The role of asbestos fiber dimensions in the prevention of mesothelioma

Our plain-English summary of The role of asbestos fiber dimensions in the prevention of mesothelioma, by L. Tomatis, S. Cantoni, F. Carnevale, et al (International Journal of Occupational and Environmental Health, 2007).

The study

• Authors: L. Tomatis, S. Cantoni, F. Carnevale, E. Merler, F. Mollo, P. Ricci, S. Silvestri, P. Vineis, B. Terracini
• Journal: International Journal of Occupational and Environmental Health
• Published: 2007;13(1):64-9
• Type of article: Review
• Cited by: 12 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

A recent interpretation of the pathogenetic role of asbestos fiber size in the development of mesothelioma and in the possibility of mesothelioma prevention needs clarification. This point of view is based on a biased interpretation of the literature. Epidemiologic, experimental, and molecular evidence suggests that the arguments for the role of fiber size relative to dose, dose-response effect, and genetic susceptibility are scientifically unsound. Their proponent also states that means available in the past for the implementation of dust-control measures and/or personal protective equipment would not have contributed to reducing the frequency of mesothelioma among exposed subjects, an argument again based on invalid assumptions.

In plain English

This article was a commentary, not an original study. The authors responded to Chiappino's 2005 article. That article argued that only "ultrathin" and "ultrashort" asbestos fibers cause pleural mesothelioma, that genetic susceptibility matters greatly, and that dust controls and respirators available before the 1980s could not have prevented mesothelioma. Citing other researchers' studies, the authors argued that larger fibers are also found in the parietal pleura. They noted a cited Belgian study finding "black spots" in 92.7% of 150 consecutive autopsies. They also noted a cited study in which most fibers in the omentum and mesentery of 20 occupationally exposed workers with mesothelioma (three with peritoneal mesothelioma) were longer than 5 micrometers. They cited evidence that mesothelioma risk rises with dose, including a French survey finding a significant excess of mesothelioma at low cumulative exposures. They called the genetic evidence contradictory and weak. They said wall-mounted air extractors in workshops with large amounts of dust expelled unfiltered air outdoors, and that respirator filters stop particles smaller than the filtering capacity the manufacturer states. The authors concluded that the evidence rejects Chiappino's hypothesis.

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 (published as a Special Contribution) critiquing a 2005 article by Chiappino; not an original study
• Who was studied: No study population; the authors re-examined the publications Chiappino cited and other published literature
• Exposure: Asbestos fibers of different lengths and diameters; exposure dose; dust-control measures and personal respiratory protection used from the 1960s to the 1980s
• Main results:
  • The authors argued, from the studies Chiappino cited and others, that although smaller fibers are the majority, larger fibers are also found in the parietal pleura
  • A cited study found parietal pleura "black spots" in 92.7% of 150 consecutive autopsies of urban inhabitants in Belgium
  • In a cited study, most fibers detected in the omentum and mesentery of 20 occupationally exposed workers suffering from mesothelioma, including three shipyard workers with peritoneal mesothelioma, were longer than 5 micrometers; the authors said Chiappino's view is not valid for peritoneal mesothelioma
  • A cited French survey found a significant excess of mesothelioma at cumulative exposure as low as 5 fibers/mL/year or lower
  • A cited asbestos workers' mortality survey in England and Wales found higher mesothelioma frequency in workers first exposed before the 1969 Regulation, when exposure intensity was higher, than in those first exposed after 1970
  • The authors described the evidence for genes such as NAT2, GSTM1 and DNA repair genes as contradictory, with weak associations
  • The authors stated that in workshops with large amounts of dust, wall-mounted air extractors expelled polluted air directly outside with no filtering system
  • The authors stated that HEPA filters were commercially available in Italy at the beginning of the 1950s and were used to filter air released into the environment, not to protect workers inside
  • The authors stated that respirator filters stop particles and fibers much smaller than the filtering capacity the manufacturer indicates
• The authors' conclusion: The authors concluded that epidemiologic, experimental and molecular evidence rejects Chiappino's hypothesis that only ultrathin, ultrashort fibers cause pleural mesothelioma and that repeated exposure is irrelevant

Topics

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

Medical terms in this study, explained in our Lexicon: Fiber Dimensions, Mesothelioma, Dose-response relationship.

Related studies

• Lung mineral fibers of former miners and millers from Thetford-Mines and asbestos regions: a comparative study of fiber concentration and dimension — A. Nayebzadeh, A. Dufresne, et al. (2001)
• Potential significance of airborne fiber dimensions measured in the U.S. refractory ceramic fiber manufacturing industry — T.J. Lentz, C.H. Rice, et al. (1999)
• Changes in numbers and dimensions of chrysotile asbestos fibers in lungs of rats following short-term exposure — V.L. Roggli, A.R. Brody (1984)
• Fiber dimensions and aspect ratio of crocidolite, chrysotile and amosite particles detected in lung tissue specimens — F.D. Pooley, N. Clark (1979)
• Measurement of airborne fibers: a review — P.A. Baron (2001)
• Activation of alveolar macrophages and peripheral red blood cells in rats exposed to fibers/particles — F. Afaq, P. Abidi, et al. (1998)

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