Updated Reference Ranges for Aminotransferase Levels of Korean Children and Young Adolescents Based on the Risk Factors for Metabolic Syndrome

We investigated the reference values of liver enzymes based on cardiometabolic risks among children and adolescents using the Korea National Health and Nutrition Examination Survey. A total of 8091 subjects aged 10-18 years were included from the data from 2007-2017. Overall, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and the AST/ALT ratio varied with sex and age. AST levels tended to decrease with age, but ALT levels had a U-shaped curve, which resulted in a gradual increase in the AST/ALT ratio after age 13. The prevalence of MetS was strongly associated with elevated AST or ALT and a decreased AST/ALT ratio. The prevalence ratios of the development of MetS were also elevated in groups with high levels of AST and ALT and a low AST/ALT ratio. Particularly in the combined ALT and AST/ALT analyses, borderline-high levels also showed a high prevalence ratio of MetS. Liver enzymes were also involved in the increase in the adjusted mean values for each risk factor for MetS. Here, we provided updated reference values for liver enzymes based on the analysis between population-based data and cardiometabolic risk factors; AST, ALT and the AST/ALT ratio might be useful in the early diagnosis and treatment of MetS.