title: Do asthma and allergy influence subsequent pet keeping? An analysis of childhood and adulthood.
abstract: BACKGROUND
  Asthma and allergy might influence the choice of keeping pets, leading to apparent protective effects of pets on allergic disease.
  
  
  OBJECTIVE
  We investigated the effects of asthma and allergy on subsequent pet keeping in childhood and adulthood.
  
  
  METHODS
  Information about asthma and pet keeping at ages 0 to 4, 5 to 15, 20 to 44, and 26 to 56 years was provided by 9812 subjects participating in the 9-year follow-up of the European Community Respiratory Health Survey.
  
  
  RESULTS
  In childhood asthma debut at younger than 5 years was associated with less cat keeping at 5 to 15 years (odds ratio [OR], 0.60; 95% CI, 0.44-0.82), an effect only observed when the parents did not have asthma or allergy (P(interaction) = .045). Childhood asthma did not influence adult pet ownership, unless there were adult symptoms. Adults less often acquired cats at follow-up if they had 3 or more asthma symptoms (OR, 0.78; 95% CI, 0.64-0.95), were taking asthma medication (OR, 0.48; 95% CI, 0.31-0.74), had hay fever (OR, 0.75; 95% CI, 0.62-0.91), had atopy (OR, 0.75; 95% CI, 0.61-0.91), or had specific IgE to cat (OR, 0.57; 95% CI, 0.39-0.82) at baseline. Adults who already had pets usually continued keeping the same type of pet, except that the presence of 3 or more asthma symptoms was associated with less subsequent dog keeping (OR, 0.69; 95% CI, 0.53-0.89). Pet removal between surveys to reduce allergen was reported by 4.7%.
  
  
  CONCLUSIONS
  Selective avoidance subsequent to asthma or allergy was observed for childhood cat keeping and adult cat acquisition. Avoidance would produce an apparent protective effect of cats on childhood asthma (large OR, 0.83). Avoidance was generally not observed for dogs or birds.
  
  
  CONCLUSIONS
  A part of the protective effects of childhood cats on asthma and allergy can be attributed to selective avoidance.
authors.affiliation: Department of Thoracic Medicine, Institute of Medicine, University of Bergen, Norway. cecile.svanes@med.uib.no
authors.forename: Cecilie
authors.initials: C
authors.lastname: Svanes
authors.forename: Jan-Paul
authors.initials: JP
authors.lastname: Zock
authors.forename: Josep
authors.initials: J
authors.lastname: Antó
authors.forename: Shyamali
authors.initials: S
authors.lastname: Dharmage
authors.forename: Dan
authors.initials: D
authors.lastname: Norbäck
authors.forename: Matthias
authors.initials: M
authors.lastname: Wjst
authors.forename: Joachim
authors.initials: J
authors.lastname: Heinrich
authors.forename: Deborah
authors.initials: D
authors.lastname: Jarvis
authors.forename: Roberto
authors.initials: R
authors.lastname: de Marco
authors.forename: Estel
authors.initials: E
authors.lastname: Plana
authors.forename: Chantal
authors.initials: C
authors.lastname: Raherison
authors.forename: Jordi
authors.initials: J
authors.lastname: Sunyer
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000485:Allergens / Q000276:immunology*; D000818:Animals; D000829:Animals, Domestic / Q000276:immunology*; D001249:Asthma / Q000453:epidemiology* / Q000276:immunology*; D001717:Birds; D002415:Cats; D002648:Child; D002675:Child, Preschool; D004285:Dogs; D005060:Europe / Q000453:epidemiology; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008875:Middle Aged
chemical_list: D000485:Allergens