title: Very low birth weight and respiratory outcome: association between airway inflammation and hyperresponsiveness.
abstract: BACKGROUND
  The respiratory outcomes after preterm birth have changed, and it is unclear whether increased airway hyperresponsiveness (AHR) later in childhood is associated with airway inflammation.
  
  
  OBJECTIVE
  To investigate the association between AHR and fractional exhaled nitric oxide (FeNO), including the alveolar concentration of nitric oxide, in school-age children with very low birth weight (VLBW).
  
  
  METHODS
  Twenty-nine children with VLBW, 33 children with a history of early wheeze, and 60 healthy controls underwent a FeNO measurement and bronchial challenge test with histamine. Atopy was assessed with skin prick tests.
  
  
  RESULTS
  Children with VLBW had well-preserved baseline lung function but significantly increased AHR, expressed as the dose response slope (P < .001). Geometric mean FeNO levels were similar between VLBW children and healthy controls, and a history of bronchopulmonary dysplasia had no effect. In the VLBW and early wheeze groups, AHR was associated with FeNO (r = 0.47, P = .01, and r = 0.43, P = .013, respectively), but in a stratified analysis, this association was significant only in atopic individuals. By using the multiple flow FeNO technique, the bronchial nitric oxide flux rather than alveolar nitric oxide concentrations were associated with AHR in both children with early wheeze and VLBW.
  
  
  CONCLUSIONS
  We conclude that in VLBW children AHR is related to FeNO but only in atopic individuals. Similar to children with early wheeze, this association is dependent on bronchial flux rather than alveolar nitric oxide concentration. It is likely that AHR is modified by atopic inflammation rather than by inflammatory process due to prematurity.
authors.affiliation: Skin and Allergy Hospital, Helsinki University Central Hospital, Helsinki, Finland. pekka.malmberg@hus.fi
authors.forename: L Pekka
authors.initials: LP
authors.lastname: Malmberg
authors.forename: Anna S
authors.initials: AS
authors.lastname: Pelkonen
authors.forename: Kristiina
authors.initials: K
authors.lastname: Malmström
authors.forename: Kristiina M
authors.initials: KM
authors.lastname: Saarinen
authors.forename: Merja
authors.initials: M
authors.lastname: Kajosaari
authors.forename: Arja
authors.initials: A
authors.lastname: Hakulinen
authors.forename: Mika J
authors.initials: MJ
authors.lastname: Mäkelä
mesh_terms: D016535:Bronchial Hyperreactivity / Q000453:epidemiology / Q000503:physiopathology*; D002648:Child; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D019102:Infant, Very Low Birth Weight; D008297:Male; D011014:Pneumonia / Q000209:etiology / Q000503:physiopathology*; D012129:Respiratory Function Tests