Invited commentary: Is it possible to investigate the quantitative relation between asbestos and mesothelioma in a community-based study?

Our plain-English summary of Invited commentary: Is it possible to investigate the quantitative relation between asbestos and mesothelioma in a community-based study?, by J. Siemiatycki, P. Boffetta (American Journal of Epidemiology, 1998).

The study

• Authors: J. Siemiatycki, P. Boffetta
• Journal: American Journal of Epidemiology
• Published: 1998;148(2):143-7
• Type of article: Comment
• Cited by: 19 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Summary of the article

This invited commentary discussed whether a community-based study can measure the quantitative relation between asbestos exposure and mesothelioma. It responded to a study by Iwatsubo et al. in the same journal issue, a community-based case-control study in selected areas of France. In that study, a panel of industrial hygiene experts assessed asbestos exposure from interview-based job descriptions. The study reported elevated mesothelioma risk at very low cumulative exposure (fourfold risk at 0.5 fiber/ml-years).

The authors described three problems that they considered specific to asbestos and mesothelioma:

• **Diagnostic bias:** Physicians who knew of a patient's asbestos work history may have been more likely to diagnose mesothelioma.
• **Information bias:** Cases may recall asbestos exposure more readily than controls. They cited a study by Spirtas et al. in which the relative risk among men was 27 when based on next-of-kin reports, compared with 11 when based on an occupation list.
• **Exposure assessment bias:** Experts may have underestimated the higher exposure levels before 1970, which would inflate the estimated risk per unit dose.

The authors stated that all three biases would exaggerate risk per unit dose, while nondifferential random exposure error would act in the opposite direction. They also raised selection bias and possible differences in potency between amphibole and chrysotile fibers.

They concluded that the association between asbestos and mesothelioma is incontrovertible. They called the French study a valiant effort that deserves replication under conditions that reduce these problems, and they considered direct data from low- or intermediate-exposure populations important.

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 article was an invited commentary, not an original study. The authors discussed a French community-based case-control study by Iwatsubo and colleagues that tried to measure how mesothelioma risk rose with asbestos exposure at relatively low levels. Exposure was rated by industrial hygiene experts from interviews. The commentators noted it appeared to show a fourfold risk at 0.5 fiber/ml-years. They argued that three possible biases made such estimates hard to interpret: diagnoses that may have depended on doctors knowing of asbestos work, cases recalling exposure more readily than controls, and experts possibly underestimating past exposure. All three, if present, would exaggerate risk per unit dose. Exposure error that is both random and alike for cases and controls would work the other way, though they warned that some error alike for both groups can exaggerate odds ratios; the balance could not be judged. They also noted amphibole fibers may be more potent than chrysotile, limiting how far results generalize. The authors stated the asbestos-mesothelioma link was not in doubt. They concluded the study deserved replication under conditions reducing these problems.

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: invited commentary on another study (no new data)
• Who was studied: No study population of its own. The authors discussed the study by Iwatsubo et al., a community-based case-control study of mesothelioma in selected areas of France.
• Exposure: Asbestos exposure at relatively low levels. In the study discussed, exposure was assessed from interview job descriptions by a panel of industrial hygiene experts. The commentary also discussed amphibole versus chrysotile fiber types.
• Main results:
  • The authors described the Iwatsubo study as appearing to show elevated mesothelioma risk at very low cumulative exposure (fourfold risk at 0.5 fiber/ml-years). This is that study's finding, not this commentary's.
  • Diagnostic bias: the authors argued that misdiagnosis of mesothelioma may have depended on whether the physician knew of the patient's asbestos work.
  • Information bias: the authors argued that cases may recall asbestos exposure more than controls. Because self-reports were used as a trigger for expert review, exposure ratings may have been biased in the same direction.
  • Exposure assessment bias: the authors argued that experts may have underestimated past exposure levels, which would overestimate excess risk per unit dose.
  • The authors disputed the Iwatsubo authors' view that blind (nondifferential) exposure assessment could only weaken odds ratios. They noted that for ordinal exposure groups, certain patterns of nondifferential misclassification can exaggerate odds ratios.
  • The authors noted that when the Iwatsubo study used higher exposure values for the relatively highly exposed, odds ratios were lowered.
  • The authors argued that all three biases, if operating, would exaggerate risk per unit dose. Nondifferential random exposure error would work in the opposite direction.
  • The authors said the relative size of these opposing biases could not be judged from the available information.
  • The authors noted it is possible that amphibole fibers are more potent than chrysotile for mesothelioma. A dose-response relation from one study might therefore apply only to populations with a similar mix of fiber types.
• The authors' conclusion: The authors stated they did not question the association between asbestos and mesothelioma. They concluded that the Iwatsubo study deserved to be replicated under conditions that reduce these methodological problems, and that generating data on populations with relatively low exposure was important.

Topics

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

Medical terms in this study, explained in our Lexicon: Mesothelioma, Asbestos Exposure, Case-Control Study, Industrial Hygiene, Cumulative Exposure, Work History, Relative Risk, Selection Bias.

Related studies

• Invited commentary — R.M. Flores (2014)
• Invited commentary — B.C. Tong (2014)
• Invited commentary — D. Rice (2010)
• Invited commentary — C.P. Clarke (2011)
• Invited commentary — H.I. Pass (2012)
• Invited commentary — J.S. Donington (2013)

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