title: Prevalence and determinants of atopy and allergic diseases among school-age children in rural Saskatchewan, Canada.
abstract: BACKGROUND
  There have been few investigations of farming-related activities or specific characteristics resulting in the associations between those exposures and atopic disease.
  
  
  OBJECTIVE
  To study the associations between farm-associated exposures and atopic diseases.
  
  
  METHODS
  As part of a longitudinal study of lung health in rural residents, a cross-sectional baseline study was conducted in rural Saskatchewan, Canada. This included an initial survey phase followed by a clinical testing phase. A subsample of 584 children (grades 1-8) completed skin prick testing to assess atopic status. Atopy was defined as a positive reaction to any of 6 allergens (local grasses, wheat dust, cat dander, house dust mite, Alternaria species, or Cladosporium species) of at least 3 mm compared with the negative control.
  
  
  RESULTS
  Of those who completed clinical testing, the prevalence of atopy was 19.4%, that of hay fever was 8.8%, and that of eczema was 27.4%. Based on skin prick testing, sensitization was highest for cat dander (8.6%) followed by local grasses (8.2%) and house dust mite (5.1%). After adjustment for potential confounders, home location (farm vs non-farm) was not associated with atopic status. However, livestock farming was protective against atopy (adjusted odds ratio 0.38, 95% confidence interval 0.17-0.88). In contrast, current residence on a farm was associated with an increase in the likelihood of hay fever in these children (adjusted odds ratio 3.68, 95% confidence interval 1.29-10.45). Also, regular farming activities in the past year were associated with an increased risk of hay fever.
  
  
  CONCLUSIONS
  In children, livestock exposure has a protective effect on skin prick test positivity, whereas farm living and activities increase the risk of hay fever.
authors.affiliation: Department of Community Health and Epidemiology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Luan M
authors.initials: LM
authors.lastname: Chu
authors.affiliation: Canadian Center for Health and Safety in Agriculture, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Donna C
authors.initials: DC
authors.lastname: Rennie
authors.affiliation: Department of Medicine, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Donald W
authors.initials: DW
authors.lastname: Cockcroft
authors.affiliation: Department of Community Health and Epidemiology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada; Canadian Center for Health and Safety in Agriculture, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Pahwa
authors.affiliation: Canadian Center for Health and Safety in Agriculture, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Dosman
authors.affiliation: Canadian Center for Health and Safety in Agriculture, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: L
authors.initials: L
authors.lastname: Hagel
authors.affiliation: Canadian Center for Health and Safety in Agriculture, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Karunanayake
authors.affiliation: Department of Public Health Sciences, Queen's University, Kingston, Ontario, Canada.
authors.forename: William
authors.initials: W
authors.lastname: Pickett
authors.affiliation: Canadian Center for Health and Safety in Agriculture, University of Saskatchewan, Saskatoon, Saskatchewan, Canada. Electronic address: josh.lawson@usask.ca.
authors.forename: Joshua A
authors.initials: JA
authors.lastname: Lawson
mesh_terms: D000383:Agriculture; D000485:Allergens / Q000276:immunology; D000528:Alternaria / Q000276:immunology; D000818:Animals; D001249:Asthma / Q000453:epidemiology*; D002170:Canada / Q000453:epidemiology; D002415:Cats; D002648:Child; D002963:Cladosporium / Q000276:immunology; D003430:Cross-Sectional Studies; D004485:Eczema / Q000453:epidemiology; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000453:epidemiology*; D058751:Livestock / Q000276:immunology; D008137:Longitudinal Studies; D008297:Male; D006109:Poaceae / Q000276:immunology; D039981:Pyroglyphidae / Q000276:immunology; D012221:Rhinitis, Allergic, Perennial / Q000453:epidemiology*; D006255:Rhinitis, Allergic, Seasonal / Q000453:epidemiology*; D012423:Rural Health; D012424:Rural Population; D012525:Saskatchewan / Q000453:epidemiology; D012882:Skin Tests; D011795:Surveys and Questionnaires; D021182:Wheat Hypersensitivity / Q000276:immunology
chemical_list: D000485:Allergens