title: Truncating the dose range for methacholine challenge tests: three occupational studies.
abstract: The methacholine challenge test protocol was assessed in the reanalysis of three occupational studies. We evaluated the impact of truncating the range of methacholine on responsiveness, as defined by slope and PC(20). In original analysis, reactivity was similar for apprentices and auto body shop workers, whereas boilermakers were more responsive. Truncating high concentrations did not change the classification of subjects with PC(20) <8 or 16 in any population. However, when responsiveness was measured by slope, the mean responsiveness increased, from -7.9 to -15.3 for apprentices and -7.2 to -10.0 for auto-body shop workers. Results support the American Thoracic Society's recommended maximum of 16 mg/ml and provide evidence that extending the dose range beyond that does not increase sensitivity, whereas stopping before 16 may exaggerate response. Furthermore, to ensure validity, neither slope nor PC(20) should be extrapolated beyond data.
authors.affiliation: Department of Work Environment, University of Massachusetts, Lowell, MA 01854, USA.
authors.forename: Ilir
authors.initials: I
authors.lastname: Agalliu
authors.forename: Ellen A
authors.initials: EA
authors.lastname: Eisen
authors.forename: Russ
authors.initials: R
authors.lastname: Hauser
authors.forename: Carrie A
authors.initials: CA
authors.lastname: Redlich
authors.forename: Meredith H
authors.initials: MH
authors.lastname: Stowe
authors.forename: Mark R
authors.initials: MR
authors.lastname: Cullen
authors.forename: David H
authors.initials: DH
authors.lastname: Wegman
authors.forename: David C
authors.initials: DC
authors.lastname: Christiani
authors.forename: Susan M
authors.initials: SM
authors.lastname: Kennedy
mesh_terms: D000328:Adult; D001249:Asthma / Q000175:diagnosis* / Q000503:physiopathology; D001985:Bronchial Provocation Tests; D016085:Bronchoconstrictor Agents / Q000008:administration & dosage*; D002985:Clinical Protocols; D004305:Dose-Response Relationship, Drug; D005260:Female; D015989:Healthy Worker Effect; D006801:Humans; D007221:Industry; D008297:Male; D008669:Metallurgy; D016210:Methacholine Chloride / Q000008:administration & dosage*; D018986:Motor Vehicles; D009784:Occupational Diseases / Q000175:diagnosis*; D014481:United States; D000078329:Workforce
chemical_list: D016085:Bronchoconstrictor Agents; D016210:Methacholine Chloride