Vitamin D status and circulating biomarkers of endothelial dysfunction and inflammation in non-diabetic obese individuals: a pilot study

INTRODUCTION Obesity and inadequate vitamin D status are associated with endothelial dysfunction and cardiovascular disease. We evaluated the associations between vitamin D status (i.e. serum levels of 25-hydroxyvitamin D (25(OH)D)), biomarkers of endothelial dysfunction (i.e. serum concentrations of soluble intercellular adhesion molecule 1 (sICAM-1) and soluble E-selectin (sE-selectin)), inflammatory markers (i.e. high-sensitivity C-reactive protein (hsCRP) and fibrinogen) and cardiometabolic risk factors. MATERIAL AND METHODS Fifty obese (body mass index (BMI) ≥ 30 kg/m2) non-diabetic adults (mean age: 36.2 ±5.4 years) without pre-existing cardiovascular abnormalities and 25 clinically healthy, normal weight and age-matched individuals were included. Anthropometric parameters, markers of glucose and lipid metabolism, and serum levels of inflammatory and endothelial dysfunction biomarkers were assessed in all subjects. RESULTS The mean serum 25(OH)D level was significantly lower in the obese group than in controls (33.5 ±15.2 vs. 60.1 ±23.1 nmol/l; p < 0.001). In the obese group, sE-selectin (36.4 (32.1-47.2) vs. 32.4 (24.6-35.5) ng/ml, p < 0.05) and hsCRP (6.0 ±3.4 vs. 3.5 ±1.0 mg/l, p < 0.05) were significantly higher in individuals with lower than median vitamin D levels (i.e. 31 nmol/l) compared with those with higher vitamin D levels. In multivariable linear regression analysis, hsCRP (β = -0.43; p < 0.001) and sE-selectin (β = -0.30; p = 0.03) were independently and significantly associated with serum 25(OH)D levels in the obese group. CONCLUSIONS Vitamin D levels may be related to increased levels of biomarkers of endothelial dysfunction and inflammation in obese non-diabetic individuals.