Vitamin D deficiency tied to higher T2D risk

Increased serum concentration of 25(OH)D appears to contribute to a reduced risk of type 2 diabetes (T2D) across the glycaemic spectrum below the threshold for diabetes, reports a study. Improving the lipid profile may be partly responsible for the favourable association. 

A total of 379,699 individuals without T2D at baseline from the UK Biobank were included in this prospective study. The authors conducted analyses based on glycaemic status and HbA1c levels. They calculated the hazard ratios (HRs) and 95 percent confidence intervals (CIs) using Cox proportional hazard models. 

T2D developed in 6,315 participants with normoglycaemia and 9,085 patients with prediabetes during a median follow-up of 14.1 years. 

In multivariate analyses, incident T2D risk was lower in individuals with 25(OH)D ≥75 nmol/L among the normoglycaemia group (HR, 0.62, 95 percent CI, 0.56–0.70) and the prediabetes group (HR, 0.64, 95 percent CI, 0.58–0.70) than those with 25(OH)D <25 nmol/L. 

Vitamin D receptor polymorphisms showed significant interactions with 25(OH)D among participants with prediabetes (p=0.17 for interaction), while the association between higher concentration of 25(OH)D and a reduced T2D risk was more pronounced in individuals carrying the T allele of rs1544410. 

In addition, “[t]riglyceride levels mediated 26 percent and 34 percent of the association between serum 25(OH)D and incident T2D among participants with normoglycemia and prediabetes, respectively,” the authors said.