title: Longitudinal study on cat allergen exposure and the development of allergy in young children.
abstract: BACKGROUND
  The influence of cat allergen exposure in early childhood on the development of sensitization and allergic diseases is complex. Little is known about the natural course of the sensitization development within individuals.
  
  
  OBJECTIVE
  We investigated the association between cat allergen exposure in infancy and cat ownership and cat contact during childhood and the development of cat sensitization and allergic diseases up to age 6 years using a longitudinal analysis approach.
  
  
  METHODS
  Overall, 2166 children from an ongoing birth cohort study were included in the analysis. House dust samples were collected 3 months after birth. Cat allergen levels were extracted. Blood samples were collected when the children were 2 and 6 years old. Information on the allergic symptoms of children and doctor-diagnosed allergic disease were collected at each follow-up using questionnaires.
  
  
  RESULTS
  Cat allergen exposure in infancy was positively associated with sensitization at age 2 years but not at age 6 years. No associations existed between cat allergen exposure in infancy and allergic symptoms and diseases up to age 6 years. Cumulative allergen exposure from cat ownership and regular cat contact increased the risk of cat sensitization up to age 6 years.
  
  
  CONCLUSIONS
  Cat allergen exposure in infancy increases the risk of sensitization development in early childhood but not in school-age children. Cumulative allergen exposure from cat ownership and regular cat contact during childhood contribute to sensitization development up to school age.
  
  
  CONCLUSIONS
  Cat allergen avoidance at home alone might be not effective to prevent the development of allergic sensitization in young children.
authors.affiliation: GSF-National Research Centre for Environment and Health, Institute of Epidemiology, Neuherberg, Germany.
authors.forename: Chih-Mei
authors.initials: CM
authors.lastname: Chen
authors.forename: Peter
authors.initials: P
authors.lastname: Rzehak
authors.forename: Anne
authors.initials: A
authors.lastname: Zutavern
authors.forename: Bärbel
authors.initials: B
authors.lastname: Fahlbusch
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Bischof
authors.forename: Olf
authors.initials: O
authors.lastname: Herbarth
authors.forename: Michael
authors.initials: M
authors.lastname: Borte
authors.forename: Irina
authors.initials: I
authors.lastname: Lehmann
authors.forename: Heidrun
authors.initials: H
authors.lastname: Behrendt
authors.forename: Ursula
authors.initials: U
authors.lastname: Krämer
authors.forename: H-Erich
authors.initials: HE
authors.lastname: Wichmann
authors.forename: Joachim
authors.initials: J
authors.lastname: Heinrich
mesh_terms: D016902:Air Pollution, Indoor / Q000009:adverse effects*; D000485:Allergens / Q000009:adverse effects*; D000818:Animals; D002415:Cats; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004391:Dust; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000453:epidemiology / Q000209:etiology*; D007223:Infant; D008137:Longitudinal Studies; D008297:Male; D011852:Radioallergosorbent Test
chemical_list: D000485:Allergens; D004391:Dust