title: The protective effect of rural living against atopy in Mongolia.
abstract: BACKGROUND
  Farm environment in childhood protects against atopy. We investigated in a population-based study in Mongolia the effects of rural living and migration from rural to urban areas on the risk of atopy.
  
  
  METHODS
  The screening study data of 9453 subjects, aged 10-60 years, were used for taking the sample for the clinical study in which 869 subjects were examined. Asthma, allergic rhinoconjunctivitis and sensitization were clinically defined and their risk factors analysed by logistic regression.
  
  
  RESULTS
  The risks of allergic rhinoconjunctivitis [adjusted odds ratio (OR) 0.43, 95% confidence interval (CI) 0.19-0.98] and allergic sensitization (OR 0.26, 95% CI 0.13-0.55) were the lowest in subjects living in a village from birth and intermediate in subjects who had relocated from a village to a town (OR for rhinoconjunctivitis 0.68, 95% CI 0.36-1.27, OR for sensitization 0.62, 95% CI 0.35-1.12) compared with subjects living in a town from birth. Simultaneous exposure to herd animals and dung heating decreased the risk of atopy. Keeping animals was a risk-factor for asthma only in Ulaanbaatar city.
  
  
  CONCLUSIONS
  Continuing farm exposure after childhood may be important in reducing the risk of atopy.
authors.affiliation: Department of Pulmonary Diseases and Clinical Allergology, University of Turku, Turku, Finland.
authors.forename: A
authors.initials: A
authors.lastname: Viinanen
authors.forename: S
authors.initials: S
authors.lastname: Munhbayarlah
authors.forename: T
authors.initials: T
authors.lastname: Zevgee
authors.forename: L
authors.initials: L
authors.lastname: Narantsetseg
authors.forename: Ts
authors.initials: Ts
authors.lastname: Naidansuren
authors.forename: M
authors.initials: M
authors.lastname: Koskenvuo
authors.forename: H
authors.initials: H
authors.lastname: Helenius
authors.forename: E O
authors.initials: EO
authors.lastname: Terho
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003233:Conjunctivitis, Allergic / Q000453:epidemiology*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D008986:Mongolia / Q000453:epidemiology; D015995:Prevalence; D012130:Respiratory Hypersensitivity / Q000453:epidemiology*; D012307:Risk Factors; D012424:Rural Population; D014505:Urban Population; D014507:Urbanization