Response to Dr. Dunnigan's commentary. The role of chrysotile in the pathogenesis of mesothelioma

Our plain-English summary of Response to Dr. Dunnigan's commentary. The role of chrysotile in the pathogenesis of mesothelioma, by J.M. Craighead (American Journal of Industrial Medicine, 1988).

The study

• Author: J.M. Craighead
• Journal: American Journal of Industrial Medicine
• Published: 1988;14(2):241-3
• Type of article: Letter
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 000207).

In plain English

This letter to the editor presents no new study and no numerical results. The author responded to Dr. Jacques Dunnigan's 1988 commentary on whether chrysotile asbestos causes mesothelioma. Mainly citing others' work, the author wrote that recent epidemiological evidence fails to establish an association between mesothelioma and commercially processed chrysotile, though a small number of cases occurred among Quebec chrysotile miners and millers. Studies elsewhere, including the author's unpublished data from China, did not show an increased prevalence among miners. The author wrote that the literature suggests, but does not prove, that tremolite asbestos, a contaminant of some chrysotile ores, causes the Canadian cases. Workers with processed chrysotile had lower lung tremolite levels than Quebec miners and, with possible exceptions, had not developed mesothelioma. If these observations were correct, the author argued, the evidence points either against a role for tremolite or toward a threshold. The author called commercial amphibole asbestos the major cause of mesothelioma in the United States, and called the EPA's no-threshold position regulatory rather than scientific. The author concluded that exposure to processed chrysotile has not been shown clearly to cause mesotheliomas.

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 (opinion and commentary, mainly on published literature; no original study)
• Who was studied: No study population. The letter responds to a 1988 commentary by Dr. Jacques Dunnigan in the same journal.
• Exposure: Commercially processed chrysotile asbestos, tremolite asbestos as a contaminant of some chrysotile ores, and commercial amphibole asbestos, discussed in relation to mesothelioma
• Main results:
  • The author's reading of other studies: recent epidemiological evidence fails to establish an association of mesothelioma with commercially processed chrysotile, although a small number of cases developed among chrysotile miners and millers in Quebec, Canada.
  • Studies of miners in Italy, South Africa and the Soviet Union, and the author's own unpublished data from China, did not demonstrate an increased prevalence of mesotheliomas among miners.
  • The author wrote that the contemporary literature suggests, but does not prove, that tremolite asbestos causes mesotheliomas in Canadian miners and millers. The author described this claim as resting largely on circumstantial evidence.
  • The author stated that animal studies are of little help, because materials not believed to cause mesothelioma in humans also cause tumors in animals.
  • The author noted that tremolite concentrations in the lungs of workers with processed chrysotile are substantially lower than in Quebec miners, millers and mining-town residents.
  • The author noted that, with possible exceptions, workers with processed chrysotile had not developed mesothelioma.
  • Assuming these observations were correct, the author argued that the evidence points either against a role for tremolite or toward a threshold.
  • The author stated that commercial amphibole asbestos is the major cause of mesotheliomas in the United States.
  • The author described the EPA's position that no threshold exists for any type of asbestos as based on regulatory rather than scientific considerations.
• The authors' conclusion: The author concluded that exposure to processed chrysotile has not been shown clearly to cause mesotheliomas, and noted that this conclusion is contrary to Federal policy.
• Limitations the authors state:
  • The author stated that the tremolite question will remain unresolved without long-term epidemiological studies of populations exposed to pure tremolite.
  • The author stated that the available data do not allow a definable threshold to be calculated.

Topics

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

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

Related studies

• On Dr. Dunnigan's commentary linking chrysotile asbestos with mesothelioma — M.R. Becklake (1988)
• Reply to Dr. Dunnigan. Chrysotile as a mesothelial carcinogen in man — A. Churg (1988)
• Biological responses to asbestos inhalation and pathogenesis of asbestos-related benign and malignant disease — E. Solbes, R.W. Harper (2018)
• Commentary: the 1968 BOHS Chrysotile Asbestos Standard — T.L. Ogden, British Occupational Hygiene Society (2003)
• Obfuscation: a reply to Dr. Dunnigan — D.E. Lilienfeld (1988)
• On the statement by Jacques Dunnigan — J.M. Davis (1988)

Browse more research in American Journal of Industrial Medicine, or return to medical research.