Abstract: Background：Childhood obesity is one of the leading causes of nonalcoholic fatty liver disease (NAFLD). Waisttoheight ratio (WHtR) is a physical measurement index reflecting the visceral fat and cardiometabolic risk in children and adolescents, but the relationship between WHtR and NAFLD is unclear. Objective：To investigate the association of WHtR and NAFLD in children and adolescents. Design：Retrospective analysis of children's physical examination data. Methods：Resident students who participated in the 20142020 routine annual physical examination in Minhang District, Shanghai were included for the analysis. Suspected NAFLD was defined by the elevation of 97.5 percentile of alanine aminotransferase (ALT) levels according to the ageand sexspecific reference intervals for the healthy children. Based on the results of the WHtR cutoff values proposed for screening cardiometabolic risk in children and adolescents from a national wide data, we defined the WHtR elevation group as WHtR values in boys and girls being equal to or higher than 0.481 and 0.456, respectively. We used unconditional binary logistic regression to assess the association of WHtR and NAFLD after adjustment of age and gender. We used the area under the receiver operating characteristic curve (AUC), sensitivity, specificity, positive predictive value and negative predictive value to assess the ability of WHtR cutoffs in discriminating NAFLD. Main outcome measures：The association of WHtR and NAFLD. Results：Compared with the normal WHtR group, the NAFLD prevalence was significantly higher in WHtR elevation group (16.2% vs 2.3%, P<0.001), and increased with age. The NAFLD rate in boys with elevated WHtR was higher than that in girls (21.6% vs 11.0%，P<0.001), but was similar in both genders with normal WHtR (2.3% vs 2.2%，P=0.71). Elevated WHtR was associated with 71% increase in the risk of NAFLD (adjusted OR=1.71, 95% CI:1.262.31，P=0.001), and the association was similar in boys and girls with 77% increase in boys (OR=1.77, 95% CI:1.192.63，P=0.005) and 69% increase in girls (OR=1.69,95% CI: 1.052.71，P=0.005）. The AUC (95% CI), sensitivity, specificity, positive predictive value and negative predictive value of elevated WHtR for identifying NAFLD were 0.73(0.710.76), 63.2%, 83.4%, 16.8%, and 97.7%, respectively. Conclusion：Elevated WHtR is associated with NAFLD in children and adolescents. For the children and adolescent with elevated WHtR, schools and primary health care institutions should pay attention to the NAFLD occurrence in addition to abnormal blood pressure, glucose, and lipids metabolism.

Key words: Nonalcoholic fatty liver disease, Children and adolescents, Waist-to-height ratio, Prevalence