title: Cigarette tar yield and risk of upper digestive tract cancers: case-control studies from Italy and Switzerland.
abstract: BACKGROUND
  Tobacco smoking is one of the main risk factors for oral, pharyngeal and oesophageal cancers in developed countries. Information on the role of the tar yield of cigarettes in upper digestive tract carcinogenesis is sparse and needs to be updated because the tar yield of cigarettes has steadily decreased over the last few decades.
  
  
  METHODS
  We analysed two case-control studies, from Italy and Switzerland, conducted between 1992 and 1999, involving 749 cases of oral and pharyngeal cancer and 1770 controls, and 395 cases of squamous-cell oesophageal carcinoma and 1066 matched controls. Odds ratios (ORs) were estimated by unconditional multiple logistic regression models, including terms for age, sex, study centre, education and alcohol consumption.
  
  
  RESULTS
  Based on the brand of cigarettes smoked for the longest time, the multivariate ORs for current smokers compared with never smokers were 6.1 for <20 mg and 9.8 for >or=20 mg tar for oral and pharyngeal neoplasms, and 4.8 and 5.4 for oesophageal cancer, respectively. For the cigarette brand smoked in the previous six months, the ORs for >or=10 mg compared with <10 mg were 1.9 for cancer of the oral cavity and pharynx and 1.8 for oesophageal cancer, after allowance for number of cigarettes and duration of smoking.
  
  
  CONCLUSIONS
  The present study confirms the direct relationship between the tar yield of cigarettes and upper digestive tract neoplasms, and provides innovative information on lower tar cigarettes, which imply reduced risks compared with higher tar ones. However, significant excess risks were observed even in the lower tar category, thus giving unequivocal indications for stopping smoking as a priority for prevention of upper digestive tract neoplasms.
authors.affiliation: Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy. gallus@marionegri.it
authors.forename: S
authors.initials: S
authors.lastname: Gallus
authors.forename: A
authors.initials: A
authors.lastname: Altieri
authors.forename: C
authors.initials: C
authors.lastname: Bosetti
authors.forename: S
authors.initials: S
authors.lastname: Franceschi
authors.forename: F
authors.initials: F
authors.lastname: Levi
authors.forename: E
authors.initials: E
authors.lastname: Negri
authors.forename: L
authors.initials: L
authors.lastname: Dal Maso
authors.forename: E
authors.initials: E
authors.lastname: Conti
authors.forename: P
authors.initials: P
authors.lastname: Zambon
authors.forename: C
authors.initials: C
authors.lastname: La Vecchia
mesh_terms: D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000453:epidemiology / Q000209:etiology*; D016022:Case-Control Studies; D004791:Enzyme Inhibitors / Q000009:adverse effects*; D004938:Esophageal Neoplasms / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D009959:Oropharyngeal Neoplasms / Q000453:epidemiology / Q000209:etiology*; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*; D013557:Switzerland / Q000453:epidemiology; D013638:Tars / Q000009:adverse effects*
chemical_list: D004791:Enzyme Inhibitors; D013638:Tars; C024746:tobacco tar