Moderate Vitamin D Deficiency and Inflammation Related Markers in Overweight/Obese Schoolchildren

Objective: Obesity has been associated with vitamin D deficiency and increased oxidative stress, which can lead to the dysregulation of adipokines and inflammation. The aim of the present work was to examine the association of vitamin D status [25(OH)D] on inflammatory related markers in overweight/obese children. Subjects/Methods: A total of 137 Spanish schoolchildren between 9 and 12 years of age (31.4% with overweight/obesity) were studied. Being overweight was defined as BMI >= 85th percentile and obesity as BMI >= 97th percentile using the reference tables of Hernandez. Serum 25(OH)D concentrations were measured by chemiluminescent assay. Plasma tumor necrosis factor (TNF-alpha) and interleukin-6 (IL-6) were measured by immunoenzyme assay. Serum adiponectin was determined using an ELISA kit. Serum high-sensitivity C-reactive protein (hs-PCR) was tested by immunonephelometry. Results: IL-6 concentrations were higher in the overweight/obese children with deficient serum 25(OH) D (<20 ng/mL) than in those in this group but whose serum 25(OH)D concentrations were adequate (>= 20 ng/mL). Serum 25(OH)D was inversely associated with IL-6 concentrations in the overweight/obese subjects taking into account different covariates; thus, for every 1 ng/mL rise in the former, the latter fell by 0.160 pg/mL (beta = -0.160 +/- 0.068; R-2 = 0.131; p = 0.023). The obese subjects with concentrations of >= 25 ng/mL had lower hs-CRP values compared to those with concentrations of <25 ng/mL (0.053 +/- 0.035 vs. 0.356 +/- 0.613 mg/dL; p = 0.035). Conclusion: Low serum 25(OH)D was significantly associated high serum IL-6 in overweight/obese children, and with increased hs-CRP in obese children.