Response to: 'Pleural mesothelioma and occupational and non-occupational asbestos exposure: a case-control study with quantitative risk assessment' by Ferrante et al

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 Ferrante et al, by G.M. Marsh, S.M. Benson (Occupational and Environmental Medicine, 2017).

The study

• Authors: G.M. Marsh, S.M. Benson
• Journal: Occupational and Environmental Medicine
• Published: 2017;74(2):156-157
• Type of article: Letter, Comment
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Summary of the article

In this letter, the authors responded to a 2016 case-control study by Ferrante et al of occupational and non-occupational asbestos exposure and pleural malignant mesothelioma (PMM) risk among workers and residents of Casale Monferrato, Italy, site of a former asbestos cement factory. They noted that a letter by Boffetta had raised methodological concerns, including limited exposure-estimation detail, lack of reproducibility, inconsistent findings and possible biases, which Ferrante et al's reply had not fully resolved. The authors' own critical evaluation supported these concerns and found a further problem: inconsistency with other studies of non-occupational exposure. In a meta-analysis by Bourdes et al (eight studies, 13 risk estimates), only two estimates were of the same order of magnitude as Ferrante et al's, and the rest were below 10. In Hansen et al's study of crocidolite exposure among residents of Wittenoom, Australia, the highest exposure group (20 to 40.4 f/mL years) had PMM risk estimates of 3.6 or 6.3. Ferrante et al's highest environmental group had about half that exposure (10 to 24 f/mL years) but risks 2.3-fold to fourfold higher. The authors also stated that Ferrante et al's risk patterns conflicted with the established view that PMM risks are greater for amphibole fibres. They concluded that this cast further doubt on the validity and usefulness of Ferrante et al's results. One author declared acting as an expert witness for defence attorneys in criminal trials on asbestos-related cancers.

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

In this letter to the editor, which reported no new data, the authors commented on a 2016 case-control study by Ferrante et al of pleural malignant mesothelioma among workers and residents of the Casale Monferrato area of Italy, the site of a former asbestos cement factory. They wrote that their critical evaluation of that paper backed up problems already raised in a letter by Boffetta. It also found another problem: the results did not agree with other studies of non-occupational asbestos exposure. They cited a meta-analysis by Bourdes et al. In it, risk estimates for neighbourhood and household exposure ranged from 6.7 to 8.2 for mixed fibres and from 8.7 to 21 for amphiboles. They also cited a study by Hansen et al of crocidolite exposure among residents of Wittenoom, Australia, which gave risk estimates of 3.6 or 6.3 in the highest exposure group. According to the authors, Ferrante et al's highest environmental exposure group had about half the exposure of Hansen et al's, yet reported risks 2.3-fold to fourfold higher. The authors concluded that this casts further doubt on the validity and usefulness of the Ferrante et al results.

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: a critical commentary on a published case-control study. No new data were collected.
• Who was studied: No population was studied directly. The letter critiques Ferrante et al's 2016 study of pleural malignant mesothelioma among workers and residents of the Casale Monferrato area of Italy, the site of a former asbestos cement factory. It compares that study with other published studies.
• Exposure: Occupational and non-occupational (environmental, household and neighbourhood) asbestos exposure. According to the letter, the highest environmental exposure group in Ferrante et al had mixed fibre exposures between 10 and 24 f/mL years.
• Main results:
  • The authors said their evaluation backed up the issues Boffetta had raised. They also identified a further problem: Ferrante et al's results did not agree with other studies of non-occupational asbestos exposure.
  • The authors wrote that Ferrante et al did not reconcile their finding of higher pleural mesothelioma risks for environmental than for occupational exposure.
  • The Bourdes et al meta-analysis (a study by other authors) covered eight studies with 13 risk estimates. According to the letter, only two of those estimates were of the same order of magnitude as Ferrante et al's.
  • In the Bourdes et al meta-analysis, pleural mesothelioma risk estimates ranged from 6.7 for neighbourhood to 8.2 for household mixed fibre exposure, and from 8.7 for neighbourhood to 21 for household amphibole exposure.
  • In Hansen et al (a study by other authors) of environmental crocidolite exposure among Wittenoom, Australia residents, the highest exposure group had cumulative exposures of 20 to 40.4 f/mL years. Its pleural mesothelioma risk estimates were 3.6 or 6.3, depending on censoring.
  • The authors stated that Ferrante et al's highest environmental exposures were about half those in Hansen et al. Yet the risks Ferrante et al reported for environmental exposure were 2.3-fold to fourfold higher.
  • The authors wrote that Ferrante et al's risk patterns conflict with the established view that pleural mesothelioma risks are greater for amphibole fibres.
• The authors' conclusion: The authors concluded that the lack of agreement with other studies of non-occupational asbestos exposure casts further doubt on the validity and usefulness of Ferrante et al's results and conclusions.

Topics

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Asbestos Exposure, Case-Control Study, Malignant Mesothelioma, Casale Monferrato, Asbestos-Cement, Non-Occupational Exposure, Meta-Analysis.

Related studies

• Response to: Pleural mesothelioma, and occupational and non-occupational asbestos exposure: a case-control study with quantitative risk assessment — P. Boffetta (2016)
• 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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