Calcium Supplements and Risk of CVD: A Meta-Analysis of Randomized Trials

Area of Science:

• Cardiovascular Health
• Nutritional Epidemiology
• Gerontology

Background:

• Vitamin D and calcium supplementation efficacy for fracture prevention is debated.
• Potential cardiovascular disease (CVD) risks associated with calcium supplements warrant investigation.

Purpose of the Study:

• To conduct a meta-analysis of placebo-controlled trials on calcium supplements (alone or with vitamin D) and their impact on cardiovascular events and mortality.
• To assess the safety of calcium and vitamin D supplementation regarding coronary heart disease (CHD), stroke, and all-cause mortality.

Main Methods:

• A meta-analysis of 11 randomized controlled trials was performed.
• Included 7 comparisons of calcium alone and 6 of calcium plus vitamin D versus placebo.
• Analyzed aggregated study-level data for myocardial infarction (MI), CHD death, any CHD, stroke, and all-cause mortality.

Main Results:

• Calcium alone was not significantly associated with increased risk of MI, CHD death, any CHD, or stroke.
• Calcium plus vitamin D also showed no significant association with excess risk for these cardiovascular outcomes.
• Neither calcium alone nor combined with vitamin D demonstrated significant associations with all-cause mortality.

Conclusions:

• Calcium supplements, individually or combined with vitamin D, do not pose a significant hazard for CHD, stroke, or all-cause mortality.
• The study excluded excess risks above 0.3%-0.5% per year for CHD or stroke.
• Further trials are recommended for individuals with low 25(OH)D levels to evaluate fracture prevention and other outcomes.