Fiber potency vs. importance

Our plain-English summary of Fiber potency vs. importance, by V.L. Roggli, P.C. Pratt, A.R. Brody (American Journal of Industrial Medicine, 1994).

The study

• Authors: V.L. Roggli, P.C. Pratt, A.R. Brody
• Journal: American Journal of Industrial Medicine
• Published: 1994;25(4):611-2
• Type of article: Comment, Letter
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This is a letter to the editor. The authors replied to comments by Hughes and Weill on the authors' 1993 study of asbestos fiber types in mesothelioma. They agreed that a fiber type's potency (its ability to cause mesothelioma, assuming equal exposures) is different from its importance among real workers. Their data indicated that U.S. asbestos workers had much greater exposure to amosite and tremolite-contaminated chrysotile than to crocidolite. They explained that their earlier conclusion, that chrysotile and crocidolite were of roughly equal importance in U.S. mesotheliomas, rested on two assumptions. It also rested on finding approximately equal numbers of the two fiber types 5 micrometers or longer. The authors also reported unpublished scanning electron microscopy results from 120 mesothelioma cases. In eight, asbestos body and fiber counts were not distinguishable from a comparison population. In about 20%, long chrysotile fibers exceeded comparison levels, but all of these also had elevated commercial amphiboles. No case had elevated chrysotile only. Five cases had elevated tremolite without detectable excess amosite or crocidolite. The authors did not agree that their conclusions regarding chrysotile were unjustified.

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• Design: letter to the editor replying to a comment by Hughes and Weill; it includes brief unpublished observations
• Who was studied: 120 cases of mesothelioma analyzed by the authors to date (unpublished observations), compared with the authors' comparison/reference population; dates and locations not given
• Exposure: asbestos body counts and asbestos fiber counts by fiber type (chrysotile, tremolite, amosite, crocidolite) measured by scanning electron microscopy
• Main results:
  • The authors stated that their data indicated exposures to amosite and tremolite-contaminated chrysotile were much greater among U.S. asbestos workers than exposure to crocidolite
  • In the authors' earlier 1993 study, approximately equal numbers of chrysotile and crocidolite fibers 5 micrometers or longer were found
  • In 8 of the 120 mesothelioma cases, asbestos body and fiber counts for each fiber type were not distinguishable from the comparison population
  • In about 20% of the 120 cases, the concentration of chrysotile fibers 5 micrometers or longer exceeded that of the comparison population
  • All cases with elevated chrysotile also had elevated commercial amphiboles; no mesothelioma case had elevated chrysotile only
  • Five cases had elevated tremolite compared with the reference population, without detectable excesses of amosite or crocidolite; these were to be reported separately
• The authors' conclusion: The authors agreed with Hughes and Weill on the distinction between fiber potency and fiber importance. Based on their 1993 study and the unpublished observations, they did not agree that their conclusions regarding chrysotile were unjustified.
• Limitations the authors state:
  • The 1993 report did not quantify fiber concentrations by fiber type, so no comparison with a control or reference population was possible in that report
  • The conclusion about equal importance of chrysotile and crocidolite depends on two assumptions: that mainly fibers 5 micrometers or longer matter, and that fibers accumulating in the lung cause disease

Topics

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

Medical terms in this study, explained in our Lexicon: Fiber Potency.

Related studies

• Potency versus importance in fiber pathogenicity — J.M. Hughes, H. Weill (1994)
• A comparison of asbestos fiber potency and elongate mineral particle (EMP) potency for mesothelioma in humans — D.H. Garabrant, S.T. Pastula (2018)
• Empirical model of mesothelioma potency factors for different mineral fibers based on their chemical composition and dimensionality — A. Korchevskiy, J.O. Rasmuson, et al. (2019)
• Fibers in lung tissues of mesothelioma cases among miners and millers of the township of Asbestos, Quebec — A. Dufresne, M. Harrigan, et al. (1995)
• Pulmonary mineral fibers after occupational and environmental exposure to asbestos in the Russian chrysotile industry — A. Tossavainen, E. Kovalevsky, et al. (2000)
• The importance of fiber biopersistence and lung dose in determining the chronic inhalation effects of X607, RCF1, and chrysotile asbestos in rats — T.W. Hesterberg, G.A. Hart, et al. (1998)

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