Background: Previous studies suggest that vitamin D is inversely associated with mortality and cardiovascular disease (CVD) risk, but data on the association between serum 25-hydroxyvitamin D (25(OH)D) and incident heart failure are limited.
Aims: To examine serum 25(OH)D as a predictor of total mortality and cardiovascular outcomes in an Australian community-based cohort.
Methods: Serum 25(OH)D was measured in the Busselton Health Study 1994/1995 Cohort (n=3946, age 25-84 years). During 20 years follow-up (excluding the first 2 years), 889 (22.5%) participants died including 363 (9.2%) from cardiovascular disease (CVD); 944 (23.9%) experienced a CVD event including 242 (6.1%) who had a heart failure event.
Results: The mean serum 25(OH)D concentration was 60.6 (SD 18.0) nmol/L. In the full cohort, higher baseline serum 25(OH)D was associated with significantly reduced all-cause mortality (covariate-adjusted hazard ratio [HR] 0.83 per SD of 25(OH)D, 95% CI 0.77-0.90), CVD death (HR 0.85, 95% CI 0.74-0.96) and heart failure (HR 0.81, 95% CI 0.69-0.94), but not for CVD events combined (HR 0.99, 95% CI 0.92-1.07). In restricted cubic spline regression models, serum 25(OH)D below 65 nmol/L was associated with higher total mortality and 25(OH)D below 55 nmol/L with CVD mortality and heart failure; there were no additional benefits for 25OHD above 80 nmol/L. In participants without CVD at baseline (n = 3220) results were similar, but hazard ratios were attenuated and associations with CVD mortality no longer significant.
Conclusion In a community-based cohort, lower vitamin D is associated with increased risk of all-cause mortality, CVD death and heart failure.