title: Peak expiratory flow variability and exercise responsiveness in methacholine-hyperresponsive adolescents with asthma remission.
abstract: 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.
authors.affiliation: Department of Pediatrics and Clinical Research Institute, Seoul National University Hospital, Seoul, Korea. kohyy@plaza.snu.ac.kr
authors.forename: Young Yull
authors.initials: YY
authors.lastname: Koh
authors.forename: Hee
authors.initials: H
authors.lastname: Kang
authors.forename: Young
authors.initials: Y
authors.lastname: Yoo
authors.forename: Jinho
authors.initials: J
authors.lastname: Yu
authors.forename: Kyu Min
authors.initials: KM
authors.lastname: Nah
authors.forename: Chang Keun
authors.initials: CK
authors.lastname: Kim
mesh_terms: 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
chemical_list: D016085:Bronchoconstrictor Agents; D016210:Methacholine Chloride