end points in all trials. Dose–response metaregression analysis of cohort studies was limited by potential confounding, ecological bias, and imprecise measures of calcium exposures. Data were scarce regarding very high calcium intake—that is, beyond recommended tolerable upper intake levels.

Conclusion

Calcium intake within tolerable upper intake levels (2000 to 2500 mg/d) is not associated with CVD risk in generally healthy adults.

Primary Funding Source

National Osteoporosis Foundation.

Key Finding

  • Calcium intake from foods or supplements at levels within recommended ranges is not associated with increased risk of cardiovascular disease risk among healthy adults.
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