title: Methacholine challenge is insufficient to exclude bronchial hyper-responsiveness in a symptomatic military population.
abstract: BACKGROUND
  Bronchial hyper-responsiveness in a military population has been evaluated by direct and indirect challenge methods. We hypothesized that negative methacholine challenge testing (MCT) was not sufficient to exclude significant bronchial hyper-responsiveness in a symptomatic military population with exertional dyspnea. The purpose of our study was to identify bronchial hyper-responsiveness in symptomatic military recruits and active duty personnel with normal baseline spirometry and negative pharmacologic bronchoprovocation testing.
  
  
  METHODS
  We performed a retrospective single center electronic chart review of symptomatic service members with a negative MCT who completed a subsequent exercise challenge test (ECT).
  
  
  RESULTS
  ECT was positive in 45 (26.4%) of 171 subjects (98 recruits). Subjects with a positive ECT had lower baseline forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC) and FEV1/FVC than those with a negative ECT, and these differences were statistically significant. The mean drop in FEV1 with exercise challenge positive patients was 17.9 ± 9.2%, and the mean drop in FEV1 with MCT was significantly greater in exercise challenge positive patients (-9.5 ± 5.5 vs. -7.6 ± 5.5, p = 0.042). Exercise-induced bronchoconstriction (EIB) was observed in 41% of all recruits who subsequently did not complete training. Only 1 recruit subject of 28 with EIB completed training.
  
  
  CONCLUSIONS
  Methacholine challenge is an insufficient screening test to detect bronchial hyper-responsiveness in a symptomatic military population. In military recruits, EIB is associated with training failure.
authors.affiliation: Naval Medical Center San Diego , San Diego, CA , USA and.
authors.forename: Justin
authors.initials: J
authors.lastname: Stocks
authors.forename: Michael
authors.initials: M
authors.lastname: Tripp
authors.forename: Thuy
authors.initials: T
authors.lastname: Lin
mesh_terms: D016535:Bronchial Hyperreactivity / Q000175:diagnosis*; D001985:Bronchial Provocation Tests; D016084:Bronchoconstriction; D016085:Bronchoconstrictor Agents; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D016210:Methacholine Chloride; D008889:Military Personnel; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D016085:Bronchoconstrictor Agents; D016210:Methacholine Chloride
keywords: Exercise challenge testing; exercise-induced bronchoconstriction; methacholine challenge testing; military recruit