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Occupational risk factors associated with work-exacerbated asthma in Quebec
  1. Catherine Lemiere1,
  2. Denis Bégin2,
  3. Michel Camus2,
  4. Amélie Forget1,
  5. Louis-Philippe Boulet3,
  6. Michel Gérin2
  1. 1Department of Chest Medicine, Hôpital du Sacré-Cœur de Montréal, Université de Montréal, Montréal, Québec, Canada
  2. 2Department of Environmental and Occupational Health, Université de Montréal, Montréal, Québec, Canada
  3. 3Institut Universitaire de cardiologie et de pneumologie du Québec, Université Laval, Saint Foy, Québec, Canada
  1. Correspondence to Dr Catherine Lemiere, Department of Chest Medicine, Sacré-Coeur Hospital, 5400 Gouin West, Montreal, Quebec H4J 1C5, Canada; catherine.lemiere{at}


Background There is limited information regarding the occupational exposures of subjects with a diagnosis of work-exacerbated asthma (WEA).

Objectives To: (1) identify potential specific occupational, chemical, biological and physical agents associated with incident cases of WEA and (2) compare these agents with occupational exposures of occupational asthma (OA) and non-work-related asthma (NWRA) cases.

Methods Subjects were workers with work-related asthma (WRA) or NWRA referred between 2005 and 2008 to two Quebec clinics specialised in the field of WRA. Specific inhalation challenges were performed to differentiate OA from WEA. Work exposures were assessed using a detailed occupational questionnaire. Exposures to 41 chemical and biological agents were coded in a semiquantitative way according to a combination of indices for concentration in workplace air, frequency and confidence of exposure by an occupational hygienist expert in occupational exposure coding. This expert was blind to the medical status of WEA, OA or NWRA. Five physical agents were coded on a yes/no scale.

Results 153 subjects were enrolled (53 WEA, 67 OA and 33 NWRA). WEA cases were significantly more exposed to ammonia, engine exhaust fumes, silica, mineral fibres, aerosol propellants and solvents, and significantly less exposed to animal derived dust and enzymes than were OA cases. Exposure to physical conditions did not differ between WEA and OA.

Conclusions Exposures associated with WEA differ from those associated with OA in this study. A proportion of subjects with WEA may suffer from low-dose irritant asthma, which remains a hypothesis to be tested.

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