Surveillance of mesothelioma and workers' compensation in British Columbia, Canada

Our plain-English summary of Surveillance of mesothelioma and workers' compensation in British Columbia, Canada, by T.L. Kirkham, M.W. Koehoorn, C.B. McLeod, et al (Occupational and Environmental Medicine, 2011).

The study

• Authors: T.L. Kirkham, M.W. Koehoorn, C.B. McLeod, P.A. Demers
• Journal: Occupational and Environmental Medicine
• Published: 2011;68(1):30-5
• Cited by: 20 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objectives: To determine the rate of workers' compensation for mesothelioma cases in the Canadian province of British Columbia, examine trends in mesothelioma cases and compensation over time, and identify factors associated with compensation status for mesothelioma cases.

Methods: Mesothelioma cases in the provincial cancer registry were linked at the individual level with accepted claims for mesothelioma in the provincial workers' compensation system for the period 1970-2005.

Results: 391 of the 485 workers' compensated claims were linked (81% match rate) with a record in the cancer registry for an overall mesothelioma compensation rate of 33% over the study period and a high of 49% in the last 5 years. Compensation rates were lower for women, older (retired) as well as younger workers, and sites other than the pleura.

Conclusions: Although the workers' compensation rate for mesothelioma increased over time, the rate was much lower than anticipated for cases believed to be work-related cancers. Several key factors may significantly influence awareness by clinicians and workers of the work-relatedness of mesothelioma and of workers' compensation benefits. Regulatory agencies need to develop policies or effective notification systems to ensure that all newly diagnosed mesothelioma cases seek compensation benefits.

In plain English

This study linked, person by person, accepted mesothelioma compensation claims in British Columbia, Canada, with histology-confirmed cases in the provincial cancer registry, 1970 to 2005. The registry held 1182 cases. Of 485 accepted claims, 391 were matched to a registry record, so 391 of 1182 registry cases were compensated, an overall rate of 33%. Case numbers and the compensation rate rose over time; the rate peaked at 49% in 1999 and 2004. Compensation rates were 37.9% for men, 6.6% for women, 36.6% for pleural mesothelioma and 12.6% for other sites. In an adjusted analysis of 1053 cases, women had higher odds than men of not being compensated (odds ratio 8.06, 95% confidence interval 4.23 to 15.37). The odds ratio was 4.07 (2.74 to 6.05) for ages 75 and older versus 55 to 64, and 5.45 (2.26 to 13.17) for peritoneal versus pleural cases. Rates varied by region, from 76.5% to 25.8%. The authors concluded that mesothelioma was compensated at much lower levels than anticipated for work-related cases. They noted that some cases may have been compensated in other provinces.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Population-based surveillance study using individual-level record linkage of a provincial cancer registry with workers' compensation claims, with logistic regression of factors associated with not being compensated
• Who was studied: 1182 mesothelioma cases in the BC Cancer Agency registry and 485 accepted mesothelioma claims from WorkSafeBC, British Columbia, Canada, 1970 to 2005. The adjusted model included 1053 cases.
• Exposure: Asbestos exposure was not measured. The study compared compensation status (accepted workers' compensation claim or not) by sex, age at diagnosis, cancer site, year of diagnosis and geographical location.
• Main results:
  • Of 485 accepted compensation claims, 391 were matched to a cancer registry record (81% match rate). The 391 compensated cases out of 1182 registry cases gave an overall compensation rate of 33% for 1970 to 2005.
  • Mesothelioma case numbers rose over time, with the highest number (77) diagnosed in 2001, then appeared to plateau. The compensation rate also rose, peaking at 49% in 1999 and in 2004.
  • Compensation rate by sex: 37.9% for males (379 of 1000) and 6.6% for females (12 of 182). In the adjusted model, women had an OR of 8.06 (95% CI 4.23 to 15.37) for not having a compensation claim, compared with men.
  • Compared with those aged 55 to 64 at diagnosis, adjusted ORs for not being compensated were: 4.07 (95% CI 2.74 to 6.05) for age 75 and older; 1.91 (1.32 to 2.76) for 65 to 74; 1.75 (1.05 to 2.92) for 45 to 54; and 2.2 (0.93 to 5.17, not statistically significant) for under 45. The unadjusted compensation rate was 45.5% for ages 55 to 64 and 29.2% for other ages.
  • Compensation rate by cancer site: 36.6% for pleural mesothelioma and 12.6% for other sites. Compared with pleural cases, adjusted ORs for not being compensated were 5.45 (95% CI 2.26 to 13.17) for peritoneal, 5.50 (2.19 to 13.79) for other sites, and 2.26 (0.94 to 5.41) for cases coded to the lung. The lung result was not statistically significant, and the authors said lung-coded cases are likely coding errors.
  • Unadjusted analyses showed higher odds of non-compensation for cases diagnosed in the 1970s (OR 3.56) and 1980s (OR 1.46) than for those diagnosed in the 1990s and later. This effect was not seen in the adjusted model. In the adjusted model, cases diagnosed in 2000 to 2005 had an OR of 0.60 (0.44 to 0.83) compared with the 1990s.
  • Compensation rates ranged from 76.5% to 25.8% across health regions, with densely populated urban areas tending to have lower rates. Kootenay Boundary had an adjusted OR of 0.09 (0.03 to 0.31) for non-compensation, compared with Okanagan.
  • Among compensated cases, 77.2% had been employed in manufacturing, construction and service sectors.
• The authors' conclusion: The authors concluded that mesothelioma was compensated at much lower levels than anticipated for work-related cases. They found that women, younger and older people, those with sites other than the pleura, and those diagnosed in more urban areas were less likely to be compensated or to seek compensation.
• Limitations the authors state:
  • The study had no data on other factors that may influence whether a worker files a claim, such as social or economic status, awareness of the disease, and occupation or industry for non-compensated cases.
  • Possible misclassification: some non-compensated registry cases may have been compensated in another province, and the authors had no access to other provinces' claims.
  • 94 of the 485 claims could not be matched to the registry. Had all been matched, the compensation rate would have been 41%.
  • 129 cases were missing geographical location, reducing the regression sample to 1053. Some of the 16 geographical categories had few cases, which likely widened confidence intervals.
  • The authors assumed that non-compensated cases had not applied rather than been rejected. This assumption was based on a personal communication and still needed to be confirmed.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Mesothelioma, Cancer Registry, Pleura.

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