title: Effects of smoking, gender and occupational exposure on the risk of severe pulmonary fibrosis: a population-based case-control study.
abstract: OBJECTIVE
  To estimate the effects of smoking, gender and occupational exposure on the risk of developing severe pulmonary fibrosis (PF), including dose-response and interaction effects.
  
  
  METHODS
  National case-control study of 171 patients (cases) who had started a long-term oxygen therapy for PF in Sweden between February 1997 and April 2000, and 719 random control participants from the general population. Of these cases, 137 had probable idiopathic PF (IPF). The ORs for smoking, gender and occupational exposure were estimated using Mantel-Haenszel analysis and conditional logistic regression, controlling for age and year of diagnosis.
  
  
  RESULTS
  The adverse effect of smoking was amplified by male gender and occupational exposure, OR 4.6 (95% CI 2.1 to 10.3) for PF, and OR 3.0 (1.3 to 6.5) for IPF, compared with in non-exposed women. Higher cumulative smoking exposure was linearly associated with increased risks. Compared with smoking less than 10 pack-years, smoking ≥20 pack-years was associated with increased risk of PF and IPF, OR 2.6 (1.4 to 4.9) and OR 2.5 (1.3 to 5.0), respectively.
  
  
  CONCLUSIONS
  Smoking has a dose-related association with increased risk of severe PF. Men with a history of smoking and occupational exposure is a particular risk group for developing severe PF.
authors.affiliation: Department of Clinical Sciences, Division of Respiratory Medicine & Allergology, Lund University, Lund, Sweden.
authors.forename: Magnus
authors.initials: M
authors.lastname: Ekström
authors.forename: Torbjörn
authors.initials: T
authors.lastname: Gustafson
authors.forename: Kurt
authors.initials: K
authors.lastname: Boman
authors.forename: Kenneth
authors.initials: K
authors.lastname: Nilsson
authors.forename: Göran
authors.initials: G
authors.lastname: Tornling
authors.forename: Nicola
authors.initials: N
authors.lastname: Murgia
authors.forename: Kjell
authors.initials: K
authors.lastname: Torén
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects*; D011658:Pulmonary Fibrosis / Q000209:etiology*; D012307:Risk Factors; D012720:Severity of Illness Index; D012737:Sex Factors; D012907:Smoking / Q000009:adverse effects*