Prospective study of occupational asthma to laboratory animal allergens : stability of airway responsiveness to methacholine challenge for one year.
The stability of airway hyperresponsiveness was studied in a group of 1 78 young adults working with laboratory animals.
At the time of their entry into the study, 132 of 178 subjects (74%) had less that 20% response to the inhalation of 25 mg/ml methacholine, whereas 26 (15%) had a methacholine dose causing a 20% fall in forced expiratory volume in 1 second after fewer than 80 breath units, the distribution of methacholine responsiveness did not differ at 6 months and 1 year ; 155 of 178 volunteers (90.4%) responded during the repeated challenges to doses within one dilution on their results at entry.
One hundred forty-one subjects were consistently unreactive during the year, and 17 were consistently reactive.
Approximately equal numbers gained and lost reactivity.
Those with consistently positive responses to methacholine were more likely to have skin test reactivity and chest symptoms.
The presence of consistent chest symptoms was loosely associated with consistent methacholine responsiveness ; 55% of those with consistent hyperresponsive airways had symptoms, and 24% of those who consistently had symptoms had hyperresponsive airways.
We concluded that the methacholine response is relatively stable during the course of a year in laboratory animal workers who remain at their jobs and that the presence of a positive skin test response to laboratory animals or of chest symptoms does not change the pattern of stable responsiveness.
Mots-clés Pascal : Asthme, Médecine travail, Animal laboratoire, Allergène, Hyperréactivité, Bronche, Méthacholine chlorure, Etude longitudinale, Exploration, Homme, Epreuve pharmacologique, Appareil respiratoire pathologie, Bronchopneumopathie obstructive, Immunopathologie
Mots-clés Pascal anglais : Asthma, Occupational medicine, Laboratory animal, Allergen, Hyperreactivity, Bronchus, Follow up study, Exploration, Human, Pharmacologic test, Respiratory disease, Obstructive pulmonary disease, Immunopathology
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 95-0281109
Code Inist : 002B06C02. Création : 01/03/1996.