title: Meta-analysis of determinants for pet ownership in 12 European birth cohorts on asthma and allergies: a GA2LEN initiative.
abstract: BACKGROUND
  Studies on pet ownership as a risk or protective factor for asthma and allergy show inconsistent results. This may be on account of insufficient adjustment of confounding factors.
  
  
  OBJECTIVE
  The objective of this study was to describe determinants of cat and dog ownership in European families with and without allergies.
  
  
  METHODS
  Within the EU-funded network of excellence GA(2)LEN, we performed meta-analyses with data from 12 ongoing European birth cohort studies on asthma and allergy. Each of the birth cohort studies enrolled between 485 and 4089 children. Pet ownership, allergic status (asthma, allergic rhinitis, eczema) of parents and siblings, parental education, access to ground floor, and number of people living at home were assessed by questionnaires.
  
  
  RESULTS
  Among the 25 056 families from seven European countries cats (14.9%) were more common than dogs (12.0%). Allergic family history significantly reduced the odds to own a cat (adjusted combined random-effect OR 0.91; 95% CI 0.85-0.99), or dog (0.90; 0.86-0.94). A higher parental educational level had even more pronounced effects on cat (0.84; 0.71-0.98), and dog ownership (0.61; 0.54-0.70). Elder siblings reduced the odds to own cats, but not dogs. Convenient ground access significantly increased the odds, whereas crowding at home was not associated with cat or dog ownership.
  
  
  CONCLUSIONS
  The chances to own a cat or dog were significantly reduced in allergic families, in parents with a higher educational level, and in homes without convenient ground access. In addition to parental allergies, social and housing factors should be considered as potential confounders in studies on pet exposure and allergic diseases.
authors: Department of Dermatology, Allergy Center, Odense University Hospital, Odense, Denmark.
authors: E
authors: E
authors: Eller
authors: S
authors: S
authors: Roll
authors: C-M
authors: CM
authors: Chen
authors: O
authors: O
authors: Herbarth
authors: H-E
authors: HE
authors: Wichmann
authors: A
authors: A
authors: von Berg
authors: U
authors: U
authors: Krämer
authors: M
authors: M
authors: Mommers
authors: C
authors: C
authors: Thijs
authors: A
authors: A
authors: Wijga
authors: B
authors: B
authors: Brunekreef
authors: M P
authors: MP
authors: Fantini
authors: F
authors: F
authors: Bravi
authors: F
authors: F
authors: Forastiere
authors: D
authors: D
authors: Porta
authors: J
authors: J
authors: Sunyer
authors: M
authors: M
authors: Torrent
authors: A
authors: A
authors: Høst
authors: S
authors: S
authors: Halken
authors: K C
authors: KC
authors: Lødrup Carlsen
authors: K-H
authors: KH
authors: Carlsen
authors: M
authors: M
authors: Wickman
authors: I
authors: I
authors: Kull
authors: U
authors: U
authors: Wahn
authors: S N
authors: SN
authors: Willich
authors: S
authors: S
authors: Lau
authors: T
authors: T
authors: Keil
authors: J
authors: J
authors: Heinrich
mesh_terms: D016902:Air Pollution, Indoor; D000485:Allergens / Q000276:immunology*; D000818:Animals; D002415:Cats / Q000276:immunology*; D015331:Cohort Studies; D004285:Dogs / Q000276:immunology*; D005191:Family Characteristics; D006801:Humans; D006967:Hypersensitivity / Q000209:etiology / Q000276:immunology*; D011795:Surveys and Questionnaires
chemical_list: D000485:Allergens