Over recent decades, with the increase in the prevalence of childhood overweight/obesity, the prevalence of pediatric non-alcoholic fatty liver disease (NAFLD) has increased.

The aim of this study was to investigate the prevalence of NAFLD and its predisposing factors in overweight and obese children of Urmia, Northwest of Iran.

In this cross-sectional study, a total of 843 children aged 2 to 19 years were recruited out of 10800 children referred to the Digestive Disease Clinic of Shahid Motahari Hospital during 2016 - 2017. Anthropometric and laboratory measurements and abdominal ultrasound were performed for the children. Demographic data and their medical history were collected by a questionnaire. Unconditional logistic regression was used to predict the predisposing factors of NAFLD.

Fatty liver was diagnosed by ultrasound in 9.5% of overweight and 21.4% of obese children. The prevalence of NAFLD in obese children was 9.26% for the 2 - 5.9-year age group, 22.3% for the 6 - 11.9-year age group and 35.5% for the 12 - 19-year age group. Compared to the normal liver group, the adjusted odds ratios (ORs) [95% confidence interval (CI)] for predictive factors of NAFLD were as follows: ALT: 1.05 (1.03 - 1.09), ALK: 1.02 (1.01 - 1.03), AST: 1.04 (1.02 - 1.08), triglycerides: 1.1 (1. 08 - 1.21), TSH: 1.18 (1.1 - 1.40), FBS: 1.04 (1.01 - 1.08) and HOMA-IR: 1.19 (1.03 - 1.38). Compared to the age group of 2 - 5.9 years, the odds ratio of NAFLD was increased by 4 and 8 times in the age group 6 - 11.9 and 12 - 19 years, respectively.

There was a strong relationship between pediatric NAFLD and ALT, AST and HOMA-IR in the overweight and obese children. Our findings emphasized the importance of prevention of obesity and early intervention to prevent abnormalities among obese children.