Vitamin D and risk of death from vascular and non-vascular causes in the Whitehall study and meta-analyses of 12,000 deaths.
Tomson J., Emberson J., Hill M., Gordon A., Armitage J., Shipley M., Collins R., Clarke R.
AIMS: To examine the independent relevance of plasma concentrations of 25-hydroxyvitamin D [25(OH)D] for vascular and non-vascular mortality. METHODS AND RESULTS: We examined associations of plasma concentrations of 25(OH)D and cause-specific mortality in a prospective study of older men living in the UK and included findings in meta-analyses of similar studies identified by a systematic search reporting on vascular and all-cause mortality. In a 13-year follow-up of 5409 men (mean baseline age 77 years), 1358 died from vascular and 1857 from non-vascular causes. Median season-adjusted baseline 25(OH)D concentration was 56 (interquartile range: 45-67) nmol/L. After adjustment for age and seasonality, higher concentrations of 25(OH)D were inversely and approximately linearly (log-log scale) associated with vascular and non-vascular mortality throughout the range 40-90 nmol/L. After additional adjustment for prior disease and cardiovascular risk factors, a doubling in 25(OH)D concentration was associated with 20% [95% confidence interval (CI): 9-30%] lower vascular and 23% (95% CI: 14-31%) lower non-vascular mortality. In meta-analyses of prospective studies, individuals in the top vs. bottom quarter of 25(OH)D concentrations had 21% (95% CI: 13-28%) lower vascular and 28% (95% CI: 24-32%) lower all-cause mortality. CONCLUSIONS: Despite strong inverse and apparently independent associations of 25(OH)D with vascular and non-vascular mortality, causality remains uncertain. Large-scale randomized trials, using high doses of vitamin D, are required to assess the clinical relevance of these associations.