Recent Views on Pneumonoconioses

Our plain-English summary of Recent Views on Pneumonoconioses, by E.L. Collis (Proceedings of the Royal Society of Medicine, 1931).

The study

• Author: E.L. Collis
• Journal: Proceedings of the Royal Society of Medicine
• Published: 1931;24(5):531-42
• Cited by: 6 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. 003058).

Abstract

Silicosis has been intensively studied since it was isolated from other diseases caused by dust. These studies have shown that silicosis may be fairly advanced without seriously impairing general health; it may, however, itself lead to a fatal result. More often it acts almost specifically in preparing the way for pulmonary infections, of which serious tuberculosis is the chief. The occurrence of such a superadded infection not infrequently precipitates a latent condition of silicosis. The close relation existing clinically between tuberculosis and silicosis has been demonstrated by animal experiment.Other dusts than silica have also been demonstrated to cause generalized pulmonary fibrosis, which is usually finer in character, although more injurious to the functions of the lungs than is silicosis; but such fibrosis has not been found to be specifically associated with superadded tuberculous infection.Each dust calls for special study. Up to the present, investigation of dusts from certain silicates has shown them to be of great importance. Of these, asbestos has been found to be most definitely injurious, and to originate a definite and characteristic condition. Other silicates, such as basalt, appear to set up a condition which only differs in degree from that caused by asbestos.Dust arising from pure coal does not appear to be injurious, or, on the other hand, to be in any way protective against infections. Raw coal, however, often contains sufficient minerals for its dust to originate pulmonary fibrosis. When such fibrosis is present, whether due to silica arising from intervening rocks or from silicates, the coal particles are so retained in the lungs as to block the lymph passages, and impair capacity.Certain other dusts, for example dusts arising from marble or limestone, exert little, if any, influence on the lungs. Such dusts are soluble in the body fluids, and are not left to block the pulmonary tissues.

In plain English

This 1931 article by E. L. Collis was a review, which the author called a progress report. It summarized recent industrial, epidemiological and experimental research on lung diseases caused by dust. Most of it concerned silica. Citing other studies, the author reported that silicosis prepared the way for pulmonary tuberculosis, a link also seen in animal experiments. Dusts from pure coal, marble and limestone were described as not obviously harmful. On asbestos, the author drew on studies of workers in asbestos textile factories. Asbestos dust was reported to cause a distinct type of lung fibrosis that varied in intensity with exposure, developed fully in seven to nine years, and could cause death after about thirteen years' exposure. On X-ray it looked finer and more diffuse than silicosis, and there was no special tendency to tuberculosis. Asbestos bodies in the sputum and lungs were described as a useful diagnostic sign. The author concluded that asbestos was the most characteristically injurious of the silicate dusts and caused a type of fibrosis distinct from silicosis.

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: Narrative review (progress report) summarizing recent work on dust diseases of the lungs, organized by industrial hazard
• Who was studied: Studies reviewed by the author: industrial and epidemiological studies of workers in dusty trades and experiments using industrial dusts. These covered granite, slate, coal mining, coal trimmers, haematite mining, the Carrara marble industry, Portland cement, and asbestos textile factories. No new population was studied.
• Exposure: Industrial dusts: silica, asbestos (described as hydrated silicates, usually of magnesium; no specific fiber types named), basalt and other silicates, coal, iron ore, marble and limestone, and Portland cement
• Main results:
  • From the asbestos studies reviewed: asbestos dust caused a distinct type of fibrosis that varied in intensity with exposure, developed fully in seven to nine years, and could cause death after about thirteen years' exposure.
  • In asbestos workers, the fibrosis on X-ray was finer than silicosis and lacked the nodular type. There was no special tendency to tuberculosis.
  • Asbestos bodies (20 to 100 microns long, golden brown) found in the sputum and lungs were described as a useful diagnostic sign.
  • From the silica studies reviewed: silicosis acted almost specifically in preparing the way for serious pulmonary tuberculosis.
  • Coal trimmers, exposed to coal dust only, had excess mortality from pneumonia and bronchitis but died at about the standard rate from pulmonary tuberculosis.
  • Fine dusts from marble and limestone were found innocuous, even when inhaled in large amounts for many years.
• The authors' conclusion: The author concluded that each dust calls for special study and that dusts of certain silicates appear to be of great importance. Asbestos was described as the most characteristically injurious, and its study had led to recognition of a definite type of fibrosis distinct from silicosis.
• Limitations the authors state:
  • The author described the paper only as a progress report, not repeating long-accepted data.
  • The suggested link between dusts and cardiovascular degeneration had not yet received full pathological support.

Topics

Medical terms in this study, explained in our Lexicon: Silicosis, Pulmonary Fibrosis, Fibrosis, Silicate.

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