Unreliable proposed 'new standard' for assessing asbestos exposure

Our plain-English summary of Unreliable proposed 'new standard' for assessing asbestos exposure, by D. Egilman, X. Baur, C.L. Soskolne (Occupational and Environmental Medicine, 2016).

The study

• Authors: D. Egilman, X. Baur, C.L. Soskolne
• Journal: Occupational and Environmental Medicine
• Published: 2016;73(10):709
• Type of article: Letter, Comment
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This is a letter to the editor, not a research study, and it reports no new data. Its authors criticised a published UK study by Gilham and colleagues. As the letter describes it, that study concluded that there is a linear dose–response relationship between asbestos lung burden and mesothelioma, and that lung burden could predict future mesothelioma rates in people born since 1965. The letter's authors argued that the study relied only on fibre counts in lung tissue measured decades after exposure. They noted that only 2% of the fibres found were chrysotile, while chrysotile made up as much as 90% of the asbestos used in the UK, and that chrysotile does not persist in the lung. They objected that only fibres longer than 5 micrometres were counted, which they said leaves out most chrysotile in lung tissue. They also questioned the laboratory methods, including that no positive or negative controls were reported. Citing a Collegium Ramazzini review, they argued that a careful occupational history is a better indicator of lung cancer risk from chrysotile than lung fibre burden analysis. The authors concluded that the study rested on incorrect assumptions that produced an invalid analysis and invalid conclusions.

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 study; no new data
• Who was studied: No people were studied by the letter's authors; the letter discusses the UK lung-burden study by Gilham and colleagues of pleural mesothelioma and lung cancer
• Exposure: Asbestos lung burden (fibre counts in lung tissue) as a measure of exposure, with particular attention to chrysotile
• Main results:
  • The letter's authors pointed out that in the Gilham study only 2% of fibres identified in lung tissue were chrysotile, while chrysotile made up as much as 90% of the asbestos used in the UK
  • The letter's authors stated that chrysotile does not persist in the lung, and cited a 1978 paper by Peto saying chrysotile is quickly eliminated from the lung but remains in the pleura
  • The letter's authors argued that counting only fibres longer than 5 micrometres leaves out most chrysotile in lung tissue, and that literature has found short chrysotile fibres predominate in the pleura
  • The letter's authors said the study implies chrysotile does not cause mesothelioma, an inference they called based on the false premise that lung fibre counts stand in for exposure and risk
  • Citing a Collegium Ramazzini review, the letter's authors argued that a careful occupational history is a more sensitive and specific indicator of lung cancer risk from chrysotile than lung fibre burden analysis
  • The letter's authors criticised the laboratory methods: specimens were dried in a vacuum desiccator before ashing, which may break fibres, no positive or negative controls were reported, and results vary greatly between laboratories
• The authors' conclusion: The authors concluded that the Gilham paper and its accompanying commentary rest on incorrect assumptions that produce an invalid analysis and invalid conclusions

Topics

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

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