Thinking about Occupation-Response and Exposure-Response Relationships: Vehicle Mechanics, Chrysotile, and Mesothelioma

Our plain-English summary of Thinking about Occupation-Response and Exposure-Response Relationships: Vehicle Mechanics, Chrysotile, and Mesothelioma, by K. Teschke (The Annals of Occupational Hygiene, 2016).

The study

• Author: K. Teschke
• Journal: The Annals of Occupational Hygiene
• Published: 2016;60(4):528-30
• Type of article: Letter
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Summary of the article

The author, whose 1997 study was included as a 'tier 1' study in the 2016 meta-analysis by Garabrant et al. of mesothelioma among motor vehicle mechanics, addressed two questions about interpreting such evidence. First, she asked whether studies of vehicle mechanics and brake repair were appropriate settings to examine mesothelioma risk from chrysotile, since jobs and tasks act only as surrogates for exposure. In three studies in the meta-analysis that recorded brake repair separately, at least 34% of vehicle mechanics reported no brake repair work, and 12 of the 16 included studies examined only the vehicle mechanic job or broader categories. In the four studies reporting on brake repair, exposure occurred mostly long before 1980 and was likely intermittent. She argued that both the occupation and the task were poor surrogates, that associations were likely attenuated by subjects with background or low exposure, and that studies measuring chrysotile exposure would be more reliable. Second, she argued that evidence of an elevated occupation–disease association should not be required to decide whether a person's disease arose from workplace exposure, because exposures vary within jobs and not every job can be studied. She concluded that the relevant questions were whether chrysotile causes mesothelioma and whether the individual had sufficient exposure. She disclosed expert witness work in a 2011–2012 mesothelioma case.

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 is a letter to the editor, not a new study. Its author was first author of a 1997 study that a 2016 meta-analysis by Garabrant and colleagues, on mesothelioma among motor vehicle mechanics, included as a 'tier 1' study. The author argued that the vehicle mechanic job and the brake repair task are poor stand-ins for chrysotile exposure. Drawing on three studies in that meta-analysis, the author noted that at least 34% of vehicle mechanics reported no brake repair work. Of the 16 included studies, 12 looked only at the mechanic job or at broader categories such as garage workers. In the four studies reporting on brake repair, the period of potentially disease-causing exposure was mostly long before 1980. At that time brake work was one task of many and was likely intermittent. Because exposure varied so much within the job, the author argued, a true exposure–response relationship would be weakened or hidden when analysed by occupation instead. The author also argued that people should not have to show an elevated risk for their own job to have a disease recognized as work-related. The author disclosed acting as an expert witness in a mesothelioma case in 2011–2012.

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: Letter to the editor (commentary on a published meta-analysis; no new data)
• Who was studied: No new population was studied. The letter discusses the studies in the 2016 Garabrant et al. meta-analysis of mesothelioma among motor vehicle mechanics, which included the author's own 1997 study as a 'tier 1' study.
• Exposure: Chrysotile asbestos, and whether the vehicle mechanic occupation and the brake repair task are adequate stand-ins (surrogates) for chrysotile exposure in studies of mesothelioma
• Main results:
  • In three studies cited in the meta-analysis that recorded brake repair work separately from the mechanic job, at least 34% of the vehicle mechanics reported no brake repair work.
  • Of the 16 studies included in the meta-analysis, 12 examined only the vehicle mechanic job or broader job categories (such as garage workers, auto repair and related services, and auto engineers).
  • In the four studies in the meta-analysis that reported on brake repair, the period of potentially disease-causing exposure was mostly long before 1980. In that period, the author wrote, mechanics largely worked in gas stations, brake work was one possible task of many, and exposure was likely intermittent.
  • The author argued that, because exposures vary so much within an occupation, a true exposure–response relationship will be weakened or not observable when it is examined through an occupation–response analysis instead.
  • Citing another paper (Burdorf and Heederik, 2011), not this letter, the author noted that a 9-fold stronger relationship between chrysotile and mesothelioma was observed with better exposure data.
  • On whether an elevated occupation–disease association should be required before a person's disease is attributed to exposures in that occupation, the author's answer was no. The author's reasoning was that the job itself does not cause disease, but its exposures may.
  • Disclosure: the author was first author of one of the reviewed studies and in 2011–2012 acted as an expert witness, at the request of a law firm, in a mesothelioma case. The author stated this was also the motivation for the letter.
• The authors' conclusion: The author concluded that the most reliable epidemiological study would measure chrysotile exposure and assess the exposure–response relationship, rather than rely on an occupation or task as a surrogate for exposure.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Chrysotile, Mesothelioma.

Medical terms in this study, explained in our Lexicon: Chrysotile, Mesothelioma, Meta-Analysis, Expert Witness.

Related studies

• A meta-analysis of asbestos and lung cancer: is better quality exposure assessment associated with steeper slopes of the exposure-response relationships? — V. Lenters, R. Vermeulen, et al. (2011)
• Asbestos exposures of mechanics performing clutch service on motor vehicles — H.J. Cohen, D.R. Van Orden (2008)
• Response to Kay Teschke. Re: Mesothelioma among Motor Vehicle Mechanics: An Updated Review and Meta-analysis — D.H. Garabrant, D.D. Alexander, et al. (2016)
• Response to Murray M. Finkelstein, letter to the editor re Bernstein et al: Health risk of chrysotile revisited. Crit Rev Toxicol, 2013; 43(2): 154-183 — D. Bernstein, J. Dunnigan, et al. (2013)
• Chrysotile asbestos exposure associated with removal of automobile exhaust systems (ca. 1945-1975) by mechanics: results of a simulation study — D.J. Paustenbach, A.K. Madl, et al. (2006)
• Cancer mortality in Chinese chrysotile asbestos miners: exposure-response relationships — X. Wang, E. Yano, et al. (2013)

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