Chest
ReviewChrysotile, Tremolite, and Malignant Mesothelioma in Man
Section snippets
THE EXISTENCE OF CHRYSOTILE-INDUCED MESOTHELIOMA IN MAN
Table 1 presents a survey of the literature reporting chrysotile-induced mesotheliomas. There are a total of 142 mesotheliomas in this whole set of reports, of which, for reasons to be considered shortly, at most 53 can be accepted as chrysotile-induced tumors. The table is grouped in sections: reports of mesothelioma occurring in persons exposed either directly or indirectly to chrysotile mine dust; reports of secondary application workers in largely chrysotile-using factories where some
MESOTHELIOMAS ASSOCIATED WITH TREMOLITE EXPOSURE IN MAN
Cases of mesothelioma induced by tremolite not associated with chrysotile in man are rare (Table 2). McDonald et al29 reported a group of workers mining tremolite-contaminated vermiculite in which four mesothelomas (2.4 percent of deaths) were found. Tremolite has been found as an environmental contaminant and in the lungs of persons in a local area in Greece in which the death rate from mesothelioma is reported to be 1 percent.30,31 Brown et al32 described a mesothelioma in a miner of New York
AMOUNT OF EXPOSURE REQUIRED FOR INDUCTION OF MESOTHELIOMA BY CHRYSOTILE
The small number of chrysotile-associated mesotheliomas, as well as the possibility of amosite and crocidolite contamination, make any estimate of dose extremely difficult. At the low end of the scale, however, it is worth emphasizing that there is no evidence of an increased mesothelioma risk in long-term residents of the Quebec chrysotile mining towns, despite the fact that these persons are exposed for a lifetime to several hundred times the ambient chrysotile levels found in most North
THE ROLE OF TREMOLITE VS CHRYSOTILE IN MESOTHELIOMA INDUCTION
It has been suggested that the fiber which causes mesothelioma in those exposed to chrysotile is the tremolite contaminant rather than the chrysotile itself.7,8 Given that amosite and crocidolite are powerful mesothelial carcinogens in man, and, as shown in Table 2, that long fiber tremolite in the absence of chrysotile also produces a high yield of deaths or tumors, this idea is appealing, but direct proof is difficult.
If tremolite is the agent of mesothelioma, disease incidence should be
CONCLUSIONS
Despite great interest in the topic, and despite the current furor in the United States over the dangers of mesothelioma from exposure to chrysotile asbestos at very low levels in buildings, an extensive search of the literature reveals only 53 possible cases of chrysotile induced mesothelioma, of which 41 occurred in individuals exposed directly to chrysotile mine dust. For those exposed to chrysotile products, the risk appears to be much lower, and here it is likely that some of the reported
AUTHOR'S NOTE
In compiling this manuscript, I have unintentionally left out the study of Yazicioglu et al. Pleural calcifications, pleural mesotheliomas, and bronchial cancers caused by tremolite dust Thorax 1980; 35:564-69. These authors report what appears to be a high incidence of mesothelioma in persons living in a village where a tremolite containing whitewash and stucco is made from outcrops of local rock. Their illustrations suggest that the tremolite is a fairly long, high aspect ratio, fiber.
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Cited by (111)
Journey to the centre of the lung. The perspective of a mineralogist on the carcinogenic effects of mineral fibres in the lungs
2023, Journal of Hazardous MaterialsCitation Excerpt :Based on a review which did not differentiate co-exposure with amphibole asbestos, Kanarek (2011) stated that chrysotile causes mesothelioma worldwide. As a matter of fact, the mesothelioma potency of chrysotile versus crocidolite is probably the most debated issue in “asbestos” matter (Churg, 1988). On one side, there is a body of epidemiological evidences supporting the model that chrysotile mesothelioma potency is much lower than crocidolite mesothelioma potency (McDonald et al., 1980; Peto, 1980; Hodgson and Darnton, 2010) and that the risk of pleural mesothelioma in humans is deemed to be negligible for exposures to airborne chrysotile not contaminated by amphibole (Yarborough, 2007).
Environment and Mesothelioma
2021, Encyclopedia of Respiratory Medicine, Second EditionMeasuring EMPs in the lung what can be measured in the lung: Asbestiform minerals and cleavage fragments
2018, Toxicology and Applied PharmacologyCitation Excerpt :For particles with poor biopersistence, such as fibrous glass or chrysotile asbestos, it is difficult to accurately measure the past dose with lung tissue analyses. Nonetheless, there is a growing consensus that it is the fibers that accumulate within the lung (typically over decades) that are responsible for disease (Roggli & Vollmer, 2008; Wagner & Pooley, 1986; Churg, 1988) Furthermore, studies have shown that biopersistence of MMVF is an important factor in determining the pathogenic potential of a particular fiber (Searl et al., 1999; Wheeler, 1990). Because of the overlap in morphological features between asbestiform fibers and cleavage fragments of the various asbestos minerals, it is recommended that one use caution in classifying fibers that are <10 μm in length and more than one μm in diameter.
Observational research - Opportunities and limitations
2013, Journal of Diabetes and its ComplicationsCitation Excerpt :Several examples include the association between hyperglycemia and diabetes complications including retinopathy, nephropathy, peripheral neuropathy, and ischemic heart disease (American Diabetes Association, 2013). Other well known examples include hypertension and stroke, smoking and lung cancer, asbestosis and mesothelioma, and LDL and HDL cholesterol concentrations and risk of ischemic heart disease (Churg, 1988; Gordon, Kannel, Castelli, & Dawber, 1981; Kannel, Wolf, Verter, & McNamara, 1970; Pirie, Peto, Reeves, Green, & Beral, 2013). In the case of complications due to hyperglycemia, high LDL-cholesterol concentration, and hypertension, clinical trials to reduce these levels have resulted in reductions in the rate of these outcomes, further supporting a causal association (1991; 1994; 1998a, 1998b).
Cytotoxicity induced by exposure to natural and synthetic tremolite asbestos: An in vitro pilot study
2013, Acta HistochemicaCitation Excerpt :Its commercial use has been less extensive than that of chrysotile, amosite, and crocidolite. Amosite, tremolite and chrysotile fibers have been found in most lungs of miners with heavy mixed exposure to amphiboles and chrysotile (Churg, 1988; Churg and Vedal, 1994). The tremolite fibers could be important in the pathogenesis of lung tumors, since greater relative amounts of tremolite were found in patients with mesothelioma.
Cause-specific mortality in relation to chrysotile-asbestos exposure in a Chinese cohort
2012, Journal of Thoracic OncologyCitation Excerpt :Chrysotile represents 95% of all the asbestos ever used and is now the only type of asbestos commercially used in the world.21 Although there is general agreement that chrysotile asbestos can cause lung cancer and mesothelioma, the difference in carcinogenic potency between chrysotile and amphibole is still an ongoing debate.22,23 In this study, only chrysotile was used in the asbestos-manufacturing plant.2
Supported by grants from the National Cancer Institute of Canada ana the Medical Research Council of Canada.