Inhalation of low concentrations of asbestos

Our plain-English summary of Inhalation of low concentrations of asbestos (The Medical Journal of Australia, 1972).

The study

• Journal: The Medical Journal of Australia
• Published: 1972;1(17):839-40
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 002426).

In plain English

This unsigned editorial comment in the Medical Journal of Australia summarized a study by R. L. H. Murphy and co-workers, published in the New England Journal of Medicine in 1971. It reported no research of its own. As the editorial described it, dust counts taken while pipes were covered with asbestos in new ship construction averaged just above the recommended threshold of 5 million particles per cubic foot of air. They reached 60 on occasion, and a weighted average was almost 33, over 6 times the threshold. The 101 pipe coverers, employed an average of 17 years, were compared with 94 controls. By the study's criteria, 11 of the 101 pipe coverers had asbestosis, while one of the 94 controls had pulmonary fibrosis, attributed to smoke inhalation. Obstructive airways disease was equally common in both groups. Diffusion capacity was significantly reduced in the pipe coverers, and no active tuberculosis was found. The study's authors concluded that prolonged exposure to dust only marginally above the accepted threshold appears to be hazardous.

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: Editorial comment summarizing another group's study, a comparison of exposed shipyard pipe coverers with controls by Murphy and co-workers, New Engl. J. Med. 1971. This article reports no original research.
• Who was studied: In the summarized study, 101 shipyard pipe coverers, employed in the shipyard an average of 17 years, matched with 94 controls
• Exposure: Asbestos dust from covering pipes with asbestos in new ship construction. Counts averaged just above the recommended 5 million particles per cubic foot (MPPCF), reached 60 MPPCF on occasion, and a duration-weighted average was almost 33 MPPCF. No fiber type is named.
• Main results:
  • By the study's criteria (exposure history, radiological Code 5 and 6, clinical signs, and vital capacity of 80% or less of predicted), 11 of the 101 pipe coverers had asbestosis. One of the 94 controls had pulmonary fibrosis, attributed to smoke inhalation.
  • Evidence of obstructive airways disease was equally common in the controls and the pipe coverers.
  • Respiratory gas diffusion capacity was significantly reduced in the pipe coverers. All those with asbestosis had severely reduced single-breath and exercise steady-state diffusion capacity.
  • Tuberculin skin sensitivity did not differ significantly between the two groups, and no active pulmonary tuberculosis was found.
  • Prevalence of asbestosis increased with workers' age and with duration of exposure.
  • Breathlessness on exertion was more common in exposed workers than in controls, without significant differences in ventilatory capacity.
• The authors' conclusion: The study's authors, as reported in the editorial, concluded that prolonged exposure to dust concentrations only marginally above the accepted threshold level appears to be hazardous. The editorial noted the study's relevance in Australia because it focused on workers exposed close to the acceptable threshold.
• Limitations the authors state:
  • The study's authors said assessing asbestosis prevalence is difficult because the disease needs long exposure to develop (at least 10 years at moderate dust levels) and because exposure levels vary widely with workshop practice.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis.

Related studies

• The effects of the inhalation of asbestos in rats — J.C. Wagner, G. Berry, et al. (1974)
• The sizes, shapes, and mineralogy of asbestos structures that induce lung tumors or mesothelioma in AF/HAN rats following inhalation — D.W. Berman, K.S. Crump, et al. (1995)
• Inhalation carcinogenesis from various forms of asbestos — A.L. Reeves, H.E. Puro, et al. (1974)
• Experimental studies in rats on the effects of asbestos inhalation coupled with the inhalation of titanium dioxide or quartz — J.M. Davis, A.D. Jones, et al. (1991)
• Malignant mesothelioma induced in baboons by inhalation of amosite asbestos — I. Webster, B. Goldstein, et al. (1993)
• Rheumatic complaints and pulmonary response to chrysotile dust inhalation in the mines and mills of Quebec — F.M. White, J. Swift, et al. (1974)

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