Analysis of the cores of asbestos bodies from members of the general population: patients with probable low-degree exposure to asbestos

Our plain-English summary of Analysis of the cores of asbestos bodies from members of the general population: patients with probable low-degree exposure to asbestos, by A. Churg, M.L. Warnock (The American Review of Respiratory Disease, 1979).

The study

• Authors: A. Churg, M.L. Warnock
• Journal: The American Review of Respiratory Disease
• Published: 1979;120(4):781-6
• Cited by: 34 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. 004375).

Abstract

Asbestos bodies were isolated from the lungs of 21 patients who had 300 to 9,000 of such bodies/g of lung tissue, a concentration frequently found in manual laborers in the general population who are not primary asbestos workers. All of the 123 bodies examined by electron diffraction produced diffraction patterns consistent with amphibole varieties of asbestos. Electron microprobe analysis (energy dispersive x-ray spectroscopy) of 46 bodies revealed that 38 of the cores were composed of the commercial amphiboles, amosite and crocidolite, whereas only 8 were composed of the noncommercial amphiboles, anthophyllite and tremolite. Review of the occupations of these patients revealed that all but one had blue-collar jobs. For many of these persons, putative sources of asbestos exposure such as construction work could be defined, but for some, the source could not be determined. One woman was apparently exposed to asbestos in the practice of her hobby of ceramics, in which she used anthophyllite-contaminated clay. We concluded that commercial amosite/crocidolite asbestos forms the cores of most asbestos bodies in manual laborers in the general population and that the source is usually occupational.

In plain English

The authors examined asbestos bodies from the lungs of 21 urban autopsy and surgical patients who had more than 300 such bodies per gram of lung, a level they used to define modest exposure. None was a primary asbestos worker or had asbestosis. The 19 men and two women were aged 41 to 91, and all but possibly one had worked as blue-collar manual laborers. Counts ranged from 306 to 9,000 bodies per gram. All 123 bodies examined by electron diffraction gave patterns consistent with amphibole asbestos, and no chrysotile cores were identified. Of 46 bodies whose chemistry could be measured, 38 matched amosite or crocidolite (which the method could not tell apart), seven matched anthophyllite and one matched tremolite. For some patients the exposure source was unclear. The authors believed one woman's exposure came from a ceramics clay that they found contained anthophyllite fibers. They concluded that commercial amosite/crocidolite asbestos forms the cores of most asbestos bodies in manual laborers in the general population and that the source is usually occupational.

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: Laboratory analysis of asbestos bodies isolated from autopsy and surgical lung tissue (case series). Asbestos body counts were made by light microscopy, core identification by electron diffraction, and chemical analysis by electron microprobe (energy dispersive x-ray spectroscopy). Occupational and other exposure histories came from a standardized questionnaire.
• Who was studied: 21 patients (19 men, 2 women, aged 41 to 91), all over 40 and resident for at least 20 years in a city of at least 100,000. They came from about 350 urban autopsy and surgical patients with asbestos body counts and detailed histories. Thirty-two of these had more than 300 asbestos bodies per gram of lung, and 11 of those lacked enough tissue for study. The authors were at the University of Chicago and the University of California, San Francisco.
• Exposure: No measured doses. Exposure was inferred from asbestos body counts of more than 300 per gram of lung, which the authors took to indicate modest, low-degree exposure. Occupational and hobby histories mostly involved blue-collar jobs such as construction and steel mill work. None of the patients was a primary asbestos worker.
• Main results:
  • Asbestos body counts in the 21 patients ranged from 306 to 9,000 bodies per gram of lung, and 19 of the 21 counts were below 2,000.
  • All 123 bodies examined by electron diffraction gave patterns consistent with amphibole asbestos. No chrysotile or nonasbestos cores were identified.
  • Of the 46 bodies analyzed by microprobe, 38 were chemically consistent with amosite or crocidolite, 7 with anthophyllite and 1 with tremolite.
  • By patient: 16 patients had only amosite/crocidolite bodies, 2 had only anthophyllite bodies, and 3 had a mixture of types.
  • Among the 19 men, 35 of 43 analyzed bodies (81 %) had amosite or crocidolite cores.
  • With the possible exception of Patient 2, all patients had been blue-collar manual laborers.
  • For some patients the source of exposure could not be determined; for example, Patient 16 was a bus driver and salesman.
  • Patient 20, a woman with 540 bodies per gram of lung, had several possible exposure sources. The authors believed her exposure came from her ceramics hobby. Samples of the commercial modeling slip she used all contained substantial quantities of anthophyllite fibers.
• The authors' conclusion: The authors concluded that commercial amosite/crocidolite asbestos forms the cores of most asbestos bodies in manual laborers in the general population and that the source is usually occupational.
• Limitations the authors state:
  • Sodium could not be measured accurately with their equipment, so amosite and crocidolite could not be told apart.
  • Coat material on the bodies prevented chemical analysis of most cores; only 46 of the 123 diffracted bodies could be analyzed by microprobe.
  • The authors noted that electron diffraction patterns produced by amphiboles are not unique and may be mimicked by other minerals; they agreed that combining diffraction with an x-ray energy spectrum is the ideal procedure.
  • Where the exposure source was unclear, the authors could not tell whether this reflected incomplete occupational histories obtained from relatives of autopsied patients or exposure the patient did not know about.
  • The patients were drawn from a study of asbestos bodies and lung cancer. As a result, about half had lung cancer and the patients were relatively old.

Topics

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

Medical terms in this study, explained in our Lexicon: Asbestos Bodies, Amphibole Group, Electron Microprobe Analysis, energy dispersive X-ray spectroscopy (EDS), Amosite, Crocidolite, Anthophyllite, Tremolite.

Related studies

• Nonasbestos pulmonary mineral fibers in the general population — A. Churg (1983)
• Analysis of cores of ferruginous bodies from former asbestos workers — R.F. Dodson, M.F. O'Sullivan, et al. (1982)
• Asbestos fibers in the general population — A. Churg, M.L. Warnock (1980)
• Fiber size and number in workers exposed to processed chrysotile asbestos, chrysotile miners, and the general population — A. Churg, B. Wiggs (1986)
• Chrysotile biopersistence in the lungs of persons in the general population and exposed workers — A.M. Langer, R.P. Nolan (1994)
• Asbestos Bodies Burden in the Autopsy Lung Tissue from General Thai Population — P. Incharoen, T. Hama, et al. (2019)

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