Relation between elevated serum alanine aminotransferase and metabolic syndrome in Korean adolescents

Background: Concern is growing about nonalcoholic fatty liver disease, not only because it is a common liver disorder but also because it is one of the leading causes of chronic liver disease. Unexplained elevations in aminotransferase concentrations have been strongly associated with adiposity and thus may represent non-alcoholic fatty liver disease. Objective: We investigated the relation between nonviral or non-alcoholic elevations in alanine aminotransferase (ALT) and the metabolic syndrome in Korean adolescents. Design: Data were obtained from 1594 subjects aged 10-19 y from the Korean National Health and Nutrition Examination Survey 1998, a cross-sectional health survey of a nationally representative sample of noninstitutionalized civilian South Koreans. Body mass index, waist circumference, blood pressure, fasting glucose, lipid profiles, and serum ALT were measured. Results: The prevalence of elevated ALT (>40 U/L) was 3.6% in boys and 2.8% in girls. The prevalence of metabolic syndrome was 3.3% in both boys and girls. The components of the metabolic syndrome were significantly worse in the group with elevated ALT concentrations than in the group with normal ALT concentrations. The odds ratios (95% CIs) for elevated ALT were 6.6 (3.7, 11.8), 2.3 (1.2, 4.6), and 3.0 (1.6, 5.8) in the adolescents with abdominal obesity, high triacylglycerol concentrations, and low HDL-cholesterol concentrations, respectively. The odds ratios for elevated ALT were 1.5 (0.7, 3.1), 2.6(1.1, 6.2), and 6.2 (2.3, 16.8) in the adolescents with 1, 2, and ≥3 risk factors (metabolic syndrome), respectively. Conclusion: The metabolic syndrome was strongly associated with elevated ALT concentrations in Korean adolescents, and this association existed in a graded fashion across the number of metabolic components.