Peak expiratory flow variability and exercise responsiveness in methacholine-hyperresponsive adolescents with asthma remission.
The aim of this study was to investigate whether bronchial hyperresponsiveness in adolescents with long-term asthma remission is associated with increased peak expiratory flow (PEF) variability and/or increased bronchial response to exercise (BRE). Twenty-nine adolescents with asthma remission (neither symptoms nor any medication used during the previous two years), but with persistent methacholine hyperresponsiveness (PC20 < 18 mg/mL; remission group), 29 methacholine PC20-matched adolescents with symptomatic asthma (symptomatic group), and 20 healthy subjects (control group) were studied. Subjects recorded PEF twice daily for 14 days and PEF variability, expressed as amplitude % mean, was calculated. Subjects also underwent a standardized exercise challenge; BRE was defined as a maximal % fall in FEV1 within 30 min after exercise. The mean (+/- SD) PEF variations in the symptomatic group and in the remission group were 12.10 +/- 6.35% and 10.02 +/- 4.73%, respectively, which were significantly higher than that (5.94 +/- 2.44%) of the control group. On the other hand, the degree of BRE (7.36 +/- 3.85%) in the remission group was significantly lower than that (22.31 +/- 10.50%) of the symptomatic group, and similar to that (5.98 +/- 2.70%) of the control group. Methacholine hyperresponsiveness in asthma remission during adolescence is associated with increased PEF variability but not with increased BRE.
Koh
Young Yull
YY
Department of Pediatrics and Clinical Research Institute, Seoul National University Hospital, Seoul, Korea. kohyy@plaza.snu.ac.kr
Kang
Hee
H
Yoo
Young
Y
Yu
Jinho
J
Nah
Kyu Min
KM
Kim
Chang Keun
CK
D000293:Adolescent; D001249:Asthma / Q000175:diagnosis* / Q000503:physiopathology; D016535:Bronchial Hyperreactivity / Q000175:diagnosis* / Q000503:physiopathology; D001985:Bronchial Provocation Tests; D016085:Bronchoconstrictor Agents; D017079:Exercise Tolerance; D006801:Humans; D016210:Methacholine Chloride; D010366:Peak Expiratory Flow Rate; D012075:Remission, Spontaneous
D016085:Bronchoconstrictor Agents; D016210:Methacholine Chloride