Asbestos-associated disease in employees of Devonport Dockyard

Our plain-English summary of Asbestos-associated disease in employees of Devonport Dockyard, by G. Sheers (Annals of the New York Academy of Sciences, 1979).

The study

• Author: G. Sheers
• Journal: Annals of the New York Academy of Sciences
• Published: 1979;330:281-7
• Cited by: 16 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. 004023).

Summary of the article

This paper described asbestos-associated abnormalities during the 10 years after 1966 in Devonport Dockyard, the largest of the four main UK naval dockyards. About 15,000 men worked there, and past exposure was to chrysotile and, in most cases, also crocidolite and amosite. A 1966 one-in-ten sample showed a prevalence of all asbestos-associated abnormality of 4.5% (pleural 4.2%, pulmonary fibrosis 0.3%). Of 971 men with normal radiographs in 1966 who were re-examined in 1977, 96 had nonmalignant asbestos-related abnormalities: 79 plaques, 11 diffuse pleural fibrosis and six pulmonary fibrosis. Annual attack rates were 8.4 per thousand for pleural abnormalities and 0.5 per thousand for pulmonary fibrosis. Among 256 men with pleural abnormalities followed for over 10 years, 38% of hyaline plaques were unchanged, and 10% overall progressed to pulmonary fibrosis. Acute pleural reactions were seen in 52 cases. Among 410 men with pleural abnormalities there were 75 deaths in 1967-1976, with an excess of cancer deaths, mainly mesothelioma. No excess bronchial carcinoma mortality was demonstrable in men with plaques. Of 103 mesothelioma cases diagnosed in the Plymouth area, 100 were associated with dockyard work or naval service. The author concluded that a dockyard pleural plaque could no longer be assumed to be only a marker of exposure, and that fibrosing disease was now seldom severe. He expected mesothelioma incidence to keep rising into the 1980s.

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 paper, from Plymouth General Hospital, England, brought together surveys and follow-up studies of men at Devonport Dockyard, which employed some 15,000 men, after 1966. Past exposure had been to chrysotile and, in most cases, crocidolite and amosite. When men with normal 1966 chest X-rays were re-examined in 1977, 96 of 971 had new nonmalignant asbestos-related abnormalities, mostly pleural plaques. This gave average annual rates of 8.4 per thousand for pleural abnormalities and 0.5 per thousand for pulmonary fibrosis. Of 256 men with pleural abnormalities followed for 10 years, 10% progressed to pulmonary fibrosis. No excess of bronchial carcinoma deaths was demonstrable in 303 men with plaques compared with 1351 men with normal X-rays. Thirty-eight mesothelioma deaths were known from 1967 to 1976 among 5120 men aged 35-64 working in the dockyard in 1966 whose first exposure was over 20 years earlier. Among 283 men with plaques in the same age groups there were six deaths, more than double the expected number. The author concluded that a dockyard plaque can no longer be assumed to be only a marker of exposure.

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: Overview of the author's and colleagues' surveys and follow-up studies of one dockyard workforce: a 1966 prevalence survey of a one-in-ten sample, its 1977 re-examination, follow-up of men with pleural abnormalities, and mesothelioma case counts
• Who was studied: Men employed at Devonport Dockyard, Plymouth, England (about 15,000 men). Fewer than 3% handled asbestos products continuously. An estimated 7000 others were exposed intermittently as neighborhood workers. Subgroups included a one-in-ten sample examined in 1966 and re-examined in 1977, and an accumulated series of 410 men with pleural abnormalities.
• Exposure: Asbestos exposure in dockyard work before preventive measures were introduced in 1965: chrysotile and, in most cases, crocidolite and amosite. Exposure was continuous for a few men and intermittent, at widely varying and sometimes very high dust concentrations, for many neighborhood workers.
• Main results:
  • Of 971 men with normal radiographs in 1966 who were re-examined in 1977, 96 had nonmalignant asbestos-related abnormalities: 79 plaques, 11 diffuse pleural fibrosis, and 6 new cases of pulmonary fibrosis (5 in men with intermittent exposure).
  • In the re-examined sample, the average annual attack rate was 8.4 per thousand for pleural abnormalities and 0.5 per thousand for pulmonary fibrosis.
  • In the nine-year follow-up of the most heavily exposed men, there were six deaths directly attributable to pulmonary fibrosis out of 36 cases.
  • Among 256 men with pleural abnormalities followed for over 10 years (preliminary results), about 30% of both plaque types developed additional fibrosing reactions. In 10% (26 of 256) these progressed to pulmonary fibrosis.
  • Smokers and ex-smokers made up 92% of men with diffuse pleural fibrosis, acute pleural reactions or pulmonary fibrosis. The figure was 86% for hyaline plaques, 84% for calcified plaques, and 84% for normal men aged 40 and over.
  • A proportional cancer registration study for 1960-1969 showed a ratio of 107 for bronchial carcinoma in dockyard workers, compared with 100 for all Plymouth males. The difference was not statistically significant.
  • Among 410 men with pleural abnormalities there were 75 deaths from 1967 to 1976. These included 11 from bronchial carcinoma and 8 from mesothelioma. A proportional analysis showed an excess of cancer deaths, mainly due to mesothelioma.
  • Seven bronchial carcinoma deaths occurred among 303 men whose first abnormality was a simple pleural plaque. No excess bronchial carcinoma mortality was demonstrable compared with the 1351 men with normal radiographs in 1966.
  • Of 103 mesothelioma cases diagnosed in the Plymouth area, 100 were associated with dockyard work or service in naval vessels.
  • Thirty-eight mesothelioma deaths were known from 1967 to 1976 among 5120 men aged 35-64 who were working in the dockyard in 1966 and whose first exposure was more than 20 years earlier. The author estimated a maximum of 43.
  • Among 283 men in the same age groups with pleural plaques there were six deaths in the same period, more than double the expected number.
• The authors' conclusion: The author concluded that the risk of later pulmonary fibrosis appeared broadly similar for all kinds of pleural abnormality, so a dockyard-related pleural plaque can no longer be assumed to be only a marker of exposure. The author also judged that the rising incidence of mesothelioma appeared likely to continue into the 1980s.
• Limitations the authors state:
  • The 1966 prevalence figures probably underestimate the true position.
  • Many symptomless acute pleural episodes have probably gone unrecognized.
  • The increase in extent of calcified plaques may be partly due to easier radiological recognition.
  • Only a tentative discussion of bronchial carcinoma mortality was possible on the evidence available.
  • Mesothelioma deaths outside the Plymouth area were probably missed.
  • It was still too soon to see changes in the rate of new cases that might follow the end of exposure.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Shipyards and maritime work.

Medical terms in this study, explained in our Lexicon: Chrysotile, Crocidolite, Amosite, Pulmonary Fibrosis, Fibrosis, Mesothelioma, Carcinoma, Pleural Plaques.

Related studies

• 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)
• Experience with asbestos disease and its control in Great Britain's naval dockyards — P.G. Harries (1976)
• The health of welders in naval dockyards. The risk of asbestos-related diseases occurring in welders — G.H. McMillan (1983)
• Case-control study of lung cancer in civilian employees at the Portsmouth Naval Shipyard, Kittery, Maine — R.A. Rinsky, J.M. Melius, et al. (1988)
• Incidence of bronchial carcinoma in shipyard workers with pleural plaques — J.R. Edge (1979)
• Effects of asbestos in dockyard workers — G. Sheers, A.R. Templeton (1968)

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