The biological effects of mineral fibres

Our plain-English summary of The biological effects of mineral fibres, by J.M. Davis (The Annals of Occupational Hygiene, 1981).

The study

• Author: J.M. Davis
• Journal: The Annals of Occupational Hygiene
• Published: 1981;24(2):227-34
• Type of article: Review
• Cited by: 8 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. 004059).

Abstract

The history of asbestos-related disease and the results of research into the ways in which asbestos fibres are able to damage tissue are reviewed. Although crocidolite has been accepted as constituting a particularly great hazard and is subject to a more stringent hygiene standard that has effectively terminated its use in the U.K., experimental studies on animals have not proved it to be more carcinogenic than chrysotile. It is possible that rats react differently from humans, but more likely possibilities are that in past industrial usage crocidolite produced higher dust concentrations than amosite or chrysotile and that chrysotile is less durable than crocidolite in the lungs over the 10-20 yr that tumour induction takes in man. Other mineral fibres, both natural and man-made, have come under study and there is some evidence from laboratory experiments that they may produce similar effects to asbestos if of comparable size. The position for man-made insulation fibres appears relatively good and the results of studies of human populations exposed to glass fibre have so far been negative. While not all mineral fibres may constitute a health hazard if used industrially, there is enough evidence of potential harm to indicate that all new types of fibre should be subjected to careful testing.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.

In plain English

This article was a review by J. M. G. Davis of the Institute of Occupational Medicine, Edinburgh. It covered the history of asbestos-related disease and research, mostly in experimental animals, on how mineral fibres damage tissue. The author noted that crocidolite had been accepted as a particularly great hazard in people. Even so, the animal studies reviewed had not shown it to be more carcinogenic than chrysotile, whether the dust was inhaled or injected into the pleural or peritoneal cavities. The author suggested two possible reasons: past industrial use of crocidolite may have produced higher dust levels, or chrysotile may not survive as long in human lungs. In the studies reviewed, glass fibres injected into animals' body cavities produced mesotheliomas, while inhaled glass fibre produced little tissue reaction. Studies of glass fibre workers had so far been negative. The review also described reports by other researchers of pleural mesothelioma linked to erionite fibres in Turkish villages. The author concluded there was enough evidence of potential harm that all new fibre types should be carefully tested in animals before factory use.

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: narrative review (no new data collected)
• Who was studied: No new population. The review covered published experimental studies, mainly in animals (rats, hamsters, guinea pigs, mice), and published studies of human workers and communities, including glass fibre workers in the USA and Britain and villages in Turkey.
• Exposure: Asbestos (crocidolite, chrysotile, amosite). Man-made fibres (glass fibre and other insulation fibres). Other natural and industrial fibres (erionite, cummingtonite grunerite from iron-ore mining, sepiolite, polygorscite, potassium titanate, fibrous Dawsonite). Exposure was by inhalation, intratracheal injection, or injection or implantation into the pleural or peritoneal cavities in animals.
• Main results:
  • In the experimental studies reviewed, crocidolite was not more carcinogenic than chrysotile, whether given by inhalation or by injection into the pleural or peritoneal cavities.
  • In two rat inhalation studies using UICC samples (Wagner et al. 1974; Davis et al. 1978), crocidolite did not produce more mesotheliomas than chrysotile. In both studies, chrysotile produced the most bronchial carcinomas.
  • Stanton and colleagues found that, after implantation, carcinogenicity was related to the percentage of fibres longer than 8 micrometres and less than 1.5 micrometres in diameter. Because a constant mass of dust was used, an effect of fibre number was not ruled out. Glass fibres in this size range were almost as effective as asbestos fibres.
  • Glass and other insulation fibres produced ferruginous bodies, fibrosis and mesotheliomas when injected into the pleural or peritoneal cavities of animals. Inhalation studies with glass fibre showed little tissue reaction.
  • Human studies of glass fibre workers were negative so far. These included chest radiographs of 1400 American men exposed for at least 10 years, and 70 British men with a mean exposure of 20 years. In two American groups of 416 and 1448 men, pulmonary tumour incidence was slightly less than in the general population.
  • Baris and co-workers (1978) reported that in some isolated Turkish villages, where local rock contains erionite fibres, as many as 40% of all deaths were due to pleural mesothelioma.
  • Potassium titanate was reported to be extremely carcinogenic to rats after intrapleural implantation. Fibrous Dawsonite produced mesotheliomas in rats after intrapleural injection; no inhalation studies of Dawsonite had been done.
  • Epidemiological studies of iron-ore miners and local populations exposed to cummingtonite grunerite fibres (Lake Superior area, USA) showed no evidence of a health hazard.
• The authors' conclusion: The author concluded that not all mineral fibres may be a health hazard in industrial use. However, there was enough evidence of potential harm from several mineral types to indicate that all new fibre types should be carefully tested by animal experiments before being introduced into factories.
• Limitations the authors state:
  • There were no dust figures for factories making products from the different asbestos types 30 to 40 years earlier, so the higher-dust explanation for the crocidolite hazard could not be checked for factories.
  • It had not been determined whether the fibre-size findings from implantation studies also apply after inhalation.
  • Very few inhalation studies of fine glass fibre had been done, so the author considered it too soon to say fine glass fibres are not hazardous.

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: Crocidolite, Carcinogenic, Chrysotile, Amosite.

Related studies

• Guidelines for mineral fibre analyses in biological samples: report of the ERS Working Group. European Respiratory Society — P. De Vuyst, A. Karjalainen, et al. (1998)
• Sectioning and imaging hard mineral fibres in biological tissues — N.F. Johnson, K. Ibe (1981)
• Adsorption of benzo(a)pyrene on to asbestos and manmade mineral fibres in an aqueous solution and in a biological model solution — P. Gerde, P. Scholander (1988)
• Biological durability and oxidative potential of a stonewool mineral fibre compared to crocidolite asbestos fibres — S. Hippeli, K. Dornisch, et al. (1997)
• Comparing biological effects of mineral fibres — J. Dunnigan (1989)
• Comparing biological effects of mineral fibres — J.M. Meijers (1990)

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