Context: Vitamin D has been shown to influence cardiac contractility and myocardial calcium homeostasis.
Objectives: We aimed to elucidate whether insufficient vitamin D status is associated with heart failure and sudden cardiac death (SCD).
Design, setting, and participants: We measured 25-hydroxyvitamin D [25(OH)D] levels in 3299 Caucasian patients who were routinely referred to coronary angiography at baseline (1997-2000).
Main outcome measures: The main outcome was cross-sectional associations of 25(OH)D levels with measures of heart failure and Cox proportional hazard ratios for deaths due to heart failure and for SCD according to vitamin D status.
Results: 25(OH)D was negatively correlated with N-terminal pro-B-type natriuretic peptide and was inversely associated with higher New York Heart Association classes and impaired left ventricular function. During a median follow-up time of 7.7 yr, 116 patients died due to heart failure and 188 due to SCD. After adjustment for cardiovascular risk factors, the hazard ratios (with 95% confidence intervals) for death due to heart failure and for SCD were 2.84 (1.20-6.74) and 5.05 (2.13-11.97), respectively, when comparing patients with severe vitamin D deficiency [25(OH)D <25 nmol/liter)] with persons in the optimal range [25(OH)D > or =75 nmol/liter]. In all statistical analyses, we obtained similar results with 25(OH)D and with 1,25-dihydroxyvitamin D.
Conclusions: Low levels of 25(OH)D and 1,25-dihydroxyvitamin D are associated with prevalent myocardial dysfunction, deaths due to heart failure, and SCD. Interventional trials are warranted to elucidate whether vitamin D supplementation is useful for treatment and/or prevention of myocardial diseases.