title: Peak expiratory flow variability and bronchial responsiveness to methacholine. An epidemiologic study in 117 workers.
abstract: We studied the relationships between peak expiratory flow (PEF) variability and bronchial responsiveness to methacholine in 117 workers attending the annual compulsory examination (mean age, 38.7 yr +/- 9.5; men, 86.3%). Subjects recorded their highest PEF out of three, every 3 waking hours (i.e., five times a day) for 7 days, each using a newly purchased Vitalograph peak flow meter, and underwent methacholine challenge tests with a maximal cumulative dose of 1,200 micrograms. Those with a FEV1 fall of 15% or more were considered as reactors. The variability of PEF was expressed as the amplitude percent mean, calculated from daily amplitude (highest-lowest reading/mean reading of the day x 100), averaged over 6 days, from the second to the seventh. This index had a continuous distribution, skewed towards the greatest amplitudes, and correlated negatively with FEV1 (r = -0.25, p = 0.01). Subjects with asthma (n = 8) had greater variations. In the 109 nonasthmatics, greater variability was observed in subjects with wheeze apart from colds, breathlessness, or hay fever; the average amplitude was greater in reactors than in nonreactors to methacholine (16.9% versus 9.3%, p less than 0.001). The subjects with excessive PEF variability were all methacholine reactors, but they were only a subgroup of the reactors. These results provide evidence that excessive PEF variability is an indicator of bronchial hyperresponsiveness to methacholine in a population sample.
authors.affiliation: National Institute of Health and Medical Research INSERM U226, Paris, France.
authors.forename: F
authors.initials: F
authors.lastname: Neukirch
authors.forename: R
authors.initials: R
authors.lastname: Liard
authors.forename: C
authors.initials: C
authors.lastname: Segala
authors.forename: M
authors.initials: M
authors.lastname: Korobaeff
authors.forename: C
authors.initials: C
authors.lastname: Henry
authors.forename: J
authors.initials: J
authors.lastname: Cooreman
mesh_terms: D000328:Adult; D001985:Bronchial Provocation Tests; D002940:Circadian Rhythm; D003902:Detergents; D005541:Forced Expiratory Volume; D006801:Humans; D008450:Maximal Midexpiratory Flow Rate; D016210:Methacholine Chloride; D008875:Middle Aged; D009784:Occupational Diseases / Q000175:diagnosis*; D010366:Peak Expiratory Flow Rate; D012372:ROC Curve; D012140:Respiratory Tract Diseases / Q000175:diagnosis*
chemical_list: D003902:Detergents; D016210:Methacholine Chloride