title: Childhood wheezing phenotypes and FeNO in atopic children at age 8.
abstract: BACKGROUND
  Fractional exhaled Nitric Oxide (FeNO) is a surrogate biomarker of the degree of eosinophilic airway inflammation. Using longitudinal latent class analysis, five wheezing phenotypes have been identified, characterized by different ages of onset and prognosis.
  
  
  OBJECTIVE
  To assess FeNO measured at 4 and 8 years in children with different phenotypes of wheeze and atopy.
  
  
  METHODS
  Children participated in the Prevention and Incidence of Asthma and Mite Allergy (PIAMA) study, a prospective birth cohort in the Netherlands. Respiratory health was assessed yearly by questionnaires until the age of 8 years; these data were used to identify five wheezing phenotypes. Associations between FeNO and wheezing phenotypes were investigated using weighted linear regression.
  
  
  RESULTS
  Data on wheezing phenotypes and FeNO at 4 and 8 years were available in 588 and 973 children respectively. Compared with the phenotype of never and transient wheeze, FeNO at 4 years was higher in intermediate onset and persistent wheeze. FeNO at 8 years of age differed significantly between all phenotypes, with highest FeNO values for persistent, intermediate onset, and late onset wheeze. Rise in FeNO from 4 to 8 years in intermediate and late onset wheezers was significantly higher compared to FeNO rise in never and transient wheezers. Stratified analyses showed that the increase in FeNO in persistent, intermediate, and late onset wheeze was only present in children with allergic sensitization at 8 years.
  
  
  CONCLUSIONS
  The FeNO measured at 8 years was associated with specific wheezing phenotypes, only among atopic children.
authors.affiliation: Department of Pediatrics, Erasmus University Medical Center, Sophia Children's Hospital, Rotterdam, The Netherlands.
authors.forename: R J P
authors.initials: RJ
authors.lastname: van der Valk
authors.forename: D
authors.initials: D
authors.lastname: Caudri
authors.forename: O
authors.initials: O
authors.lastname: Savenije
authors.forename: G H
authors.initials: GH
authors.lastname: Koppelman
authors.forename: H A
authors.initials: HA
authors.lastname: Smit
authors.forename: A H
authors.initials: AH
authors.lastname: Wijga
authors.forename: D S
authors.initials: DS
authors.lastname: Postma
authors.forename: M
authors.initials: M
authors.lastname: Kerkhof
authors.forename: B
authors.initials: B
authors.lastname: Brunekreef
authors.forename: J C
authors.initials: JC
authors.lastname: de Jongste
mesh_terms: D001249:Asthma / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D045853:Exhalation; D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000503:physiopathology*; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D010641:Phenotype; D012135:Respiratory Sounds / Q000503:physiopathology*
chemical_list: D009569:Nitric Oxide