Asbestosis and silicosis

Our plain-English summary of Asbestosis and silicosis, by G.R. Wagner (Lancet, 1997).

The study

• Author: G.R. Wagner
• Journal: Lancet
• Published: 1997;349(9061):1311-5
• Type of article: Review
• Cited by: 127 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Interstitial fibrosis resulting from workplace exposure to asbestos and crystalline silica persists throughout the world despite knowledge of the causes and effective means for prevention. Asbestosis and silicosis occurrence is predictable among people overexposed to dusts in various industries and occupations such as mining, construction, manufacturing, and building maintenance. Asbestosis and silicosis are incurable and may be progressive even after dust exposure has ceased, therefore early recognition and supportive interventions are important. Although current disease is a result of past exposures, effective control of current workplace exposures is the only way to prevent continued occurrence of these potentially debilitating diseases. Physicians can contribute to this effort through accurate diagnosis and disease reporting.

In plain English

This article was a narrative review of asbestosis and silicosis, non-cancer lung-scarring diseases caused by workplace asbestos and crystalline silica dust. It presented no new data, drawing on published surveillance figures and research. Citing a US surveillance report, it stated that 8761 US death certificates listed asbestosis and 4882 listed silicosis between 1979 and 1992. Asbestosis mentions rose steadily while silicosis mentions fell. It stated that under usual exposure conditions, asbestosis rarely becomes visible on chest X-ray earlier than 15 to 20 years after first exposure. It cited work finding that 10 to 20% of people with substantial asbestos or silica exposure and pathological abnormalities had X-rays classified as normal. It stated that no treatment reverses either disease and that both can progress after exposure stops. It added that mesothelioma and lung cancer are associated with asbestos exposure even without X-ray signs of scarring. The author concluded that current cases reflect past failures to prevent disease, and that current workplace conditions will inevitably lead to future disease without exposure control.

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: Narrative review (single-author clinical review in the Lancet's occupational medicine series); no original data collected
• Who was studied: No study population of its own; the review summarised published surveillance data (mainly US death certificates and state surveillance, plus some European mortality rates), epidemiological and clinical research, and WHO screening recommendations
• Exposure: Workplace exposure to asbestos (the review states that all forms can cause interstitial fibrosis and that exposures tend to be to mixed fibre types) and to crystalline silica, in mining, construction, manufacturing and building maintenance
• Main results:
  • Citing a NIOSH surveillance report: in the USA between 1979 and 1992, 4882 death certificates listed silicosis and 8761 listed asbestosis as an underlying or contributing cause of death. Mentions of asbestosis rose steadily while mentions of silicosis decreased.
  • Under usual exposure conditions, fibrosis from asbestos rarely becomes visible on X-ray earlier than 15 to 20 years from first exposure
  • Citing published work: 10 to 20% of people with substantial asbestos or silica exposure and associated pathological abnormalities have chest X-rays classified within the ILO normal range. The plain X-ray was therefore judged to be around 80% sensitive.
  • There is no effective treatment to reverse asbestosis or silicosis, and both can progress even if exposure ceases
  • Cancers of the mesothelium or lung are associated with asbestos exposure even in the absence of fibrosis on chest X-ray
  • Mesothelioma risk is unrelated to tobacco use, and no modifiable risk factors have been discovered. Tobacco use seems to increase lung-cancer risk synergistically in asbestos workers.
  • The health risk to building occupants where asbestos is in good repair and undisturbed is not considered significant. Documented exposures in offices and classrooms are orders of magnitude below those of maintenance and custodial workers, in whom asbestosis has been documented.
  • World asbestos production and consumption peaked in the mid-1970s at around 5.0 million metric tons and declined to less than 2.5 million tons in 1994
• The authors' conclusion: The author concluded that current cases of asbestosis and silicosis result from past failure to apply available information. The author stated that current workplace conditions will inevitably lead to future disease unless a comprehensive and continuing commitment is made to exposure control.
• Limitations the authors state:
  • The author noted that surveillance systems underestimate case numbers because many cases are undiagnosed
  • The author noted that international data on incidence, prevalence and trends are sparse and not comparable
  • The author noted that evidence that removal from exposure protects against progression is sparse

Topics

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

Medical terms in this study, explained in our Lexicon: Silicosis, Interstitial Fibrosis, Crystalline.

Related studies

• TruCutR needle biopsy in asbestosis and silicosis: correlation of histological changes with radiographic changes and pulmonary function in 41 patients — P. Tukiainen, E. Taskinen, et al. (1978)
• Serum oncoproteins and growth factors in asbestosis and silicosis patients — P.W. Brandt-Rauf, S. Smith, et al. (1992)
• Mechanisms in the pathogenesis of asbestosis and silicosis — B.T. Mossman, A. Churg (1998)
• Current concepts about the pathogenesis of silicosis and asbestosis — R.D. deShazo (1982)
• Cancer incidence and mortality among Finnish asbestos sprayers and in asbestosis and silicosis patients — P. Oksa, E. Pukkala, et al. (1997)
• Serum concentrations of Krebs von den Lungen-6, surfactant protein D, and matrix metalloproteinase-2 as diagnostic biomarkers in patients with asbestosis and silicosis: a case-control study — C. Xue, N. Wu, et al. (2017)

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