Choice of rating method for assessing occupational asbestos exposure: study for compensation purposes in France

Our plain-English summary of Choice of rating method for assessing occupational asbestos exposure: study for compensation purposes in France, by C. Gramond, P. Rolland, A. Lacourt, et al (American Journal of Industrial Medicine, 2012).

The study

• Authors: C. Gramond, P. Rolland, A. Lacourt, S. Ducamp, S. Chamming's, Y. Creau, M. Hery, J. Laureillard, B. Mohammed-Brahim, E. Orlowski, C. Paris, J.C. Pairon, M. Goldberg, P. Brochard, PNSM Study Group
• Journal: American Journal of Industrial Medicine
• Published: 2012;55(5):440-9
• Cited by: 9 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: In the course of setting up the National Mesothelioma Surveillance Program (PNSM), established in France in 1998, the question arose as to the most suitable method of assessing occupational exposure. The aim of this study was to define the most suitable rating method for assessing occupational asbestos exposure in order to assess medico-social care.

Method: The study included 100 subjects-50 cases of mesothelioma and 50 controls-randomly selected and representing 457 jobs held. Job asbestos exposure was assessed by a six-expert panel using two methods: "by job" rating, where all the jobs in were assessed regardless of the subjects; and "by subject" rating, where all the jobs of a subject were assessed at the same time. Consensus was obtained and subjects' exposure was calculated for each rating. Then, two internal experts assessed job asbestos exposure with the "by subject" rating. Kappa coefficients were used to measure agreement between the ratings.

Results: Agreement between "by job" and "by subject" ratings was very good for subject probability of exposure (kappa = 0.84) and cumulative exposure index (kappa = 0.80). Agreement between the six-expert panel and the two internal experts was good for subject exposure (kappa for probability = 0.71; kappa for cumulative exposure index= 0.68).

Conclusion: This study shows that the two rating systems have good or very good agreement. These results validate the routine use in the PNSM of the "by subject" rating, with the advantage of being convenient and quick to provide feedback on occupational asbestos exposure to mesothelioma cases for compensation.

Copyright © 2012 Wiley Periodicals, Inc.

In plain English

For France's National Mesothelioma Surveillance Program (PNSM), which informs compensation, the authors compared two expert methods of rating occupational asbestos exposure, using 50 mesothelioma cases and 50 controls (457 jobs) randomly drawn from a case-control study. A six-expert panel, blinded to case status, rated 'by job' (the reference, grouping the same job across subjects) and 'by subject' (each person's whole work history). Agreement between the methods, as weighted kappa, was 0.84 (95% CI 0.78 to 0.91) for subjects' highest probability of exposure and 0.80 (95% CI 0.72 to 0.88) for a cumulative exposure index. Unweighted kappas were 0.69 (95% CI 0.58 to 0.79) and 0.62 (95% CI 0.51 to 0.74). Two in-house experts rating by subject agreed with the panel on these measures at weighted kappa 0.71 (95% CI 0.61 to 0.81) and 0.68 (95% CI 0.59 to 0.77). The authors concluded the methods agreed well and adopted two-expert 'by subject' rating for routine PNSM use. They noted possible bias from rating each job alongside a person's others and possible recall bias from the one-month gap between ratings.

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: Methods-comparison (agreement) study of expert exposure-assessment methods, using questionnaires from a case-control study within the French National Mesothelioma Surveillance Program
• Who was studied: 100 subjects (50 mesothelioma cases and 50 controls) randomly drawn from the 371 cases and 732 controls of the PNSM case-control study in France. Together they had held 457 jobs (248 jobs of cases, 209 jobs of controls). 80% were men and the average age was 70 years.
• Exposure: Occupational asbestos exposure in each job, as rated by experts from detailed job-history questionnaires. Ratings covered probability, main type (direct, indirect, passive), frequency and average intensity (low to very high, in f/ml). From these a cumulative exposure index per subject was calculated. No fiber types are specified. Other agents were also assessed, but only asbestos results are reported.
• Main results:
  • Six-expert panel, 'by subject' versus 'by job' rating, probability of exposure for the 457 jobs: agreement was good. Unweighted kappa was 0.63 (95% CI 0.57 to 0.68 in Table VI). Weighted kappa was 0.79 (95% CI 0.75 to 0.83).
  • For jobs, sensitivity of 'by subject' rating against 'by job' rating was 82.3% and specificity was 97.6%. 36 jobs (7.9%) rated as exposed by job, including six 'definite', were rated not exposed by subject.
  • Six-expert panel, for the 100 subjects: highest probability of exposure had unweighted kappa 0.69 (95% CI 0.58 to 0.79) and weighted kappa 0.84 (95% CI 0.78 to 0.91). The cumulative exposure index had unweighted kappa 0.62 (95% CI 0.51 to 0.74) and weighted kappa 0.80 (95% CI 0.72 to 0.88).
  • For subjects, sensitivity of 'by subject' rating against 'by job' rating was 91.0% and specificity was 93.9%.
  • The two ratings gave the same cumulative exposure index category for 71% of subjects.
  • Each of the six experts, rating jobs both ways: intra-expert agreement ranged from 0.69 to 0.76 for probability of job exposure, from 0.74 to 0.81 for subject probability, and from 0.55 to 0.76 for the cumulative exposure index.
  • Two internal experts versus the six-expert panel, both using 'by subject' rating, for jobs: unweighted kappa 0.61 (95% CI 0.55 to 0.68), weighted kappa 0.72 (95% CI 0.67 to 0.77). Sensitivity was 86.2% and specificity 85.5%.
  • Two internal experts versus the panel, for subjects: highest probability had unweighted kappa 0.58 and weighted kappa 0.71 (95% CI 0.61 to 0.81). The cumulative exposure index had weighted kappa 0.68 (95% CI 0.59 to 0.77), but its unweighted kappa was only fair at 0.37 (95% CI 0.25 to 0.48). Sensitivity was 87.3% and specificity 86.5%.
• The authors' conclusion: The authors concluded that 'by subject' rating agreed well or very well with 'by job' rating. They decided to use 'by subject' rating by two internal experts routinely in the PNSM, as a practical method for quick feedback on exposure for compensation.
• Limitations the authors state:
  • In 'by subject' rating, the rating of one job could be influenced by the ratings of the same person's other jobs. Because cases may search harder for possible exposures than controls, this could cause differential misclassification.
  • The two ratings were only one month apart, so recall bias cannot be excluded.
  • 'By subject' rating is difficult for experts to apply, because they move from one job to another.

Topics

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

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Mesothelioma, Occupational Exposure, Cumulative Exposure.

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