Association between 25-hydroxyvitamin D deficiency and cardiovascular disease in type 2 diabetic patients with mild kidney dysfunction

Background. A potentially modifiable and underestimated risk factor for cardiovascular disease (CVD) in subjects with kidney dysfunction is 25-hydroxyvitamin D deficiency, although the relationship between inadequate vitamin D status and manifest CVD in type 2 diabetic subjects with mild kidney impairment has not been extensively examined. Methods. We evaluated the relationship between serum 25-hydroxyvitamin D concentrations, baseline kidney function (estimated using the modification of diet in renal disease equation) and manifest CVD (myocardial infarction, angina, ischaemic stroke, coronary revascularization or carotid endarterectomy) among 462 consecutive patients with type 2 diabetes. Results. In the whole population, the mean age was 62 +/- 7 years, 64% were men, 76.3% had hypertension and the mean estimated glomerular filtration rate (GFR) was 94 +/- 33 ml/min/1.73 m(2). Kidney function was strongly and inversely associated with CVD. In multivariate logistic regression analysis, there was an inverse association between serum 25-hydroxyvitamin D concentrations and prevalent CVD [odds ratio 0.95 (95% CI 0.92-0.98; P = 0.001)] in the whole population independent of baseline kidney function and other known risk factors. Additionally, the association between serum 25-hydroxyvitamin concentrations and CVD [odds ratio 0.97 (95% CI 0.94-0.99; P = 0.045)] remained statistically significant in participants in the lowest estimated GFR tertile after adjustment for potential confounders. Conclusions. Decreased 25-hydroxyvitamin D concentrations are independently associated with prevalent CVD in type 2 diabetic patients with mild kidney dysfunction.