non-alcoholic fatty liver disease in overweight and obese children; can ultrasonography substitute laboratory studies? a case-control study

Background: non-alcoholic fatty liver disease (nafld) comprises a large burden on the global healthcare system with a high prevalence and lethal outcomes. moreover, this disease is showing an incremental trend over time, partly due to the rise in obesity rates among children. objectives: in this study, we aimed to elucidate the correlation of ultrasonographic and laboratory-assisted diagnosis of nafld in obese and normal-weight children. methods: this study assessed 50 pediatric obese or overweight children with bmis higher than the 85th percentile for their age and sex, as well as 50 age-and sex-matched control counterparts using ultrasonography and a liver enzyme panel. the prevalence of nafld and the differences in lab studies were evaluated. then, receiver operating characteristics (roc) curves were used to determine the optimal cut-off value for nafld based on liver enzymes. results: a total of 100 participants were included in this study, 58% of whom were male. the mean age of the participants was 10.41 ± 2.224 years. the prevalence of sonographically diagnosed nafld in obese and overweight children was 34.0% (95% ci: 21.2% - 48.8%). the prevalence of nafld when assessed by lab values in this population was 58.0% (95% ci: 43.2% - 71.8%), with a low measure of agreement (k = 0.239, p = 0.058). high bmi increased the risk of nafld to about 8.5 times its baseline in the normal-bmi population. non-alcoholic fatty liver disease patients had significantly higher values for aspartate aminotransferase (ast) (p < 0.001), alanine aminotransferase (alt) (p < 0.001), and gamma-glutamyl transferase (ggt) (p < 0.001), but not alkaline phosphatase (alp) (p = 0.743). the roc curves for ast, alt, ggt, and bmi percentile had areas of 0.800, 0.899, 0.807, and 0.874, respectively, all of which could be used for screening nafld. a cut-off value of 43.5 iu/l for ast had a specificity and positive predictive value of 100% for the diagnosis of nafld in children. conclusions: obese and overweight children are 8.5 times more likely to develop nafld compared to their normal-bmi peers. for the evaluation of this disease, liver enzyme panels integrated with ultrasonographic assessment should be utilized.