title: Effect of age on relationship between exhaled nitric oxide and airway hyperresponsiveness in asthmatic children.
abstract: BACKGROUND
  Numerous studies have examined the relationship between the fractional concentration of exhaled nitric oxide (Feno) and airway hyperresponsiveness (AHR). Our objective was to determine the effects of age on the relationship between Feno and AHR in asthmatic children.
  
  
  METHODS
  AHR was examined in 267 asthmatic patients (age range, 5 to 20 years). A challenge test was performed using acetylcholine chloride (Ach). We determined the provocative concentration of Ach producing a 20% decrease in FEV(1) from baseline (PC(20)). Feno was examined using the recommended online method before the Ach challenge test.
  
  
  RESULTS
  In children < 12 years of age (range, 5 to 11 years), decreasing AHR (PC(20)) was significantly related to higher Feno (r = -0.43; beta = -0.28; p < 0.001). In adolescents >or= 12 years of age (range, 12 to 20 years), decreasing PC(20) was associated with peripheral airway obstruction (FEV(1): r = 0.32; beta = 5.5; p = 0.002; forced expiratory flow at 50% of the FVC: r = 0.24; beta=8.4; p = 0.006; and forced expiratory flow at 25% of FVC: r = 0.28; beta=11.4; p = 0.002). AHR and Feno were weakly related (r = -0.18; beta = -0.14; p = 0.02).
  
  
  CONCLUSIONS
  In children with asthma, AHR is associated with airway inflammation. AHR in children with asthma may consist of variable components mainly reflecting airway inflammation. In contrast, in adolescents with asthma, AHR is associated with airway structural changes and weakly with airway inflammation. AHR in adolescents with asthma may consist of chronic components mainly reflecting airway remodeling.
authors.affiliation: Department of Pediatrics, Fukuoka National Hospital, Minami-ku, Fukuoka, Japan. Electronic address: cmotomura@mfukuoka2.hosp.go.jp.
authors.forename: Chikako
authors.initials: C
authors.lastname: Motomura
authors.affiliation: Department of Pediatrics, Fukuoka National Hospital, Minami-ku, Fukuoka, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Odajima
authors.affiliation: Department of Pediatrics, Fukuoka National Hospital, Minami-ku, Fukuoka, Japan.
authors.forename: Junichiro
authors.initials: J
authors.lastname: Tezuka
authors.affiliation: Department of Pediatrics, Fukuoka National Hospital, Minami-ku, Fukuoka, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Murakami
authors.affiliation: Department of Pediatrics, Fukuoka National Hospital, Minami-ku, Fukuoka, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Moriyasu
authors.affiliation: Department of Pediatrics, Fukuoka National Hospital, Minami-ku, Fukuoka, Japan.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Kando
authors.affiliation: Department of Pediatrics, Fukuoka National Hospital, Minami-ku, Fukuoka, Japan.
authors.forename: Naohiko
authors.initials: N
authors.lastname: Taba
authors.affiliation: Department of Pediatrics, Fukuoka National Hospital, Minami-ku, Fukuoka, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Hayashi
authors.affiliation: Department of Pediatrics, Fukuoka National Hospital, Minami-ku, Fukuoka, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Okada
authors.affiliation: Department of Pediatrics, Fukuoka National Hospital, Minami-ku, Fukuoka, Japan.
authors.forename: Sankei
authors.initials: S
authors.lastname: Nishima
mesh_terms: D000280:Administration, Inhalation; D000293:Adolescent; D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000367:Age Factors; D001249:Asthma / Q000175:diagnosis* / Q000188:drug therapy* / Q000453:epidemiology; D015415:Biomarkers / Q000378:metabolism; D016535:Bronchial Hyperreactivity / Q000175:diagnosis* / Q000378:metabolism; D001985:Bronchial Provocation Tests; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D045853:Exhalation / Q000187:drug effects / Q000502:physiology; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D016014:Linear Models; D008297:Male; D015999:Multivariate Analysis; D009569:Nitric Oxide / Q000378:metabolism*; D011237:Predictive Value of Tests; D011336:Probability; D011379:Prognosis; D015203:Reproducibility of Results; D012129:Respiratory Function Tests; D012720:Severity of Illness Index; D013147:Spirometry; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000305:Adrenal Cortex Hormones; D015415:Biomarkers; D009569:Nitric Oxide