Report To The U.S. Consumer Product Safety Commission By The Chronic Hazard Advisory Panel On Asbestos

Our plain-English summary of Report To The U.S. Consumer Product Safety Commission By The Chronic Hazard Advisory Panel On Asbestos, by Cpsc (1983).

The study

• Author: Cpsc
• Published: Washington, Dc: Consumer Product Safety Commission, Directorate For Health Sciences (1983)
• Type of article: Government report
• Our copy: from Johns-Manville's own medical library, J-M no. 004534.

In plain English

In July 1983 a seven-member advisory panel reported to the U.S. Consumer Product Safety Commission on asbestos. The report was a review of published human, animal and laboratory studies. It also analyzed dose-response data from eleven studies of asbestos workers. The Panel found that asbestos causes lung cancer and mesothelioma, that risk rises with exposure, and that there was no evidence of a safe threshold dose. Estimates of how fast lung cancer risk rises with dose varied almost 100-fold between studies, and fiber type could not explain the difference. The Panel assumed a straight-line dose-response with no threshold. On that basis it calculated ranges of lifetime risk of death from cancer caused by continuous exposure to 0.01 fibers per ml. For male smokers exposed continuously for 70 years from birth, these were 55.6 to 557.3 per 100,000 for mesothelioma and 49.0 to 489.9 per 100,000 for lung cancer. Panel members disagreed about the evidence for other cancers. The Panel concluded that asbestos at all levels of exposure should be regarded as a potential human carcinogen. It stressed that its risk estimates were very uncertain.

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 by a seven-member scientific advisory panel of published human epidemiological, animal and in vitro studies, with the panel's own dose-response analysis and low-dose risk extrapolation
• Who was studied: No new population was studied. The Panel reviewed published studies, including eleven mortality studies of asbestos workers (miners and millers, cement, textile, friction-material, amosite factory and insulation workers) used for its dose-response analysis. The Panel met five times between January and June 1983.
• Exposure: Asbestos fibers, mainly chrysotile, amosite, crocidolite and anthophyllite, with some discussion of tremolite and actinolite. The report covers occupational and non-occupational exposure, including asbestos in consumer products, and extrapolates to continuous exposure at 0.01 fibers per ml.
• Main results:
  • Lung cancer and mesothelioma make up the majority of cancers caused by asbestos.
  • Cancer risk increases as asbestos exposure increases, and the Panel found no evidence of a threshold dose below which there is no effect.
  • Estimates of the lung cancer dose-response slope varied almost 100-fold across studies. Fiber type could not explain the differences: both the lowest value and one of the highest came from chrysotile exposure.
  • Because of the lower underlying risk, the absolute increase in lung cancer from asbestos in non-smokers is about one tenth of that in smokers.
  • Mesothelioma risk rises rapidly with time since first exposure. As a result, the lifetime effect of exposure in childhood is likely to be much greater than that of exposure beginning in adulthood.
  • The Panel used a linear no-threshold model to estimate lifetime risks of death caused by continuous exposure to 0.01 fibers per ml. For male smokers, the 70-year risks were 55.6 to 557.3 per 100,000 for mesothelioma and 49.0 to 489.9 per 100,000 for lung cancer. These figures were obtained by adding risks across time periods, following the article's example of exposure beginning at birth.
  • Epidemiological studies suggest that chrysotile has a lower potential than other fiber types for producing peritoneal mesothelioma.
  • Panel members disagreed about the strength of the evidence linking other cancers (digestive tract, oral, pharyngeal, laryngeal and kidney) with asbestos exposure.
  • The Panel was not aware of any reported disabling asbestosis in people exposed outside work.
  • Information on reproductive and teratologic effects was limited, so the Panel reached no conclusions on this question.
• The authors' conclusion: The Panel concluded that, on scientific grounds and as a matter of public health prudence, the Commission should regard asbestos at all levels of exposure as a potential human carcinogen.
• Limitations the authors state:
  • The risk estimates are very uncertain, and the actual risk in a given situation can lie outside the estimated ranges.
  • Estimates of past exposure in the worker studies involve considerable uncertainty.
  • Few studies obtained information on the smoking habits of the workers studied.
  • The data supporting a linear dose-response come from exposures two or three orders of magnitude higher than those of interest in the general environment.

Topics

Medical terms in this study, explained in our Lexicon: Dose-response relationship, Lung Cancer, Mesothelioma.

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