Background: Obesity in children and adolescents has been described as a pandemic of the new millennium. This study evaluated the association between normal transaminase and obesity in high school students undergoing health examination at a university hospital.
Methods: 1,225 high school students in Seoul were taken routine medical examination. Among them, 199 students with obesity who showed normal AST level were enrolled. Blood pressure, fasting plasma glucose level,serum AST/ALT levels, and total cholesterol level were measured.
Results: When subjects were divided into 3 groups according to ALT level (upper normal, middle, and lower normal ranges), upper normal group showed a significantly higher BMI level, systolic blood pressure, AST, and total cholesterol level. ALT level was also positively related to BMI, blood pressure, total cholesterol, and AST levels. ALT level was the only independent variable which correlated with BMI.
Conclusion: In obese adolescents, ALT level in upper normal range may serve as a predictor for degree of obesity. More active intervention should be taken towards those group for preventing long term complications.

Keywords: Obesity, Alanine transaminase, Nonalcoholic fatty liver disease