title: Bronchial challenges and respiratory symptoms in elite swimmers and winter sport athletes: Airway hyperresponsiveness in asthma: its measurement and clinical significance.
abstract: This study was aimed at the following: (1) the prevalence of airway hyperresponsiveness (AHR) and exercise-induced bronchoconstriction (EIB) in swimmers and winter sport athletes according to the previously recommended regulatory sport agencies criteria, (2) the relationship between respiratory symptoms and AHR/EIB, (3) the impact of the chosen cutoff value for AHR on its prevalence, and (4) the effect on the prevalence of the positive eucapnic voluntary hyperpnea (EVH) test of using the highest vs the lowest spirometric post-EVH values to calculate the magnitude of the airway response. We compared the prevalence of respiratory symptoms with responses to methacholine challenge and EVH in 45 swimmers, 45 winter sport athletes, and 30 controls. Two methacholine challenge cutoffs for AHR were analyzed: <or= 4 mg/mL (the sport agencies' criteria for AHR) and <or= 16 mg/mL. Sixty percent of swimmers, 29% of winter sport athletes, and 17% of controls had evidence of EIB or AHR (with the <or= 4 mg/mL criteria). Among athletes with a methacholine provocative concentration inducing a 20% decrease in the FEV(1) between 4 and 16 mg/mL, 43% of swimmers and 100% of winter sport athletes were symptomatic (P < .05). Prevalence of positive EVH tests were 39% in swimmers, 24% in winter sport athletes, and 13% in controls when the highest FEV(1) value measured at each time point post-EVH was used to identify maximal response for calculation of airway response, although these prevalences were higher if we used the lowest value. This study suggests that AHR/EIB is frequent in swimmers, whereas the frequently reported respiratory symptoms in winter sport athletes are often not related to AHR/EIB. Furthermore, the choice of methods for assessing methacholine challenge and EVH responses influences the prevalences of AHR and EIB.
  
  
  BACKGROUND
  clinicaltrials.gov; Identifier NCT 00686491 and NCT 00686452.
authors.affiliation: Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, QC, Canada.
authors.forename: Valérie
authors.initials: V
authors.lastname: Bougault
authors.forename: Julie
authors.initials: J
authors.lastname: Turmel
authors.forename: Louis-Philippe
authors.initials: LP
authors.lastname: Boulet
mesh_terms: D000280:Administration, Inhalation; D000293:Adolescent; D001250:Asthma, Exercise-Induced / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D056352:Athletes; D016535:Bronchial Hyperreactivity / Q000503:physiopathology*; D001985:Bronchial Provocation Tests / Q000379:methods*; D016084:Bronchoconstriction / Q000502:physiology*; D016085:Bronchoconstrictor Agents / Q000008:administration & dosage; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008297:Male; D016210:Methacholine Chloride / Q000008:administration & dosage; D015995:Prevalence; D011792:Quebec / Q000453:epidemiology; D012307:Risk Factors; D013550:Swimming / Q000502:physiology*; D055815:Young Adult
chemical_list: D016085:Bronchoconstrictor Agents; D016210:Methacholine Chloride