title: Fraction of exhaled nitric oxide and wheezing phenotypes in preschool children.
abstract: BACKGROUND
  Asthma is a chronic lower airway inflammatory disease. Nitric oxide is an inflammatory mediator produced endogenously in the airway. Previous studies have demonstrated that the fractional concentration of exhaled nitric oxide (FeNO) is increased in asthma.
  
  
  OBJECTIVE
  To investigate if FeNO concentrations were correlated with wheezing phenotypes in preschool children and to compare the FeNO results with airway hyperresponsiveness (AHR) and pulmonary function test (PFT) results.
  
  
  METHODS
  We performed skin prick tests, methacholine provocation tests, PFT, impulse oscillometry bronchodilator response (IOS BDR) tests, and FeNO measurements in 372 preschool children between the ages of 4 and 6 years. Wheezing phenotypes were defined according to the age of onset and persistency.
  
  
  RESULTS
  Persistent wheezers had higher FeNO levels than transient wheezers and non-wheezers. Among persistent wheezers, those with atopy and AHR had significantly higher FeNO levels than those without atopy or AHR. FeNO levels were significantly higher in late-onset wheezers than early-onset wheezers and non-wheezers. Among late-onset wheezers, those with atopy and AHR had a significantly higher FeNO concentration than those without atopy or AHR as well as those with either atopy or AHR. However, there were no significant differences in AHR, PFT, or IOS BDR between persistent and transient wheezers or between late-onset wheezers and early-onset wheezers.
  
  
  CONCLUSIONS
  FeNO may be a better marker for asthma phenotypes in preschool children than AHR and PFT results.
authors.affiliation: Department of Pediatrics, Kangbuk Samsung Hospital, Seoul, Korea.
authors.forename: Mi-Ae
authors.initials: MA
authors.lastname: Oh
authors.forename: Jung Yeon
authors.initials: JY
authors.lastname: Shim
authors.forename: Young-Ho
authors.initials: YH
authors.lastname: Jung
authors.forename: Ju-Hee
authors.initials: JH
authors.lastname: Seo
authors.forename: Hyung
authors.initials: H
authors.lastname: Young Kim
authors.forename: Ji-Won
authors.initials: JW
authors.lastname: Kwon
authors.forename: Byoung-Ju
authors.initials: BJ
authors.lastname: Kim
authors.forename: Hyo Bin
authors.initials: HB
authors.lastname: Kim
authors.forename: Woo Kyung
authors.initials: WK
authors.lastname: Kim
authors.forename: So-Yeon
authors.initials: SY
authors.lastname: Lee
authors.forename: Gwang Cheon
authors.initials: GC
authors.lastname: Jang
authors.forename: Dae Jin
authors.initials: DJ
authors.lastname: Song
authors.forename: Ha-Jung
authors.initials: HJ
authors.lastname: Kim
authors.forename: Yee-Jin
authors.initials: YJ
authors.lastname: Shin
authors.forename: Jung-Won
authors.initials: JW
authors.lastname: Park
authors.forename: Sang-Heon
authors.initials: SH
authors.lastname: Cho
authors.forename: Joo-Shil
authors.initials: JS
authors.lastname: Lee
authors.forename: Soo-Jong
authors.initials: SJ
authors.lastname: Hong
mesh_terms: D001249:Asthma / Q000150:complications / Q000175:diagnosis / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D001985:Bronchial Provocation Tests; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D045853:Exhalation; D005260:Female; D006801:Humans; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D010641:Phenotype; D012129:Respiratory Function Tests; D012130:Respiratory Hypersensitivity / Q000150:complications / Q000175:diagnosis / Q000378:metabolism; D012135:Respiratory Sounds / Q000209:etiology / Q000502:physiology*; D012882:Skin Tests; D011795:Surveys and Questionnaires
chemical_list: D015415:Biomarkers; D009569:Nitric Oxide