title: Prevalence of aeroallergen sensitization and increased exhaled nitric oxide values in schoolchildren of different socioeconomic status.
abstract: BACKGROUND
  Screening for allergic diseases allows an early diagnosis to be made, thus reducing socioeconomic burden and enhancing quality of life. We determined the prevalence of elevated exhaled nitric oxide (eNO) levels and sensitization to common airborne allergens in schoolchildren from different socioeconomic backgrounds.
  
  
  METHODS
  The study population comprised 271 children (136 boys) aged between 8 and 12 years in whom we applied skin prick tests and determined eNO levels.
  
  
  RESULTS
  Thirty-five percent of the children were identified as atopic. There was a significantly higher prevalence of atopy in boys (43% vs. 27%). Among the children with a high socioeconomic status, 37% were atopic, compared with 30% of those with a low socioeconomic status. We observed a significantly lower prevalence of pollen sensitization in children of lower socioeconomic status (10% vs. 20%). In the atopic group, 51% had elevated eNO levels, while in the nonatopic group this value was 4%. The mean (SD) eNO level was 33.4 (26.6) ppb in the atopic group and 11.9 (6.4) ppb in the nonatopic group. No differences were found for eNO values in terms of gender or socioeconomic status.
  
  
  CONCLUSIONS
  Our results emphasize the high prevalence of atopy in our population and suggest that determination of eNO levels could help to provide an early diagnosis. We also observed the following: (a) a significant difference in mean eNO values between atopic and nonatopic children; (b) a significantly lower prevalence of pollen sensitization in children of lower socioeconomic status; and (c) a higher prevalence of atopy in boys.
authors.affiliation: Allergy Division, Hospital S. João, EPE, Porto, Portugal. ruisilva@inbox.com
authors.forename: R
authors.initials: R
authors.lastname: Silva
authors.forename: L
authors.initials: L
authors.lastname: Cruz
authors.forename: T
authors.initials: T
authors.lastname: Vieira
authors.forename: A
authors.initials: A
authors.lastname: Leblanc
authors.forename: A
authors.initials: A
authors.lastname: Ferreira
authors.forename: J
authors.initials: J
authors.lastname: Fonseca
authors.forename: A
authors.initials: A
authors.lastname: Moreira
authors.forename: M G
authors.initials: MG
authors.lastname: Castel-Branco
mesh_terms: D000485:Allergens / Q000276:immunology*; D001944:Breath Tests / Q000379:methods; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D011058:Pollen / Q000276:immunology*; D011174:Portugal / Q000453:epidemiology; D012221:Rhinitis, Allergic, Perennial / Q000453:epidemiology / Q000276:immunology* / Q000378:metabolism; D012882:Skin Tests / Q000379:methods; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires; D014505:Urban Population
chemical_list: D000485:Allergens; D009569:Nitric Oxide