title: To what degree is the association between educational inequality and laryngeal cancer explained by smoking, alcohol consumption, and occupational exposure?
abstract: OBJECTIVE
  The aim of this study was to measure the extent to which the association between socioeconomic status and laryngeal cancer among males is mediated by smoking, alcohol consumption, and occupational exposure.
  
  
  METHODS
  We used Karlson et al's decomposition method for logit models, which returns the percentage of change in odds ratios (OR) due to confounding. This population-based, case-control study on laryngeal cancer was conducted in Germany in 1998-2000 and included 208 male cases and 702 controls. Information on occupational history, smoking, alcohol consumption, and education was collected through face-to-face interviews. Jobs coded according to ISCO-68 were linked to a recently developed job-classification index covering physical and psychosocial dimensions. A sub-index focused on jobs involving potentially carcinogenic agents (CAI) for the upper-aero digestive tract.
  
  
  RESULTS
  When adjusted for smoking and alcohol consumption, higher OR were found for lower education. This OR decreased after further adjustment using the overall job index [2.9, 95% confidence interval (95% CI) 1.4-6.2], similar to the OR using the sub-index CAI (OR 2.7, 95% CI 1.3-5.8). Applying the Karlson et al method, 25.4% (95% CI 22.6-28.2%) of the reduction in these OR was due to occupational exposure (CAI), while smoking and alcohol consumption contributed to around 26.1% (95% CI 23.2-28.9%) and 2.7% (95% CI 1.7-3.8%), respectively.
  
  
  CONCLUSIONS
  Occupational aspects, in particular the exposure to carcinogenic agents, explain a large portion of the association between low educational level and laryngeal cancer risk among males. Occupational effects are now easier to quantify using this recently developed and easily applicable index.
authors.affiliation: Institute of Public Health, University of Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany. Irene.Santi@uni-heidelberg.de.
authors.forename: Irene
authors.initials: I
authors.lastname: Santi
authors.forename: Lars Eric
authors.initials: LE
authors.lastname: Kroll
authors.forename: Andreas
authors.initials: A
authors.lastname: Dietz
authors.forename: Heiko
authors.initials: H
authors.lastname: Becher
authors.forename: Heribert
authors.initials: H
authors.lastname: Ramroth
mesh_terms: D000368:Aged; D000428:Alcohol Drinking; D016022:Case-Control Studies; D004522:Educational Status; D005260:Female; D006801:Humans; D007822:Laryngeal Neoplasms / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012907:Smoking