title: Health impacts of second-hand exposure to cat allergen Fel d 1 in infants.
abstract: BACKGROUND
  Recent cross-sectional studies suggested that highest sensitization prevalences occur with moderate cat allergen exposures. We aimed to assess the impact of moderate levels of second-hand cat allergen exposure on the incidence of specific sensitization and wheezing in the framework of a birth cohort study. Therefore we restricted our analysis to infants without a cat at home since birth.
  
  
  METHODS
  At infant's age 3 months, cat allergen levels were measured in the mattress dust of 1840 families without cats. At age 2 years, serum IgE specific to Fel d 1 was analyzed. Incidence of wheezing apart from respiratory infection was assessed by questionnaire. Logistic regression models were used to calculate adjusted odds ratios (OR) for the association between second-hand cat allergen exposure and health outcomes.
  
  
  RESULTS
  Until age 2 years, 13 of 1301 infants (1%) were sensitized to cat allergen and 56 of 1492 infants (4%) had ever-wheezing without infection. Early exposure to second-hand cat allergen levels >or= 1 microg/g dust increased substantially the risk for specific sensitization to Fel d 1 (OR 10.9, 95% CI 3.4-35.0) and ever-wheeze without infection (OR 2.0, 95% CI 1.1-3.9) at age 2 years.
  
  
  CONCLUSIONS
  Second-hand exposure to cat allergen in homes without cats is detrimental in terms of allergy development in infants.
authors.affiliation: GSF National Research Center for Environment and Health, Institute of Epidemiology, Neuherberg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Heissenhuber
authors.forename: J
authors.initials: J
authors.lastname: Heinrich
authors.forename: B
authors.initials: B
authors.lastname: Fahlbusch
authors.forename: M
authors.initials: M
authors.lastname: Borte
authors.forename: H-E
authors.initials: HE
authors.lastname: Wichmann
authors.forename: G
authors.initials: G
authors.lastname: Bolte
mesh_terms: D016902:Air Pollution, Indoor / Q000009:adverse effects / Q000032:analysis; D000818:Animals; D002415:Cats; D015331:Cohort Studies; D004306:Dose-Response Relationship, Immunologic; D004781:Environmental Exposure / Q000009:adverse effects / Q000032:analysis; D005192:Family Health; D005260:Female; D005500:Follow-Up Studies; D005858:Germany / Q000453:epidemiology; D006023:Glycoproteins / Q000008:administration & dosage / Q000009:adverse effects* / Q000276:immunology*; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000453:epidemiology / Q000276:immunology; D007114:Immunization; D007073:Immunoglobulin E / Q000276:immunology; D007229:Infant Welfare; D007231:Infant, Newborn; D008297:Male; D015999:Multivariate Analysis; D012135:Respiratory Sounds / Q000209:etiology; D012307:Risk Factors; D011795:Surveys and Questionnaires
chemical_list: D006023:Glycoproteins; D007073:Immunoglobulin E; C059296:Fel d 1 protein, Felis domesticus