Relationship between insulin-like growth factor-1, insulin resistance and metabolic profile with pre-obesity and obesity in children

Objectives: Childhood obesity is a serious medical condition with alarmingly high rates worldwide. There is controversy regarding the relationship between insulin-like growth factor-1 (IGF-1) and pediatric obesity. We investigated the relationship between IGF-1, insulin resistance and metabolic profile with childhood pre-obesity/obesity. Methods: The study involved 201 children aged 7-15 years, divided in three groups according to their nutritional status (International Obesity Task Force criteria): normal-weight (n=84), pre-obese (n=82), obese (n=35). Laboratory IGF-1, insulin, fasting blood glucose (FBG), lipid profile, alanine-aminotransferase (ALT), uric acid (UA), anthropometric and body composition parameters were analyzed. Body mass index and IGF-1 standard deviation score (SDS), waist-to-height ratio (WtHR) and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) score were calculated. Results: Pre-obese/obese children had significantly higher IGF-1 SDS, FBG, insulin, HOMA-IR, UA, ALT, triglycerides, and lower high-density lipoprotein cholesterol (HDL-c); obese group had higher WtHR and low-density lipoprotein cholesterol (LDL-c) compared to controls (p<0.05). In obese group, IGF-1 SDS was positively correlated with fat free/muscle mass, total body water (p<0.05) and negatively correlated with LDL-c (p<0.05). In pre-obese/obese HOMA-IR and insulin were positively correlated with age, total body fat (TBF) (p<0.05) and negatively correlated with HDL-c (pre-obese) (p<0.05). Multivariate ordinal logistic regression analyses showed that IGF-1 SDS (OR=1.94; 95% CI: 1.21-3.11), TBF (OR=1.37; 95%CI: 1.21-1.54) were predictors of nutritional status (p<0.001). FBG (OR=42.39; 95%CI: 2.31-77.2) and UA (OR=1.03; 95%CI: 1.01-1.05) were predictors of IR (p<0.001). Conclusions: IGF-1 SDS and TBF were predictors of nutritional status. Further studies are required to clarify the role of IGF-1 in pathophysiology of obesity and its comorbidities.