Response to: Pleural mesothelioma, and occupational and non-occupational asbestos exposure: a case-control study with quantitative risk assessment

Our plain-English summary of Response to: Pleural mesothelioma, and occupational and non-occupational asbestos exposure: a case-control study with quantitative risk assessment, by P. Boffetta (Occupational and Environmental Medicine, 2016).

The study

• Author: P. Boffetta
• Journal: Occupational and Environmental Medicine
• Published: 2016;73(10):712
• Type of article: Letter, Comment
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Summary of the article

In this letter, the author responded to a case-control study by Ferrante et al of pleural mesothelioma in Casale Monferrato. That study had reported associations with occupational and non-occupational (household and residential) asbestos exposure and focused on quantitative risk estimates. The author stated that the qualitative findings matched those reported in other heavily exposed populations, but argued that important limitations restricted interpretation of the quantitative results. He noted response rates of 89% among cases and 63% among controls, and proxy interviews for 46% of cases and 93% of controls. He described these differences as potential sources of selection and information bias, with reporting bias of particular concern given local knowledge of asbestos hazards. He cited findings he considered anomalous. Odds ratios for environmental exposure appeared higher than those for occupational exposure at the same exposure levels, notably in the highest category, despite lower average exposure (15 vs 260 fb/mL years). Odds ratios also increased as the specificity of exposure assessment decreased. He further stated that exposure assessment methods were insufficiently described, and that retrospective estimates based on scanty environmental data may overestimate the dose-response slope. He also argued that the focus on cumulative exposure obscured the role of time since first exposure. He concluded that the study failed to provide a reliable quantitative estimate of the association. The author declared having acted as an expert witness in asbestos-related litigation.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.

In plain English

This is a letter to the editor, not a new study. The author commented on a case-control study of pleural mesothelioma in Casale Monferrato by Ferrante and colleagues, which reported associations with occupational and non-occupational (household and residential) asbestos exposure. The author called these associations hardly surprising but criticized the study's quantitative risk estimates. The author pointed to response rates of 89% among cases and 63% among controls, and proxy interviews for 46% of cases and 93% of controls, as possible sources of selection and information bias. The author raised reporting bias as a concern given local knowledge of asbestos's cancer effects. The author also noted that odds ratios for environmental exposure appeared higher than those for occupational exposure at the same exposure levels, and that odds ratios rose as exposure assessment became less specific. The author argued both patterns pointed to bias. The author concluded that the study fails to provide a reliable quantitative estimate. The author disclosed having acted as an expert witness in asbestos-related litigation.

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: letter to the editor commenting on a published case-control study; it presents no new data
• Who was studied: The letter discusses Ferrante et al's case-control study of pleural mesothelioma in Casale Monferrato (Italy). The letter does not give the study's numbers of cases or controls.
• Exposure: Occupational and non-occupational (household and residential) asbestos exposure, as studied by Ferrante et al
• Main results:
  • The author wrote that, qualitatively, the associations Ferrante et al reported were not surprising, because similar findings had been reported in other heavily exposed populations.
  • The author noted that the response rate in the Ferrante study was 89% among cases and 63% among controls.
  • The author noted that interviews were done with proxies for 46% of cases and 93% of controls. The author argued that these differences were potential sources of selection and information bias.
  • The author raised reporting bias, from participants and proxies, as a particular concern because the local community widely knew that asbestos causes cancer.
  • The author pointed out that, in Ferrante et al's supplementary table 2, odds ratios for environmental exposure appeared higher than those for occupational exposure at the same exposure levels. This was especially so in the highest category, even though average exposure there was lower (15 versus 260 fb/mL years).
  • The author pointed out that, in Ferrante et al's supplementary table 1, odds ratios increased as the specificity of the asbestos exposure assessment decreased. The author argued this goes against expectations and supports a role for bias.
  • The author criticized the limited detail Ferrante et al gave on the instruments used for exposure assessment.
  • The author raised two further criticisms, described as relatively minor. First, the study focused on cumulative exposure rather than time since first exposure. Second, controls' exposure histories did not appear to be cut off at the date of diagnosis of the corresponding cases.
  • Disclosure: the author stated having acted as an expert witness in asbestos-related litigation.
• The authors' conclusion: The author concluded that the Ferrante et al study fails to provide a reliable estimate of the quantitative association between asbestos exposure and mesothelioma risk.

Topics

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Asbestos Exposure, Case-Control Study, Casale Monferrato, Recall Bias, Odds Ratio, Environmental Exposure, Occupational Exposure.

Related studies

• Response to: 'Pleural mesothelioma and occupational and non-occupational asbestos exposure: a case-control study with quantitative risk assessment' by Ferrante et al — G.M. Marsh, S.M. Benson (2017)
• Authors's response: Pleural mesothelioma and occupational and non-occupational asbestos exposure: a case-control study with quantitative risk assessment — D. Ferrante, D. Mirabelli, et al. (2016)
• Pleural mesothelioma and asbestos exposure: a case-control study with quantitative risk assessment-response to Marsh and Benson's letter — D. Ferrante, D. Mirabelli, et al. (2017)
• Pleural mesothelioma and occupational and non-occupational asbestos exposure: a case-control study with quantitative risk assessment — D. Ferrante, D. Mirabelli, et al. (2016)
• Occupational risk factors for mortality from stomach and lung cancer among rubber workers: an analysis using internal controls and refined exposure assessment — K. Straif, L. Chambless, et al. (1999)
• A trial on the quantitative risk assessment of man-made mineral fibers by the rat intraperitoneal administration assay using the JFM standard fibrous samples — S. Adachi, K. Kawamura, et al. (2001)

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