Considerations of specificity in assessing the relationship between asbestos and cancer

Our plain-English summary of Considerations of specificity in assessing the relationship between asbestos and cancer, by O. Wong (American Journal of Industrial Medicine, 1993).

The study

• Author: O. Wong
• Journal: American Journal of Industrial Medicine
• Published: 1993;23(3):521-3
• Type of article: Comment, Review
• Cited by: 10 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Summary of the article

In this commentary, the author responded to a 1991 paper by Dr. Enterline, which had concluded that scientists decided asbestos was a cause of cancer in Germany in 1943 and reached a consensus in the United States in 1964. The author argued that the statement "asbestos is a cause of cancer" lacked specificity. He said causal statements should specify fiber type, fiber length, fiber concentration, duration of exposure, type of industry and cancer site. He suggested applying causation criteria such as those set out by Hill in 1965, and stated that case reports cannot replace epidemiologic studies. He noted that scientists were still debating whether chrysotile can cause mesothelioma. As a second example, he discussed lung cancer in garage mechanics. He gave their typical 8-hour time-weighted average exposure to chrysotile in brake lining dust as below 0.05 fibers/cc. He summarized three cohort studies: London bus mechanics (SMR 0.92), Danish auto mechanics (SMR 1.01) and Stockholm bus garage workers (SMR 1.15, not statistically significant). His meta-analysis of these studies gave a summary lung cancer SMR of 1.01 (95% confidence limits 0.80-1.26), based on 80 observed deaths. He also cited a French case-control study of 1,625 lung cancer cases, which reported a smoking-adjusted relative risk of 1.06 for motor vehicle mechanics. The author concluded that the data did not support an association between brake lining dust and lung cancer, and that specificity is vital in cancer risk assessment.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.

In plain English

This commentary responded to a 1991 paper by Enterline, which had concluded that scientists decided asbestos was a cause of cancer in Germany in 1943 and reached a consensus in the United States in 1964. The author argued that the statement "asbestos is a cause of cancer" lacks specificity. In the author's view, causal statements should name the fiber type, fiber length, concentration, duration of exposure, industry and cancer site, and should be judged with criteria such as those set out by Hill. The author wrote that scientists were still debating whether chrysotile can cause mesothelioma. As a second example, the author discussed lung cancer in garage mechanics, who are exposed to brake lining dust containing chrysotile at levels the author called extremely low. The author pooled three cohort studies by other researchers, from London, Stockholm and Denmark, covering 24,808 workers. Together they had 80 observed lung cancer deaths against 79.4 expected, a combined standardized mortality ratio of 1.01 (95% confidence limits 0.80 to 1.26). The author concluded that these studies gave no data to support an association between lung cancer and brake lining dust, and that specificity is vital in cancer risk assessment.

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: Commentary (opinion piece responding to another author's paper), including the author's own pooled analysis (meta-analysis) of three previously published cohort studies of garage mechanics
• Who was studied: No new population was studied. The pooled analysis combined three earlier cohort studies of garage mechanics: 2,313 bus mechanics in London, 695 bus garage workers in Stockholm and 21,800 auto mechanics in Denmark, 24,808 workers in total. The author also cited a French case-control study of 1,625 histologically confirmed lung cancer cases.
• Exposure: Brake lining dust containing chrysotile asbestos among garage mechanics, described by the author as extremely low exposure. Citing an earlier letter by the author, the article gives the typical 8-hour time-weighted average fiber concentration as about 0.05 fibers per cc; the comparison symbol in front of the number is damaged in the scan.
• Main results:
  • Author's pooled analysis of the three cohort studies of garage mechanics (24,808 workers): 80 observed lung cancer deaths against 79.4 expected, combined lung cancer SMR 1.01, 95% confidence limits 0.80 to 1.26
  • London bus mechanics (subgroup of 2,313, data from Rushton as reported by the author): lung cancer SMR 0.92, based on 22 observed and 23.9 expected deaths
  • Danish auto mechanics (21,800, Hansen study as reported by the author): 41 lung cancer deaths observed against 40.7 expected, SMR 1.01
  • Stockholm bus garage workers (695, Gustavsson study as reported by the author): 17 lung cancer deaths observed against 14.8 expected, SMR 1.15, not statistically significant
  • French case-control study (Benhamou, as reported by the author): after adjusting for cigarette smoking, the relative risk of lung cancer for motor vehicle mechanics was 1.06, based on 65 cases
• The authors' conclusion: The author concluded that the studies discussed gave no data to support or suggest an association between lung cancer and exposure to brake lining dust. The author also concluded that Enterline may have oversimplified the issue, that unresolved questions remain (such as whether chrysotile causes mesothelioma), and that specificity is vital in any cancer risk assessment.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Auto mechanics and brake work, Lung cancer.

Medical terms in this study, explained in our Lexicon: Fiber Length, Causation, Chrysotile, Mesothelioma, Lung Cancer, Time-Weighted Average (TWA), Brake Lining, Meta-Analysis.

Related studies

• Evaluation of the size and type of free particulates collected from unused asbestos-containing brake components as related to potential for respirability — M.A. Atkinson, M. O'sullivan, et al. (2004)
• High level of Ets-related gene expression has high specificity for prostate cancer: a tissue microarray study of 11 483 cancers — S. Minner, A.M. Luebke, et al. (2012)
• Specificity of high-resolution CT findings in pulmonary asbestosis: do patients scanned for other indications have similar findings? — C.J. Bergin, R.A. Castellino, et al. (1994)
• The analysis of novel microRNA mimic sequences in cancer cells reveals lack of specificity in stem-loop RT-qPCR-based microRNA detection — P. Winata, M. Williams, et al. (2017)
• Mesothelioma among car mechanics? — H.J. Woitowitz, K. Rödelsperger (1994)
• Mortality rates among employees potentially exposed to chrysotile asbestos at two automotive parts factories — M.M. Finkelstein (1989)

Browse more research in American Journal of Industrial Medicine, or return to medical research.