Linking chrysotile asbestos with mesothelioma

Our plain-English summary of Linking chrysotile asbestos with mesothelioma, by J. Dunnigan (American Journal of Industrial Medicine, 1988).

The study

• Author: J. Dunnigan
• Journal: American Journal of Industrial Medicine
• Published: 1988;14(2):205-9
• Cited by: 28 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. 000210).

Summary of the article

In this commentary, the author responded to a court decision, reported in Mealey's Litigation Reports (1987), that chrysotile asbestos caused the mesothelioma of a shipyard worker. The court was aware that the worker had been exposed to substantial amounts of both chrysotile and amphiboles. The author argued that the decision ran counter to a consensus on the different abilities of asbestos fiber types to cause mesothelioma, and he reviewed published studies. The cohort studies he cited covered workers making millboard and paper, textiles, friction materials, asbestos-cement products and gas masks. In several of these studies, the few mesotheliomas found occurred in workers exposed to crocidolite or to mixed fibers. In one U.K. friction-materials factory, at least 8 of 10 mesothelioma deaths among 13,460 workers occurred in workers who made railway brake blocks specified with crocidolite. Lung-burden studies reported more amphibole fibers, mainly amosite and crocidolite, in mesothelioma cases than in controls, with similar amounts of chrysotile. In chrysotile miners and millers with mesothelioma, Churg found about 540 x 10^6 tremolite-group fibers/g, compared with 58 x 10^6 in miner controls. The author concluded that court decisions should rest on the best evidence, including tissue burden analysis, or on the current consensus. He stated that this consensus is that amphiboles are mainly responsible for mesothelioma, whereas chrysotile alone has little or no mesothelioma-producing potential.

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 1988 article is a commentary, not a new study. The author wrote in response to a court decision, reported in Mealey's Litigation Reports. The court had found that chrysotile caused the mesothelioma of a shipyard worker exposed to both chrysotile and amphiboles. The author argued that the decision ran against what the author called a consensus that asbestos fiber types differ in their potential to cause mesothelioma, and reviewed published research in support. One cited study covered a friction-materials factory: at least 8 of 10 mesothelioma deaths among 13,460 workers occurred in people who made brake blocks in which crocidolite was specified. Another covered two groups of women making gas masks. Five mesotheliomas occurred among 570 who used crocidolite pads, and none had so far been reported among 757 who packed civilian respirators containing chrysotile. Cited lung-tissue studies reported more amphibole fibers in mesothelioma cases than in controls, with similar amounts of chrysotile. The author concluded that the consensus at the time was that amphiboles are mainly responsible for mesothelioma, and that chrysotile alone has little or no mesothelioma-producing potential.

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: Commentary reviewing previously published worker cohort studies and lung fiber (tissue burden) studies; no new data
• Who was studied: No study population of its own. The author reviewed published studies of asbestos workers (chrysotile miners and millers, textile, friction-materials, asbestos-cement and gas-mask workers) and lung-tissue studies of mesothelioma cases and controls.
• Exposure: Chrysotile compared with amphibole asbestos (amosite, crocidolite, and tremolite contaminating chrysotile ore), discussed in relation to mesothelioma
• Main results:
  • The author cited Churg's study of long-term chrysotile miners and millers with mesothelioma. In five of six workers, both chrysotile and tremolite/actinolite/anthophyllite amphibole fibers were found in the lungs. The other worker had chrysotile ore components and amosite.
  • In those five miners and millers, Churg found 64 million chrysotile fibers and 540 million tremolite-group fibers per gram of dry lung tissue. Long-term chrysotile miner controls without asbestos-related disease had 23 million chrysotile fibers and 58 million tremolite-group fibers per gram.
  • McDonald and Fry, as cited, reported only one mesothelioma death among 2,341 deaths in two factories using mostly chrysotile. By contrast, they reported 18 deaths among 1,429 workers in a factory using mixed fiber types.
  • Newhouse and colleagues, as cited, studied a UK friction-materials factory that used crocidolite during two brief periods. Of 13,460 workers there were 10 mesothelioma deaths, and at least 8 of the 10 were in workers who made the railway brake blocks in which crocidolite was specified.
  • Acheson and colleagues, as cited, studied women making gas masks. Five mesotheliomas were found among 570 women who inserted crocidolite pads into respirators. No cases had so far been reported among 757 women packing civilian respirators that contained chrysotile.
  • Wagner and colleagues, as cited, examined lung tissue from asbestos-related deaths. Amphiboles were present at up to 100 times the levels in controls, while chrysotile amounts were similar.
  • Churg's 1985 study of mesothelioma patients in British Columbia, as cited, found lung chrysotile within the general-population range. Amosite and crocidolite averaged 300-fold the levels of a reference population.
• The authors' conclusion: The author concluded that court decisions should rest on the best available evidence, including tissue mineral analysis, or on the current scientific consensus. In the author's view, that consensus was that amphiboles are mainly responsible for mesothelioma and chrysotile alone has little or no mesothelioma-producing potential.

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, Mesothelioma, Amphibole Group, Asbestos Millboard, Asbestos-Cement, Crocidolite, Amosite, Tremolite.

Related studies

• On Dr. Dunnigan's commentary linking chrysotile asbestos with mesothelioma — M.R. Becklake (1988)
• Linking chrysotile asbestos with mesothelioma — G.K. Sluis-Cremer (1988)
• Linking expert judgement and trends in occupational exposure into a job-exposure matrix for historical exposure to asbestos in the Netherlands — P. Swuste, M. Dahhan, et al. (2008)
• Deposition and clearance of chrysotile asbestos — A. Churg (1994)
• Quantification of the pathological response and fate in the lung and pleura of chrysotile in combination with fine particles compared to amosite-asbestos following short-term inhalation exposure — D.M. Bernstein, R.A. Rogers, et al. (2011)
• The pathological response and fate in the lung and pleura of chrysotile in combination with fine particles compared to amosite asbestos following short-term inhalation exposure: interim results — D.M. Bernstein, R.A. Rogers, et al. (2010)

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