The radiographic pleural abnormalities in asbestos exposure: relationship to physiologic abnormalities

Our plain-English summary of The radiographic pleural abnormalities in asbestos exposure: relationship to physiologic abnormalities, by R.N. Jones, T. McLoud, S.D. Rockoff (Journal of Thoracic Imaging, 1988).

The study

• Authors: R.N. Jones, T. McLoud, S.D. Rockoff
• Journal: Journal of Thoracic Imaging
• Published: 1988;3(4):57-66
• Type of article: Review
• Cited by: 30 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. 000915).

Abstract

The effects of asbestos-induced benign pleural conditions on pulmonary function have been controversial since this subject was first studied in the mid-1960s. Firm conclusions have been difficult to reach because of (1) the difficulty of taking into account asbestos exposure, which may have effects on pulmonary function other than those mediated through pleural lesions, (2) the disagreement over the type and extent of radiographic pleural abnormalities, (3) the imprecision in measuring pulmonary function, and (4) the numerous potential confounding factors of reduced pulmonary function, such as cigarette smoking, age, concurrent occupational exposures, and prior chest diseases or trauma. This article critically evaluates the published reports on the functional significance of asbestos-induced pleural conditions. The results of this analysis lead to the conclusion that (1) pleural plaques are not associated with clinically significant reductions in pulmonary function, (2) diffuse pleural thickening, when extensive, can severely impair ventilation, and (3) restriction with a preserved diffusing capacity is the expected pattern when pleural lesions are responsible for reduced pulmonary function.

In plain English

This article was a critical review of published reports, dating from the mid-1960s onward, on whether benign pleural conditions caused by asbestos exposure reduce lung (pulmonary) function. The authors described the pleural conditions seen on chest radiographs. They then discussed why such studies are hard to interpret, including disagreement over classifying pleural abnormalities on radiographs, imprecise lung function measurement, and confounding factors such as smoking and age. They judged that the most common shortcoming of the reviewed studies was selection bias. The authors concluded that pleural plaques, as an isolated radiographic finding, do not by themselves produce clinically significant reductions in lung function. In groups of people, however, plaques are probably associated with small reductions in average lung function once other influences are controlled for, though most published studies had not done this adequately. They also concluded that diffuse pleural thickening can produce clinically severe impairment of breathing (ventilation). When pleural thickening is the main cause, the impairment is usually restriction with preserved diffusing capacity. Finally, they concluded that the effects of fissural thickening had not been fully explored.

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: critical review of published literature (no new study population)
• Who was studied: published studies of the lung-function effects of benign asbestos-induced pleural abnormalities, from the mid-1960s to 1988
• Exposure: asbestos exposure and the benign pleural conditions it can cause (pleural plaques, diffuse pleural thickening, fissural thickening, pleurisy with effusion)
• Main results:
  • The authors identified sources of imprecision in the studies: disagreement in classifying radiographic pleural abnormalities, imprecise lung function measurement, and confounding factors such as smoking and age
  • The authors judged selection bias to be the most common shortcoming of the reviewed studies
  • Pleural plaques as an isolated radiographic finding do not by themselves produce clinically significant reductions in lung function
  • In groups of persons, plaques are probably associated with small reductions in mean lung function after the study has controlled for other influencing variables
  • Most published studies of plaques had not adequately controlled for other factors affecting lung function
  • Diffuse pleural thickening from asbestos exposure can produce clinically severe impairment of ventilation
  • When pleural thickening is the sole or major cause of impaired lung function, the impairment usually consists of restriction with preserved diffusing capacity
  • The exposure relationships and lung-function effects of fissural thickening had not been fully explored
• The authors' conclusion: The authors concluded that the discordant findings in the literature result mainly from selection bias and from imprecision in characterizing exposure, controlling for confounders, and measuring responses.
• Limitations the authors state:
  • No single article or group of articles gives a definitive account, so the review had to draw pieces of evidence from many articles

Topics

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

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Confounding, Occupational Exposure, Pleural Plaques, Diffuse Pleural Thickening, Diffusing Capacity (DLCO).

Related studies

• Radiographic abnormalities and mortality in subjects with exposure to crocidolite — N.H. de Klerk, A.W. Musk, et al. (1993)
• Spirometric impairments in long-term insulators. Relationships to duration of exposure, smoking, and radiographic abnormalities — A. Miller, R. Lilis, et al. (1994)
• Overstating the consequences of radiographic abnormalities — J.J. Flynn, S. Kardos, et al. (2004)
• Radiographic abnormalities in asbestos insulators: effects of duration from onset of exposure and smoking. Relationships of dyspnea with parenchymal and pleural fibrosis — R. Lilis, A. Miller, et al. (1991)
• Symptomatic benign pleural effusions among asbestos insulation workers: residual radiographic abnormalities — R. Lilis, Y. Lerman, et al. (1988)
• Risk and significance of chest radiograph and pulmonary function abnormalities in an elderly cohort of former nuclear weapons workers — M.A. Mikulski, P.G. Hartley, et al. (2011)

Browse more research in Journal of Thoracic Imaging, or return to medical research.