Malignant mesothelioma incidence among talc miners and millers in New York State

Our plain-English summary of Malignant mesothelioma incidence among talc miners and millers in New York State, by M.M. Finkelstein (American Journal of Industrial Medicine, 2012).

The study

• Author: M.M. Finkelstein
• Journal: American Journal of Industrial Medicine
• Published: 2012;55(10):863-8
• Cited by: 22 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: There is controversy about the potential for dust from the talc mines and mills of New York State to cause mesothelioma. Honda et al. published a study of mortality among New York talc workers and concluded that it was unlikely that the two deaths from mesothelioma were caused by talc ore dust. However, fibers of tremolite and anthophyllite have been found in the lungs of talc workers and Hull concluded that "New York talc exposure is associated with mesothelioma, and deserves further public health attention."

Methods: Data concerning additional cases of mesothelioma in the cohort have been posted by NIOSH. I used information from the NIOSH website and the Honda report to analyze the incidence of mesothelioma during the years 1990-2007.

Results: There were at least five new cases of mesothelioma in the cohort and mesothelioma incidence rates were at least five (1.6-11.7) times the rate in the general population (P < 0.01).

Conclusions: I conclude that: (1) mesothelioma has been diagnosed among members of the cohort at a rate in excess of that in the general population; (2) fibers of tremolite and anthophyllite have been detected in dust and the lungs of talc workers; and (3) these fibers are known causes of mesothelioma. It is prudent, on the balance of probabilities, to conclude that dusts from New York State talc ores are capable of causing mesothelioma in exposed individuals.

Copyright © 2012 Wiley Periodicals, Inc.

In plain English

This single-author commentary asked whether New York State talc miners and millers developed mesothelioma more often than expected. It used white men from one talc facility (the RTV cohort) earlier studied by Honda and colleagues. New cases from 1990 to 2007 came from records posted in public responses to a NIOSH draft document. Six cohort members died between 1994 and 2007; five had confirmed mesothelioma, and in the sixth, adenocarcinoma could not be excluded. The author estimated about one expected case, assuming a median cohort age of 72 and using a U.S. rate for white men aged 65 to 74. The incidence rate ratio was 5 (1.6–11.7), or 6 (2.2–13.0) counting the sixth man. Three men may have had asbestos exposure outside the talc industry before joining RTV. The author did not follow the cohort, assumed no deaths through 2007 among men alive in 1989, and said rates are likely lower-bound estimates. Citing earlier reports of tremolite and anthophyllite fibers in talc dust and workers' lungs, the author concluded it was prudent, on the balance of probabilities, to judge these dusts capable of causing mesothelioma.

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: Commentary presenting an analysis of mesothelioma incidence in an existing worker cohort. Cases were identified from documents posted on the NIOSH website, and person-years were estimated from data in an earlier published study (Honda et al. 2002).
• Who was studied: The RTV cohort: white men who worked at least 1 day at a New York State talc mining and milling facility from 1948 through 1989. Honda followed 782 men to 1989, and 567 were alive at the end of 1989. This analysis covered the 18 years from 1990 to 2007.
• Exposure: Dust from mining and milling New York State talc. A 1980 NIOSH industrial hygiene report cited by the author described the ore at RTV as mainly talc, tremolite, anthophyllite and serpentines.
• Main results:
  • Six men from the cohort died after 1989, between 1994 and 2007, aged 64 to 86. Five had mesothelioma diagnosed at biopsy, surgery or autopsy. The sixth may have had mesothelioma, but adenocarcinoma could not be excluded, and his death was certified as gastrointestinal cancer.
  • The expected number of cases was approximate rather than calculated from individual ages. The author assumed about 10,000 person-years after 1989 and a median cohort age of 72 in 2007. The author then applied the U.S. incidence rate (published rates for the year 2001) for white men aged 65 to 74, 1.0 per 10,000 per year, which gave about one expected case.
  • Incidence rate ratio for the RTV cohort compared with American males: 5 (95% confidence limits 1.6–11.7) if Subject 6 did not have mesothelioma.
  • Incidence rate ratio: 6 (95% confidence limits 2.2–13.0) if Subject 6 did have mesothelioma. In both cases the author reported the ratio as significantly above 1.
  • Among the six men, all but one had been exposed to dust for 20 years or more. Latency periods ranged from 34 to 49 years. Five had worked in the mill and one had been a miner.
  • Four of the six men had evidence of talc worker's pneumoconiosis.
  • Three men had possible asbestos exposure outside the talc industry before joining the RTV facility: Navy service as a radar man, one year in a Navy Yard, and brake work at a service station. Two of them (Subjects 3 and 4) had also worked at other talc mines before that exposure. The author judged the extent likely low, except possibly for the Navy Yard worker.
• The authors' conclusion: The author concluded that mesothelioma occurred in the cohort at a rate above that of the general population. The author noted that tremolite and anthophyllite fibers, known causes of mesothelioma, have been detected in the dust and in workers' lungs. While acknowledging that several workers may have had asbestos exposure elsewhere, the author judged it prudent, on the balance of probabilities, to conclude that New York State talc ore dusts are capable of causing mesothelioma.
• Limitations the authors state:
  • The cohort was not actively followed. Cases came only from documents submitted to NIOSH, so some cases may have been missed. The author said this would underestimate the rate ratio.
  • Person-years could not be calculated accurately. The author assumed that all 567 men alive at the end of 1989 survived to the end of 2007, which the author called clearly wrong. The author said this overestimates person-years, so the rates are likely lower-bound estimates.
  • Without access to the underlying Honda cohort, the expected number of cases could not be computed precisely. The author instead assumed a median age of 72 in 2007.
  • Two or three of the men may also have had asbestos exposure from other sources.

Topics

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

Medical terms in this study, explained in our Lexicon: Mesothelioma, Talc, Tremolite, Anthophyllite, NIOSH, Incidence.

Related studies

• Letter to the editor on commentary: malignant mesothelioma incidence among talc miners and millers in New York state by M M Finkelstein — R.P. Nolan, J.F. Gamble, et al. (2013)
• Mortality among talc miners and millers in New York State — M. Kleinfeld, J. Messite, et al. (1967)
• Pneumoconiosis and malignant mesothelioma in a family operated metal casting business that used industrial talc from New York state — M.M. Finkelstein (2013)
• Exposure to asbestiform minerals and radiographic chest abnormalities in a talc mining region of upstate New York — E.F. Fitzgerald, A.D. Stark, et al. (1991)
• Reply to letter by Nolan and colleagues--re: the carcinogenicity of New York state talc dusts in humans — M. Finkelstein (2013)
• An update of a mortality study of talc miners and millers in Italy — M. Coggiola, D. Bosio, et al. (2003)

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