Prevalence of radiographic abnormalities among Northern California shipyard workers

Our plain-English summary of Prevalence of radiographic abnormalities among Northern California shipyard workers, by P.L. Polakoff, B.R. Horn, O.R. Scherer (Annals of the New York Academy of Sciences, 1979).

The study

• Authors: P.L. Polakoff, B.R. Horn, O.R. Scherer
• Journal: Annals of the New York Academy of Sciences
• Published: 1979;330:333-9
• Cited by: 19 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. 004019).

Summary of the article

The authors measured how common chest X-ray changes compatible with asbestos exposure were among shipyard workers in Northern California. They took posterior-anterior chest radiographs of 359 male volunteers who were present or former workers at the Mare Island and Hunter's Point Naval Shipyards in the San Francisco Bay Area. All had at least 10 years since first exposure to asbestos. The article does not state when the study was done. At least two of the authors read each film using the ILO-U/C classification. Later, 311 workers completed a questionnaire on occupation, smoking, respiratory symptoms and medical history. The data were analysed by chi-square. Normal films were found in 147 workers (40.9%) and abnormal films in 213 (59.1%). Of these, 36.2% were mildly and 19.8% moderately abnormal. Parenchymal changes were found in 158 workers (44%) and pleural changes in 94 (26%). Pleural changes became more common with age and with time since first exposure: 18% among those who started after 1953 and 43% among those who started before 1953. Ten workers (2.8%) had pleural calcification. Overall parenchymal changes did not vary with age or time since exposure. Only 12 workers (3.3%) had changes of 1/2 or greater. Seven workers had mass lesions, four known to be lung carcinoma. Abnormalities were spread evenly across occupations. Eighty-five percent of respondents were smokers or ex-smokers. The authors concluded that all past shipyard workers, regardless of craft, are at risk of asbestos-related disease and recommended medical surveillance.

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 chest X-ray survey covered 359 male volunteers, present and former workers at the Mare Island and Hunter's Point Naval Shipyards in the San Francisco Bay Area, all at least 10 years past their first asbestos exposure. Fiber types were not named. At least two authors read each film using the ILO-U/C classification, and 311 workers later completed a questionnaire. Films were normal in 147 workers (40.9%); the article counts 213 (59.1%) as abnormal. Lung-tissue (parenchymal) changes appeared in 158 workers (44%) and pleural changes in 94 (26%). Seven had mass lesions, four known to be lung cancer. Pleural changes increased with age and with time since first exposure: 18% among those starting after 1953 versus 43% among earlier starters. Overall parenchymal changes did not rise with age or time since exposure, though more advanced changes were more common in older groups. Abnormalities were spread evenly across trades. The authors concluded that past shipyard workers of every craft are at risk of asbestos-related disease. They noted that studying volunteers may have biased the results.

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 chest X-ray survey of volunteer shipyard workers, with a questionnaire given at a later date
• Who was studied: 359 male volunteers, present and former workers at Mare Island and Hunter's Point Naval Shipyards, San Francisco Bay Area. 311 of them completed the questionnaire. The article does not give the dates of the study.
• Exposure: Asbestos exposure in shipyard work, with at least 10 years since first exposure. Fiber types and doses were not reported. Trades among questionnaire respondents included welder, pipefitter, insulator, machinist, boilermaker, shipfitter, electrician, sheet metalworker, sandblaster and others.
• Main results:
  • Of the 359 workers, 147 (40.9%) had normal chest films. The text reports 213 (59.1%) as having abnormal films.
  • 36.2% of workers had mildly abnormal films and 19.8% had moderately abnormal films. The text says these are 'of the abnormal films', but Table 1 gives them as percentages of all 359 workers.
  • Parenchymal abnormalities were found in 158 workers (44%) and pleural changes in 94 (26%).
  • Eleven workers had other radiographic changes, including seven with mass lesions. Four of those lesions were known to be lung carcinoma.
  • Pleural abnormalities increased with age (reported as less than 0.01). In the 60-69 age group, 54% had pleural abnormalities.
  • Pleural calcifications were found on 10 of the 359 chest films (2.8%), all in workers over age 50.
  • Only 12 films (3.3%) had parenchymal changes of 1/2 or greater.
  • The frequency of abnormal parenchymal films did not change with age: 40% in the 30-39 group and 43% in the 60-69 group. More advanced parenchymal changes were more frequent in older age groups (reported as less than 0.01).
  • Among questionnaire respondents, pleural changes were found in 18% of those who began working after 1953, compared with 43% of those whose asbestos exposure began before 1953.
  • Parenchymal abnormalities showed no significant change with increasing time since onset of asbestos exposure.
  • Among the 311 questionnaire respondents, abnormalities were distributed evenly across all occupations listed.
  • 85% of questionnaire respondents were smokers or ex-smokers. Smokers and non-smokers had the same prevalence of parenchymal and pleural abnormalities.
  • About 43% of workers reported chronic cough. Workers with parenchymal disease had a higher frequency of cough (reported as less than 0.05) and a significantly higher frequency of dyspnea. Workers with pleural disease did not have more dyspnea.
• The authors' conclusion: The authors concluded that everyone who worked in the shipyards in the past, regardless of craft, is at risk of developing asbestos-related disease.
• Limitations the authors state:
  • All workers were volunteers, so the study may have selected workers with abnormalities in all age groups.
  • Parenchymal changes may have been due to other factors, such as cigarette smoking or exposure to other toxic agents.
  • Readers vary much more in interpreting parenchymal changes than pleural changes.
  • Few workers were nonsmokers, and selection bias could have affected the smoking findings.

Topics

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

Medical terms in this study, explained in our Lexicon: Chest X-Ray, Asbestos Exposure, Pleural Calcification, Carcinoma.

Related studies

• Radiographic search for asbestos-related disease in a naval shipyard — J.S. Felton (1979)
• Lung cancer prevalence among shipyard workers — W.J. Nicholson, R. Lilis, et al. (1980)
• Asbestosis, pulmonary symptoms and functional impairment in shipyard workers — K.H. Kilburn, R. Warshaw, et al. (1985)
• Incidence of bronchial carcinoma in shipyard workers with pleural plaques — J.R. Edge (1979)
• Mortality among shipyard workers in Genoa, Italy — R. Puntoni, M. Vercelli, et al. (1979)
• Airway obstruction in asbestos-exposed shipyard workers: with and without irregular opacities — K.H. Kilburn, R.H. Warshaw (1990)

Browse more research in Annals of the New York Academy of Sciences, or return to medical research.