Letter re Marsh et al

Our plain-English summary of Letter re Marsh et al, by M. Finkelstein (Inhalation Toxicology, 2012).

The study

• Author: M. Finkelstein
• Journal: Inhalation Toxicology
• Published: 2012;24(2):139-40; author reply 141-2
• Type of article: Letter, Comment
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

In this letter to the editor, the author criticized a 2011 paper by Marsh and colleagues. That paper analyzed lung tremolite and commercial amphibole levels in 10 mesothelioma cases among brake repair workers, using data from Butnor et al. (2003). The author has consulted for plaintiff's attorneys in asbestos litigation. Through legal discovery, a plaintiff's attorney gave the author Dr Roggli's laboratory counting sheets. The author compared them with Marsh's Table 1, which reports fibers per gram of wet lung tissue for fibers 5 microns or longer, and found discrepancies in 7 of 20 data points (35%). In Cases 2, 3 and 4 no tremolite fibers were recorded, yet tremolite figures of 440, 4110 and 1160 were reported. In Cases 1 and 6 no amosite or crocidolite fibers were recorded, yet commercial amphibole figures of 3270 and 490 were reported. In Cases 8 and 9, identical counts received different concentrations. The author added that, according to Dr Roggli, the amphibole figures may include asbestos bodies, which the paper never describes. The author suggested the paper be withdrawn, corrected, re-analyzed and resubmitted.

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 paper (Marsh et al., 2011), based on the author's comparison of laboratory counting sheets with that paper's published data table
• Who was studied: The 10 mesothelioma cases among brake mechanics described by Butnor et al. (2003), whose lung fiber data Marsh et al. analyzed. The author reviewed Dr Roggli's case files for these cases, received in January 2011 from a plaintiff's attorney through legal discovery.
• Exposure: Lung levels of tremolite and of commercial amphiboles (amosite and crocidolite) in brake repair workers, which Marsh et al. had compared using regression analyses
• Main results:
  • Comparing the laboratory counting sheets with Table 1 of Marsh et al., the author found discrepancies in 7 of the 20 (35%) data points among the Butnor cases.
  • In Cases 2, 3 and 4 no tremolite fibers were detected on the lab sheets. Marsh et al. Table 1 reported 440, 4110 and 1160 tremolite fibers per gram of wet lung tissue (fibers 5 microns or longer) for these cases.
  • In Cases 1 and 6 no amosite or crocidolite fibers were detected on the lab sheets. Marsh et al. Table 1 reported 3270 and 490 commercial amphibole fibers per gram of wet lung tissue (fibers 5 microns or longer) for these cases.
  • In Case 8, one amosite fiber and one tremolite fiber were counted, but Table 1 reported 120 and 240 fibers per gram of wet lung tissue respectively. The author stated these cannot both be correct. In Case 9, two samples were analyzed, but Marsh et al. reported results for only one. In both samples the crocidolite and tremolite counts were the same, yet Table 1 gave them different concentrations.
  • The author wrote that Dr Roggli had said the reported commercial amphibole concentrations may be the sum of fibers 5 microns or longer and asbestos bodies. The author called this an unusual procedure that is not described in the published paper.
  • Case 9 had worked as a supervisor in a commercial automotive repair shop where the brake shoes used contained crocidolite. The author wrote that the presence of both crocidolite and tremolite in this man's lungs is consistent with deposition and retention of fibers from friction products in people working in the repair environment.
• The authors' conclusion: The author concluded that, in many cases, the data Marsh and colleagues analyzed do not match the fiber counts recorded by the electron microscopist. The author suggested the paper be withdrawn, the data corrected and re-analyzed, and the paper resubmitted.
• Limitations the authors state:
  • For Case 5 the laboratory counting sheet was missing, and the author took the data from a summary sheet instead.
  • The author presented the explanation that asbestos bodies were added to the fiber counts as unconfirmed, based on what Dr Roggli had told the author.

Topics

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

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