UK Naval Dockyards asbestosis study: survey of the sample population aged 50-59 years

Our plain-English summary of UK Naval Dockyards asbestosis study: survey of the sample population aged 50-59 years, by C.E. Rossiter, P.G. Harries (British Journal of Industrial Medicine, 1979).

The study

• Authors: C.E. Rossiter, P.G. Harries
• Journal: British Journal of Industrial Medicine
• Published: 1979;36(4):281-91
• Cited by: 22 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. 002099).

Abstract

As part of a general morbidity study of all civilian employees in the four Royal Naval Dockyards, the clinical, radiological and physiological effects of exposure to asbestos in 1200 men aged 50-59 years were studied in detail. The sample included all men on the Register of Asbestos Workers, one in three of those currently in occupations where intermittent exposure to asbestos may occur, and one in 30 of the remainder. The conclusions are mainly in accord with those of the comprehensive morbidity study of all the civilian dockyard workers, and show that smoking played a large part in increasing prevalence rates of radiographic, clinical, and physiological abnormalities in this population. A sub-group of 39 men, who were working as asbestos laggers or sprayers before 1957, was identified. These men showed much more extensive disease than any other sub-group, yet, even so, the smokers were worse than the non-smokers. Of these smokers, 48% had small opacities of category 1/1 or more, 76% reported that they coughed during the day and 53% had crepitations; forced expiratory volume and transfer factor were also markedly reduced in these 21 smokers. Although asbestos exposure had been intermittent for the majority of the population, the prevalences of pleural thickening, small opacities, current respiratory symptoms and crepitations were shown to be related to duration of exposure to asbestos.

In plain English

The study surveyed civilian men aged 50-59 in the four UK Royal Naval Dockyards in 1972 and 1973. The 1200 men included everyone on the Register of Asbestos Workers and smaller fractions of other trades. Dockyard workers had been exposed intermittently to amosite, chrysotile and crocidolite. Of these men, 1103 had full-size chest X-rays, 1062 were interviewed, 1055 were examined and 1042 had lung function tests. Pleural thickening, seen in 28.5% of men, was associated with duration of exposure. Apart from the subgroup described below, the authors reported that smoking had a much greater effect on cough than asbestos exposure. Men who had been asbestos laggers or sprayers before 1957 (39 men) had much more disease. Of them, 30.8% had small lung opacities of category 1/1 or more, against 2.9% of all other men. Smokers fared worst: 10 of 21 had such opacities, against none of seven non-smokers. The authors suggested there is no single pattern of response to asbestos, and that fibre type and type of work both matter. They noted that past job histories were not available for sampling.

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 morbidity survey of a random sample, stratified by current occupation. It used chest radiographs, a questionnaire interview, clinical examination and lung function tests.
• Who was studied: 1200 male civilian in-yard workers aged 50-59 at the Devonport, Chatham, Portsmouth and Rosyth Naval Dockyards, enumerated between March 1972 and August 1973. The sample included all 195 Registered Asbestos Workers, 40% of electrical fitters, welders, plumbers and similar trades, 33% of shipwrights and engine fitters, and about 3% of all other occupations.
• Exposure: Mostly intermittent exposure in naval dockyards to amosite, chrysotile and crocidolite. Exposure was measured as years of exposure to asbestos. A subgroup of 39 men had worked as asbestos laggers or sprayers before 1957.
• Main results:
  • Participation varied by assessment. Of the male in-yard workers, 1103 had a full-size chest radiograph, 1062 were interviewed, 1055 of those interviewed were clinically examined, and 1042 had lung function tests.
  • Small opacities of category 1/1 or more were found in 30.8% of the 39 men who were asbestos laggers or sprayers before 1957, compared with 2.9% of all other men.
  • Among the 39 pre-1957 laggers and sprayers, small opacities of category 1/1 or more were found in 10 of 21 smokers, two of 11 ex-smokers and none of seven non-smokers. The authors described these differences as significant (p less than 0.02).
  • Small opacities of category 2 or more were recorded for only eight men (0.7%). Six of them were Registered Asbestos Workers who had been laggers or sprayers before 1957. The other two had never been exposed to asbestos.
  • Overall, 28.5% of men had pleural thickening. Its prevalence was associated with duration of asbestos exposure, rising from 17.3% in men with 0-9 years of exposure to 41.2% in men with 30 or more years. There was no evidence of an association with smoking.
  • Pleural calcification was related to duration of exposure. It was more common in non-smokers (8.8%) than in ex-smokers (6.1%) and smokers (3.5%).
  • Apart from the pre-1957 laggers and sprayers, smoking had a much greater effect than asbestos exposure on the prevalence of cough. There was only slight evidence of a relation to duration of exposure.
  • Among the pre-1957 laggers and sprayers, 16 of 21 smokers reported cough during the day.
  • Persistent crackles (crepitations) were found in 52.6% (10 out of 19 examined) of smokers who were pre-1957 laggers and sprayers. This differed significantly from the average of 8% for all other groups.
  • Pre-1957 laggers and sprayers had lower FEV1 than the rest of the Registered Asbestos Workers, particularly among smokers. They also had the lowest transfer factor values.
• The authors' conclusion: The authors observed that their findings were similar to some earlier studies and different from others. They suggested that this means there is no single pattern of response to asbestos, and that both fibre type and type of work are important determinants of biological response.
• Limitations the authors state:
  • Retrospective occupational histories were not available, so sampling for occupation groups 2, 3 and 4 was based only on current occupation.
  • At Devonport a different gas-sampling technique gave lower values for residual volume and transfer factor, which also affected total lung capacity.
  • Lung function results reflected the medical screening that men had before entry onto the Register of Asbestos Workers.

Topics

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

Medical terms in this study, explained in our Lexicon: Insulator, Asbestos Exposure, Pleural Thickening.

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)
• UK Naval Dockyards Asbestosis Study: radiological methods in the surveillance of workers exposed to asbestos — G. Sheers, C.E. Rossiter, et al. (1978)
• The health of welders in naval dockyards. The risk of asbestos-related diseases occurring in welders — G.H. McMillan (1983)
• Protection of dockyard workers against asbestosis — P.G. Harries (1970)
• Correlation between fibre content of the lungs and disease in naval dockyard workers — J.C. Wagner, C.B. Moncrieff, et al. (1986)
• The rise and fall in incidence of malignant mesothelioma from a British Naval Dockyard, 1979-1999 — A.K. Hilliard, J.K. Lovett, et al. (2003)

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