Background Non-Alcoholic Fatty Liver Disease (NAFLD), the main cause of childhood liver abnormalities, is rising with the increase of pediatric obesity and overweight. This study aimed to investigate the prevalence of NAFLD and its predisposing factors in children of Urmia province, northwest of Iran.

Methods In this cross-sectional study, 508 overweight and obese children (251 boys) aged 6– 19 years were recruited by convenience sample from the Shahid Motahari Hospital during 2016–2017. The anthropometric and laboratory measurement and abdominal ultrasonography for liver echogenicity and size were conducted. A questionnaire was also used to obtain information on demographical characteristic and alcohol consumption. Eligibility criteria were: (1) 6 ≤ age ≤ 19 years; (2) BMI > 85th percentile for gender and age (3) absence of any drug toxicity; (5) abstinence from alcohol; (6) absence of hepatitis B, C and Wilson’s disease. Fatty liver was diagnosed by ultrasonography using standard criteria. Serum Alanine aminotransferase (ALT), Aspartate aminotransferase (AST), Alkaline Phosphate (ALK), Triglyceride (TG), Cholesterol (Chol), Low density lipoprotein (LDL) -cholesterol, High density lipoprotein (HDL)-cholesterol, Thyroid stimulating hormone (TSH) and glucose, were measured in children blood samples using standard laboratory methods. Insulin resistance was estimated using the homeostasis model assessment of the insulin resistance (HOMA-IR). Univariable and multivariable logistic regression and 95% confidence interval was used to evaluate predictors of NAFLD.

Results NAFLD was diagnosed in 8.5% of overweight and 24.9% of obese children. In obese children the prevalence of NAFLD was 22.3% for age group 6–11.9 years and 35.5% for age group 12–19 years. There was no significant difference between girls and boys (P= 0.521). Age was similar in children with and without NAFLD (P= 0.766). An increase of 10 U/L of ALT, AST and ALK increased the odds of NAFLD 6%, 5% and 3%, respectively. An increase of 10 mg/dl of triglycerides and glucose were associated with a 12% and 8% increase and one of TSH with a 15% increase in the odds of NAFLD. An increase of 1 unit of HOMA-IR was associated with a 21% increase in the odds of NAFLD.

Conclusions ALT, AST, ALK and HOMA-IR can predict the progression of NAFLD. Findings emphasize on the importance of prevention of obesity and early intervention to prevent abnormalities among obese children.