Clinical, Radiological, and Physiological Findings in Asbestosis

Our plain-English summary of Clinical, Radiological, and Physiological Findings in Asbestosis, by M. Kleinfeld, J. Messite, J. Shapiro (1966).

The study

• Authors: M. Kleinfeld, J. Messite, J. Shapiro
• Published: Archives of Internal Medicine, vol. 117, June 1966, pp. 813-819
• Type of article: Journal article
• Our copy: from Johns-Manville's own medical library. The article is still under copyright, so we describe it here rather than post it.

In plain English

This study, from New York and published in 1966, examined 21 asbestos insulators. Each had more than ten years of exposure to asbestos dust and chest X-ray findings compatible with asbestosis, and their average exposure was 29.2 years. They were compared with a control group of men who had no occupational dust exposure. Ten of the 21 had chronic cough, seven had breathlessness on exertion, and eight had crackling sounds at the lung bases. On X-ray, lung infiltration was minimal in eight, moderate in nine and severe in four, and five showed pleural calcification. Heart tracings were normal in 15, and none showed the main criteria for cor pulmonale. The authors said cor pulmonale could not be ruled out without pulmonary artery pressure data. Breathing tests showed low vital capacity in 14 workers, low total lung capacity in 8 and low diffusion capacity in 13. Sixteen of the workers were compared with 20 asbestos workers whose X-rays were negative. The group with positive X-rays had significantly lower vital capacity, total lung capacity and diffusion capacity. The authors concluded that the abnormal lung function findings were consistent with a restrictive breathing and diffusion capacity impairment.

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: clinical study (case series) of asbestos workers with radiological findings of asbestosis, compared with an unexposed control group, plus a comparison with asbestos workers who had negative X-rays
• Who was studied: 21 asbestos insulators, each with more than ten years of asbestos dust exposure and X-ray findings compatible with asbestosis; studied by the Division of Industrial Hygiene, New York; published June 1966. Controls were men of varied occupations with no occupational dust exposure (the number of controls is unclear in the scanned text).
• Exposure: Asbestos dust exposure as insulators. The only exposure data available were duration of exposure, with a mean of 29.2 years. The words naming the fiber types are illegible in the scanned text.
• Main results:
  • Of the 21 asbestos workers, ten had chronic cough, seven had exertional breathlessness, eight had basilar crepitations (crackles), and six had clubbing.
  • 16 of the 21 asbestos workers (76.2%) had a positive smoking history, a statistically significantly higher proportion than in the control group.
  • Electrocardiograms were normal in 15 of the 21 asbestos workers, and no individual showed electrocardiographic findings meeting the major criteria of cor pulmonale.
  • On chest X-ray, pulmonary infiltration was grade 1 in eight workers, grade 2 in nine and grade 3 in four. Pleural calcification was seen in five, and no cardiac enlargement was found in any case.
  • Among the asbestos workers, lung function was low for vital capacity in 14, for total lung capacity in 8 and for diffusion capacity in 13.
  • Apart from vital capacity and diffusion capacity, the asbestos workers' group mean lung function values fell within the 95% confidence limits of the control group.
  • Workers with dyspnea and lung crepitations had significantly lower mean vital capacity and total lung capacity than those without these findings. Correlation was poor with clubbing and weak with degree of pulmonary infiltration.
  • 16 of the 21 workers were compared with 20 asbestos workers of similar age and exposure duration whose X-rays were negative. Clinical findings did not differ significantly, but the positive-X-ray group had significantly lower vital capacity, total lung capacity and diffusion capacity.
• The authors' conclusion: The authors concluded that the abnormal lung function findings were consistent with a restrictive breathing and diffusion capacity impairment. They also stated that such a functional lesion, together with a consistent chest X-ray and a history of sustained asbestos dust exposure, is strong evidence of asbestosis.
• Limitations the authors state:
  • Without data on pulmonary artery pressures, cor pulmonale could not be ruled out with certainty.
  • The only exposure data available were on the duration of exposure.

Topics

Medical terms in this study, explained in our Lexicon: Insulator, Chest X-Ray, Pleural Calcification, Cor Pulmonale, Total Lung Capacity (TLC).

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