Pleural plaques and respiratory function

Our plain-English summary of Pleural plaques and respiratory function, by B. Järvholm, A. Sandén (American Journal of Industrial Medicine, 1986).

The study

• Authors: B. Järvholm, A. Sandén
• Journal: American Journal of Industrial Medicine
• Published: 1986;10(4):419-26
• Cited by: 45 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. 000405).

Abstract

This cross-sectional study was comprised of 202 nonsmoking shipyard workers with varying exposures to asbestos. Their chest X-rays were normal or contained no abnormality other than pleural plaques. They participated in a health examination of workers exposed to asbestos, which comprised a total of 3,904 persons. One hundred and fifteen of the 202 workers had no deviations from normal X-rays, and 87 had pleural plaques but no other finding on their X-rays. Three out of the 115 workers with normal X-rays and 13 of the 87 with pleural plaques had FVCs below the reference limits (p less than 0.005). The workers with plaques had an average of 6.9% lower FVC. Even after stratification for asbestos exposure, men with plaques were found to have lower FVCs than men without plaques. This difference was largest for those with heavy exposure to asbestos.

In plain English

This cross-sectional study asked whether pleural plaques were linked to reduced lung function. The authors studied 202 lifelong nonsmoking men aged 40-65. They were drawn from 3,904 people examined in 1977-1979 after past asbestos exposure, mostly to chrysotile, at shipyards in Gothenburg, Sweden. Of these men, 115 had normal chest X-rays and 87 had pleural plaques with no other X-ray finding. Forced vital capacity (FVC), a measure of how much air the lungs can blow out, was on average 6.9% lower in men with plaques. FVC was below the reference limit in 3 of the 115 men without plaques and in 13 of the 87 men with plaques (p less than 0.005). When the men were grouped by self-reported exposure, FVC was 3.4% lower in men with plaques among low-exposure men and 8.2% lower among heavy-exposure men. Only the heavy-exposure difference was statistically significant. Among men without plaques, FVC did not clearly differ by exposure level. The authors concluded that pleural plaques are associated with slightly impaired lung function, possibly because of lung scarring not visible on X-ray.

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 study using data from a health examination of asbestos-exposed shipyard workers
• Who was studied: 202 lifelong nonsmoking men aged 40-65 from shipyards in Gothenburg, Sweden, selected from 3,904 people examined in 1977-1979. Of these, 115 had normal X-rays and 87 had pleural plaques only. Men with other X-ray abnormalities, such as asbestosis, were excluded, as were men with less than 20 years since first exposure.
• Exposure: Asbestos used at the shipyards, mostly chrysotile (2-6 tons per month in the 1950s and 1960s). Exposure level was self-reported and grouped as low (low or very low and less than 4 hours per week, N = 77) or heavy (heavy or very heavy and more than 4 hours per week, N = 67). A further 58 'Others' were not included in the exposure-level comparisons.
• Main results:
  • FVC was below the reference limit in 3 of 115 men without plaques and in 13 of 87 men with plaques (p < 0.005). The article prints these as 3% and 16%, but 13 of 87 works out to about 15%.
  • Across all ages combined, FVC was 6.9% lower in men with pleural plaques than in men without
  • After grouping by exposure level, the FVC difference between men with and without plaques was 3.4% for low-exposure men and 8.2% for heavy-exposure men. It was statistically significant only for heavy-exposure men (p < 0.02).
  • Among heavily exposed men, 8 had FVC below the reference limit, and 7 of these had pleural plaques (p < 0.05, Fisher's exact test)
  • Among men without plaques, there was no indication of impaired lung function by exposure level (FVC difference between low and high exposure 0.9%, p > 0.05)
  • An additional multivariate analysis also found plaques associated with about a 5% decrease in FVC
• The authors' conclusion: The authors concluded that pleural plaques are associated with slightly impaired lung function. They suggested a possible explanation is pulmonary fibrosis not visible on X-ray, perhaps combined with reduced chest mobility in men with large plaques.
• Limitations the authors state:
  • Chest X-rays have low sensitivity for plaques, so several cases of plaques probably went undetected, making an effect harder to detect
  • The reproducibility of the spirometry results was not checked

Topics

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

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

Related studies

• Abnormal pulmonary function associated with diaphragmatic pleural plaques due to exposure to asbestos — K.H. Kilburn, R.H. Warshaw (1990)
• Systematic review of pleural plaques and lung function — L.E. Kerper, H.N. Lynch, et al. (2015)
• Incidence of bronchial carcinoma in shipyard workers with pleural plaques — J.R. Edge (1979)
• Asbestos-related lesions of the pleura: parietal plaques compared to diffuse thickening studied with chest roentgenography, computed tomography, lung function, and gas exchange — G. Hillerdal, P. Malmberg, et al. (1990)
• The natural course of lung function decline in asbestos exposed subjects with pleural plaques and asbestosis — M. Barnikel, P.M. Million, et al. (2019)
• Pleural plaques and lung function in the Marysville worker cohort: a re-analysis — K. Zu, G. Tao, et al. (2016)

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