A workers' compensation claim population for occupational asthma. Comparison of subgroups

Chest. 1995 Mar;107(3):634-41. doi: 10.1378/chest.107.3.634.


Study objective: (1) To compare patients with claims submitted to the Ontario Workers' Compensation Board (WCB) for occupational asthma, in relation to the WCB decisions reached of occupational asthma (OA); aggravation of asthma from irritant exposures (AA); unrelated asthma; no asthma; and (2) to assess determinants of outcome of WCB accepted claims at permanent disability assessments.

Design: A retrospective review of 609 claims submitted to the WCB 1984 to 1988.

Results: The WCB decision reached was OA in 39% of claims, mostly attributed to isocyanates (57% of these). A further 39% were accepted for AA. Exposure to a known sensitizer occurred in 91% with OA and to an irritant in 67% with AA. Forty percent with AA were attributed to a spill or accidental exposure and 68% had preceding asthma. Those with AA were more likely to have clearing of symptoms by the time of their main assessment (43% vs 20% with OA) and were more likely to have remained in the same work (35% vs 20% with OA). Of 200 OA accepted claims reviewed at a mean of 1.9 years later, clearing of asthma occurred in 19% and milder asthma in 47%. Outcome was best with early diagnosis (p < 0.05), and milder impairment of pulmonary function at initial assessment (p < 0.05).

Conclusions: Patients with asthma induced by a workplace sensitizer demonstrate some differences from those related to workplace irritants. Accurate categorization and early removal of those with OA offers the best prognosis.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Asthma / economics*
  • Asthma / etiology
  • Asthma / physiopathology
  • Female
  • Humans
  • Irritants
  • Male
  • Middle Aged
  • Occupational Diseases / economics*
  • Occupational Diseases / etiology
  • Occupational Diseases / physiopathology
  • Ontario
  • Prognosis
  • Retrospective Studies
  • Workers' Compensation / statistics & numerical data*


  • Irritants