ABSTRACT Obesity is an independent risk factor for developing cardiovascular disease and increases insulin resistance in children. Interleukin (IL)-18 is a novel pro-inflammatory cytokine with potential atherogenetic properties. This study ai- med to identify circulating levels of IL-18 in obese children and examine the effects of combined nutritional education-physical activity course on circulating IL-18. Plasma IL-18, body mass index (BMI), fasting glucose and insulin, homeostasis model assessment insulin resistance (HOMA IR), lipid profile, uric acid, high- sensitive C-reactive protein (hs-CRP), and homocysteine were determined in 70 obese children aged 10-12 years before and after attending a 13-week weight reduction program, which included physical activities and nutritional education. Twenty-five age-matched non-obese children served as controls. At baseline, obese children had significantly higher levels of BMI, fasting insulin, HOMA IR, triglyceride (TG), uric acid, hs-CRP, and IL-18 but lower high-density lipoprotein-cholesterol (HDL-C) than non-obese children. Plasma IL-18 levels in obese children decreased significantly after the weight reduction program. At baseline, plasma IL-18 levels in obese children positively correlated with BMI, HOMA IR, insulin and TG but negatively correlated with HDL-C. There was a significant relationship between plasma IL-18 and BMI changes. Moreover, fasting insulin was responsible for IL-18 variability in obese children. These findings suggest that elevated plasma IL-18 levels in obese children are partly associated with parameters of obesity and insulin resistance, and are significantly affected by modest weight loss.
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