Mesothelioma In Relation To Exposure

Our plain-English summary of Mesothelioma In Relation To Exposure, by F.D. Pooley (1973).

The study

• Author: F.D. Pooley
• Published: Biological Effects Of Asbestos (J.C. Wagner, Editor), Lyon: Iarc Scientific Publications, Volume 8, Pp. 222-225 (1973)
• Type of article: Conference paper
• Our copy: from Johns-Manville's own medical library, J-M no. 002405. The article is still under copyright, so we describe it here rather than post it.

In plain English

This paper reported an electron-microscope examination of lung tissue from 120 people with mesothelioma from Great Britain, Canada, Sweden and Holland. It compared them with 135 people without mesothelioma, taken randomly at autopsy in Great Britain, Sweden and Holland. The author stated that neither group was representative. Cases were placed in six exposure categories by fibres counted per microscope grid, and fibres were identified as amphibole or chrysotile. Over 92% of mesothelioma cases contained asbestos fibre and over 50% were above category 5. Over 50% of non-mesothelioma cases had no fibres found. When each fibre type was graded separately across all cases, amphibole levels were above category 5 in 38% of the 120 mesothelioma cases and chrysotile levels in 16%. For the 135 non-mesothelioma cases the figures were 2.2% for amphibole and 3.0% for chrysotile. Only 18 of 120 mesothelioma cases had asbestos bodies, all formed on amphibole fibre. No mesothelioma case had heavy chrysotile exposure. The author concluded that mesothelioma lung tissue contained more asbestos fibres than general-population tissue, mostly amphibole, while noting the groups were not statistically controlled.

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: Descriptive electron-microscope study of asbestos fibres in lung tissue, comparing mesothelioma cases with non-mesothelioma autopsy cases
• Who was studied: Lung tissue from 120 mesothelioma cases from Great Britain, Canada, Sweden and Holland, and from 135 non-mesothelioma cases obtained randomly at autopsy in Great Britain, Sweden and Holland
• Exposure: Asbestos fibres found in lung tissue, classed as amphibole or chrysotile. Cases were grouped into six exposure categories by fibres per electron-microscope grid, from more than 10,000 per grid (category 1) to zero (category 6).
• Main results:
  • Over 92% of the mesothelioma cases were positive for asbestos fibre, and over 50% were above category 5.
  • Over 50% of the non-mesothelioma cases were negative for fibres, and over 90% fell in category 5 or below.
  • Amphibole was the more predominant fibre type in the mesothelioma group and chrysotile in the non-mesothelioma group.
  • Each fibre type was graded separately in Table 8, over all 120 mesothelioma cases. The amphibole level was above category 5 in 38% of them, with 2, 3, 16 and 25 cases in categories 1 to 4.
  • Over all 120 mesothelioma cases, the chrysotile level was above category 5 in 16%, with 4 cases in category 3 and 15 in category 4.
  • Over all 135 non-mesothelioma cases, the chrysotile level was above category 5 in 3.0% and the amphibole level in 2.2%.
  • Only 18 of the 120 mesothelioma cases contained asbestos bodies. All bodies detected were formed on amphibole fibre.
  • No mesothelioma case had heavy exposure to chrysotile asbestos.
  • Mesothelioma cases from Sweden, Holland and Canada were generally in lower exposure categories than those from Great Britain.
• The authors' conclusion: The author concluded that lung tissue from mesothelioma cases contained larger numbers of asbestos fibres than tissue from the general population, and that the more predominant fibre type in mesothelioma cases was amphibole.
• Limitations the authors state:
  • Neither the mesothelioma cases nor the non-mesothelioma cases could be considered representative.
  • The results were not obtained from statistically controlled groups.
  • Larger studies of mesothelioma cases are needed.
  • More sophisticated instrumentation is needed to confirm which type of amphibole is present. The specific amphibole type could only be identified in categories 1 and 2.

Topics

Medical terms in this study, explained in our Lexicon: Mesothelioma, Autopsy, Amphibole Group, Chrysotile, Asbestos Bodies.

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