Comment on 'estimating the asbestos-related lung cancer burden from mesothelioma mortality' - IARC and chrysotile risks (original) (raw)
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Annals of Occupational Hygiene, 2002
Introduction. The risk of asbestos diseases cannot be measured directly in populations with low level chrysotile asbestos exposure. Risk assessments must be used to extrapolate risks from past heavy industrial asbestos exposures to today's low chrysotile exposures. We tested the US Environmental Protection Agency (EPA) mesothelioma risk model in a population having experienced relatively high and mostly non-occupational chrysotile exposures. Methods. Female mesotheliomas first diagnosed from 1970 to 1989 in chrysotile asbestos mining districts (Asbestos and Thetford) were identified from the Quebec Tumour Registry and hospital records gathered throughout the province. Diagnoses were reviewed by three pathologists. An international expert panel estimated historical ambient exposure levels in these districts. A 'time-area-job-family exposure' matrix was derived from these estimates, occupational and cohabitation exposure estimates and a survey of 817 female residents. We applied the EPA mesothelioma incidence model to the population time-area-job-family exposure matrix and compared this predicted incidence with that actually observed. Results. Ambient airborne asbestos exposures were between 0.1 and 3 fibres/ml before 1970. The EPA asbestos risk model predicted 150 (range 30-750) female mesotheliomas in Asbestos, while only one case (peritoneal) was observed; 500 cases (range 100-2500) were predicted in Thetford Mines, while 10 cases (pleural) were observed. These large discrepancies cannot be explained by random or systematic errors.
Lung cancer and mesothelioma risk assessment for a population environmentally exposed to asbestos
International Journal of Hygiene and Environmental Health, 2014
Asbestos-related cancer risk is usually a concern restricted to occupational settings. However, recent published data on asbestos environmental concentrations in Thetford Mines, a mining city in Quebec, Canada, provided an opportunity to undertake a prospective cancer risk assessment in the general population exposed to these concentrations. Using an updated Berman and Crump dose-response model for asbestos exposure, we selected population-specific potency factors for lung cancer and mesothelioma. These factors were evaluated on the basis of population-specific cancer data attributed to the studied area's past environmental levels of asbestos. We also used more recent population-specific mortality data along with the validated potency factors to generate corresponding inhalation unit risks. These unit risks were then combined with recent environmental measurements made in the mining town to calculate estimated lifetime risk of asbestos-induced lung cancer and mesothelioma. Depending on the chosen potency factors, the lifetime mortality risks varied between 0.7 and 2.6 per 100,000 for lung cancer and between 0.7 and 2.3 per 100,000 for mesothelioma. In conclusion, the estimated lifetime cancer risk for both cancers combined is close to Health Canada's threshold for "negligible" lifetime cancer risks. However, the risks estimated are subject to several uncertainties and should be confirmed by future mortality rates attributed to present day asbestos exposure.
An update of cancer mortality among chrysotile asbestos miners in Balangero, northern Italy.
British journal of …, 1990
The mortality experience of a cohort of chrysotile miners employed since 1946 in Balangero, northern Italy was updated to the end of 1987 giving a total of 427 deaths out of 27 010 man-years at risk. A substantial excess mortality for all causes (standardised mortality ratio (SMR) = 149) was found, mainly because of high rates for some alcohol related deaths (hepatic cirrhosis, accidents). For mortality from cancer, however, the number of observed deaths (82) was close to that expected (76-2). The SMR was raised for oral cancer (SMR 231 based on six deaths), cancer of the larynx (SMR 267 based on eight deaths), and pleura (SMR 667 based on two deaths), although the excess only reached statistical significance for cancer of the larynx. Rates were not increased for lung, stomach, or any other type of cancer. No consistent association was seen with duration or cumulative dust exposure (fibre-years) for oral cancer, but the greatest risks for laryngeal and pleural cancer were in the highest category of duration and degree of exposure to fibres. Although part of the excess mortality from laryngeal cancer is probably attributable to high alcohol consumption in this group of workers, the data suggest that exposure to chrysotile asbestos (or to the fibre balangeroite that accounts for 0-2-
Asbestos-Related Research: First Objectivity then Conclusions
Journal of Environmental Studies, 2015
Asbestos-related risks have been extrapolated from the past, when high-dose occupational exposures were frequent. The linear no-threshold dose-response pattern has been assumed, but its applicability to low-dose asbestos exposures has never been proven. Morphologically, malignant mesothelioma can resemble various cancers. There are diagnostic algorithms; however, a tumor diagnosed by standard methods as mesothelioma is not a welldefined entity, in all cases substantially different from other cancers. Well-aimed search and screening effect have probably contributed to the enhanced incidence of mesothelioma and other asbestosrelated diseases in exposed populations. Asbestos-related diseases have been extensively studied in Russia. The prevailing view is that, if all precautions are observed, modern technologies of asbestos production and processing are acceptably safe, whereas bans and prohibitions applied by some countries are excessive. At the same time, there are economic interests to promote chrysotile. Biases due to industrial interests have compromised the objectivity of some asbestosrelated reports. In the author's opinion, the "all fibers equal" basis of official regulations can be accepted provisionally pending objective and reliable evidence on toxicity of different asbestos types and manmade substitutes. On the basis of independent scientific data, the bans and restrictions on asbestos in some countries should be reexamined and potentially revised. Any permit of continued production or use of asbestos materials must be coupled with regulations and efficient measures to prevent environmental contamination associated even with minimal additional risks.
Ongoing downplaying of the carcinogenicity of chrysotile asbestos by vested interests
Journal of Occupational Medicine and Toxicology, 2021
Industries that mine, manufacture and sell asbestos or asbestos-containing products have a long tradition of promoting the use of asbestos, while placing the burden of economic and health costs on workers and society. This has been successfully done in recent years and decades in spite of the overwhelming evidence that all asbestos types are carcinogenic and cause asbestosis. In doing so, the asbestos industry has undermined the WHO campaign to reach a worldwide ban of asbestos and to eliminate asbestos-related diseases. Even worse, in recent years they succeeded in continuing asbestos mining and consuming in the range of about 1.3 million tons annually. Nowadays, production takes place predominantly in Russia, Kazakhstan and China. Chrysotile is the only asbestos type still sold and represents 95% of asbestos traded over the last century.The asbestos industry, especially its PR agency, the International Chrysotile Association, ICA, financed by asbestos mining companies in Russia, K...
Asbestos-related cancers: the ‘Hidden Killer’ remains a global threat
Expert Review of Anticancer Therapy, 2020
Introduction: Asbestos, the most frequent cause of occupational cancer, continues to be consumed on a massive scale, with millions of people exposed on a daily basis. This review explains why we have failed in curtailing the silent epidemic of asbestos-related disease and why the numbers of asbestos victims are likely to remain high. Emerging and developed countries have to be reminded that asbestos exposure has yet to become a problem of the past. The worldwide spread of asbestos, followed by the surge of asbestos-related cancers, resembles the lung cancer epidemic caused by smoking and stimulated by manufacturers. Areas covered: Underreporting of malignant mesothelioma and asbestos-induced lung cancer, frequently-used arguments in the amphibole/chrysotile debate and the conclusion from bona-fide research organizations, that all forms of asbestos are carcinogenic, are reviewed. Special attention is paid to the consequences of ubiquitous environmental asbestos and the 'changing face' of malignant mesothelioma in countries with heavy asbestos use in the past. Expert opinion: Experts in oncology, respiratory medicine, occupational and public health, and basic researchers must take responsibility and acknowledge the ongoing silent epidemic of asbestos-related diseases. The call for a worldwide asbestos ban is more urgent than ever.
Asbestos Exposure of Chrysotile Miners and Millers in Balangero, Italy
Annals of Work Exposures and Health, 2020
The largest chrysotile mine in Western Europe was active in Balangero (Italy) from 1917 to 1990. We quantitatively assessed exposure to asbestos in the framework of a cohort study on mortality of Balangero miners and millers. Using documents filed at the Italian State Archive we reconstructed the job-histories of cohort members. The concentration of asbestos fibres by work-area was derived from industrial hygiene surveys since 1968 and monitoring programs since 1975. Earlier exposures had been estimated based on the experimental reconstruction of past working conditions. In the mine concentrations of about 20 fibres per millilitre (f/ml) were initially present, decreasing to 5 in the mid-1950s and to <1 in late 1970s. In milling areas higher levels were present and did not fall below 1 f/ml until the mid-1980s. Cumulative exposure of cohort members, as the sum over their job-history of their year- and area-specific exposures, were <10 fibre/millilitre years (f/ml-y) in 18% of ...