Vitamin D and Cardiovascular Health: A Narrative Review of Risk Reduction Evidence.

Area of Science:

• Cardiovascular Health
• Endocrinology
• Nutritional Science

Background:

• The association between vitamin D and cardiovascular disease (CVD) risk is debated.
• Low serum 25-hydroxyvitamin D [25(OH)D] concentrations (<40-50 nmol/L) correlate with increased CVD incidence.
• Observational studies suggest an inverse correlation between 25(OH)D levels and CVD mortality.

Purpose of the Study:

• To evaluate the role of vitamin D in cardiovascular disease (CVD) risk reduction.
• To analyze evidence from observational studies and randomized controlled trials (RCTs) on vitamin D supplementation and CVD.
• To assess the biological plausibility and clinical implications of vitamin D for cardiovascular health.

Main Methods:

• Review of prospective observational studies on 25(OH)D levels and CVD incidence/mortality.
• Analysis of randomized controlled trials (RCTs) investigating vitamin D supplementation and cardiovascular outcomes.
• Examination of temporal ecological studies and application of Hill's criteria for causality.

Main Results:

• Low 25(OH)D is consistently linked to higher CVD risk.
• Some RCTs show vitamin D3 supplementation (60,000 IU/month) reduced major cardiovascular events by 13-17% in specific populations.
• Vitamin D supplementation has shown modest reductions in CVD risk factors and improved endothelial function.

Conclusions:

• Vitamin D plays a role in CVD risk reduction, supported by observational data and some RCTs.
• Vitamin D supplementation, especially vitamin D3, should be considered for CVD prevention and management.
• Optimal serum 25(OH)D concentrations (above 75 nmol/L) may require at least 2000 IU/day supplementation, particularly with insufficient sun exposure.