Asbestotic radiological abnormalities among United States merchant marine seamen

Our plain-English summary of Asbestotic radiological abnormalities among United States merchant marine seamen, by I.J. Selikoff, R. Lilis, G. Levin (British Journal of Industrial Medicine, 1990).

The study

• Authors: I.J. Selikoff, R. Lilis, G. Levin
• Journal: British Journal of Industrial Medicine
• Published: 1990;47(5):292-7
• Cited by: 32 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. 003871).

Abstract

There has been limited information concerning the prevalence of radiologically evident parenchymal and pleural fibrosis consistent with prior exposure to asbestos among merchant marine seamen, despite the wide use of asbestos in ship construction until the late 1970s and subsequent exposure of seamen to the asbestos that had been installed. A total of 3324 chest radiographs (1985-7) of long term United States seamen were reviewed. One third (34.8%) had parenchymal or pleural abnormalities, or both (ILO classification); pleural changes were predominant. Abnormalities increased with longer duration from onset of shipboard exposure (as defined by first year at sea). The prevalence of asbestotic changes was greater among seamen who had served in the engine department (391/420; 42.5%) compared with seamen in other departments, including deck (301/820; 36.6%), steward (278/981; 28.4%), or with service in multiple departments (167/541; 30.9%). Since many vessels, particularly those built before 1978, contain asbestos materials, appropriate engineering controls (including complete removal, if possible) are required as well as appropriate medical surveillance for those who served aboard such ships.

In plain English

This study reviewed chest x-rays of long-term United States merchant marine seamen, taken in 1985-7. Members on union lists of about 10,000 active and retired seamen were invited for an x-ray, and roughly half came. One experienced B reader read 3488 films using the 1980 ILO classification, without knowing ages or jobs. After 102 unreadable films and 62 women were excluded, 3324 films were analysed. In 1157 of 3324 seamen (34.8%), the films showed lung-tissue (parenchymal) changes, pleural changes, or both, consistent with asbestos exposure. Pleural changes alone were the most common finding (601, 18.1%). Engine department seamen had the highest rate (391 of 920, 42.5%) and stewards the lowest (279 of 981, 28.4%). Pleural-only changes rose with years since first going to sea, reaching 21.2% (336 of 1588) at 40 or more years. Parenchymal changes did not rise steadily. Thirteen lung cancers were seen on the films. The authors concluded that abnormalities were more common in higher-exposure engine room jobs and rose with time since first exposure. They noted that disease can be present without x-ray changes.

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 survey: chest x-rays read by one B reader using the 1980 ILO classification, without knowledge of age, job or years at sea
• Who was studied: 3324 long-term United States merchant marine seamen with chest x-rays from 1985-7. They were drawn from union membership lists of about 10,000 active and retired seamen; roughly half of those invited attended. Of 3488 films, 102 unreadable films and 62 films of women were excluded. By department: engine 920, deck 823, steward 981, multiple departments 541, not known 59. Mean years at sea was about 28.
• Exposure: Asbestos installed aboard ships: bulkhead systems in living spaces, insulation of hot water and steam piping, boilers and tanks, block insulation and asbestos cement. Exposure was represented by shipboard department and years since first year at sea. No fiber types and no measured exposure levels were given.
• Main results:
  • All seamen: 1157 of 3324 (34.8%) had parenchymal or pleural abnormalities, or both, consistent with asbestos exposure
  • All seamen: pleural abnormalities were the only change in 601 (18.1%)
  • All seamen: small irregular parenchymal opacities (profusion 1/0 or higher) as the only abnormality in 329 (9.9%)
  • All seamen: both parenchymal and pleural changes in 227 (6.8%)
  • Engine department: highest prevalence of abnormalities, 42.5% (391 of 920 in Table 7)
  • Steward department: lowest prevalence, 28.4% (279 of 981 in Table 7)
  • Deck department: 36.6% (301 of 823 in Table 7; the article's abstract prints a different denominator)
  • Seamen who served in multiple departments: 30.9% (167 of 541)
  • All seamen: pleural changes alone (without parenchymal changes) rose with years since first exposure. They reached 21.2% (336 of 1588) in the longest-duration group, 40 or more years in Table 8. A further 119 of these 1588 (7.5%) had both pleural and parenchymal changes.
  • All seamen: total abnormalities were highest in the longest-duration group, at 38.5% (612 of 1588 in Table 8)
  • Parenchymal abnormalities did not increase steadily with years since first exposure
  • 13 cases of lung cancer were detected among the 3324 films
• The authors' conclusion: The authors concluded that abnormalities were more common in job classifications with higher asbestos exposure (engine room) and increased with years since first exposure. The link with duration was stronger for pleural than for parenchymal changes.
• Limitations the authors state:
  • Asbestos-related disease could be present without any x-ray abnormality
  • No quantitative data on shipboard asbestos fiber exposure levels had been published

Topics

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

Medical terms in this study, explained in our Lexicon: Merchant Marine, Fibrosis, Chest X-Ray, ILO Classification, Engineering Controls.

Related studies

• Asbestos related abnormalities among United States merchant marine seamen — P.J. Barrett (1990)
• Historical state of knowledge of the health risks of asbestos posed to seamen on merchant ships — D.G. Dodge, B.D. Beck (2016)
• Cancer mortality in merchant seamen — M. Greenberg (1991)
• Asbestos disease in United States shipyards — I.J. Selikoff, R. Lilis, et al. (1979)
• Radiological evidence of asbestos disease among ship repair workers — I.J. Selikoff, W.J. Nicholson, et al. (1980)
• Pulmonary function and pleural fibrosis: quantitative relationships with an integrative index of pleural abnormalities — R. Lilis, A. Miller, et al. (1991)

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