title: Smoking as an independent risk factor of liver fibrosis in primary biliary cirrhosis.
abstract: OBJECTIVE
  Smoking has been identified as a potential predisposition factor for primary biliary cirrhosis (PBC). However, it remains unclear whether it is associated with more active and severe disease. Our aim was to assess the relationships between smoking and the severity of the elementary histological lesions, as well as the biochemical and immunological features of PBC.
  
  
  METHODS
  Smoking history data were collected from 223 PBC patients using a standardized questionnaire. Histological data were available in 164 patients at presentation. Liver fibrosis and histological inflammatory activity were semi-quantified according to a METAVIR-based classification system. Odds ratios (OR) were assessed using a logistic regression analysis.
  
  
  RESULTS
  Smoking history prior to diagnosis was reported in 58 patients (26%). Twenty-five patients (11%) were active smokers at diagnosis. Male gender (OR, 4.5), alcohol intake >20 g/d (OR, 4.2), and F3-F4 fibrosis stage (OR, 2.7), but not inflammatory grade, bile duct changes, biochemical or immunological features, were associated with smoking history. Smoking intensity was significantly higher in patients with F3-F4 stage (8.1±14.2 pack-years vs. 3.0±7.0 pack-years; p=0.01). Adjusted logistic regression identified smoking history and smoking intensity as independent risk factors of advanced fibrosis. Each pack-year of increase in smoking intensity was associated with a 5.0% (95% CI, 1.3-8.7%) increased likelihood of advanced fibrosis.
  
  
  CONCLUSIONS
  Smoking increases, in a dose-dependent fashion, the risk of liver fibrosis in PBC without apparent increase in the histological inflammatory activity, bile duct lesions, biochemical, and immunological features of the disease. PBC patients should be strongly encouraged not to smoke.
authors.affiliation: Service d'Hépatologie, Centre de référence des Maladies Inflammatoires des Voies Biliaires, Hôpital Saint-Antoine, Assistance Publique-Hôpitaux de Paris (APHP), France. christophe.corpechot@sat.aphp.fr
authors.forename: Christophe
authors.initials: C
authors.lastname: Corpechot
authors.forename: Farid
authors.initials: F
authors.lastname: Gaouar
authors.forename: Yves
authors.initials: Y
authors.lastname: Chrétien
authors.forename: Catherine
authors.initials: C
authors.lastname: Johanet
authors.forename: Olivier
authors.initials: O
authors.lastname: Chazouillères
authors.forename: Raoul
authors.initials: R
authors.lastname: Poupon
mesh_terms: D000328:Adult; D000368:Aged; D000428:Alcohol Drinking / Q000009:adverse effects; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008103:Liver Cirrhosis / Q000209:etiology* / Q000473:pathology; D008105:Liver Cirrhosis, Biliary / Q000150:complications* / Q000276:immunology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*