Nonalcoholic fatty liver disease prevalence in urban school-aged children and adolescents from the Yangtze River delta region: a cross-sectional study.

PURPOSE To determine the prevalence of nonalcoholic fatty liver disease (NAFLD) and explore the relationship of NAFLD with anthropometric parameters among school children from the Yangtze River delta region. METHODS A cross sectional study on childhood NAFLD was conducted using the stratified cluster sampling method in four regions of the Yangtze River delta in September 2009 to October 2011. In all, 7,229 students, aged 7-18 years, from 12 primary, middle and high schools participated in the study. Height, weight, and waist circumference were measured; body mass index (BMI) and waist to height ratio (WHtR) were calculated and liver ultrasonography was performed. RESULTS The overall NAFLD prevalence was 5.0%; 7.5% in boys, 2.5% in girls, 5.6% in subjects with peripheral obesity, 12.9% in those with abdominal obesity and 44.8% in those with mixed obesity. The prevalence was also increased with regional difference. Binary logistic regression analysis showed that WHtR was the major independent risk factor for childhood NAFLD, causing a 14.4-fold increase in NAFLD risk. Receiver operating characteristic curve analysis also showed that WHtR was the best obesity index to evaluate the presence of NAFLD in Chinese schoolchildren with the optimal cutoff of 0.47. CONCLUSIONS Mixed obesity had the strongest association with NAFLD. Male gender and regional urbanization also influenced NAFLD prevalence among schoolchildren. WHtR may be an effective indicator to predict NAFLD.