Correlation between fibre content of the lungs and disease in naval dockyard workers

Our plain-English summary of Correlation between fibre content of the lungs and disease in naval dockyard workers, by J.C. Wagner, C.B. Moncrieff, R. Coles, et al (British Journal of Industrial Medicine, 1986).

The study

• Authors: J.C. Wagner, C.B. Moncrieff, R. Coles, D.M. Griffiths, D.E. Munday
• Journal: British Journal of Industrial Medicine
• Published: 1986;43(6):391-5
• Cited by: 45 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. 000444).

Abstract

In the period 1966-82 lungs from 333 workers who had been employed at a Royal Naval dockyard were referred to the MRC Pneumoconiosis Unit where they were investigated for the severity of asbestosis, the presence of tumours, and an assessment of mineral fibre content and the type and amount of mineral present. The occupational exposure to mineral dust has been coded for 189 of these cases. There is good correlation between the severity of asbestosis and the coded exposures, electron microscopic mineral fibre count, and the fibre count as seen under the light microscope. The information collected showed that mesotheliomas occurred in those who had had minimal or slight asbestosis, by contrast with the pulmonary carcinomas found in those with moderate to severe asbestosis. The amphibole (crocidolite and amosite) lung content correlated with severity of asbestosis.

In plain English

This study examined lungs from 333 necropsies in the Plymouth area, sent during 1966-81 because local pathologists suspected asbestos-related disease. After exclusions, 189 men who had worked at the Royal Naval dockyard and had full occupational histories were analysed. Asbestosis was graded from none to marked/severe. Lung fibres were counted and identified by type using microscopy. Each man received an exposure rating based on his jobs and years worked. The authors reported that asbestosis grade correlated with fibre counts and with exposure ratings. Pleural mesothelioma caused 74 of the 189 deaths (39%), mostly among men with minimal (24 of 36) or slight (35 of 69) asbestosis. Lung cancer caused death in 3 of 36 men with minimal asbestosis and 13 of 16 with marked/severe asbestosis. Seven of 19 men without asbestosis also died of lung cancer, which the authors could not explain. The proportions of crocidolite and amosite rose with asbestosis grade. Once amphiboles were set aside, the chrysotile share appeared unrelated to grade. The authors concluded that disease severity may be correlated with amphibole fibre content and exposure ratings.

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: Pathological and mineralogical study of lungs taken at necropsy (post-mortem case series), with asbestosis grade, tumours and lung fibre content compared against coded occupational exposure ratings
• Who was studied: Lungs from 333 necropsies in the Plymouth area were referred during 1966-81. Pathologists sent cases at their discretion when they believed asbestos-related disease might have been the main or a contributory cause of death. After exclusions, 189 former Royal Naval dockyard workers remained, all male, with a mean age at death of 64. Exclusions were identification problems (4), insufficient tissue (22), occupation outside the dockyard (48), no full occupational history (59), dockyard work not confirmed in records (10) and one woman.
• Exposure: Occupational asbestos exposure at a naval dockyard, scored as an exposure rating: a code for each occupation, approximating its severity, multiplied by years in that job. Lung fibres were measured by light microscopy (Ashcroft technique) and by analytical transmission electron microscopy, which identified amosite, crocidolite, chrysotile and mullite.
• Main results:
  • Pleural mesothelioma accounted for 74 of 189 deaths (39%). It was more frequent in men with minimal asbestosis (24 of 36, 67%) and slight asbestosis (35 of 69, 51%) than in men with moderate (11 of 49, 22%) or marked/severe asbestosis (1 of 16, 6%).
  • Among men with asbestosis, lung cancer deaths increased with asbestosis grade: minimal 3 of 36 (8%), slight 9 of 69 (13%), moderate 17 of 49 (35%), marked/severe 13 of 16 (81%). Lung cancer caused 49 of 189 deaths (26%) overall.
  • Among the 19 men with no asbestosis, 7 (37%) had lung cancer. The authors described this as unexpected and unexplained.
  • Mean electron microscope fibre counts (x 10 to the 6th) rose with asbestosis grade: none 23.0, minimal 42.1, slight 59.5, moderate 343.2, marked/severe 2550.3. The authors described an acceptable correlation between asbestosis grade and lung fibre content measured by both electron and light microscopy.
  • Mean exposure ratings rose with asbestosis grade: none 212, minimal 219, slight 286, moderate 368, marked/severe 495. The authors reported good agreement between pathological grade and exposure rating.
  • The proportion of amphibole fibres rose from no asbestosis to marked/severe asbestosis. For amosite the proportions were 6%, 6%, 16%, 28% and 33%. For crocidolite they were 11%, 25%, 36%, 36% and 52%.
  • After amosite and crocidolite were excluded, the chrysotile share was 46%, 50%, 48%, 52% and 43% across the grades from none to marked/severe. The authors reported that the chrysotile and mullite proportions appeared unrelated to asbestosis grade.
  • No pattern was found for deaths from general respiratory disease or for the other causes of death.
• The authors' conclusion: The authors concluded that the severity of asbestos-related diseases may be correlated with the amphibole fibre content of the lungs and with occupational exposure ratings, and that chrysotile does not increase with severity. They considered the Ashcroft light microscope technique adequate for general pathological assessment. They considered analytical transmission electron microscopy essential for research.
• Limitations the authors state:
  • The light microscope (Ashcroft) technique fails to detect low quantities of chrysotile and other fine fibres. Fine fibres such as chrysotile and some crocidolite seen by electron microscopy are not seen under the light microscope.

Topics

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

Medical terms in this study, explained in our Lexicon: Pneumoconiosis, Occupational Exposure, Mesothelioma, Carcinoma, Amphibole Group, Crocidolite, Amosite.

Related studies

• Correlation between fibre content of lung and disease in east London asbestos factory workers — R.M. Rudd (1989)
• Correlation between fibre content of the lung and disease in east London asbestos factory workers — J.C. Wagner, M.L. Newhouse, et al. (1988)
• The health of welders in naval dockyards. The risk of asbestos-related diseases occurring in welders — G.H. McMillan (1983)
• UK Naval Dockyards Asbestosis Study: radiological methods in the surveillance of workers exposed to asbestos — G. Sheers, C.E. Rossiter, et al. (1978)
• UK Naval Dockyards asbestosis study: survey of the sample population aged 50-59 years — C.E. Rossiter, P.G. Harries (1979)
• Royal Naval dockyards asbestosis research project: nine-year follow-up study of men exposed to asbestos in Devonport Dockyard — C.E. Rossiter, J.R. Heath, et al. (1980)

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