ORIGINAL RESEARCH article
Front. Public Health
Sec. Occupational Health and Safety
Volume 13 - 2025 | doi: 10.3389/fpubh.2025.1654772
This article is part of the Research TopicMineral Particles and Fibers and Human Health Risks: State-of-the-Art in Characterization, Analysis, Tissue Analytics, Exposure Thresholds for Risk, Epidemiology, and Risk Assessment for Science-Based Regulation and Disease Prevention and Implications for Occupational Health and SafetyView all 22 articles
Updates on exposure estimation for the Québec cohort of chrysotile miners and millers: Implications for risk assessment and threshold hypothesis
Provisionally accepted
- 1McGill University, Montreal, Canada
- 2Chemistry & Industrial Hygiene, Inc., Lakewood, United States
- 3Colorado School of Mines, Golden, United States
Select one of your emails
You have multiple emails registered with Frontiers:
Notify me on publication
Please enter your email address:
If you already have an account, please login
You don't have a Frontiers account ? You can register here
The McGill University cohort of Québec chrysotile miners and millers (total of 11,379 members) has been a major determinant of risk assessment. The U.S. EPA and some other meta-analyses omit this cohort, the largest ever exposed to high concentrations of chrysotile. Preliminary analyses using new data showed average cumulative exposures in the full cohort of 528.5 f/cc-years (95% CI 510.3, 546.7) or 979 f/cc-years (95% CI 945, 1013), depending on the regression equation used for the modeling. The lowest estimated exposure level observed for any mesothelioma case with diagnostic certainty was 68 f/cc-years. We confirmed that the estimation of potency factor for Québec chrysotile should not be expected to differ significantly from Darnton's estimation for non-textile chrysotile (RM=0.0014%), if better quality data for correspondence between impinger and fiber count measurements is involved. Among several estimations we made, the average meta-analytical mesothelioma potency factor for all types of chrysotile would be 0.0014% (95% CI 0.0010, 0.0.0018), and for non-textile chrysotile 0.0011% (95% CI 0.0008, 0.0015). Several estimations of a possible threshold that would correspond to non-elevated mesothelioma risk based on the Québec cohort were also made. The minimal cumulative exposure in mesothelioma cases demonstrated values that ranged from 4.8-6 MPCF-years, or 18-50 f/cc-years. Also, based on theoretical models, the threshold can be found at the level of 6.38 MPCF-years (standard deviation 2.6), or in the range from 35.9 f/cc-years (standard deviation of 15.4) to 65.9 f/cc-years (standard deviation of 29.6).
Keywords: Mesothelioma, chrysotile, Québec cohort, Midget impinger, pcm
Received: 26 Jun 2025; Accepted: 16 Sep 2025.
Copyright: © 2025 Case, Korchevskiy and Korchevskiy. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Andrey A. Korchevskiy, akorchevskiy@c-ih.com
Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.