Hypovitaminosis D: a novel risk factor for coronary heart disease in type 2 diabetes?

Vitamin D (25(OH)D) levels have been associated with cardiovascular disease. Thus, the aim of our study was to investigate the association of 25(OH)D levels with coronary heart disease (CHD) in 698 consecutive type 2 diabetic outpatients. 698 consecutive type 2 diabetic outpatients (25.2 % men, age 66 ± 9 years) and 100 (90 % men, age 65 ± 13 years) age-matched non-diabetic volunteers were enrolled. 25(OH)D assay and the main cardiovascular risk factors were explored. 25(OH)D concentration was 22 ± 10 ng/ml in control subjects and 18.23 ± 10 ng/ml in diabetic patients (p < 0.01). The prevalence of hypovitaminosis D was higher in diabetic patients than in control subjects (90 vs. 83 %, p < 0.01). Diabetic subjects with hypovitaminosis D had higher prevalence of high values of A1C (p < 0.01), BMI (p < 0.01), LDL cholesterol (p < 0.01), triglycerides (p < 0.01), and glycemia (p < 0.01) than their vitamin D-sufficient counterparts. 25(OH)D and HDL cholesterol were lower (p < 0.01), while BMI (p < 0.01), age (p < 0.01), systolic (p < 0.01) and diastolic blood pressure (p < 0.01), diabetes duration (p < 0.01), A1C (p < 0.01), glycemia (p < 0.01), fibrinogen (p < 0.01), triglycerides (p < 0.01), and total (p < 0.01) and LDL cholesterol (p < 0.01) were higher in diabetic subjects with CHD than diabetic subjects without CHD. At the logistic regression analysis, the association of vitamin D with CHD was lost, while sex (p = 0.026), diabetes duration (p = 0.023), and age (p = 0.024) were the most powerful predictors of CHD. The current study demonstrates that 25(OH)D does not have a direct effect on CHD but may have an indirect effect mediated by cardiovascular risk factors such as diabetes duration, age, and sex.