Vitamin D, Insulin Resistance and Cytokine Levels in Obese Pubertal Children

Abstract

Insulin resistance (IR) develops in obese children because of low vitamin levels and increased pro-inflammatory cytokine levels. This study aimed to analyze the relation between vitamin D, insulin resistance, tumor necrosis factor-alpha and interleukin 6 (IL-6) levels at admission and after weight loss. This study included 84 obese and 28 healthy pubertal children. Patient group was divided into four: IR positive and negative; weight loss (WL) positive and negative. Baseline and follow-up (6th month) values of serum 25-hydroxyvitamin D and other parameters were evaluated. The prevalence of serum vitamin D deficiency and insufficiency were 3.6% and 21.4% in the control group, 15.2% and 10.9% and 7.9% and 15.8% in the obese insulin positive and negative group; respectively. There was no relationship between vitamin D and IRand IL-6 levels, whereas cytokine levels were lower in obese children. As WL increased, vitamin D level and IR improved. No significant difference was found between vitamin D levels of obese and control subjects. In obese children with weight loss, an insignificant increase was observed in vitamin D, cytokines, quantitative insulin sensitivity check index values and an insignificant decrease was noted in homeostatic model assessment for IR value. Further longitudinal studies with larger patient series with greater WL are warranted.

Keywords

• insulin resistance
• interleukin 6
• obesity
• tumor necrosis factor alpha
• vitamin d