Asbestos bodies in bronchoalveolar lavage fluids of brake lining and asbestos cement workers

Our plain-English summary of Asbestos bodies in bronchoalveolar lavage fluids of brake lining and asbestos cement workers, by P. Dumortier, P. De Vuyst, P. Strauss, et al (British Journal of Industrial Medicine, 1990).

The study

• Authors: P. Dumortier, P. De Vuyst, P. Strauss, J.C. Yernault
• Journal: British Journal of Industrial Medicine
• Published: 1990;47(2):91-8
• Cited by: 31 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 000011).

Abstract

Asbestos body (AB) concentrations in bronchoalveolar lavage samples of 15 brake lining (BL) workers exposed only to chrysotile have been determined and compared with those from 44 asbestos cement (AC) workers extensively exposed to amphiboles. The mean AB concentrations (263 +/- 802 and 842 +/- 2086 AB/ml respectively) for those groups did not differ significantly but were much higher than those found in control groups. Analytical electron microscopy of asbestos body cores showed that in the BL group 95.6% were chrysotile fibres whereas in the AC group amphiboles accounted for 93.1%. The size characteristics of the central fibres differed for chrysotile and amphibole AB, the former being shorter and thinner. Examination of repeated bronchoalveolar lavage samples showed that the mechanisms of clearance of chrysotile fibres do not affect AB concentration for at least 10 months after cessation of exposure. It thus appears that routine counting of ABs in BAL allows the assessment of current or recent occupational exposures to asbestos. Exposures to chrysotile lead to AB concentrations comparable with those encountered in exposures to amphiboles.

In plain English

This study compared asbestos bodies (fibres with an iron-protein coating) in lung-washing fluid, called bronchoalveolar lavage, from men whose samples were sent to a Brussels laboratory. Fifteen worked in a brake lining factory that had used only chrysotile. Forty-four worked in two asbestos cement plants that had used crocidolite, or crocidolite and amosite, before switching to chrysotile. Every worker had asbestos bodies. The mean concentrations were 263 asbestos bodies per ml for the brake lining workers and 842 per ml for the cement workers. This difference was not statistically significant, and both groups were much higher than previously published controls. Electron microscopy of the fibres at the centre of the bodies found chrysotile in 95.6% of 159 cores from brake lining workers and amphiboles in 93.1% of 518 cores from cement workers. Chrysotile cores were shorter. In three brake lining workers, repeat samples gave similar counts, one of them taken 10 months after exposure ended. The authors concluded that asbestos bodies in lavage fluid indicate current or recent occupational asbestos exposure, even to chrysotile. They noted that the groups differed in age, exposure duration and time since exposure.

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: Comparative laboratory study of bronchoalveolar lavage (BAL) samples received for routine asbestos body counting, with light microscopy counts in all subjects and analytical electron microscopy of asbestos body cores in the 25 samples with the highest concentrations
• Who was studied: 59 men selected from more than 1500 BAL samples received by the laboratory (Erasme University Hospital, Brussels): 15 from one brake lining factory (BL group) and 44 from two asbestos cement plants (AC group: 32 from plant 1, 12 from plant 2). Full data were available for all BL subjects and for 37 AC subjects. Mean age was 45.5 years in the BL group and 53.4 years in the AC group.
• Exposure: The brake lining factory used only chrysotile imported from Canada and Italy throughout its 20-year history. Asbestos cement plant 1 used mainly crocidolite until 1981, then only chrysotile. Plant 2 used crocidolite and amosite until 1983, then chrysotile and non-asbestos fibres. Mean exposure duration was 14.5 years in the BL group and 18.9 years in the AC group, a difference that was not significant.
• Main results:
  • Every subject in both the brake lining and asbestos cement groups had asbestos bodies in their BAL fluid.
  • Mean asbestos body concentration was 263 ± 802 AB/ml of BAL in the brake lining group and 842 ± 2086 AB/ml in the asbestos cement group. The difference was not statistically significant. Both were much higher than in previously published controls.
  • 86.7% of the brake lining group and 97.9% of the asbestos cement group had more than 1 AB/ml.
  • In the brake lining group, chrysotile was found in all seven samples analysed by electron microscopy and made up 95.6% of the 159 central fibres analysed.
  • In the asbestos cement group, amphiboles made up 93.1% of 518 cores analysed. All but one were commercial amphiboles (amosite or crocidolite), and one was anthophyllite. Chrysotile cores were found in 11 asbestos cement subjects.
  • Tremolite was never found among the 677 asbestos body cores analysed. A few uncoated tremolite fibres (five and three) were seen on grids from two brake lining samples, all shorter than 10 µm.
  • Repeated BAL samples in three brake lining workers gave 273 and 351, 13.5 and 15, and 3119 and 3165 AB/ml. The authors described these as within the method's reproducibility limits. The second samples were taken 10, zero and one months after exposure ended.
  • Asbestos bodies built on chrysotile were shorter than those on amphiboles but had a higher aspect ratio (both p less than 0.01).
  • 81.5% of chrysotile, 87.8% of crocidolite and 28.6% of amosite cores were less than 0.2 µm in diameter. The authors noted these would not be detected by phase contrast light microscopy without coating.
  • Clinical data were available for 15 brake lining and 38 asbestos cement subjects. None of the 15 brake lining subjects had radiographic asbestos-related disease or mesothelioma, and 2 had bronchial carcinoma. Among the 38 asbestos cement subjects, 24 had radiographic evidence of asbestos-related disease, 6 had mesothelioma and 4 had bronchial carcinoma.
  • All subjects with bronchial carcinoma were smokers.
• The authors' conclusion: The authors concluded that the study confirms the diagnostic value of asbestos bodies in BAL as indicators of current or recent occupational exposure to asbestos, including chrysotile.
• Limitations the authors state:
  • The two groups differed in exposure duration and in time since exposure ended, which restricts the comparison of concentrations.
  • Differences in disease between the groups may be biased by age, duration of exposure and time since exposure ended, as well as by fibre type.
  • The study's data on how long chrysotile asbestos bodies persist cover only the first 10 months after exposure ended, and more experimental data are needed.
  • Only partial subject data were obtained for seven asbestos cement workers.
  • The lowest concentrations (under 10 AB/ml) in the worker groups overlapped with controls. The authors attributed this possibly to the quality of BAL and to variation in exposure intensity in the factories.

Topics

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

Medical terms in this study, explained in our Lexicon: Asbestos Bodies, Bronchoalveolar Lavage (BAL), Brake Lining, Asbestos-Cement, Chrysotile, Amphibole Group, Occupational Exposure.

Related studies

• Diagnostic value of asbestos bodies in bronchoalveolar lavage fluid — P. De Vuyst, P. Dumortier, et al. (1987)
• Erionite bodies and fibres in bronchoalveolar lavage fluid (BALF) of residents from Tuzköy, Cappadocia, Turkey — P. Dumortier, L. Coplü, et al. (2001)
• Fibres and asbestos bodies in bronchoalveolar lavage fluids of asbestos sprayers — T. Tuomi, P. Oksa, et al. (1992)
• Analysis of ferruginous bodies in bronchoalveolar lavage from foundry workers — R.F. Dodson, M. O'Sullivan, et al. (1993)
• Asbestos bodies in bronchoalveolar lavage fluid in relation to occupational history — A. Karjalainen, S. Anttila, et al. (1994)
• Pleural plaques, asbestos exposure, and asbestos bodies in bronchoalveolar lavage fluid — E. Orlowski, J.C. Pairon, et al. (1994)

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