title: Normal limit for serum alanine aminotransferase level and distribution of metabolic factors in old population of kalaleh, iran.
abstract: BACKGROUND
  Normal or elevated values of serum alanine aminotransferase level (ALT) vary in different studies mostly related to characteristics of reference population including age, gender, body mass index, nonalcoholic fatty liver disease (NAFLD), and metabolic syndrome prevalence.
  
  
  OBJECTIVE
  To measure upper normal limit (UNL) for serum ALT in an apparently healthy Iranian old population (which we had not sufficient data before this study), and its modulating factors.
  
  
  METHODS
  All inhabitants (> 50 years old) of Kalaleh, Golestan, Iran (N = 1986) were invited to the study. ALT measurements were performed for all subjects using the same laboratory method. Upper limit of normal (ULN) ALT was calculated based on its 95th percentile in normal weight subjects. Modulating factors of ALT were determined by multivariate analysis.
  
  
  RESULTS
  A total of 1309 subjects, with the mean age of 61.5 ± 7.5 years were included. UNL of ALT was 18.8 U/L and 21.4 U/L in women and men, respectively. Based on univariate analysis, waist circumference (r = 0.124, P = 0.01), body mass index (r = 0.118, P = 0.01), triglyceride (r = 0.143, P = 0.01), and having metabolic syndrome (OR = 2.04) modulate ALT levels in men. Also triglyceride (r = 0.119, P = 0.01) modulates ALT levels in women.
  
  
  CONCLUSIONS
  The calculated level for UNL of ALT is considerably far lower than previous accepted value. Age, gender, ethnicity, and metabolic factors should be accounted in future studies to determine normal ALT level.
authors.affiliation: Department of Epidemiology, Faculty of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran ; Center for Educational Research in Medical Sciences, Tehran University of Medical Sciences, Tehran, IR Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Kabir
authors.affiliation: Digestive Disease Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, IR Iran.
authors.forename: Akram
authors.initials: A
authors.lastname: Pourshams
authors.affiliation: Golestan Research Center of Gastroenterology and Hepatology, Golestan University of Medical Sciences, Gorgan, IR Iran.
authors.forename: Masoud
authors.initials: M
authors.lastname: Khoshnia
authors.affiliation: Digestive Disease Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, IR Iran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Malekzadeh
keywords: Age Groups; Alanine Aminotransferase; Gender