Relationship between vitamin D status and incidence of vascular events in the Veterans Affairs Diabetes Trial

Objective: Few studies have examined the relationship between vitamin D levels and incident cardiovascular events in large well-characterized patient cohorts. Therefore, our objective was to determine if low vitamin D levels predicted vascular complications of diabetes. Methods: Prospective analysis of 936 veterans with type 2 diabetes (59.7 +/- 8.4 years, 96.9% male) who participated in the Veteran Affairs Diabetes Trial (VADT) was conducted. 25(OH)-vitamin D was measured a median of two years after entry and participants were subsequently followed 3.7 years. Hazard ratios (HRs) were calculated for cardiovascular endpoints in relation to 25(OH)-vitamin D quartile. For microvascular endpoints, logistic regression was used to calculate odds ratios. Results: After adjusting for age, minority status, treatment arm and history of prior event, individuals in the lowest vitamin D quartile (i.e., 1-15.9 ng/ml) were at similar risk of MI [HR = 1.13 (95% CI: 0.53, 2.42)], CHD [HR = 0.87 (95% CI: 0.49, 1.55)], congestive heart failure [HR = 1.44 (95% CI: 0.67, 3.06)], and death from any cause [HR = 1.04 (95% CI: 0.53, 2.04)] as individuals in the highest vitamin D quartile (i.e., 29.9-77.2 ng/ml). Similarly, there were no differences in the odds associated with retinopathy or renal disease onset or progression in the lowest versus highest vitamin D quartile. Conclusions: These data indicate that vitamin D status had no significant impact on the incidence of vascular events in a cohort of high-risk veterans with diabetes in which traditional risk factors were managed according to current treatment guidelines. (C) 2013 Elsevier Ireland Ltd. All rights reserved.