Effect of age on relationship between exhaled nitric oxide and airway hyperresponsiveness in asthmatic children.
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.
Motomura
Chikako
C
Department of Pediatrics, Fukuoka National Hospital, Minami-ku, Fukuoka, Japan. Electronic address: cmotomura@mfukuoka2.hosp.go.jp.
Odajima
Hiroshi
H
Department of Pediatrics, Fukuoka National Hospital, Minami-ku, Fukuoka, Japan.
Tezuka
Junichiro
J
Department of Pediatrics, Fukuoka National Hospital, Minami-ku, Fukuoka, Japan.
Murakami
Yoko
Y
Department of Pediatrics, Fukuoka National Hospital, Minami-ku, Fukuoka, Japan.
Moriyasu
Yoshio
Y
Department of Pediatrics, Fukuoka National Hospital, Minami-ku, Fukuoka, Japan.
Kando
Naoyuki
N
Department of Pediatrics, Fukuoka National Hospital, Minami-ku, Fukuoka, Japan.
Taba
Naohiko
N
Department of Pediatrics, Fukuoka National Hospital, Minami-ku, Fukuoka, Japan.
Hayashi
Daisuke
D
Department of Pediatrics, Fukuoka National Hospital, Minami-ku, Fukuoka, Japan.
Okada
Kenji
K
Department of Pediatrics, Fukuoka National Hospital, Minami-ku, Fukuoka, Japan.
Nishima
Sankei
S
Department of Pediatrics, Fukuoka National Hospital, Minami-ku, Fukuoka, Japan.
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
D000305:Adrenal Cortex Hormones; D015415:Biomarkers; D009569:Nitric Oxide