title: Liver enzymes: interaction analysis of smoking with alcohol consumption or BMI, comparing AST and ALT to γ-GT.
abstract: BACKGROUND
  A detrimental interaction between smoking and alcohol consumption with respect serum γ-glutamyltransferase (γ-GT) has recently been described. The underlying mechanisms remain unknown. The present work aimed to provide further insights by examining similar interactions pertaining to aspartate and alanine transaminase (AST, ALT), routine liver markers less prone to enzyme induction.
  
  
  RESULTS
  The present cross-sectional analysis was based on records from routine occupational health examinations of 15,281 male employees predominantly of the construction industry, conducted from 1986 to 1992 in Southern Germany. Associations of smoking intensity with log-transformed activities of γ-GT, AST, and ALT were examined in regression models adjusted for potential confounders and including an interaction of smoking with alcohol consumption or body mass index (BMI). Statistically significant interactions of smoking were observed with both alcohol consumption (AST and ALT, each with P<0.0001) and BMI (AST only, P<0.0001). The interactions all were in the same directions as for γ-GT, i.e. synergistic with alcohol and opposite with BMI.
  
  
  CONCLUSIONS
  The patterns of interaction between smoking and alcohol consumption or BMI with respect to AST and ALT resembled those observed for γ-GT. This renders enzyme induction a less probable mechanism for these associations, whereas it might implicate exacerbated hepatocellular vulnerability and injury.
authors: Division of Clinical Epidemiology and Aging Research C070, German Cancer Research Center (DKFZ), Heidelberg, Germany. L.Breitling@dkfz-heidelberg.de
authors: Lutz P
authors: LP
authors: Breitling
authors: Volker
authors: V
authors: Arndt
authors: Christoph
authors: C
authors: Drath
authors: Hermann
authors: H
authors: Brenner
mesh_terms: D000328:Adult; D000410:Alanine Transaminase / Q000097:blood*; D000428:Alcohol Drinking / Q000097:blood*; D001219:Aspartate Aminotransferases / Q000097:blood*; D015992:Body Mass Index; D006801:Humans; D008099:Liver / Q000201:enzymology*; D008297:Male; D008875:Middle Aged; D012907:Smoking / Q000097:blood*; D005723:gamma-Glutamyltransferase / Q000097:blood*
chemical_list: D005723:gamma-Glutamyltransferase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase