Respiratory Disease in U.S. Soft-Coal Miners

Our plain-English summary of Respiratory Disease in U.S. Soft-Coal Miners, by H.L. Hardy, W.B. King JR (1962).

The study

• Authors: H.L. Hardy, W.B. King JR
• Published: 1962
• 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 1962 clinical study was not about asbestos; it examined respiratory disease in U.S. soft-coal miners. Of 65 non-working miners seeking care for breathing complaints at four clinics in Pennsylvania, Ohio and West Virginia, 30 were studied in detail, including lung-function tests, psychiatric interviews and, in five, lung biopsy. The men had a median age of 62 years and a median of 35 years in the mines. Their exposures included coal dust, silica-containing sand and rock dust, fumes from blasting and cable fires, and cigarette smoke. Twenty-one (70 per cent) had bronchitis, and all of them smoked cigarettes. Seven of these had breathing impairment without X-ray pneumoconiosis. Three had conglomerate X-ray densities, two of them with active tuberculosis. Biopsy confirmed silicosis in two men. None of the 17 men given cardiac catheterization showed right ventricular failure at rest. The authors concluded that the miners' disabling disease was not only pneumoconiosis. They described it as a disease of the respiratory tract that may result from chemicals and dust interacting with ageing, smoking and infection. They noted that the group was small, selected and not random.

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 case series: detailed hospital study of 30 disabled miners, with illustrative case reports
• Who was studied: 30 non-working U.S. soft-coal miners with respiratory complaints, chosen from 65 examined at four clinics in the soft-coal regions of Pennsylvania, Ohio and West Virginia. Median age 62 years (range 41 to 71); all had over 25 years in the mines.
• Exposure: Coal dust, plus sand and rock dust containing silica, fumes from blasting and cable fires, and cigarette smoking (22 miners smoked daily for 25 or more years). No asbestos exposure was studied.
• Main results:
  • 21 of the 30 miners (70 per cent) had bronchitis.
  • All miners with bronchitis were cigarette smokers. Of the nine miners without bronchitis, only one was a smoker.
  • Seven miners with bronchitis, shortness of breath and respiratory insufficiency on lung-function study did not show radiologic pneumoconiosis.
  • Three of the 30 miners showed conglomerate X-ray densities. Active tuberculosis was found in two of them.
  • Lung biopsy confirmed silicosis in two miners.
  • Of 17 miners given cardiac catheterization, none showed right ventricular failure at rest.
  • There was little correlation among chest X-ray, cardiac study, lung-function tests and biopsy in establishing the diagnosis.
  • After symptoms began, 14 miners (47 per cent) delayed seeing a doctor for one to nineteen years.
• The authors' conclusion: The authors concluded that disabling pulmonary disease in soft-coal miners is not only a pneumoconiosis from dust deposition. In their view it is a disease of the respiratory tract that may be due to inhaled harmful chemicals and dust, interacting with ageing, smoking habits and infection.
• Limitations the authors state:
  • The miners were not a randomly selected sample, and the social and psychological findings cannot be taken as representative of other miners.
  • The group was too select and too small to allow broad conclusions.
  • The miners' accounts of their work could not be checked against company records.
  • Pulmonary hypertension may have reversed because the men had been away from work for some time.
  • The exact composition of the fumes the miners inhaled could not be determined.

Topics

Medical terms in this study, explained in our Lexicon: Biopsy, Pneumoconiosis, Silicosis.

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