title: Aminotransferase upper reference limits and the prevalence of elevated aminotransferases in the Korean adolescent population.
abstract: OBJECTIVE
  For the pediatric population, upper reference limits (URLs) for aminotransferase levels have not been established. The prevalence of high aminotransferase levels provides important information regarding the burden of liver disease in the current childhood obesity endemic.
  
  
  METHODS
  We set the URL of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) for participants ages 10 to 19 years (n = 2746) from the 2007 to 2009 Korea National Health and Nutrition Examination Survey at the 97.5th percentile of that population who were determined to be at low risk for liver disease (n = 1717; low risk was defined as testing negative for hepatitis B virus surface antigens, the absence of alcohol use disorder, having normal body mass index, and having normal lipid or carbohydrate metabolism).
  
  
  RESULTS
  The URLs for ALT were 33 IU/L for boys and 25 IU/L for girls, and the corresponding limits for AST were 33 IU/L for boys and 28 IU/L for girls. The weighted prevalence of elevated ALT levels was 6.5% in the sample, 8.2% in boys and 4.5% in girls. The prevalence of elevated AST levels was 3.9% and had no sex differences. We also found that elevated ALT levels are associated with male sex, older age, obesity, and presence of abnormal lipid levels. Having elevated AST levels is associated with obesity, younger age, and exhibiting laboratory indicators of abnormal lipid metabolism.
  
  
  CONCLUSIONS
  Aminotransferase URLs are being established for the first time, and our results may be useful in determining a baseline level for monitoring the secular trends of liver disease in future studies of adolescent populations.
authors: Department of Internal Medicine, Inje University Haeundae Paik-Hospital, Inje University College of Medicine, Busan, Korea.
authors: Seung Ha
authors: SH
authors: Park
authors: Ha Young
authors: HY
authors: Park
authors: Jong Woo
authors: JW
authors: Kang
authors: Jinse
authors: J
authors: Park
authors: Kyong Jin
authors: KJ
authors: Shin
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000410:Alanine Transaminase / Q000378:metabolism*; D001219:Aspartate Aminotransferases / Q000378:metabolism*; D002648:Child; D050171:Dyslipidemias / Q000201:enzymology; D005260:Female; D006801:Humans; D050356:Lipid Metabolism; D008099:Liver / Q000201:enzymology*; D008107:Liver Diseases / Q000201:enzymology / Q000453:epidemiology*; D008297:Male; D009765:Obesity / Q000201:enzymology; D015995:Prevalence; D012016:Reference Values; D056910:Republic of Korea / Q000453:epidemiology; D012737:Sex Factors; D055815:Young Adult
chemical_list: D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase