title: Atopic and non-atopic asthma in a farming and a general population.
abstract: BACKGROUND
  In a previous study inverse associations between asthma and exposure to fungal spores and endotoxins in atopic farmers and positive associations with the same factors in non-atopic farmers were documented. No external reference population had been included. We, therefore, compared this farming population with the general population from an adjacent region.
  
  
  METHODS
  Random samples of a farming (n=2,106) and a rural (n=351) and urban (n=727) general population were selected. Atopy was assessed by serum IgE and asthma by questionnaires.
  
  
  RESULTS
  The asthma prevalence was 4.0% among farmers, 5.7% in the rural, and 7.6% in the urban population. Atopy was similar (9-10%). Most asthmatics were not atopic, 67-75%. Farmers had asthma less often than the general population OR 0.52 (95% CI 0.36-0.75); both atopic (OR 0.33 (95% CI 0.15-0.69)) and non-atopic asthma (OR 0.60 (95% CI 0.39-0.93)).
  
  
  CONCLUSIONS
  This may indicate a protective effect of the farm environment on asthma but a healthy worker effect may also play a role.
authors.affiliation: National Institute of Occupational Health, Oslo, Norway. Winjuad.Eduard@stami.no
authors.forename: Wijnand
authors.initials: W
authors.lastname: Eduard
authors.forename: Ernst
authors.initials: E
authors.lastname: Omenaas
authors.forename: Per Sigvald
authors.initials: PS
authors.lastname: Bakke
authors.forename: Jeroen
authors.initials: J
authors.lastname: Douwes
authors.forename: Dick
authors.initials: D
authors.lastname: Heederik
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000382:Agricultural Workers' Diseases / Q000453:epidemiology / Q000209:etiology / Q000276:immunology; D001249:Asthma / Q000453:epidemiology* / Q000209:etiology / Q000276:immunology; D003876:Dermatitis, Atopic / Q000453:epidemiology / Q000209:etiology / Q000276:immunology; D004731:Endotoxins / Q000276:immunology; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D016273:Occupational Exposure / Q000009:adverse effects*; D015995:Prevalence; D012424:Rural Population; D013172:Spores, Fungal / Q000276:immunology; D011795:Surveys and Questionnaires
chemical_list: D004731:Endotoxins