title: Early farm residency and prevalence of asthma and hay fever in adults.
abstract: BACKGROUND
  Asthma and hay fever have been found to be both positively and negatively associated with farming lifestyles in adulthood. Lack of congruency may depend upon early life exposure.
  
  
  OBJECTIVE
  To assess the importance of different periods of farm residency for asthma and hay fever in an adult Canadian population.
  
  
  METHODS
  We conducted a questionnaire survey in rural Saskatchewan, Canada. We assessed a history of asthma and hay fever with five categories of farm residency that were mutually exclusive: first year of life only, currently living on a farm, both first year of life and currently living on a farm, other farm living, and no farm living. Generalized estimating equations were used to adjust for clustering effects of adults within households.
  
  
  RESULTS
  Of the 7148 responding, 30.6% had an early farm living experience only, 34.4% had both early and current farm living experiences, while 17.4% had never lived on a farm. The overall prevalence of ever asthma and hay fever was 8.6% and 12.3%, respectively, and was higher in women. Sex modified the associations between ever asthma and hay fever with farm residency variables whereby women had a decreased risk for both asthma [adjusted odds ratio (ORadj): 0.67, 95% confidence interval (CI):0.47-0.96] and hay fever (ORadj: 0.60, 95% CI: 0.44-0.83) with an early farm exposure only. Men currently living on a farm without an early farm exposure had an increased risk for ever asthma (ORadj: 1.82, 95% CI: 1.02-3.24).
  
  
  CONCLUSIONS
  Farm residency in the first year of life shows a protective effect for adult asthma and hay fever that appears to differ by sex.
authors.affiliation: a Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan , Saskatoon , Saskatchewan , Canada .|b College of Nursing, University of Saskatchewan , Saskatoon , Saskatchewan , Canada .
authors.forename: Donna C
authors.initials: DC
authors.lastname: Rennie
authors.affiliation: a Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan , Saskatoon , Saskatchewan , Canada .
authors.forename: Chandima P
authors.initials: CP
authors.lastname: Karunanayake
authors.affiliation: c Department of Epidemiology and Community Medicine, Faculty of Medicine , University of Ottawa , Ottawa , Ontario , Canada .
authors.forename: Yue
authors.initials: Y
authors.lastname: Chen
authors.affiliation: a Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan , Saskatoon , Saskatchewan , Canada .|d Department of Medicine , University of Saskatchewan , Saskatoon , Saskatchewan , Canada .
authors.forename: Joshua A
authors.initials: JA
authors.lastname: Lawson
authors.affiliation: a Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan , Saskatoon , Saskatchewan , Canada .
authors.forename: Louise
authors.initials: L
authors.lastname: Hagel
authors.affiliation: e School of Public Health, University of Alberta , Edmonton , Alberta , Canada , and.
authors.forename: Ambikaipakan
authors.initials: A
authors.lastname: Senthilselvan
authors.affiliation: a Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan , Saskatoon , Saskatchewan , Canada .|f Department of Community Health and Epidemiology , University of Saskatchewan , Saskatoon , Saskatchewan , Canada .
authors.forename: Punam
authors.initials: P
authors.lastname: Pahwa
authors.affiliation: a Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan , Saskatoon , Saskatchewan , Canada .|d Department of Medicine , University of Saskatchewan , Saskatoon , Saskatchewan , Canada .
authors.forename: James A
authors.initials: JA
authors.lastname: Dosman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000383:Agriculture; D001249:Asthma / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D015995:Prevalence; D006255:Rhinitis, Allergic, Seasonal / Q000453:epidemiology*; D012423:Rural Health; D012424:Rural Population; D012525:Saskatchewan / Q000453:epidemiology; D012737:Sex Factors; D055815:Young Adult
keywords: Chronic asthma; farming; rhinitis; rural; sex; wheeze