Mineral fibres and mesothelioma

Our plain-English summary of Mineral fibres and mesothelioma, by J.C. Wagner, F.D. Pooley (Thorax, 1986).

The study

• Authors: J.C. Wagner, F.D. Pooley
• Journal: Thorax
• Published: 1986;41(3):161-6
• Type of article: Editorial
• Cited by: 35 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. 000443).

Summary of the article

In this editorial, the authors considered the evidence linking asbestos and other mineral fibres to diffuse mesothelioma of the pleura and peritoneum. They discussed four groups: commercial asbestos minerals; asbestos minerals as environmental contaminants (for example tremolite in talc, in chrysotile deposits and in agricultural soils); naturally occurring fibrous minerals such as erionite and absorbent clays; and man-made mineral fibres. They stated that the evidence linking crocidolite with mesothelioma was clear. Drawing on epidemiological, lung-tissue mineralogical and animal studies, some of them unpublished, they concluded that the fibres responsible for mesothelioma have a diameter of less than 0.25 µm and probably a length greater than 5 µm. Fine erionite fibres from Oregon produced mesotheliomas after inhalation in all cases, whereas no other fibre, including crocidolite, had produced tumours in more than 10% of cases. Early intrapleural experiments suggested that attapulgite, used as an asbestos substitute, might produce nearly as many mesotheliomas as the contaminated chrysotile it was replacing. Insulation wools showed no significant adverse effects in animals, but an extremely fine glass microfibre produced mesotheliomas. Mullite was the most common fibre found in human lung tissue. The authors concluded that any straight mineral fibre of the defined length and diameter must be regarded as a possible hazard. They also concluded that analysis of the fibres retained in the lungs, using transmission electron microscopy, was essential, because environmental dust studies could be misleading.

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 1986 Thorax editorial reviewed evidence linking asbestos and other mineral fibres to pleural and peritoneal mesothelioma. It was not a formal research report, but it also described preliminary, unpublished findings from the authors' ongoing work. It covered asbestos minerals (chrysotile, crocidolite and amosite were the commercially produced types, while anthophyllite, tremolite and actinolite mattered mainly as contaminants), natural fibres such as erionite and absorbent clays, and man-made mineral fibres. Drawing on earlier investigations, the authors concluded that fibres responsible for mesotheliomas are under 0.25 micrometres in diameter and probably longer than 5.0 micrometres. They reported that in animal inhalation experiments, erionite from Oregon produced mesotheliomas in all cases. By contrast, no other fibre, including crocidolite, had ever produced tumours in more than 10% of cases after inhalation. Early, partly unpublished experiments suggested some absorbent clays could produce mesotheliomas when placed directly into the chest cavity. The authors concluded that any straight mineral fibre of the defined length and diameter must be regarded as a possible hazard. They noted that evidence on non-asbestos fibres was sparse and largely preliminary.

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: Editorial (narrative review of published evidence that also reports preliminary findings from the authors' ongoing and unpublished experiments)
• Who was studied: No single study population. The editorial drew on earlier human studies, animal experiments and lung-tissue analyses from several countries, plus the authors' unpublished observations
• Exposure: Asbestos minerals (chrysotile, crocidolite and amosite as the commercially produced types; anthophyllite, tremolite and actinolite with minimal commercial production but important as contaminants), naturally occurring fibres (erionite and other zeolites; absorbent clays such as attapulgite, palygorskite and sepiolite), and man-made mineral fibres including glass, slag and rock wools, ceramic fibres and mullite
• Main results:
  • From the investigations reviewed, the authors concluded that fibres responsible for mesotheliomas have a diameter of less than 0.25 micrometres and probably a length greater than 5.0 micrometres
  • In an earlier experimental study of three forms of tremolite, only the very fine tremolite fibre produced significant cytotoxicity in cell tests and a high incidence of mesotheliomas after pleural implantation
  • In earlier lung-tissue studies of mesothelioma cases in Britain and the United States, the amount of chrysotile in the lungs of those with the tumours was of the same order as in controls. The British cases were associated with crocidolite; the American cases had amosite as well as crocidolite
  • In animal inhalation experiments, Oregon erionite fibres produced mesotheliomas in all cases. The authors stated that no other fibre, including crocidolite, had ever produced tumours in more than 10% of cases after inhalation
  • Preliminary unpublished evidence showed fine erionite fibres in human and sheep lungs from the suspected Turkish villages but not in material from elsewhere in Turkey
  • Early experiments suggested that attapulgite used as a chrysotile substitute may produce nearly as many mesotheliomas as the contaminated chrysotile it replaces when implanted intrapleurally. Unpublished experiments showed that palygorskite produced a high incidence of mesotheliomas after intrapleural inoculation
  • Animal experiments with vitreous insulation wools failed to show any significant adverse effects. An extremely fine glass microfibre did produce mesotheliomas, but slightly coarser, otherwise identical fibres did not
  • Mullite was the most common fibre found in human lung tissue in the authors' studies, with extraordinarily high counts in workers from coal-fired electricity power stations. Occasionally these workers had mesotheliomas, with mullite as a major component of the dust in their lungs
• The authors' conclusion: The authors concluded that any mineral fibre, if straight and of the defined length and diameter, must be regarded as a possible hazard able to cause malignant change in the mesothelial membranes. They also concluded that analysing the fibres in lung tissue is essential, because environmental dust studies can be misleading
• Limitations the authors state:
  • Information about the effects of fibrous minerals other than asbestos is sparse and largely preliminary
  • Most industrial workers were exposed to more than one mineral, making it difficult to establish exposure to a single fibre type
  • The epidemiological evidence for a causative role of fine erionite fibre still required strengthening
  • Information on the potential of man-made fibres to cause disease is limited

Topics

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

Medical terms in this study, explained in our Lexicon: Mesothelioma, Pleura, Peritoneum, Asbestos, Tremolite, Talc, Chrysotile, erionite.

Related studies

• Carcinogenesis and mineral fibres — J.C. Wagner, G. Berry, et al. (1980)
• Respiratory cancer incidence in Swedish construction workers exposed to man-made mineral fibres and asbestos — G. Engholm, A. Englund, et al. (1987)
• Mesotheliomas in rats following inoculation with acid-leached chrysotile asbestos and other mineral fibres — G. Monchaux, J. Bignon, et al. (1981)
• Lung dust analysis in the assessment of past exposure of man-made mineral fibre workers — J.C. McDonald, B.W. Case, et al. (1990)
• Morphological transformation of Syrian hamster embryo cells induced by mineral fibres and the alleged enhancement of benzo[a]pyrene — S.O. Mikalsen, E. Rivedal, et al. (1988)
• Binding of environmental carcinogens to asbestos and mineral fibres — G. Harvey, M. Pagé, et al. (1984)

Browse more research in Thorax, or return to medical research.