Asbestos In Lung Tissue

Our plain-English summary of Asbestos In Lung Tissue, by P.D. Oldham (1973).

The study

• Author: P.D. Oldham
• Published: Biological Effects Of Asbestos (J.C. Wagner, Editor), Lyon: Iarc Scientific Publications, Volume 8, Pp. 231-235 (1973)
• Type of article: Conference paper
• Our copy: from Johns-Manville's own medical library, J-M no. 004829. The article is still under copyright, so we describe it here rather than post it.

In plain English

This paper reported two surveys, carried out under IARC auspices, of how often asbestos bodies were found in lung tissue at post-mortem. The first, fully reported elsewhere by Um (1971), was summarised here. It examined lung sections from London hospital autopsies of patients over 20 in 1936, 1946, 1956 and 1966. No asbestos bodies were found in the 1936 cases. The proportion rose in later years, fairly consistently across ages and both sexes. The author estimated a rise of about 1% per year in persons over 30. The second survey compared 10 centres in 1967-69, using lung sections from persons over 25 allocated at random among observers. Proportions positive ranged from 1 of 158 cases in Galway to 68 of 181 (38%) in Finland. Glasgow had 26% and the London Hospital 23%. The author noted that only relative, not absolute, figures could be obtained. The author added that, unless gross over-recording occurred, and if only definite bodies were counted, the results must be underestimates. The author linked higher figures to areas with docks and asbestos factories.

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: Two post-mortem lung tissue surveys: a temporal comparison of London autopsies (previously fully reported by Um, 1971, and summarised here) and a multi-centre geographical comparison
• Who was studied: Temporal study: 100 consecutive necropsies of patients over 20 for each of 1936, 1946, 1956 and 1966 from the former London County Council hospitals, plus 27 extra patients in 1936. Geographical study: consecutive post-mortems on persons over 25 at 10 centres (Finland, Glasgow, London Hospital, Dresden, Belfast, London RPGS, Liverpool, Nottingham, Dorchester, Galway), 1967-69
• Exposure: Presence of asbestos bodies in lung sections as a marker of exposure in general populations; no fiber types named. A model linked the chance of having asbestos bodies to the calendar years lived through and the total asbestos in Britain, based on UK imports rising to about 150,000 tons per year in the early 1960s
• Main results:
  • In the 1936 London cases, no men or women were found to have asbestos bodies
  • In the London series, the rise over time was fairly consistently present in all age groups and in both sexes
  • In the London area, the proportion with asbestos bodies appeared to be rising by about 1% per year in persons over 30
  • Finland centre: 68 of 181 cases positive (38%)
  • Glasgow centre: 50 of 192 cases positive (26%)
  • London Hospital centre: 41 of 178 cases positive (23%)
  • Galway centre: 1 of 158 cases positive (the percentage is illegible in the scanned table)
  • Across the 10 areas in 1967-69, the proportion positive ranged from 1% to 38%
  • The spread between centres was too large to be due to sampling variation from a single level of positivity, but the three suggested middle clusters of centres were not reliably established
  • Differences between observers could have been due to chance; their significance level was about 5%
• The authors' conclusion: The author concluded that the clustering of centres accorded in a general sense with expectation. Glasgow and the London Hospital collect cases from areas that include docks and asbestos factories. Dorchester and Nottingham were described as industrial towns without an asbestos industry, and Galway as entirely rural. The two London centres gave proportions that accorded well with the prediction from the temporal study.
• Limitations the authors state:
  • Only relative figures, not absolute ones, could be obtained for each centre
  • Unless gross over-recording occurred, and if only definite bodies were counted, the results must be underestimates of the true proportion of people with asbestos bodies. This is because a tissue sample can miss bodies present elsewhere in the lung.
  • The choice of areas depended partly on the availability of co-operative pathologists
  • In the temporal study, by 1966 hospital coverage no longer included the east London areas where asbestos factories are sited
  • No centre had reached the planned 200 post-mortems by March 1971
  • Each case could be recorded only as positive or negative for asbestos bodies
  • Three observers saw rather few sections

Topics

Medical terms in this study, explained in our Lexicon: IARC, Asbestos Bodies.

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