title: Early-life allergen exposure and atopy, asthma, and wheeze up to 6 years of age.
abstract: BACKGROUND
  Although it is widely assumed that the incidence of childhood respiratory allergies to common aeroallergens is directly related to allergen exposure in early life, few longitudinal studies have investigated this issue, and available data are scarce and mainly limited to high-risk groups.
  
  
  OBJECTIVE
  To assess, in a prospective manner and in a general population, the role of early life exposures to Der p1 and Fel d1 on the inception of sensitization and asthma.
  
  
  METHODS
  Pregnant women and their children were recruited for the Asthma Multicentre Infant Cohort Study. Overall, 1,611 newborns were initially enrolled in three cohorts in the United Kingdom and Spain. Der p1 and Fel d1 allergens were measured in household dust samples at 3 months of age for 1,474 (91.5%) participants, and skin prick tests were performed at 6 years of age on 1,182 (80.2%) participants. Wheeze and diagnosed asthma were reported in yearly questionnaires.
  
  
  RESULTS
  Exposure to Der p1 early in life was not related to a positive specific prick test or to asthma or persistent wheeze at 6 years of age. Fel d1 showed an association with all these outcomes (third vs. first tertile; odds ratio, 4.43 for positive specific prick test and 2.6 for diagnosed asthma).
  
  
  CONCLUSIONS
  Dose-response relationships between allergen exposure and sensitization or asthma may be allergen specific and nonlinear; a minimum threshold level is needed to induce sensitization, but no dose-response relationship exists above this level. The effect of a particular allergen seems to be similar on atopy and asthma inception.
authors.affiliation: Menorca Health Area, ib-salut Menorca, Institute Universitary d'Investigacio en Ciencies de la Salut, Menorca, Spain. mtorrent@smen.es
authors.forename: Matias
authors.initials: M
authors.lastname: Torrent
authors.forename: Jordi
authors.initials: J
authors.lastname: Sunyer
authors.forename: Raquel
authors.initials: R
authors.lastname: Garcia
authors.forename: Jessica
authors.initials: J
authors.lastname: Harris
authors.forename: Maria V
authors.initials: MV
authors.lastname: Iturriaga
authors.forename: Carme
authors.initials: C
authors.lastname: Puig
authors.forename: Oriol
authors.initials: O
authors.lastname: Vall
authors.forename: Josep M
authors.initials: JM
authors.lastname: Anto
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Newman Taylor
authors.forename: Paul
authors.initials: P
authors.lastname: Cullinan
mesh_terms: D039741:Antigens, Dermatophagoides / Q000009:adverse effects* / Q000276:immunology; D060829:Arthropod Proteins; D001249:Asthma / Q000453:epidemiology / Q000209:etiology* / Q000276:immunology; D002648:Child; D003546:Cysteine Endopeptidases; D004306:Dose-Response Relationship, Immunologic; D004391:Dust / Q000276:immunology*; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D006023:Glycoproteins / Q000009:adverse effects* / Q000276:immunology; D006801:Humans; D007223:Infant; D008297:Male; D015999:Multivariate Analysis; D015995:Prevalence; D011446:Prospective Studies; D012044:Regression Analysis; D012135:Respiratory Sounds / Q000209:etiology* / Q000276:immunology; D012307:Risk Factors; D012882:Skin Tests; D013030:Spain / Q000453:epidemiology; D006113:United Kingdom / Q000453:epidemiology
chemical_list: D039741:Antigens, Dermatophagoides; D060829:Arthropod Proteins; D004391:Dust; D006023:Glycoproteins; D003546:Cysteine Endopeptidases; C451162:Dermatophagoides pteronyssinus antigen p 1; C059296:Fel d 1 protein, Felis domesticus