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 Hernández. Serum 25(OH)D concentrations were measured by chemiluminescent assay. Plasma tumor necrosis factor (TNF-α) 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 (β=-0.160±0.068; R2=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.