Reply to "No Increased Risk for Mesothelioma in Relation to Natural-Occurring Asbestos in Southern Nevada"

Our plain-English summary of Reply to "No Increased Risk for Mesothelioma in Relation to Natural-Occurring Asbestos in Southern Nevada", by F. Baumann, B.J. Buck, R.V. Metcalf, et al (Journal of Thoracic Oncology, 2015).

The study

• Authors: F. Baumann, B.J. Buck, R.V. Metcalf, B.T. McLaurin, D. Merkler, M. Carbone
• Journal: Journal of Thoracic Oncology
• Published: 2015;10(7):e64-5
• Type of article: Letter, Comment
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

In plain English

This is a letter to the editor, not a new study. The authors replied to a letter by Pinheiro and Jin that criticized the authors' earlier paper linking naturally occurring asbestos in Southern Nevada to mesothelioma in young people and women. The letter reported no new data. The authors argued that incidence rates cannot separate work-related from environmental mesothelioma. They described a pattern: occupational exposure gives a male-to-female ratio of 4 to 8:1, environmental-only exposure about 1:1 (citing other studies), and mixed exposure a lower ratio and a higher proportion of cases under 55. They said they had made no statistical comparison with the seven states listed in their Table 2. They acknowledged an error in that table's total. They said the critics' confidence intervals were too wide for any significant comparison. Citing an air report on the Boulder City bypass, they stated that airborne asbestos fibers were present. The authors concluded that Southern Nevadans are exposed to asbestos and therefore at increased risk. They noted that mixed-exposure epidemiology has never specifically been studied.

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 (a reply to a critique of the authors' earlier paper); no new study or data
• Who was studied: No new population was studied. The letter defends the authors' earlier analysis of mesothelioma in Southern Nevada. That analysis used public state-level incidence data for 2006–2010 and CDC mesothelioma mortality data by county for 1999–2010.
• Exposure: Naturally occurring asbestos (NOA) in the Southern Nevada environment. The letter names no specific fiber type in its main text.
• Main results:
  • Argument (background, not new data): the authors stated that occupational exposure leads to a male-to-female mesothelioma ratio of 4 to 8:1, with a mean age at diagnosis of 74.
  • Argument citing other studies: the authors stated that where people were only environmentally exposed, the male-to-female ratio is about 1:1 and the mean age at diagnosis is 50 to 60.
  • Argument: the authors stated that where both types of exposure exist, the male-to-female ratio falls and the proportion of cases under 55 rises. They used these patterns as indicators of possible environmental exposure.
  • The authors said they made no statistical comparison between Nevada and the seven states listed in their Table 2. They said those numbers were given only as examples.
  • The authors acknowledged an erroneous total number of mesotheliomas in Table 2 of their earlier paper. They also pointed out an arithmetic error in the critics' letter.
  • The authors argued that, because the numbers were small, the confidence intervals in the critics' own Table 1 were too large to allow any significant comparison.
  • Citing a Tetra Tech site report, the authors stated that ambient air measured for phase I of the Boulder City bypass showed airborne asbestos fibers. They also stated that some individuals may be exposed to higher concentrations through desert recreation.
• The authors' conclusion: The authors concluded that Southern Nevadans are exposed to asbestos fibers and are therefore at increased risk for mesothelioma and other asbestos-related diseases. They based this on defining risk as the product of hazard and exposure, not on measured rates. They said the critics' title cannot be supported by data, and they asked to investigate further with Nevada health authorities.
• Limitations the authors state:
  • The authors stated that the epidemiology of mesothelioma from mixed environmental and occupational exposure has never specifically been studied.
  • The authors stated that environmental epidemiology deals with small numbers and with exposures that cannot be assessed for individuals.

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.

Related studies

• No Increased Risk for Mesothelioma in Relation to Natural-Occurring Asbestos in Southern Nevada — P.S. Pinheiro, H. Jin (2015)
• The Presence of Asbestos in the Natural Environment is Likely Related to Mesothelioma in Young Individuals and Women from Southern Nevada — F. Baumann, B.J. Buck, et al. (2015)
• Investigating palygorskite's role in the development of mesothelioma in southern Nevada: Insights into fiber-induced carcinogenicity — D. Larson, A. Powers, et al. (2016)
• Researchers explore possible link between mesothelioma and dust emissions in southern Nevada — L.H. O'Hanlon (2013)
• Ophiolitic outcrops, naturally occurring asbestos exposure and mortality risk from malignant mesothelioma in Calabria (Southern Italy) — A. Scarselli, A. Marinaccio, et al. (2021)
• Exposures estimates of the Wittenoom mining workforce and town residents - Implications associated with risk estimation for persons exposed to asbestiform riebeckite — A.J. Rogers (2018)

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