An X-Ray Study Of The Lungs Of Workmen In The Asbestos Industry, Covering A Period Of Ten Years

Our plain-English summary of An X-Ray Study Of The Lungs Of Workmen In The Asbestos Industry, Covering A Period Of Ten Years, by A.W. George, R.D. Leonard (1939).

The study

• Authors: A.W. George, R.D. Leonard
• Published: Radiology 33:196-202 (1939)
• Type of article: Journal article
• Our copy: from Johns-Manville's own medical library, J-M no. 002899. The article is still under copyright, so we describe it here rather than post it.

In plain English

This 1939 paper reported the authors' x-ray observations over about ten years at a Massachusetts brake-lining plant. The dust there was mainly asbestos, with less than 30 per cent silica. In 1928 and 1929 the authors diagnosed asbestosis by x-ray in 12 workers. An insurer later wanted all of the plant's approximately eight hundred employees examined; the authors examined most and found three definitely advanced cases, who worked until the 1936 closing. After the closing, 90 workers claimed disability from asbestosis. The authors made a positive x-ray diagnosis in 12 of them and called three questionable. The other 78 were negative on physical and x-ray examination. At a later hearing, the 12 workers diagnosed in 1928 and 1929 testified that they were free of symptoms. The authors described the x-ray picture as a 'ground-glass' increased density limited to both lower lobes, and they found no case complicated by tuberculosis. The authors concluded that, at least in this industry, asbestosis was not progressive once a worker was removed from the dust. They also concluded that diagnosis must rest mainly on the x-ray.

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: Descriptive report of the authors' clinical and x-ray observations of asbestos-exposed workers at one plant over about ten years (a case series with commentary); the authors call it a cursory paper
• Who was studied: Workers at one large Massachusetts plant that manufactured brake lining, examined from 1928 onward. The plant had approximately eight hundred employees when an insurer wanted all of them examined; the authors examined the majority. The group also included 90 workers who claimed disability after the plant closed in 1936. The paper mentions that the authors' wider experience covered over three thousand dust-exposed workmen in various industries.
• Exposure: Dust that was principally asbestos with less than 30 per cent silica, in brake-lining manufacture. Dry weaving was used first and was later changed to wet weaving. No specific fiber type is named.
• Main results:
  • Among workers examined in 1928 and 1929, x-ray changes were found in 12 cases, on which the authors based a diagnosis of asbestosis. These 12 were put on compensation or given a lump-sum settlement.
  • An insurance company wanted all employees of the plant (approximately eight hundred) examined clinically and by x-ray before taking on the risk. The majority were examined by the authors at the plant. Three cases were definitely advanced, and these men continued working until the plant closed in 1936.
  • After the plant closed, 90 workmen claimed disability due to asbestosis. The authors made a positive diagnosis in 12, with three more questionable.
  • Of the 90 claimants, 78 were left whose physical and x-ray examinations were negative. Of these 78, 30 came to trial, and the authors were able to examine 10 of those 30.
  • At a hearing, the 12 workers diagnosed positive in 1928 and 1929 testified that they were free of all symptoms. Except for several women in the group, they were doing laborious work in new occupations.
  • The authors found little parallel between how much disease showed on x-ray and how severe the symptoms were. All their positive cases showed about the same amount of lung involvement.
  • The typical x-ray finding was increased density on both sides, limited to the lower lobes of both lungs, described as 'ground-glass' or 'smoky'. Asbestos dust also produced changes in the pleura.
  • In this series the authors found no case of asbestosis complicated by tuberculosis.
• The authors' conclusion: The authors concluded that each asbestos industry must be studied separately, taking into account the silica content of the dust and whether a dry or wet method was used. They also concluded that asbestosis is not a progressive disease once the individual has been removed from the dust hazard. In their view, their study gave no evidence that asbestosis has any causal relation to tuberculosis. Finally, they concluded that diagnosis must depend mainly on x-ray evidence, because no clinical findings are pathognomonic (unique to the disease).
• Limitations the authors state:
  • The authors described the paper as rather cursory.
  • The authors said their conclusion that the disease is not progressive depended on their original diagnoses being correct, and applied at least to this particular industry.
  • The authors noted that a theoretical early or incipient asbestosis, before lung changes are visible, cannot be diagnosed by x-ray.

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