The sequelae of exposure to asbestos dust

Our plain-English summary of The sequelae of exposure to asbestos dust, by J.C. Wagner (Annals of the New York Academy of Sciences, 1965).

The study

• Author: J.C. Wagner
• Journal: Annals of the New York Academy of Sciences
• Published: 1965;132(1):691-5
• 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. 001547).

Summary of the article

This paper summarized the main points of a conference on the biological effects of asbestos, covering the inhalation, deposition and retention of asbestos dust and their consequences. The author stressed that the effects of different types of exposure should be distinguished, taking account of the mineral variety of asbestos and its contaminants. He reported that the presence of long fibers in small air spaces had now been explained, with emphasis on fiber diameter. The primary site of lodgment was described as the alveoli arising directly from the respiratory bronchioles. In experimental animals, the amount of chrysotile retained clearly differed from that of amosite and crocidolite at equal doses. Asbestos bodies and fibers in sputum were described as evidence of exposure, not of asbestosis, and the author called for agreed identification methods in post-mortem prevalence surveys. Asbestosis was described as a slow, insidiously progressive fibrosis that begins as a focal lesion at the respiratory bronchioles. Four theories of how the disease develops were reviewed, and the author preferred the stagnation of phagocytes theory. Lung carcinoma was described as strongly supported as occurring in cases with significant asbestosis. Mesotheliomas, at first linked to crocidolite, had also been reported with chrysotile and possibly anthophyllite. Gastrointestinal tumors and preliminary animal tumor experiments were noted. The author called for standard reference dusts, comparative surveys in asbestos-producing areas, and coordinated international research.

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 paper was not an original study and reported no new data. The author, of the Medical Research Council's Pneumoconiosis Research Unit in Great Britain, summarized work presented at a conference collected in this volume. The author reported that asbestos bodies and fibers in sputum indicate exposure, not asbestosis, and that asbestosis is a slow, insidiously progressive lung fibrosis. In experimental animals given equal doses of respirable material, the amount of chrysotile retained in the lungs clearly differed from that of amosite and crocidolite. No theory of how asbestosis develops was widely accepted. The earlier view that lung cancers occur in people with a significant degree of asbestosis was described as strongly supported, but whether exposure without asbestosis is linked to these tumors still needed confirming. Mesotheliomas of the pleura and peritoneum first seemed linked entirely to crocidolite, but some reported cases suggested chrysotile and possibly anthophyllite. In animal tumor experiments, the intrapleural doses were very large compared with the amount of dust present in man. The author called for comparative surveys, standard dusts and team work.

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: Summary of the papers presented at a conference (narrative overview, no original data)
• Who was studied: No defined study group. The paper summarizes conference work on human cases and experimental animals, and gives no numbers, places or dates for any study group.
• Exposure: Asbestos dust in general. The fibers named are chrysotile, amosite, crocidolite and anthophyllite. The paper also mentions contaminants from mines, mills, transport or industrial additives.
• Main results:
  • Asbestos bodies and fibers in sputum were described as a sign of exposure to asbestos dust, not evidence of asbestosis.
  • Asbestosis was described as a slow, insidiously progressive pulmonary fibrosis rather than a sudden disease after a long dormant period.
  • In experimental animals there was a clear difference between the amount of chrysotile retained in the lungs and that of amosite and crocidolite, for equal doses of respirable material.
  • The earlier idea that particles shorter than 10 microns are relatively innocuous was described as no longer tenable.
  • Several theories of how asbestosis develops were reviewed, and none was widely accepted. The author preferred the stagnation-of-phagocytes hypothesis.
  • The view that lung carcinomas occur in cases with a significant degree of asbestosis was described as strongly supported. Information was still needed on exposure without asbestosis.
  • Mesotheliomas of the pleura and peritoneum at first seemed linked entirely to crocidolite. Some reported cases suggested chrysotile and possibly anthophyllite.
  • In animal experiments the tumor yield was high, but the intrapleural dust doses were very large compared with the amount present in man.
• The authors' conclusion: The author concluded that further work needs comparative surveys in asbestos-producing areas, standard reference dusts for experiments, and team work across disciplines.
• Limitations the authors state:
  • The author stated there was insufficient evidence to say which dust parameter is the most dangerous.
  • The author stated that little is known about how asbestos fibers migrate from the lung or gut to other tissues.
  • The author described the experimental tumor findings as very preliminary.

Topics

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

Medical terms in this study, explained in our Lexicon: Deposition, Alveoli, Chrysotile, Amosite, Crocidolite, Asbestos Bodies, Sputum, Fibrosis.

Related studies

• Asbestos dust deposition and retention in rats — J.C. Wagner, J.W. Skidmore (1965)
• Diffuse mesothelioma and exposure to asbestos dust in the Merseyside area — W.G. Owen (1964)
• Exposure to brake dust and malignant mesothelioma: a study of 10 cases with mineral fiber analyses — K.J. Butnor, T.A. Sporn, et al. (2003)
• Variations in the carcinogenicity of tremolite dust samples of differing morphology — J.M. Davis, J. Addison, et al. (1991)
• Mesothelial tumors and exposure to asbestos dust — W.G. Owen (1965)
• Letter: Exposure to asbestos dust — D.C. Britton (1976)

Browse more research in Annals of the New York Academy of Sciences, or return to medical research.