title: Allergic sensitisation in early childhood: Patterns and related factors in PARIS birth cohort.
abstract: Allergic sensitisation is poorly documented in infants. This study aims to provide new insights into allergic sensitisation patterns and related factors in infancy.
  
  
  
  This study concerns 1860 infants involved in the Pollution and Asthma Risk: an Infant Study (PARIS) population-based birth cohort who had a standardised health examination when 18 months old, from 2004 to 2008. Sensitisation was assessed by measurements of serum specific IgE to 12 food and 4 inhalant allergens and defined by IgE≥0.35kUA/L. Information regarding lifestyle and environment were obtained from questionnaires prospectively administered.
  
  
  
  Prevalence of allergic sensitisation to any allergen, to food allergens, and to aeroallergens was 13.8%, 12.3%, and 2.3%, respectively. Multiple sensitisation (to at least two allergens) concerned 6.2% of toddlers. Intrinsic factors such as male gender, family history of allergy, and high birth weight increased the risk of food allergen sensitisation and multiple sensitisation. Caesarean section was also positively associated with multiple sensitisation. Day-care attendance was negatively related to food allergen, aeroallergen, and multiple sensitisation. A cat entering the baby's room in early life was strongly associated with aeroallergen sensitisation (ORa 3.21, 95%CI: 1.29-8.01). An introduction of meat in infant's diet after 6 months of age was negatively related to food allergen sensitisation (ORa 0.46, 95%CI: 0.24-0.91).
  
  
  
  Our results suggest that intrinsic factors and indicators of exposure to microorganisms such as caesarean section and day-care attendance may be associated with inhalant as well as food allergen sensitisation in infancy. For example, male gender, family history of allergy, high birth weight, and caesarean section could be positively related whereas day-care attendance could be negatively related to both aeroallergen and food allergen sensitisation. Conversely, early life exposure to inhalant allergens or food allergens may be specifically linked to either aeroallergen sensitisation or food allergen sensitisation, respectively.
authors.affiliation: EA 4064: épidémiologie environnementale, Université Paris Descartes, Sorbonne Paris Cité, Paris, France; Cellule Cohorte, Direction de l'Action Sociale, de l'Enfance et de la Santé, Mairie de Paris, Paris, France.
authors.forename: Stephan
authors.initials: S
authors.lastname: Gabet
authors.affiliation: Centre de l'Asthme et des Allergies, Groupe Hospitalier d'Enfants Trousseau-La Roche Guyon, Assistance Publique-Hôpitaux de Paris, France.
authors.forename: Jocelyne
authors.initials: J
authors.lastname: Just
authors.affiliation: Laboratoire de Biochimie et Biologie Moléculaire, Hôpital d'Enfants Armand Trousseau, Assistance Publique-Hôpitaux de Paris, Paris, France.
authors.forename: Rémy
authors.initials: R
authors.lastname: Couderc
authors.affiliation: EA 4064: épidémiologie environnementale, Université Paris Descartes, Sorbonne Paris Cité, Paris, France; Département de Biochimie, Hôpital Bichat, Assistance Publique-Hôpitaux de Paris, Paris, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Seta
authors.affiliation: EA 4064: épidémiologie environnementale, Université Paris Descartes, Sorbonne Paris Cité, Paris, France; Cellule Cohorte, Direction de l'Action Sociale, de l'Enfance et de la Santé, Mairie de Paris, Paris, France. Electronic address: isabelle.momas@parisdescartes.fr.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Momas
mesh_terms: D000485:Allergens / Q000276:immunology; D000818:Animals; D001724:Birth Weight; D002415:Cats; D002585:Cesarean Section; D015331:Cohort Studies; D003631:Day Care, Medical; D005260:Female; D005502:Food; D006801:Humans; D006967:Hypersensitivity / Q000453:epidemiology*; D007073:Immunoglobulin E / Q000097:blood; D007223:Infant; D008297:Male; D008487:Medical History Taking; D015995:Prevalence; D012307:Risk Factors
chemical_list: D000485:Allergens; D007073:Immunoglobulin E
keywords: Allergen-specific IgE; Allergic sensitization; Dietary diversification; Early life; Population-based birth cohort; Risk factors