title: Atopy: a predisposing factor for chronic bronchitis in Finland.
abstract: OBJECTIVE
  To investigate the predictive value of atopy, smoking, and living in a farm environment in the development of chronic bronchitis.
  
  
  METHODS
  This was a cross sectional and longitudinal study.
  
  
  METHODS
  Postal surveys carried out in Finland in 1975 and 1981.
  
  
  METHODS
  The study was part of the Finnish twin cohort study, which included adult twin pairs born in Finland before 1958. The cross sectional sample consisted of 18,351 subjects, including 1025 prevalent cases, and the follow up sample comprised 17,134 subjects, 553 of whom were incident cases of chronic bronchitis.
  
  
  RESULTS
  According to the cross sectional data, chronic bronchitis was associated with atopy (relative risk 1.41) and smoking (2.43). In the follow up data, chronic bronchitis was related to atopy (1.28), smoking (2.31), and farming (1.45).
  
  
  CONCLUSIONS
  The results confirm the earlier finding in the Finnish farming population that, in addition to smoking, atopy predisposes the development of chronic bronchitis. A farm environment was also found to be a predisposing factor. The results give further support to the "Dutch hypothesis" on the etiology of chronic bronchitis, according to which atopy is a predisposing factor.
authors.affiliation: Department of Clinical Allergology, University of Turku, Finland.
authors.forename: E O
authors.initials: EO
authors.lastname: Terho
authors.forename: M
authors.initials: M
authors.lastname: Koskenvuo
authors.forename: J
authors.initials: J
authors.lastname: Kaprio
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000382:Agricultural Workers' Diseases / Q000453:epidemiology; D001991:Bronchitis / Q000453:epidemiology*; D002908:Chronic Disease; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000453:epidemiology; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D012907:Smoking / Q000009:adverse effects