Occupational Asthma

Our plain-English summary of Occupational Asthma, by A. Seaton (1975).

The study

• Author: A. Seaton
• Published: Occupational Lung Diseases (W.K.C. Morgan And A. Seaton, Editors), Philadelphia: W.B. Saunders, Pp. 251-264 (1975)
• Type of article: Book excerpt
• Our copy: from Johns-Manville's own medical library, J-M no. 002828.

In plain English

This textbook chapter by A. Seaton is a review of occupational asthma, not an original study, and it does not discuss asbestos. The author described how immune reactions, particularly in atopic (allergy-prone) people, can lead to asthma at work. The chapter also described how doctors can investigate suspected cases. It described a bronchial challenge test in which a fall of 15 per cent or more in peak flow or timed vital capacity was treated as showing cause and effect, provided no such fall followed a control test with an inert substance. The chapter then summarized published reports on specific causes, including grain and flour, wood dusts, gum arabic in printing, enzymatic washing powders, aluminum soldering flux, isocyanates, platinum salts, and metals such as nickel and chromium. Figures cited from other studies included 21 per cent of exposed enzyme-powder workers affected six months after production started. They also included symptoms developing within five years in up to 30 per cent of printing workers exposed to gum arabic. The author concluded that physicians should be alert to occupational sensitization in all cases of asthma.

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: Review (textbook chapter) of occupational asthma: mechanisms, clinical features, investigation, management, and specific causes reported in the literature
• Who was studied: No study population of its own; the chapter reviews published reports on workers in various trades (millers, bakers, woodworkers, printers, enzyme detergent workers, solderers, isocyanate and platinum workers, metal workers)
• Exposure: Occupational sensitizers including grain and flour dust, wood dusts (e.g. western red cedar, iroko, oak, mahogany), gum arabic, Bacillus subtilis enzymes (alcalase) in washing powders, aminoethyl ethanolamine soldering flux, isocyanates (TDI and MDI), complex platinum salts, nickel, chromium and hard metal; asbestos is not discussed
• Main results:
  • In a bronchial challenge test described by the author, a fall of 15 per cent or more in peak flow or timed vital capacity was taken as sufficient to show cause and effect, provided no such fall followed a control test with an inert substance
  • In one cited series of bakers, 5 to 10 per cent had symptoms of asthma after ten years in the trade, and an additional 10 per cent had left the baking industry because of their symptoms
  • In printing, symptoms were reported to develop within five years in up to 30 per cent of workers exposed to gum arabic spray (from cited studies)
  • Newhouse and colleagues (cited study) found 21 per cent of exposed workers producing enzymatic washing powders affected six months after production started, with a clear relationship between sensitization and level of exposure
  • Cited work showed progressive falls in ventilatory capacity, through the week and over periods of up to two years, in workers exposed to TDI at levels below the threshold limit value
• The authors' conclusion: The author concluded that physicians need to be alert to the possibility of occupational sensitization in all cases of asthma

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