Tuberculous Lesions in Male Industry Workers

Our plain-English summary of Tuberculous Lesions in Male Industry Workers, by D.E. Cummings, R.N. Downs, M. Berg (1939).

The study

• Authors: D.E. Cummings, R.N. Downs, M. Berg
• Published: The American Review of Tuberculous, Volume 39 No. 4. April 1939.
• 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 article, read at a meeting in June 1938, reported chest X-ray surveys of male workers carried out by the Field Division of the Saranac Laboratory between 1933 and 1938. It concerned tuberculosis and silica dust. It did not concern asbestos. The authors compared tuberculous lung lesions in 5,000 workers examined at a single steel plant clinic with lesions in 5,000 white miners exposed in varying degrees to fine silica dust. Among white steel workers, 5.22 per cent had lesions. Lesions became more common with age, from about 1.0 per cent under twenty to 12.5 per cent at sixty-five to seventy-four. Among the miners, lesions rose with the X-ray signs of dust reaction. They were found in 5.38 per cent of miners classed as normal and in 64.29 per cent of those with the most advanced silicosis. Below age thirty-five, normal miners had nearly twice the lesion rate of steel workers. The authors concluded that tuberculosis with silicosis was an occupational disease in seven out of eight miners under thirty-five, but in only half of those over sixty-five. Parts of the scanned text, including several tables, were unreadable.

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: X-ray survey (stereoscopic chest roentgenograms) of industrial workers, comparing two occupational groups
• Who was studied: 5,000 men (job applicants and employees) examined at a single steel plant clinic, of whom 4,176 were white, plus 5,000 white male miners from a district mining a single mineral. The miners included office workers, mechanics and surface laborers as well as underground miners. United States, 1933 to 1938
• Exposure: Fine silica dust among the miners. Steel mill work was used as an occupation without an important tuberculosis hazard. Asbestos was not studied.
• Main results:
  • In a preliminary analysis of 4,012 white male workers with no X-ray evidence of reaction to occupational exposure, 191 had tuberculous lesions (crude incidence 4.76 per cent)
  • Among white steel mill workers, lesion incidence rose with age, from about 1.0 per cent under twenty to 12.5 per cent at sixty-five to seventy-four
  • Among white steel mill workers, an average of 2.3 new cases per 1,000 workers each year accounted for the rise with age
  • Among white male steel mill workers, about one death from tuberculosis occurred for each eighty cases with recognizable lesions
  • Among white miners, lesions were found in 5.38 per cent of those classed normal, 48.02 per cent with second-degree nodulation and 64.29 per cent with third-degree nodulation (massive silicosis). The crude rate for all miners was 12.40 per cent.
  • Normal miners under thirty-five had nearly twice the lesion prevalence of steel mill workers of the same age
  • If normal miners aged twenty-five to thirty-four developed silicosis, their chance of a tuberculous lesion was increased more than seven times. Among miners aged sixty-five to seventy-four it was merely doubled.
• The authors' conclusion: The authors concluded that tuberculosis with silicosis is an occupational disease in seven out of eight miners under thirty-five, but in only half of those over sixty-five
• Limitations the authors state:
  • The number of Negro workers was too small for an accurate analysis by age
  • An unexpected deviation in one age group might disappear if larger groups were studied

Topics

Medical terms in this study, explained in our Lexicon: Chest X-Ray, Saranac Laboratory, Silicosis, Occupational Disease.

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