Non-linear associations of 25-hydroxyvitamin D concentrations with risk of cardiovascular disease and all-cause mortality: Results from The Health Improvement Network (THIN) database.J Steroid Biochem Mol Biol. 2019 12; 195:105480.JS
There is increasing evidence that vitamin D supplementation may only be beneficial in people with vitamin D deficiency, and the lack of sufficient people with very low vitamin D levels could explain the lack of protection against cardiovascular disease (CVD) reported in recent clinical trials of vitamin D supplementation. The aim of this study was to assess associations of low to moderate circulating concentrations of 25-hydroxyvitamin D (25(OH)D with risk of incident CVD and all-cause mortality, as well as the risk of ischaemic heart disease (IHD), cerebrovascular disease, and heart failure separately.
METHODS AND RESULTS
Longitudinal analysis of electronic health records in The Health Improvement Network (THIN), a UK primary care database. The analysis included 180,263 patients age 18 years and older without a history of CVD and with circulating concentrations of 25(OH)D. After a mean follow-up of 2.2 (SD 1.7) years, there were 3747 patients diagnosed with CVD and 3912 patients died. Compared to patients in the highest quintile of 25(OHD) (≥ 67.5 nmol/L), those in the lowest 25(OH)D quintile (<23.1 nmol/L) had a hazard ratio (HR) of 1.24 (95% CI 1.12-1.38, P < 0.001) for CVD and 1.71 (1.55-1.88, P < 0.001) for mortality. The HR for both outcomes associated with 25(OH)D concentration was non-linear, being significantly increased in patients with 25(OH)D <35 nmol/L, and highest in those with 25(OH)D <25 nmol/L, although increased for mortality at 25(OH)D ≥100 nmol/L. The increased CVD HR in the lowest 25(OH)D quintile was more from IHD (1.35, 95% CI 1.13-1.60) and heart failure (1.38, 95% CI 1.08-1.77), than from cerebrovascular disease (1.13, 95% CI 0.97-1.31).
Low 25(OH)D are associated with highest risk of CVD and mortality, and are consistent with accumulating evidence that increased risk of these diseases occurs primarily in people with vitamin D deficiency.