Residential proximity to naturally occurring asbestos: health risk or ecologic fallacy?

Our plain-English summary of Residential proximity to naturally occurring asbestos: health risk or ecologic fallacy?, by C.A. Brodkin, J.R. Balmes, C.A. Redlich, et al (American Journal of Respiratory and Critical Care Medicine, 2006).

The study

• Authors: C.A. Brodkin, J.R. Balmes, C.A. Redlich, M.R. Cullen
• Journal: American Journal of Respiratory and Critical Care Medicine
• Published: 2006;173(5):573; author reply 573-4
• Type of article: Comment, Letter
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Summary of the article

This correspondence commented on a study by Pan and colleagues that used digital geologic mapping to examine residential proximity to naturally occurring asbestos (NOA) and mesothelioma risk in California. The letter writers argued that two limitations of the study design did not allow a causal association to be determined. First, the study used home address at diagnosis and did not account for the long latency of mesothelioma. They cited the CARET cohort, in which 4,060 asbestos-exposed participants, with 23 mesothelioma cases, had a mean of 35 years since first asbestos exposure. They said this was likely to cause exposure misclassification, for example a shipyard worker who retires near an NOA source. Second, distance to an NOA source was not a direct measure of exposure, so the study had the limitations of an ecologic study. They noted that ambient exposures are typically orders of magnitude below occupational levels, and that fibres must be airborne to cause disease. They concluded that the findings should be considered hypothesis generating, but that caution should also be applied to large-scale home development in NOA areas. In reply, the original authors agreed that the lack of lifetime residential history was a limitation. They reported an unpublished analysis showing no differential movement of former asbestos union members from the San Francisco Bay Area to counties with more NOA. They also suggested a prospective case-control study.

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 was a letter to the editor, not a research study. Brodkin, Balmes, Redlich and Cullen commented on an earlier study by Pan and colleagues. That study used digital geologic maps to look at whether living near naturally occurring asbestos in California was linked to mesothelioma risk.

The letter raised two limitations. First, Pan's study used home address at the time of diagnosis. The letter said this did not consider where people lived during the relevant latency period, the decades before diagnosis. The letter writers said this was likely to cause exposure misclassification. Their example was a shipyard worker who retires near an asbestos source.

Second, distance to a geologic source is not a direct measure of asbestos exposure, so the study had the limitations of an ecologic study. The letter added that asbestos in rock does not by itself mean airborne levels substantially above background.

The letter writers concluded that Pan's findings should be considered hypothesis generating. They also said caution should be applied to large-scale home building in these California areas.

A reply from Pan's group, cut off in this text, agreed that missing lifetime residential history was a limitation.

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 (correspondence) commenting on a published study, followed by a reply from that study's authors; no new data
• Who was studied: No study population of its own; the letter discusses the California study by Pan and colleagues on residential proximity to naturally occurring asbestos and mesothelioma
• Exposure: Naturally occurring asbestos (NOA), measured in Pan's study as residential distance to ultramafic rock sources; no fiber type named
• Main results:
  • The letter argued that Pan's study used home address at diagnosis and did not consider where people lived during the relevant latency period, the decades before diagnosis
  • The letter writers said this was likely to cause exposure misclassification, giving the example of a shipyard worker who retires near an NOA source
  • The letter argued that distance to an NOA source is not a direct measure of asbestos exposure, so the design suffers the limitations of an ecologic study
  • The letter stated that the presence of asbestos fibers in geologic strata does not imply airborne concentrations substantially above background levels
  • The letter writers also said caution should be applied to large-scale home development in NOA source areas in California
  • In their reply, Pan's group agreed that the lack of lifetime residential history was a limitation. They said a separate analysis, not reported, showed no differential movement of former asbestos union members from the San Francisco Bay Area to counties with more NOA
• The authors' conclusion: The letter writers concluded that Pan and colleagues' findings should be considered hypothesis generating and interpreted with caution until follow-up studies are done

Topics

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

Medical terms in this study, explained in our Lexicon: naturally occurring asbestos (NOA), Mesothelioma, Latency, Asbestos Exposure, Case-Control Study.

Related studies

• Residential proximity to naturally occurring asbestos and mesothelioma risk in California — X.L. Pan, H.W. Day, et al. (2005)
• Residential proximity to naturally occurring asbestos and mesothelioma risks: further consideration of exposure misclassification and occupational confounding — M.A. Kelsh, D.W. Berman, et al. (2006)
• High risk of malignant mesothelioma and pleural plaques in subjects born close to ophiolites — M. Bayram, I. Dongel, et al. (2013)
• Pleural mesothelioma in relation to meteorological conditions and residential distance from an industrial source of asbestos — J. Tarrés, C. Albertí, et al. (2013)
• High-risk mesothelioma relation to meteorological and geological condition and distance from naturally occurring asbestos — A. Abakay, A.C. Tanrikulu, et al. (2016)
• Community responses to naturally occurring asbestos: implications for public health practice — M.R. Culley, J. Zorland, et al. (2010)

Browse more research in American Journal of Respiratory and Critical Care Medicine, or return to medical research.