title: A workers' compensation claim population for occupational asthma. Comparison of subgroups.
abstract: 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.
  
  
  METHODS
  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.
authors.affiliation: Gage Research Institute, Department of Medicine, University of Toronto, Ontario, Canada.
authors.forename: S M
authors.initials: SM
authors.lastname: Tarlo
authors.forename: G
authors.initials: G
authors.lastname: Liss
authors.forename: P
authors.initials: P
authors.lastname: Corey
authors.forename: I
authors.initials: I
authors.lastname: Broder
mesh_terms: D000328:Adult; D001249:Asthma / Q000191:economics* / Q000209:etiology / Q000503:physiopathology; D005260:Female; D006801:Humans; D007509:Irritants; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000191:economics* / Q000209:etiology / Q000503:physiopathology; D009864:Ontario; D011379:Prognosis; D012189:Retrospective Studies; D014942:Workers' Compensation / Q000706:statistics & numerical data*
chemical_list: D007509:Irritants