Comments on a recent case-control study of malignant mesothelioma of the pericardium and the tunica vaginalis testis

Our plain-English summary of Comments on a recent case-control study of malignant mesothelioma of the pericardium and the tunica vaginalis testis, by G. Mezei, E.T. Chang, F.S. Mowat, et al (Scandinavian Journal of Work, Environment & Health, 2021).

The study

• Authors: G. Mezei, E.T. Chang, F.S. Mowat, S.H. Moolgavkar
• Journal: Scandinavian Journal of Work, Environment & Health
• Published: 2021;47(1):85-86
• Type of article: Letter, Comment
• Cited by: 10 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Summary of the article

In this letter, the authors commented on the 2020 case-control study by Marinaccio et al of malignant mesothelioma of the pericardium and the tunica vaginalis testis (mTVT) in Italy, arguing that it had several methodological problems. Comparing the published tables, they reported that the distributions of male cases (pericardial or mTVT) and controls by period of birth were clearly different (P<0.001). These differences remained in a sensitivity analysis restricted to subjects born before 1950, so in their view cases and controls were not matched on birth cohort. Cases came from across Italy, but controls came from only six regions, and the regional distribution of controls differed from that of person-time observed. On exposure ascertainment, they noted that case information was presumably obtained at registration (1993–2015), whereas the two control sets were interviewed in 2014–2015 and 2014–2016, and one set had participation below 50%. They asked for results for each control set separately, for separate analyses of definite occupational exposure, for clearer exposure classification, and for details on the 12 of 80 registered mTVT cases that were not analysed. They also questioned treating agriculture as an asbestos-exposed sector. They concluded that the reported association of occupational exposure with mTVT and male pericardial mesothelioma might be spurious, resulting from control-selection bias and deficient exposure assessment. All authors stated they were Exponent, Inc. employees who had worked as consulting and testifying experts in asbestos 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 letter to the editor collected no new data; its authors made their own statistical comparisons using another study's published tables. The four authors critiqued a 2020 Italian case-control study by Marinaccio and colleagues of asbestos exposure and mesothelioma of the pericardium and of the tunica vaginalis testis. From that study's tables, they reported that male cases and controls differed clearly by period of birth (P less than 0.001). For women with pericardial mesothelioma, cases and controls were less dissimilar (P about 0.05). They concluded that cases and controls were not matched on birth cohort, possibly biasing the results. Cases came from across Italy but controls from only six regions. Controls were interviewed in 2014 to 2015 and 2014 to 2016, many years after exposure was ascertained for most cases (1993 to 2015). One control group had under 50% participation. Exposure classification methods were not detailed, and 12 of 80 registered tunica vaginalis cases were excluded from analyses. The authors concluded this raised the possibility of a spurious association of occupational exposure with tunica vaginalis testis and male pericardial mesothelioma. All four authors disclosed working as testifying experts in asbestos 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 the methods of another published case-control study (Marinaccio et al, 2020); no new data collected, but the letter's authors made their own statistical comparisons of that study's published tables
• Who was studied: No population of its own. The letter discusses the Marinaccio et al case-control study, which used cases of pericardial mesothelioma and mesothelioma of the tunica vaginalis testis registered across Italy, with controls drawn from six regions
• Exposure: Asbestos exposure as classified in the Marinaccio et al study (occupational exposure, including categories described as probable or possible); the letter questions how it was ascertained
• Main results:
  • From the Marinaccio et al tables, the letter's authors reported that among males, mesothelioma cases (pericardial or tunica vaginalis testis) and controls had clearly different distributions by period of birth (P less than 0.001)
  • Among females, cases of pericardial mesothelioma and controls were less dissimilar by birth year (P about 0.05)
  • The letter's authors concluded that cases and controls were not matched on birth cohort, possibly biasing the results
  • The regional distribution of controls differed from that of person-time observed, so controls did not appear representative of the population at risk by region
  • Case exposure information was presumably obtained at registration; the two sets of controls were interviewed in 2014 to 2015 and 2014 to 2016, many years after exposure was ascertained for most cases (1993 to 2015)
  • Participation by one set of controls was under 50%, which the letter's authors said raised concerns about selection bias
  • The letter's authors said the exposure classification methods were not detailed, including what probable or possible exposure meant
  • 80 cases of mesothelioma of the tunica vaginalis testis were registered, but only 68 were included in the analyses; the letter refers to the 12 omitted cases
  • The letter's authors noted that exposure in the agriculture sector, named in the 2020 study, was not mentioned in an earlier Marinaccio et al study
• The authors' conclusion: The authors concluded that the few cases in industries traditionally associated with high asbestos exposure raised the possibility that the Marinaccio et al results reflect deficiencies in study design, control selection and exposure assessment. In their view, these deficiencies may have produced a spurious association of occupational exposure with tunica vaginalis testis and male pericardial mesothelioma.

Topics

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

Medical terms in this study, explained in our Lexicon: Case-Control Study, Malignant Mesothelioma, Pericardium, Tunica Vaginalis, Pericardial, Occupational Exposure, Pericardial Mesothelioma, Selection Bias.

Related studies

• Authors' response: Mezei et al's "Comments on a recent case-control study of malignant mesothelioma of the pericardium and the tunica vaginalis testis" — A. Marinaccio, D. Consonni, et al. (2021)
• Epidemiology of mesothelioma of the pericardium and tunica vaginalis testis — G. Mezei, E.T. Chang, et al. (2017)
• Comments on Vimercati et al., 2019, "Asbestos exposure and malignant mesothelioma of the tunica vaginalis testis: a systematic review and the experience of the Apulia (southern Italy) mesothelioma register" — G. Mezei, E.T. Chang, et al. (2019)
• Association between asbestos exposure and pericardial and tunica vaginalis testis malignant mesothelioma: a case-control study and epidemiological remarks — A. Marinaccio, D. Consonni, et al. (2020)
• Malignant mesothelioma of the tunica vaginalis testis related to recent asbestos — Y. Ikegami, N. Kawai, et al. (2008)
• Response to the "Letter to the Editor" by Gabor Mezei et al., Comments on Vimercati et al., 2019, "Asbestos exposure and malignant mesothelioma of the tunica vaginalis testis: a systematic review and the experience of the Apulia (Southern Italy) mesothelioma register" — L. Vimercati, D. Cavone, et al. (2019)

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