Pathologica, physiological, and radiological correlations in the pneumoconioses

Our plain-English summary of Pathologica, physiological, and radiological correlations in the pneumoconioses, by E.A. Gaensler, C.B. Carrington, R.E. Coutu, et al (Annals of the New York Academy of Sciences, 1972).

The study

• Authors: E.A. Gaensler, C.B. Carrington, R.E. Coutu, A. Tomasian, L. Hoffman, A.A. Smith
• Journal: Annals of the New York Academy of Sciences
• Published: 1972;200:574-607
• Cited by: 63 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. 001330).

In plain English

This was a preliminary report from Boston on 52 patients with pneumoconiosis. They were chosen from 152 referrals between 1950 and 1971 because each had lung tissue (mostly from open lung biopsy), chest X-rays and breathing tests. Thirty-one had been exposed mainly to asbestos and 21 mainly to silica, coal, graphite or talc. The authors noted that this selection favored early disease and was not a cross section of pneumoconiosis. Most patients had fairly normal airflow, but reduced lung volume was common. It was more severe in the asbestos group (mean vital capacity 64% of predicted) than in the silica group (74.6%). Impairment estimated from the tissue between the obvious lesions closely matched impairment measured by breathing tests (r = 0.80 in the asbestos group, 0.79 in the silica group). The amount of dust seen in the tissue did not. X-ray severity was correlated with lung function in the asbestos group (r = -0.56 for forced vital capacity) but not in the silica group, and was of little value for individual patients. The authors concluded that radiographic densities should not be used to evaluate impairment or disability.

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: Preliminary clinical, pathological, physiological and radiological correlation study of a selected case series, with illustrative individual case descriptions
• Who was studied: 52 patients selected from 152 with a tentative diagnosis of pneumoconiosis, out of 4,751 referrals to the Thoracic Services laboratories in Boston (Thorndike Memorial Laboratory, Harvard Medical School, to 1960; Boston University Medical Center to 1971), 1950-1971. All had lung tissue obtained within one year of clinical, radiological and physiological examination: open lung biopsy in 30, autopsy in 7, both in 9.
• Exposure: 31 patients were exposed primarily to asbestos (the 'asbestos group'). About half worked in asbestos products manufacture or shipyards; others worked in paper and tile manufacture, construction near laggers, and automotive work. One patient had handled Cape Blue asbestos in cigarette filter manufacture. 21 others (the 'silica group') were exposed mainly to silica (foundries, granite, abrasives), carbon (coal mining, graphite) or talc. In the talc-exposed patients, silica and asbestos amphiboles were also demonstrated.
• Main results:
  • For the whole group of 52, breathing capacity was largely maintained and obstruction was uncommon. Maximal breathing capacity averaged 90% of predicted, FEV1 averaged 77% of FVC, and mean residual volume was 105% of predicted.
  • Lung volume restriction was common and more severe in the asbestos group: mean vital capacity was 64% of predicted, against 74.6% in the silica group.
  • Functional impairment estimated from the severity of interstitial changes in the tissue between the obvious lesions correlated with measured impairment: r = 0.80 in the asbestos group and r = 0.79 in the silica group (both P < 0.01).
  • The amount of dust seen in lung sections was not related to functional impairment (asbestos bodies r = 0.06; carbon r = -0.23; silica r = 0.08).
  • X-ray severity correlated with lung function in the asbestos group (FVC r = -0.56; single-breath diffusing capacity r = -0.55; both P < 0.01). There was no correlation in the silica group (FVC r = -0.01; diffusing capacity r = 0.04; not significant).
  • In the asbestos group, the X-ray-to-function relationship was significant for the group but not useful for individuals. Patients with normal chest films had FVC from 50 to 98% and diffusing capacity from 49 to 128%. Those with grossly abnormal films had FVC from 38 to 72% and diffusing capacity from 18 to 86%.
  • For an equal X-ray profusion score, lung volume restriction and impaired gas exchange were much worse in the asbestos group than in the silica group.
  • Shortness of breath correlated more closely with breathing more than expected during a standard walking test (r = 0.70, P < 0.01) than with reduced breathing capacity (r = -0.44, P < 0.01).
  • Interstitial pneumonia was found to be a characteristic lesion of the pneumoconioses in general, not only in asbestosis or talcosis.
  • The earliest detectable abnormality was structural. For example, one former Naval shipyard pipe-department worker had a normal chest film and normal lung function tests, but abnormal lung tissue with asbestos bodies.
• The authors' conclusion: The authors concluded that tissue changes appear before functional or X-ray changes. In asbestosis, functional deficits often come before visible X-ray shadows, whereas in silicosis and coal workers' pneumoconiosis the X-ray changes come first. They took both observations to suggest that radiographic densities should not be used to evaluate pulmonary impairment or disability.
• Limitations the authors state:
  • Patient selection was not a cross section of pneumoconiosis; it favored early disease, unusual exposures, and patients operated on for other lesions.
  • There were no patients with progressive massive fibrosis or severe chronic obstructive lung disease.
  • Only a few patients had coal workers' pneumoconiosis.
  • A lung biopsy may not be representative of the whole lung.
  • Handling of the lungs at autopsy was usually not under the authors' control.
  • Emphysema is difficult to judge from biopsy specimens.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Talc and vermiculite.

Related studies

• The pneumoconioses — W. Tsai, W.K. Morgan (1996)
• Respiratory impairments due to dust exposure: a comparative study among workers exposed to silica, asbestos, and coalmine dust — X. Wang, E. Yano, et al. (1997)
• Environmental lung disease — M.X. FitzGerald, C.B. Carrington, et al. (1973)
• The classic pneumoconioses: new epidemiological and laboratory observations — A.S. Laney, D.N. Weissman (2012)
• Electron microscopic findings in the lungs of miners — G. Harrison, N.L. Lapp (1972)
• The second diagnosis: the role of the pathologist in identifying pneumoconioses in lungs excised for tumor — E.J. Mark (1981)

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