title: Allergen exposure modifies the relation of sensitization to fraction of exhaled nitric oxide levels in children at risk for allergy and asthma.
abstract: BACKGROUND
  Studies on airway inflammation, measured as fraction of exhaled nitric oxide (FENO), have focused on its relation to control of asthma, but the contribution of allergen exposure to the increase in FENO levels is unknown.
  
  
  OBJECTIVE
  We evaluated (1) whether FENO levels were increased in children with allergic sensitization or asthma; (2) whether specific allergen exposure increased FENO levels in sensitized, but not unsensitized, children; and (3) whether sedentary behavior increased FENO levels independent of allergen exposures.
  
  
  METHODS
  At age 12 years, in a birth cohort of children with a parental history of allergy or asthma, we measured bed dust allergen (dust mite, cat, and cockroach) by means of ELISA, specific allergic sensitization primarily based on specific IgE levels, and respiratory disease (current asthma, rhinitis, and wheeze) and hours of television viewing/video game playing by means of questionnaire. Children performed spirometric maneuvers before and after bronchodilator responses and had FENO levels measured by using electrochemical detection methods (NIOX MINO).
  
  
  RESULTS
  FENO levels were increased in children with current asthma (32.2 ppb), wheeze (27.0 ppb), or rhinitis (23.2 ppb) compared with subjects without these respective symptoms/diagnoses (16.4-16.6 ppb, P < .005 for all comparisons). Allergic sensitization to indoor allergens (cat, dog, and dust mite) predicted higher FENO levels and explained one third of the variability in FENO levels. FENO levels were highest in children both sensitized and exposed to dust mite. Greater than 10 hours of weekday television viewing was associated with a 0.64-log increase in FENO levels after controlling for indoor allergen exposure, body mass index, and allergic sensitization.
  
  
  CONCLUSIONS
  Allergen exposures and sedentary behavior (television viewing/video game playing) might increase airway inflammation, which was measured as the FENO.
authors.affiliation: Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA. rejoa@channing.harvard.edu
authors.forename: Joanne E
authors.initials: JE
authors.lastname: Sordillo
authors.forename: Tara
authors.initials: T
authors.lastname: Webb
authors.forename: Doris
authors.initials: D
authors.lastname: Kwan
authors.forename: Jimmy
authors.initials: J
authors.lastname: Kamel
authors.forename: Elaine
authors.initials: E
authors.lastname: Hoffman
authors.forename: Donald K
authors.initials: DK
authors.lastname: Milton
authors.forename: Diane R
authors.initials: DR
authors.lastname: Gold
mesh_terms: D000293:Adolescent; D000485:Allergens / Q000009:adverse effects* / Q000276:immunology*; D000818:Animals; D001249:Asthma / Q000175:diagnosis* / Q000276:immunology / Q000503:physiopathology; D001944:Breath Tests; D002415:Cats; D002648:Child; D004285:Dogs; D004391:Dust / Q000276:immunology; D045853:Exhalation; D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000175:diagnosis* / Q000276:immunology / Q000503:physiopathology; D007073:Immunoglobulin E / Q000097:blood; D007223:Infant; D008297:Male; D008925:Mites / Q000276:immunology; D009569:Nitric Oxide / Q000032:analysis*; D012220:Rhinitis / Q000175:diagnosis* / Q000276:immunology / Q000503:physiopathology; D013147:Spirometry
chemical_list: D000485:Allergens; D004391:Dust; D009569:Nitric Oxide; D007073:Immunoglobulin E