Comparison of fibre types and size distributions in lung tissues of paraoccupational and occupational cases of malignant mesothelioma

Our plain-English summary of Comparison of fibre types and size distributions in lung tissues of paraoccupational and occupational cases of malignant mesothelioma, by A.R. Gibbs, D.M. Griffiths, F.D. Pooley, et al (British Journal of Industrial Medicine, 1990).

The study

• Authors: A.R. Gibbs, D.M. Griffiths, F.D. Pooley, J.S. Jones
• Journal: British Journal of Industrial Medicine
• Published: 1990;47(9):621-6
• Cited by: 27 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. 003760).

Abstract

The results of analysis of mineral fibres in lung tissues from 10 paraoccupational cases of malignant mesothelioma were compared with analysis obtained from seven cases of malignant mesotheliomas that had developed in gas mask workers. Nine of the paraoccupational cases were considered to have developed their tumours because of exposure to asbestos on their husbands' working clothes and one cancer developed in the daughter of a man who had died of asbestosis. The gas mask workers had direct exposure to asbestos while working in a factory that produced military gas masks. The results of mineral fibre analysis in the paraoccupational cases were variable; six showed high crocidolite concentrations, seven raised amosite concentrations and two normal concentrations of all types of asbestos fibre measured. Chrysotile was raised in one case but crocidolite and amosite were also increased. The gas mask workers showed a consistent pattern with high crocidolite concentrations and normal or low concentrations of chrysotile and amosite. Fibre lengths for chrysotile were similar in both groups and predominantly less than 5 microns. Crocidolite fibres tended to be longer in the gas mask workers than in the paraoccupational group and longer than chrysotile in both groups. Amosite fibres tended to be more variable in width than those of chrysotile or crocidolite.

In plain English

The authors used electron microscopy to compare asbestos fibres in the lungs of two groups of people who had died of pleural mesothelioma. Ten were paraoccupational cases. Nine women were suspected of being exposed by washing their husbands' work clothes, and one woman's father had died of asbestosis. The other seven were women who had worked at a factory making military gas masks with crocidolite filters between 1940 and 1945. The gas mask workers showed a consistent pattern: mainly crocidolite, chrysotile mostly in the normal range, and amosite absent or low. The paraoccupational cases varied more. Six had high crocidolite, generally lower than in the gas mask workers, seven had raised amosite, and two had normal levels of all asbestos types. Chrysotile fibres were mostly shorter than 5 micrometres in both groups. Crocidolite fibres were longer, especially in the gas mask workers. The authors concluded that their findings support earlier evidence that amphiboles are much more important than chrysotile in causing mesothelioma. They could not say whether the two normal-level cases were due to asbestos.

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: Case series comparing lung fibre analysis at necropsy between two groups of mesothelioma cases (paraoccupational versus occupational)
• Who was studied: 17 people who had necropsies and were diagnosed with pleural mesothelioma, referred to the Cardiff and Nottingham mesothelioma panels. The 10 paraoccupational cases were nine suspected of exposure from laundering their husbands' work clothes and one (case 3) whose father died of asbestosis. They had a mean age of 62.4 and a range of 47 to 72. The 7 gas mask workers were women with a mean age of 72 and a range of 63 to 80.
• Exposure: Gas mask workers had direct exposure at a factory producing military gas masks with crocidolite filters, 1940 to 1945, lasting from 10 days to 35 months. Paraoccupational cases had household exposure from husbands' clothes. The husbands worked in shipyards, lagging, building and ordnance, with exposures that varied in asbestos type and amount.
• Main results:
  • Gas mask workers: crocidolite was the main fibre type, and chrysotile was within the normal control range in most cases.
  • Gas mask workers: amosite was absent or present only in low amounts.
  • Gas mask workers: the authors found some correlation between duration of exposure and lung fibre concentrations.
  • Paraoccupational group: 6 of 10 had high crocidolite concentrations, generally not as high as in the gas mask workers.
  • Paraoccupational group: 7 had raised amosite, but in only two (P1 and P10) was amosite raised without raised crocidolite.
  • Paraoccupational group: two cases (P3 and P9) had normal concentrations of all asbestos fibre types.
  • Paraoccupational group: one case (P7) had high chrysotile, and crocidolite and amosite were also increased in that case.
  • Paraoccupational group: 8 of 10 had increased crocidolite, amosite or both, while chrysotile was nearly always within the control range.
  • Chrysotile fibre lengths were similar in both groups and mostly under five micrometres.
  • Crocidolite fibres were longer in the gas mask workers than in the paraoccupational cases.
  • In both groups, crocidolite fibres had much greater mean lengths than chrysotile fibres.
  • Amosite fibres tended to be wider and more variable in size than chrysotile and crocidolite.
  • Tremolite was not found in significant concentrations in either group.
• The authors' conclusion: The authors concluded that their observations support previous evidence that amphiboles are much more important than chrysotile in causing malignant mesothelioma.
• Limitations the authors state:
  • There were no precise data on the periods of suspected exposure in the paraoccupational cases.
  • The husbands' exposures would have varied widely in type and amount of asbestos.
  • The crocidolite level in case P5 was so high that the authors suspected a direct exposure not identified in the occupational history.
  • For the two cases with normal fibre levels (P3 and P9), the authors could not conclude whether the mesotheliomas were due to asbestos.

Topics

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

Medical terms in this study, explained in our Lexicon: Malignant Mesothelioma, Crocidolite, Amosite, Chrysotile.

Related studies

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• Fibre distribution in the lungs and pleura of subjects with asbestos related diffuse pleural fibrosis — A.R. Gibbs, M. Stephens, et al. (1991)
• Airborne brake wear debris: size distributions, composition, and a comparison of dynamometer and vehicle tests — P.G. Sanders, N. Xu, et al. (2003)
• The effect of fibre size on the in vitro biological activity of three types of amphibole asbestos — R.C. Brown, M. Chamberlain, et al. (1978)
• Comparison of the results of asbestos fibre dust counts in lung tissue obtained by analytical electron microscopy and light microscopy — F.D. Pooley, D.L. Ranson (1986)

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