title: Household peanut consumption as a risk factor for the development of peanut allergy.
abstract: BACKGROUND
  Most children with peanut allergy (PA) react on first known oral exposure to peanut. Recent data suggest cutaneous exposure as a route of sensitization.
  
  
  OBJECTIVE
  This study aimed to establish the relevant route of peanut exposure in the development of allergy.
  
  
  METHODS
  Questionnaires were administered to children with PA and to high-risk controls (with egg allergy) and controls without allergy. Questionnaires were completed before subjects were aware of their PA status, avoiding recall bias. Questionnaires recorded maternal peanut consumption during pregnancy, breast-feeding, and the first year of life. Peanut consumption was determined among all household members, allowing quantification of environmental household exposure (household peanut).
  
  
  RESULTS
  Median weekly household peanut in the 133 PA cases was significantly elevated (18.8 g) compared with 150 controls without allergy (6.9 g) and 160 high-risk controls (1.9 g). There were no differences in infant peanut consumption between groups. Differences in maternal peanut consumption during pregnancy (and lactation) were significant but become nonsignificant after adjusting for household peanut. A dose-response relationship was observed between environmental (nonoral) peanut exposure and the development of PA, which was strongest for peanut butter. Early oral exposure to peanut in infants with high environmental peanut exposure may have had a protective effect against the development of PA.
  
  
  CONCLUSIONS
  High levels of environmental exposure to peanut during infancy appear to promote sensitization, whereas low levels may be protective in atopic children. No effect of maternal peanut consumption during pregnancy or lactation is observed, supporting the hypothesis that peanut sensitization occurs as a result of environmental exposure.
authors.affiliation: King's College London, the Medical Research Council and Asthma UK Centre in Allergic Mechanisms of Asthma, Division of Asthma, Allergy and Lung Biology, Guy's and St Thomas' National Health Service Foundation Trust, London, United Kingdom.
authors.forename: Adam T
authors.initials: AT
authors.lastname: Fox
authors.forename: Peter
authors.initials: P
authors.lastname: Sasieni
authors.forename: George
authors.initials: G
authors.lastname: du Toit
authors.forename: Huma
authors.initials: H
authors.lastname: Syed
authors.forename: Gideon
authors.initials: G
authors.lastname: Lack
mesh_terms: D010367:Arachis / Q000276:immunology*; D004781:Environmental Exposure; D005191:Family Characteristics; D006801:Humans; D021183:Peanut Hypersensitivity / Q000453:epidemiology* / Q000276:immunology*; D012307:Risk Factors; D011795:Surveys and Questionnaires; D006113:United Kingdom / Q000453:epidemiology