Workshop on the health risks associated with chrysotile asbestos: a brief review

Our plain-English summary of Workshop on the health risks associated with chrysotile asbestos: a brief review, by M. Lippmann (The Annals of Occupational Hygiene, 1994).

The study

• Author: M. Lippmann
• Journal: The Annals of Occupational Hygiene
• Published: 1994;38(4):639-42
• Type of article: Letter
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This was a letter to the editor in which the author briefly reviewed a workshop on the health risks of chrysotile asbestos, held on the island of Jersey on 14-17 November 1993. It did not present an original study. It described papers presented by others. According to those papers, the exposure-response slope was still much steeper for South Carolina textile workers than for friction-products workers, asbestos-cement workers, and Quebec chrysotile miners and millers. Lung-tissue studies of the Quebec workers found that appreciable chrysotile was retained long-term only after very heavy, long-term exposure. They also found that the ratio of retained tremolite to chrysotile rose with longer exposure. A paper by Churg reported that tremolite content in lung tissue was closely associated with mesothelioma, while chrysotile content was not. Drawing on this and other associations, the author concluded that chrysotile exposure itself had little, if any, role in causing mesothelioma. The author also concluded that most of the 32 or 33 mesotheliomas in a cohort of more than 11 000 Quebec asbestos workers were caused, at least in part, by tremolite. The author proposed air-sampling methods and noted that many research questions remained unresolved.

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 giving a brief review of papers presented by others at a workshop, including new analyses presented there; not an original study of its own
• Who was studied: Papers presented at the Workshop on the Health Risks Associated with Chrysotile Asbestos, held on the island of Jersey, 14-17 November 1993. The papers covered occupational cohorts (South Carolina textile workers, friction-products workers, asbestos-cement workers, Quebec chrysotile miners and millers) and rat inhalation studies.
• Exposure: Chrysotile asbestos, with discussion of tremolite in Quebec chrysotile workers and of amosite and chrysotile in rat inhalation studies
• Main results:
  • Papers presented at the workshop showed a much steeper exposure-response slope for South Carolina textile workers (Dement and Brown) than for friction-products workers (Berry), asbestos-cement workers (Weill) and Quebec chrysotile miners and millers (Liddell)
  • Lung-tissue studies of Quebec miners and millers (Case; Churg) found long-term retention of appreciable chrysotile only in workers with very heavy, long-term exposures. The chrysotile occurred as concentrated clusters of fibres. The ratio of retained tremolite to chrysotile increased with longer exposure.
  • Pott re-plotted rat inhalation results from Davis for short and long amosite and short and long chrysotile fibres, as percentage of animals developing cancer against the number concentration of fibres longer than 5 micrometres. The four points fitted a nearly flat curve described as a one-hit carcinogenesis model.
  • Churg reported that in Quebec asbestos miners and millers, tremolite content in lung tissue was closely associated with mesothelioma, whereas chrysotile content was not
  • 32 or 33 mesotheliomas were known to have occurred in a cohort of more than 11 000 Quebec asbestos workers
• The authors' conclusion: The author concluded that chrysotile exposure itself, even at the very high exposures of Quebec miners and millers, had little, if any, role in causing mesothelioma. The author also concluded that most of the mesotheliomas in the Quebec cohort were caused, at least in part, by the small fraction of tremolite fibres at their worksites. The author proposed air-sampling and TEM analysis methods focused on long and biopersistent fibres for future research.
• Limitations the authors state:
  • The author stated that the one-hit model fit rested on four data points and would need to be shown to fit other inhalation bioassays from the same laboratory before it could support broader conclusions
  • The author stated that many research questions remained unresolved, including which fibre lengths and diameters determine translocation pathways, retention times and biological responses within cells

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis, Chrysotile, Lung cancer, Mesothelioma.

Medical terms in this study, explained in our Lexicon: Chrysotile.

Related studies

• Editor's preface to the report of the workshop on health risks associated with chrysotile asbestos — J.M. Ellison (1994)
• Human evidence: lung cancer mortality risk from chrysotile exposure — J.M. Hughes (1994)
• Health risk of chrysotile revisited — D. Bernstein, J. Dunnigan, et al. (2013)
• Deposition and clearance of chrysotile asbestos — A. Churg (1994)
• Letter to the Editor re Bernstein et al: Health risk of chrysotile revisited. Crit Rev Toxicol, 2013; 43(2): 154-183 — M.M. Finkelstein (2013)
• Response to Murray M. Finkelstein, letter to the editor re Bernstein et al: Health risk of chrysotile revisited. Crit Rev Toxicol, 2013; 43(2): 154-183 — D. Bernstein, J. Dunnigan, et al. (2013)

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