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Chrysotile, tremolite and carcinogenicity
1Department of Occupational and Environmental Medicine, National Heart and Lung Institute, Imperial College of Science, Technology and Medicine, London, U.K.
The Annals of Occupational Hygiene
|December 31, 1997
Summary
Amphibole asbestos fibers, specifically tremolite, are linked to higher mesothelioma and lung cancer risks in Quebec chrysotile miners. Higher tremolite contamination in central mines correlated with increased cancer incidence compared to peripheral mines.
Area of Science:
- Occupational Health
- Epidemiology
- Environmental Toxicology
Background:
- Amphibole fibers, particularly tremolite, are suspected contributors to asbestos-related cancers.
- Chrysotile asbestos often contains tremolite as a contaminant.
Purpose of the Study:
- To investigate the hypothesis that tremolite asbestos fibers disproportionately increase cancer risk.
- To compare cancer incidence in Quebec chrysotile miners based on mine location and tremolite contamination levels.
Main Methods:
- Cohort study of ~11,000 Quebec chrysotile workers and matched referents.
- Analysis of deaths from mesothelioma, lung, larynx, stomach, and colorectal cancers.
- Logistic regression used to estimate cancer risks in central (high tremolite) versus peripheral (low tremolite) mines.
Main Results:
- Significantly elevated odds ratios for mesothelioma and lung cancer in central mines compared to peripheral mines.
- No significant increase in risk for laryngeal, stomach, or colorectal cancers in either mine group.
- Peripheral mines showed little to no increased risk for any of the studied cancers.
Conclusions:
- The study substantiates the hypothesis that higher tremolite contamination leads to greater cancer risks.
- The findings suggest the biopersistence of amphibole fibers may explain increased cancer risk.
- Results are relevant for asbestos control policies and selecting safe mineral fiber substitutes.