Vitamin D Levels Decline with Rising Number of Cardiometabolic Risk Factors in Healthy Adults: Association with Adipokines, Inflammation, Oxidative Stress and Advanced Glycation Markers

Introduction Hypovitaminosis D associates with obesity, insulin resistance, hypertension, and dyslipoproteinemia. We asked whether the presence of multiple cardiometabolic risk factors, and which particular combination, exerts additive negative effects on 25(OH)D-3 levels; and whether 25(OH)D-3 levels associate with markers of inflammation and oxidative stress. Subjects and Methods In non-diabetic medication-free adults central obesity (waist-to-height ratio > 0.5); elevated blood pressure (systolic BP >= 130 mm Hg and/or diastolic BP >= 85 mm Hg); increased atherogenic risk (log(TAG/HDL) >= 0.11); and insulin resistance (QUICKI < 0.322) were considered as cardiometabolic risk factors. 25(OH)D-3 status was classified as deficiency (25(OH)D-3 <= 20 ng/ml); insufficiency (levels between 20-to-30 ng/ml), or as satisfactory (> 30 ng/ml). Plasma adipokines, inflammatory and oxidative stress markers, advanced glycation end-products, and their soluble receptor were determined. Results 162 subjects were cardiometabolic risk factors-free, 162 presented increased (i.e. 1 or 2), and 87 high number (i.e. 3 or 4) of cardiometabolic risk factors. Mean 25(OH) D3 decreased with rising number of manifested risk factors (36 +/- 14 ng/ml, 33 +/- 14 ng/ml, and 31 +/- 15 ng/ml, respectively; pANOVA: 0.010), while prevalence of hypovitaminosis D did not differ significantly. Elevated blood pressure and insulin resistance appeared as significant determinants of hypovitaminosis D. Subjects presenting these risk factors concurrently displayed the lowest 25(OH)D-3 levels (29 +/- 15 ng/ml). Plasma adipokines, inflammatory and oxidative stress markers, advanced glycation end-products, and their soluble receptor generally differed significantly between the groups, but only advanced oxidation protein products and advanced glycation end-products associated fluorescence of plasma showed significant independent association with 25(OH)D-3 levels. Conclusion In apparently healthy adults increasing number of cardiometabolic risk factors associates with poorer 25(OH)D-3 status, while the association between 25(OH)D-3 status and inflammatory or oxidative stress markers remains equivocal.