Non-alcoholic fatty liver disease (NAFLD) is complicated disease and increasing worldwide. Previously, many studies of NALFD prevalences have used alanine aminotransferase (ALT) of > 40 U/L to define NAFLD, although that is too high to be reliable among adolescents. | Normal serum alanine aminotransferase and non-alcoholic fatty liver disease among Korean adolescents: A cross-sectional study using data from KNHANES 2010–2015