Which Liver Enzymes Are Better Indicators of Metabolic Syndrome in Adolescents: The Fifth Korea National Health and Nutrition Examination Survey, 2010

Background: This study aimed to examine the relationships of liver enzyme levels with metabolic syndrome in adolescents. Methods: A total of 808 adolescents (430 males and 378 females, aged 10-19 years) participated in the Fifth Korea National Health and Nutrition Examination Survey (KNHANES V-1) in 2010, the relationships between liver enzymes [aspartate aminotransferase (AST), alanine aminotransferase (ALT), ratio of AST to ALT (AST/ALT), and gamma-glutamyltransferase (GGT)] and metabolic syndrome defined by the International Diabetes Federation criteria were assessed using logistic regression and receiver operating characteristic (ROC) curve analyses. Results: After adjusting for age, higher ALT and GGT levels and a lower AST/ALT level were associated with clustering of metabolic syndrome components, whereas AST level was not associated with it in both sexes. The strength of association between the liver enzymes and clustering of metabolic syndrome components was higher in females than in males. In the non-overweight group, higher AST, ALT, and GGT levels and a lower AST/ALT level were associated with clustering of metabolic syndrome components, whereas none of the liver enzymes was associated with metabolic syndrome in the overweight group. The area under the ROC curve (AUC) of AST to determine metabolic syndrome was not significant and was significantly lower than AUCs of ALT, AST/ALT, and GGT in both sexes. The cutoff values of ALT, AST/ALT, and GGT to determine metabolic syndrome were higher in males than in females. Conclusions: ALT, AST/ALT, and GGT were found to be associated with clustering of metabolic syndrome components, and the relationships appear to be sex-and weight group-specific.