Some Clinical Observations Of Asbestosis In Mine And Mill Workers

Our plain-English summary of Some Clinical Observations Of Asbestosis In Mine And Mill Workers, by P. Cartier (1955).

The study

• Author: P. Cartier
• Published: Archives Of Industrial Health 11(3):204-207, March (1955)
• Type of article: Journal article
• Our copy: from Johns-Manville's own medical library, J-M no. 001857. The article is still under copyright, so we describe it here rather than post it.

In plain English

This was a talk read at a 1953 symposium and printed in 1955. The author reported observations from nine years of medical supervision of about 4000 asbestos mining workers at Thetford Mines, Quebec. From 1945 to 1953, yearly medical and x-ray examinations, together with study of 58 autopsies, found 128 cases of asbestosis: 72 minimal, 35 moderate and 21 advanced. Of these, 40 people had died and been autopsied, and 88 were living. X-rays detected 121 cases. Seven minimal cases were found only by pathology after being missed on chest films. Pathologists sometimes disagreed widely on how severe a case was. In the author's opinion, six of the 40 deaths were clearly from asbestosis. The other 34 died of conditions such as tuberculosis, heart disease and lung cancer, where the role of asbestosis was not known. Among the living, 59 could work without discomfort. The author concluded that asbestosis is serious in some instances but is more often tolerated for many years. The scanned text is badly scrambled in places.

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 observations (case series) from medical supervision, x-ray examinations and autopsies; a symposium paper
• Who was studied: About 4000 asbestos mining workers under the author's medical supervision at Thetford Mines, Quebec, Canada, 1945 to 1953. Among them, 128 cases of asbestosis were found: 40 dead and autopsied, 88 living.
• Exposure: Work in asbestos mining and milling. No fiber type or dust levels are given.
• Main results:
  • Of the 128 asbestosis cases, 72 were minimal, 35 moderate and 21 advanced.
  • 121 cases were diagnosed by x-ray. Seven minimal cases were diagnosed by pathology only, having been missed on standard chest films.
  • The author stated that no case of asbestosis of clinical importance had been diagnosed by the pathologist without first being detected on x-ray.
  • Different pathologists sometimes graded the same case very differently, for example as minimal by one and as advanced by another.
  • Causes of death among the 40 autopsied cases were: 12 tuberculosis, 5 coronary thrombosis, 10 cardiovascular diseases, 4 cor pulmonale, 6 bronchogenic carcinoma, 2 bronchopneumonia and bronchiectasis, and 1 cancer of the brain.
  • Tuberculosis caused 12 of the 40 deaths (30%). The author considered this not sufficient to establish a causal link between asbestos dust and tuberculosis. A 1950 analysis of the industry's employees did not show a higher tuberculosis rate than a control group.
  • For the six bronchogenic carcinoma deaths, the author stated that a general statistical survey of all employees did not seem to show statistical evidence of a causal relationship with asbestosis.
  • In the author's opinion, six of the 40 patients clearly died from asbestosis. The other 34 had a lesion that could be considered the cause of death, but the role of the asbestotic fibrosis was unknown.
  • Among the 88 living patients, 59 were able to work without discomfort. Ten with minimal asbestosis had moderate or severe symptoms, while 5 with advanced asbestosis had no clinical symptoms.
• The authors' conclusion: The author concluded that asbestosis is a serious disease in some instances, but more often can be tolerated quite well for many years, even without appreciable symptoms, as long as another serious disease does not develop. The author called for combined research by pathologists, physiologists, radiologists, cardiologists and clinicians.
• Limitations the authors state:
  • X-ray reading might fail to detect minimal asbestosis.
  • The classification of living cases into minimal, moderate and advanced was uncertain, because x-ray and pathology classifications differ significantly.
  • Many patients were 60 or older and had other diseases that could impair breathing as much as asbestosis.
  • The author did not know whether the causes of death differed from those in a comparable group of workers, and had no chance to compare them with other data.

Topics

Medical terms in this study, explained in our Lexicon: Thetford Mines, Pathology, Chest X-Ray, Lung Cancer.

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