Abnormal lung function associated with asbestos disease of the pleura, the lung, and both: a comparative analysis

Our plain-English summary of Abnormal lung function associated with asbestos disease of the pleura, the lung, and both: a comparative analysis, by K.H. Kilburn, R.H. Warshaw (Thorax, 1991).

The study

• Authors: K.H. Kilburn, R.H. Warshaw
• Journal: Thorax
• Published: 1991;46(1):33-8
• Cited by: 23 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. 003931).

Abstract

The impairment of lung function associated with different types of asbestos related disease was examined in 1298 men. The 310 men with circumscribed pleural lesions (plaques) or diffuse pleural thickening without asbestosis were compared with 596 men with asbestosis only and with 322 men with pleural abnormalities and asbestosis, as classified from chest radiographs by ILO pneumoconiosis criteria. Spirometric indices and total lung capacity (TLC; determined by planimetry) were measured and expressed as percentages of predicted values. Non-smoking men with pleural disease only had reduced values of mid and terminal expiratory flows (80.6 and 69.9% predicted) and a reduced FEV1 (89% predicted) with a forced vital capacity (FVC) of 94% predicted. TLC was 104% predicted. Thus they had airways obstruction with-out restriction. Non-smoking men with pulmonary asbestosis (ILO profusion of opacities mostly 1/0 and 1/1) had pulmonary function similar to that of men with pleural disease. FEV1 and FVC and flow rates at other lung volumes were lower in smokers with asbestosis (after adjustment for duration of smoking) than in the non-smokers with asbestosis. Airflow limitation was worse in the men with both pleural abnormalities and pulmonary asbestosis with lower values for mid expiratory flow, FEV1 and FVC (but not TLC) than those with either abnormality alone, in both non-smokers and current smokers. Men with diffuse pleural thickening that included the costophrenic angles had more airways obstruction and air trapping and lower FVC values than those with circumscribed pleural disease.

In plain English

This cross-sectional study compared breathing-test results in 1298 white male asbestos-exposed workers, mostly boilermakers and pipefitters, examined at 20 sites across the United States. All had been first exposed at least 15 years earlier, for at least five years. The article did not name fiber types. Using chest X-rays read by ILO criteria, the men were grouped as having pleural abnormalities only, asbestosis only, or both. Their results were compared with predicted values and with 370 Michigan men. In never-smokers, all three groups had lower expiratory flows than predicted, while total lung capacity was normal. Men with both conditions had slightly lower values, but these differences were not statistically significant. In current smokers, the 269 men with both had significantly lower FVC, FEV1 and mid-expiratory flow than either single group. Diffuse pleural thickening with blunted costophrenic angles was associated with significantly more impairment, with or without asbestosis. The authors concluded that asbestos-exposed men with pleural disease have impaired lung function. They suggested that pleural disease signals asbestosis too slight to see on routine X-rays.

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 comparison of lung function across groups defined by chest radiograph findings
• Who was studied: 1298 white men, selected from 4572 male boilermakers and pipefitters (others from metal or chemical trades), studied at 20 sites across the United States; 259 non-smokers, 969 current smokers and 70 ex-smokers. Study dates not given.
• Exposure: Occupational asbestos exposure; all first exposed at least 15 years before and exposed for at least five years. Fiber types not specified.
• Main results:
  • In never-smoking men, expiratory flows including FEV1 were lower than predicted in all three groups (pleural signs only, asbestosis only, both); FVC was also decreased while total lung capacity was normal.
  • Among never-smokers, the 53 men with both pleural disease and asbestosis had lower lung function values than the other groups, but the differences were not statistically significant.
  • Among current smokers, the 498 men with asbestosis only had reductions in lung function similar to those of the men with pleural disease only.
  • Among current smokers, the 269 men with both pleural disease and asbestosis had FVC 86%, FEV1 80%, FEF25-75 61%, TLC 112% and RV/TLC 53% of predicted. Their FVC, FEV1 and FEF25-75 were below those of the pleural-only and asbestosis-only groups (p less than 0.001).
  • In 333 men with pleural disease but no asbestosis, there appeared to be a gradient from calcified plaques (45 men) to plaques (98) to diffuse thickening (129), but these differences were not statistically significant.
  • In men without asbestosis, the 61 men with diffuse pleural thickening plus blunting of one or both costophrenic angles had significantly lower FVC, FEV1 and FEF25-75 than the other pleural groups.
  • In 369 men who also had asbestosis, there was no gradient of impairment across pleural types, but the 84 men with diffuse thickening and blunted or obliterated costophrenic angles had significantly lower flow rates and FVC.
  • Total lung capacity did not decrease as radiographic abnormalities increased.
• The authors' conclusion: The authors concluded that asbestos-exposed men with pleural disease have impaired lung function. They stated their view that pleural asbestos disease signifies asbestosis below the threshold of detection on routine chest radiography. They also concluded that calcified plaques are more than a marker of exposure.

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: Pleura, Diffuse Pleural Thickening, Chest X-Ray, Pneumoconiosis, Total Lung Capacity (TLC), FEV1, Asbestosis, Costophrenic angle.

Related studies

• Abnormal pulmonary function associated with diaphragmatic pleural plaques due to exposure to asbestos — K.H. Kilburn, R.H. Warshaw (1990)
• Dynamics of the lung function in asbestos pleural disease — I. Perić, D. Arar, et al. (2007)
• Cardiorespiratory responses to incremental exercise in patients with asbestos-related pleural thickening and normal or slightly abnormal lung function — A. Miller, A. Bhuptani, et al. (1993)
• Lung function and chest radiograph abnormalities among construction insulators — S.M. Kennedy, S. Vedal, et al. (1991)
• Total lung capacity. An insensitive measure of impairment in patients with asbestosis and chronic obstructive pulmonary disease? — S. Barnhart, L.D. Hudson, et al. (1988)
• Review of the Kilburn and Warshaw Chest article--airways obstruction from asbestos exposure — R.N. Jones, H.W. Glindmeyer, et al. (1995)

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