title: Exhaled nitric oxide in symptomatic children at preschool age predicts later asthma.
abstract: BACKGROUND
  Prediction of asthma in young children with respiratory symptoms is hampered by the lack of objective measures applicable in clinical routine. In this prospective study in a preschool children cohort, we assessed whether the fraction of exhaled nitric oxide (FeNO), a biomarker of airway inflammation, is associated with asthma at school age.
  
  
  METHODS
  At baseline, IgE and eosinophils were measured in the blood, and FeNO was measured offline in 391 children aged 3-47 months with lower airway symptoms. We developed an asthma predictive index (API) including high FeNO as major criterion. At follow-up, primary outcome was physician-diagnosed asthma based on standardized interviews in those children reaching school age (n = 166).
  
  
  RESULTS
  FeNO was significantly elevated in those children with later asthma (68/166) as compared to children not developing asthma. Median (IQR) FeNO was 10.5 (6.6-17.2) vs. 7.4 (5.3-10.3) ppb. Per 5 ppb FeNO increase, the odds ratio (95% CI) for asthma increased by 2.44 (1.61-3.70) without changing when adjusting for confounders. Using the new API, children scored at risk had 58.0% probability for later asthma, whereas the negative predictive value was 78.2%, which was comparable to the classical API.
  
  
  CONCLUSIONS
  In this cohort of high-risk preschool children, elevated FeNO is associated with increased risk for school-age asthma. The new API including FeNO identifies children at risk of later asthma comparably to the classical API, but does not require blood sampling.
authors: Division of Respiratory Medicine, University Children's Hospital Bern, University of Bern, Bern, Switzerland.
authors: F
authors: F
authors: Singer
authors: I
authors: I
authors: Luchsinger
authors: D
authors: D
authors: Inci
authors: N
authors: N
authors: Knauer
authors: P
authors: P
authors: Latzin
authors: J H
authors: JH
authors: Wildhaber
authors: A
authors: A
authors: Moeller
mesh_terms: D001249:Asthma / Q000175:diagnosis*; D015415:Biomarkers; D001944:Breath Tests; D002675:Child, Preschool; D004804:Eosinophils; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D007223:Infant; D008297:Male; D009569:Nitric Oxide / Q000032:analysis*; D016017:Odds Ratio; D011379:Prognosis; D011446:Prospective Studies; D012135:Respiratory Sounds
chemical_list: D015415:Biomarkers; D009569:Nitric Oxide; D007073:Immunoglobulin E