Letter concerning: Occupational exposures to cosmetic talc and risk of mesothelioma: an updated pooled cohort and statistical power analysis with consideration of latency period by Gary M. Marsh et al. (Inhal Toxicol. 2019 Aug 5:1-11. doi:10.1080/08958378.2019.1645768)

Our plain-English summary of Letter concerning: Occupational exposures to cosmetic talc and risk of mesothelioma: an updated pooled cohort and statistical power analysis with consideration of latency period by Gary M. Marsh et al. (Inhal Toxicol. 2019 Aug 5:1-11. doi:10.1080/08958378.2019.1645768), by M.M. Finkelstein (Inhalation Toxicology, 2019).

The study

• Author: M.M. Finkelstein
• Journal: Inhalation Toxicology
• Published: 2019;31(13-14):429-431
• Type of article: Letter, Comment
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This is a letter to the editor, not a new study. The author criticized a pooled analysis by Marsh and colleagues of mesothelioma in Italian, Norwegian, Austrian and French cosmetic talc miner and miller cohorts. The author argued that Marsh and colleagues misdescribed earlier work. Rohl and Langer had found tremolite or anthophyllite in 10 of 20 consumer talc products and confirmed fibers by electron beam techniques. Pneumoconiosis in the Italian miners pointed to high silica exposure, not high talc exposure. Regional Piedmont mesothelioma rates may have overstated the expected number of cases. In a hypothetical calculation based on Quebec chrysotile miners (25 mesothelioma deaths per 100,000 person-years), the author estimated that the pooled talc cohort's 113,000 person-years would yield 2.5 expected cases if talc miners had 10% of Quebec asbestos exposure and 0.25 cases at 1%. None were observed; the chances of seeing none were 8% and 78%. The author concluded that the evidence is too weak to draw conclusions about risk at the low asbestos levels talc miners experienced. The author disclosed consulting for American attorneys in cosmetic talc litigation.

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 commenting on a published pooled cohort analysis, with a hypothetical ('thought experiment') calculation; no new data collected
• Who was studied: No new population. The letter discusses the pooled Italian, Norwegian, Austrian and French cosmetic talc miner and miller cohorts analyzed by Marsh and colleagues (113,344 person-years), compared hypothetically with Quebec chrysotile miners and millers
• Exposure: Cosmetic talc and asbestos in it (tremolite, anthophyllite). The author assumed talc miners' asbestos exposure was either 10% or 1% of that of Quebec chrysotile miners and millers
• Main results:
  • The author stated that Marsh and colleagues were wrong to suggest that Rohl and Langer did not find amphibole asbestos fibers in cosmetic talcs. Rohl and Langer reported tremolite or anthophyllite in 10 of 20 products.
  • The author argued that pneumoconiosis in the Italian cohort reflected very high silica exposure, not very high talc exposure. The author cited Rubino et al. (1976), who tabulated 65 silicosis deaths.
  • The author stated that Rubino et al. (1976) did report a very small number of airborne fibers in the Italian mines, attributed to rock microinclusions containing tremolite.
  • The author argued that using Piedmont regional mesothelioma rates, in a region with asbestos industries, may overstate expected mesothelioma deaths for the Italian cohort.
  • The letter states that Anderson et al. had a microscopist (Dr. Mark Floyd) who first identified anthophyllite fibers, and that co-author Patrick Sheehan directed him to add a qualification to the report. The letter cites Egilman and Steffen (2018) for this.
  • In the hypothetical calculation, the average mesothelioma mortality rate among Quebec chrysotile miners and millers was 25 deaths per 100,000 person-years.
  • For the pooled talc cohort's 113,000 person-years, the author calculated 2.5 expected mesothelioma cases if talc miners' asbestos exposure was 10% of the Quebec level, and 0.25 cases if it was 1%.
  • No cases were observed in the pooled cohorts. At 10% of Quebec exposure, the author calculated an 8% chance of observing none.
  • At 1% of Quebec exposure, the author calculated a 78% chance of observing no cases.
  • The author calculated a 50/50 chance of seeing zero cases versus one or more cases at an asbestos exposure of about 3% of the Quebec level.
• The authors' conclusion: The letter's author concluded that, despite pooling and about 113,000 person-years, the epidemiologic evidence is too weak to draw conclusions about risk from the low asbestos exposures of talc miners, and that a much larger cohort would be needed. This differs from the conclusion of Marsh and colleagues, which the author disputes.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer, Mesothelioma, Talc and vermiculite.

Medical terms in this study, explained in our Lexicon: Occupational Exposure, Cosmetic Talc, Mesothelioma, Latency.

Related studies

• Occupational exposures to cosmetic talc and risk of mesothelioma: an updated pooled cohort and statistical power analysis with consideration of latency period — G.M. Marsh, A.M. Ierardi, et al. (2019)
• Re: Brent L. Finley, Stacey M. Benson & Gary M. Marsh (2017): Cosmetic talc as a risk factor for pleural mesothelioma: a weight of evidence evaluation of the epidemiology, Inhalation Toxicology, DOI: 10.1080/08958378.2017.1336187 — M.M. Finkelstein (2017)
• Letter concerning: Burns AM, Barlow CA, Banducci AM, Unice KM, Sahmel J. Potential Airborne Asbestos Exposure and Risk Associated with the Historical Use of Cosmetic Talcum Powder Products — M.M. Finkelstein (2019)
• Absence of mesothelioma risk maintained in an expanded international cohort of cosmetic talc miners and millers — A.M. Ierardi, G.M. Marsh (2020)
• Letter on: "Cosmetic talc as a risk factor for pleural mesothelioma: a weight of evidence evaluation of the epidemiology" — D. Mirabelli (2017)
• Response to letters regarding "Cosmetic talc as a risk factor for pleural mesothelioma: a weight of evidence evaluation of the epidemiology" — B.L. Finley, S.M. Benson, et al. (2018)

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