Effects of asbestos in dockyard workers

Our plain-English summary of Effects of asbestos in dockyard workers, by G. Sheers, A.R. Templeton (British Medical Journal, 1968).

The study

• Authors: G. Sheers, A.R. Templeton
• Journal: British Medical Journal
• Published: 1968;3(5618):574-9
• Cited by: 78 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. 001463).

Abstract

The prevalence of pleural and pulmonary abnormalities attributed to asbestos among 15,000 workers in a naval dockyard has been studied by means of a one-in-ten sample. Ninety-four per cent. of the men in the sample were examined. Of these, 3% had experienced continuous occupational exposure to asbestos and half of the remainder (representing approximately 6,800 men) had been exposed intermittently. The prevalence of pleural fibrosis ranged from 28% in continuously exposed workers to 1.9% in those with least exposure.Most cases of pulmonary fibrosis occurred in laggers and sprayers who had been continuously exposed for between 15 and 20 years. Pulmonary fibrosis was also seen in a variety of intermittently exposed trades, and had been preceded by extensive pleural thickening in some cases. Ten cases of pleural mesothelioma have occurred in the last three years and a large number of men appear to be potentially at risk.

In plain English

This 1968 report described a chest X-ray survey, made in 1966, of men at the Royal Dockyard in Devonport, England. This naval dockyard had used all types of asbestos fibre, including amosite and crocidolite. From 15,040 men, a one-in-ten sample was drawn, and 1,414 were examined (a 94% response). Men were grouped by trade, from continuous exposure (such as laggers, sprayers and painters) to varied or insignificant exposure. Abnormalities attributed to asbestos were found in 4.4% (63 of 1,414). Of these, 48 had limited pleural plaques, 11 had extensive pleural thickening and four had pulmonary fibrosis, three of whom were laggers. The authors put the prevalence of pleural abnormalities at an expected 28% among continuously exposed men, 14% (28 of 199) among intermittently exposed tradesmen 25 or more years after first exposure, and 1.9% in the least exposed group. Ten cases of pleural mesothelioma were confirmed from 1965 to 1967, all in men with intermittent exposure. The authors concluded that a large number of men appeared potentially at risk. They noted that radiographic surveys underestimate pleural abnormalities.

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: Cross-sectional radiographic prevalence survey of a one-in-ten sample of dockyard workers, made in 1966
• Who was studied: Men on the weekly pay roll of the North and South Yards of the Royal Dockyard, Devonport (15,040 men). 1,414 men in the 10% sample were examined, a 94% response.
• Exposure: All types of asbestos fibre were used in ship refitting, for example amosite steam-pipe insulation and crocidolite below the flight decks of aircraft carriers. Exposure was classed by trade: group 1 continuous (laggers, sprayers, masons, sailmaker-laggers, asbestos storemen, painters; 42 men), groups 2 and 3 intermittent (355 and 333 men), and group 4 varied or insignificant (684 men).
• Main results:
  • Prevalence of all types of abnormality attributed to asbestos in the sample: 4.4% (63 cases in 1,414 men)
  • Four cases of pulmonary fibrosis were found in the sample. Three were in the high-risk (continuously exposed) group and all three had been laggers. The fourth was a labourer who had cleared up lagging debris.
  • Eleven cases of extensive pleural thickening were found, two of them in the high-risk group (a lagger and a painter)
  • Forty-eight men in the sample showed limited pleural plaques
  • Based on the 10% sample, the expected prevalence of pleural abnormalities among the 420 continuously exposed men was 28%
  • In groups 2 and 3 combined, the prevalence of pleural abnormalities 25 years or more after first exposure was 14% (28 cases in 199 men)
  • In group 4, where over half the workers had little more than environmental exposure, the prevalence rate was 1.9%
  • The first histologically confirmed pleural mesothelioma occurred in 1964 in a boilermaker. Further confirmed cases numbered three in 1965, two in 1966 and five in 1967. All had intermittent exposure to asbestos of all types. Peritoneal involvement was not observed.
  • Two cases of bronchogenic carcinoma were found in the sample. The authors stated there was insufficient evidence to establish an association with asbestos exposure in the dockyard.
• The authors' conclusion: The authors concluded that pleural mesothelioma had occurred and that a large number of men appeared to be potentially at risk
• Limitations the authors state:
  • Rates by exposure group are subject to error because group 1 was small (3% of the total), and they are not adjusted for age
  • Exposure could not be measured as dust concentrations and time exposed, so the analysis was based on trade
  • Prevalence rates based on radiographic surveys are considerably underestimated
  • The intermediate (extensive pleural thickening) category includes borderline cases

Topics

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

Medical terms in this study, explained in our Lexicon: Occupational Exposure, Fibrosis, Pulmonary Fibrosis, Insulator, Pleural Thickening, Pleural Mesothelioma.

Related studies

• Asbestos-associated disease in employees of Devonport Dockyard — G. Sheers (1979)
• The health of welders in naval dockyards. The risk of asbestos-related diseases occurring in welders — G.H. McMillan (1983)
• A proportional study of cancer registrations of dockyard workers — K.P. Lumley (1976)
• Correlation between fibre content of the lungs and disease in naval dockyard workers — J.C. Wagner, C.B. Moncrieff, et al. (1986)
• UK Naval Dockyards Asbestosis Study: radiological methods in the surveillance of workers exposed to asbestos — G. Sheers, C.E. Rossiter, et al. (1978)
• Protection of dockyard workers against asbestosis — P.G. Harries (1970)

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