Plasma 25-hydroxyvitamin D and risk of metabolic syndrome: an ancillary analysis in the Diabetes Prevention Program

BACKGROUND/OBJECTIVES: Low blood levels of 25-hydroxyvitamin D (25OHD) have been associated with cardiometabolic disease but results are inconsistent. The objective of the study was to investigate the association of 25OHD with metabolic syndrome in a population at increased risk for diabetes. SUBJECTS/METHODS: Using baseline data from the placebo and lifestyle intervention arms of the Diabetes Prevention Program (N = 2000), multivariable logistic regression models were used to estimate the odds of prevalent metabolic syndrome and each of its individual components across 25OHD tertiles. Multivariable linear regression was used to estimate the adjusted mean difference of insulin secretion and sensitivity across the same 25OHD tertiles. In participants free of metabolic syndrome at baseline (N 546), incident metabolic syndrome in the first 2 years of follow-up was assessed using discrete-time proportional hazards regression to test its association with 25OHD concentration. RESULTS: After multivariate adjustment, participants in the highest tertile of 25OHD had lower odds of prevalent metabolic syndrome (odds ratio = 0.62; 95% confidence interval (CI) = 0.45-0.84), smaller waist circumference, higher high-density lipoprotein and lower fasting plasma glucose compared with participants in the lowest tertile of 25OHD. Higher plasma 25OHD concentration was associated with greater insulin sensitivity and lower insulin secretion. After multivariate adjustment, there was a nonsignificant lower risk of metabolic syndrome in the highest tertile of 25OHD (hazard ratio = 0.79; 95% CI = 0.48-1.32) compared with the lowest tertile. CONCLUSIONS: In a population at increased risk for diabetes, higher plasma 25OHD concentration was inversely associated with prevalent metabolic syndrome and nonsignificantly with incident metabolic syndrome.