title: Bronchial hyperresponsiveness in two populations with different prevalences of atopy.
abstract: METHODS
  Random population samples of young adults from Tartu, Estonia (n = 307) and Uppsala, Sweden (n = 498) in the framework of the European Community Respiratory Health Survey (ECRHS).
  
  
  OBJECTIVE
  To compare the prevalence and risk factors for bronchial hyperresponsiveness (BHR) to methacholine in two centres with similar climate and ethnicity but differences in the prevalence of atopy, asthma and respiratory symptoms.
  
  
  METHODS
  General population-based cross-sectional survey.
  
  
  RESULTS
  The prevalence of BHR using the cut-off points 1.5, 1.0 and 0.5 mg was 19%, 12% and 8% in Tartu and 11%, 7% and 2%, respectively, in Uppsala. Current smoking was a common risk factor for BHR in both centres. Female sex (odds ratio [OR] 2.9), sensitisation to cat (OR 5.9) and visible mould in the home (OR 2.4) were independent risk factors for BHR in Tartu. In Uppsala, BHR was significantly associated with total IgE levels (OR 2.0) and exposure to environmental tobacco smoke (OR 3.3).
  
  
  CONCLUSIONS
  The high prevalence of BHR can explain the high prevalence of respiratory symptoms in Tartu and indicates that causes other than asthma and atopy can be responsible for the high prevalence of BHR in a population.
authors.affiliation: Lung Clinic, Tartu University Clinics, Tartu, Estonia. rain.jogi@kliinikum.ee
authors.forename: R
authors.initials: R
authors.lastname: Jõgi
authors.forename: C
authors.initials: C
authors.lastname: Janson
authors.forename: G
authors.initials: G
authors.lastname: Boman
authors.forename: B
authors.initials: B
authors.lastname: Björkstén
mesh_terms: D000328:Adult; D001249:Asthma / Q000150:complications / Q000503:physiopathology; D016535:Bronchial Hyperreactivity / Q000453:epidemiology / Q000503:physiopathology*; D003430:Cross-Sectional Studies; D004957:Estonia / Q000453:epidemiology; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000453:epidemiology / Q000503:physiopathology*; D008297:Male; D015995:Prevalence; D012130:Respiratory Hypersensitivity / Q000453:epidemiology; D012307:Risk Factors; D012737:Sex Factors; D013548:Sweden / Q000453:epidemiology