The Wittenoom legacy

Changing trends in mesothelioma: Important lessons for an occupational disease registry

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The Western Australian Mesothelioma Registry: Analysis of 60 years of cases

BACKGROUND AND OBJECTIVE

Australia introduced a partial ban on asbestos consumption in 1984. There is continuing concern about exposure to asbestos in the built environment and non-occupational exposures. The aim of this study was to describe epidemiological trends of mesothelioma in Western Australia (WA) over the 60 years since the first case was recorded.

METHODS

Every case of mesothelioma notified to the WA Cancer Registry is reviewed by an expert panel. Data include demographic and clinical variables including principal mode of asbestos exposure and age at first exposure. Trends over time for survival, latency and pathological subtype of mesothelioma where analysed. Incidence rates for cases exposed during home renovation where calculated.

RESULTS

Two thousand seven hundred ninety-six cases of mesothelioma were identified with males comprising the majority (n = 2368, 84.7%). The median (IQR) age at diagnosis was 70 (62-78) years, and median latency of 47 (38-55) years. Pleural mesothelioma was recorded in 2620 (93.7%) cases with the epithelioid subtype most prevalent (n = 1730, 61.9%). Overall, median survival was 298 (128-585) days and latency 46 (37-54) years, both effectively doubling over the study period. Non-occupational exposures were proportionally higher in females (52.6%), compared with males (9.5%). Home renovation was the primary exposure in 227 (8.1%) cases, with number of cases and incidence rate ratio peaking in 2005/09 but subsequently decreasing.

CONCLUSION

The annual number of cases of mesothelioma in WA may have hit a plateau. The majority of females have non-occupational exposures and incidence rates from home renovation exposure may have peaked, suggesting the ban on asbestos has been effective.

An updated evaluation of reported no-observed adverse effect levels for chrysotile, amosite, and crocidolite asbestos for lung cancer and mesothelioma

This analysis updates two previous analyses that evaluated the exposure-response relationships for lung cancer and mesothelioma in chrysotile-exposed cohorts. We reviewed recently published studies, as well as updated information from previous studies. Based on the 16 studies considered for chrysotile (<10% amphibole), we identified the "no-observed adverse effect level" (NOAEL) for lung cancer and/or mesothelioma; it should be noted that smoking or previous or concurrent occupational exposure to amphiboles (if it existed) was not controlled for. NOAEL values ranged from 2.3-<11.5 f/cc-years to 1600-3200 f/cc-years for lung cancer and from 100-<400 f/cc-years to 800-1599 f/cc-years for mesothelioma. The range of best-estimate NOAELs was estimated to be 97-175 f/cc-years for lung cancer and 250-379 f/cc-years for mesothelioma. None of the six cohorts of cement or friction product manufacturing workers exhibited an increased risk at any exposure level, while all but one of the six studies of textile workers reported an increased risk at one or more exposure levels. This is likely because friction and cement workers were exposed to much shorter chrysotile fibers. Only eight cases of peritoneal mesothelioma were reported in all studies on predominantly chrysotile-exposed cohorts combined. This analysis also proposed best-estimate amosite and crocidolite NOAELs for mesothelioma derived by the application of relative potency estimates to the best-estimate chrysotile NOAELs for mesothelioma and validated by epidemiology studies with exposure-response information. The best-estimate amosite and crocidolite NOAELs for mesothelioma were 2-5 f/cc-years and 0.6-1 f/cc-years, respectively. The rate of peritoneal mesothelioma in amosite- and crocidolite-exposed cohorts was between approximately 70- to 100-fold and several-hundred-fold higher than in chrysotile-exposed cohorts, respectively. These findings will help characterize potential worker and consumer health risks associated with historical and current chrysotile, amosite, and crocidolite exposures.

An Approach to Overcome the Limitations of Surveillance of Asbestos Related Diseases in Low- and Middle-Income Countries: What We Learned from the Sibaté Study in Colombia

Introduction

The asbestos industry began its operations in Colombia in 1942 with the establishment of an asbestos-cement facility in Sibaté, located in the Department of Cundinamarca. Despite extensive asbestos use and production in Colombia, the country lacks a reliable epidemiological surveillance system to monitor the health effects of asbestos exposure. The Colombian health information system, known as SISPRO, did not report mesothelioma cases diagnosed in the municipality, posing a significant challenge in understanding the health impacts of asbestos exposure on the population of Sibaté.

Methods

To address this issue, an active surveillance strategy was implemented in Sibaté. This strategy involved conducting door-to-door health and socioeconomic structured interviews to identify Asbestos-Related Diseases (ARDs). Validation strategies included a thorough review of medical records by a panel of physicians, and the findings were communicated to local, regional, and national authorities, as well as the general population.

Results

The active surveillance strategy successfully identified a mesothelioma cluster in Sibaté, revealing the inadequacy of the existing health information system in monitoring asbestos-related diseases. The discovery of this cluster underscores the critical importance of implementing active surveillance strategies in Colombia, where governmental institutions and resources are often limited.

Conclusion

The findings of this study emphasize the urgent need for Colombia to establish a reliable epidemiological surveillance system for asbestos-related diseases (ARDs). Active surveillance strategies can play a crucial role in identifying mesothelioma clusters and enhancing our understanding of the health effects of asbestos exposure in low- and middle-income countries.

Using GIS to Estimate Population at Risk Because of Residence Proximity to Asbestos Processing Facilities in Colombia

The recent enactment of the law banning asbestos in Colombia raises a significant number of challenges. The largest factories that have historically processed asbestos include five asbestos-cement facilities located in the cities of Sibaté (Cundinamarca), Cali (Valle del Cauca), and Barranquilla (Atlántico), and Manizales (Caldas), which has two, as well as a friction products facility in Bogotá D.C. An asbestos chrysotile mine has also operated in Colombia since 1980 in Campamento (Antioquia). In the framework of developing the National Asbestos Profile for Colombia, in this study, we estimated the population residing in the vicinity of asbestos processing plants or the mine and, therefore, potentially at risk of disease. Using a geographic information system, demographic data obtained from the last two general population censuses were processed to determine the number of people living within the concentric circles surrounding the asbestos facilities and the mine. In previous studies conducted in different countries of the world, an increased risk of asbestos-related diseases has been reported for people living at different distance bands from asbestos processing facilities. Based on these studies, circles of 500, 1000, 2000, 5000, and 10,000 m radii, centered on the asbestos processing facilities and the mine that operated in Colombia, were combined with the census data to estimate the number of people living within these radii. Large numbers of people were identified. It is estimated that in 2005, at the country level, 10,489 people lived within 500 m of an asbestos processing facility or mine. In 2018, and within a distance of 10,000 m, the number of people was 6,724,677. This information can aid public health surveillance strategies.

Asbestos in High-Risk Communities: Public Health Implications

Asbestos-related diseases (ARDs)-mesothelioma, lung cancer, and asbestosis-are well known as occupational diseases. As industrial asbestos use is eliminated, ARDs within the general community from para-occupational, environmental, and natural exposures are more prominent. ARD clusters have been studied in communities including Broni, Italy; Libby, Montana; Wittenoom, Western Australia; Karain, Turkey; Ambler, Pennsylvania; and elsewhere. Community ARDs pose specific public health issues and challenges. Community exposure results in higher proportions of mesothelioma in women and a younger age distribution than occupational exposures. Exposure amount, age at exposure, fiber type, and genetic predisposition influence ARD expression; vulnerable groups include those with social and behavioral risk, exposure to extreme events, and genetic predispositions. To address community exposure, regulations should address all carcinogenic elongated mineral fibers. Banning asbestos mining, use, and importation will not reduce risks from asbestos already in place. Residents of high-risk communities are characteristically exposed through several pathways differing among communities. Administrative responsibility for controlling environmental exposures is more diffuse than for workplaces, complicated by diverse community attitudes to risk and prevention and legal complexity. The National Mesothelioma Registries help track the identification of communities at risk. High-risk communities need enhanced services for screening, diagnosis, treatment, and social and psychological support, including for retired asbestos workers. Legal settlements could help fund community programs. A focus on prevention, public health programs, particularization to specific community needs, and participation is recommended.

Asbestos Air Pollution: Description of a Mesothelioma Cluster Due to Residential Exposure from an Asbestos Cement Factory

The study describes a cluster of 71 malignant mesothelioma cases among Bari residents without asbestos exposure other than residential exposure. This small cohort, as expected, was composed of a majority of females (56.34%) with a M/F ratio of 0.8, ages ≤ 65 years old (52.11%) and the epithelioid morphological type (78.87%). Sixty-four subjects (90.14%) lived between 10 m and 1000 m from the asbestos cement factory (Fibronit), and the latency length was longer than 55 years for 25 subjects (35.21%). The adjusted risk (adjusted OR) of observing the epithelial form of mesothelioma among subjects living at small distances from Fibronit was high (OR = 1.870 (0.353-9.905)) for people living 550-1000 m from the site and for those living less than 550 m from the site (OR = 1.470 (0.262-8.248)). Additionally, the subjects with a high length of exposure showed a relevant risk of epithelioid mesothelioma both for 21-40 years of exposure (OR = 2.027 (0.521-7.890)) and more than 40 years of exposure (OR = 2.879 (0.651-12.736)). All of the estimates were high but not significant because this transitional study has a typically low power. The adjustment for latency showed the same trend. Using detailed information collected by the regional mesothelioma registry, this study provided evidence of a continuing health impact of the Fibronit asbestos cement factory in Bari on the resident population.

Impact of an asbestos cement factory on mesothelioma incidence in a community in Italy

BACKGROUND

Broni is a small town (9000 inhabitants) in the province of Pavia, Lombardy, north-west Italy, where the second largest Italian asbestos cement factory (Fibronit) was in operation between 1932 and 1993. Based on Lombardy Mesothelioma Registry (RML) data (2000-2011), we previously showed a high impact of asbestos exposure on malignant mesothelioma (MM) incidence among Fibronit workers, their families, and people living in Broni and in the nearby town of Stradella (11,000 residents). Given the great concern of the community, we have recently updated the data regarding 5 more years (2012-2016).

METHODS

From the RML database we extracted subjects who ever worked in Fibronit, their family members, ever residents in Broni, and subjects living in Stradella and nearby towns at the time of diagnosis. For each type of exposure we calculated standardized incidence ratios (SIR = observed/expected cases).

RESULTS

In the period 2000-2016 we registered 56 cases (2.52 expected, SIR = 22.2), 49 men (41 pleural, 8 peritoneal MM), 7 women (5 pleural, 2 peritoneal MM) with past occupational exposure in Fibronit. Among subjects never occupationally exposed and never exposed to extra-occupational sources unrelated to Fibronit, we counted 39 cases (4.24 expected, SIR = 9.2), 10 men (all pleural MM), 29 women (28 pleural, 1 peritoneal MM) in Fibronit workers' families, 91 pleural mesothelioma cases (7.43 expected, SIR = 12.2, 31 men, 60 women), ever residents in Broni, and 25 pleural mesothelioma cases (3.05 expected, SIR = 8.2, 6 men, 19 women) living in Stradella at the time of diagnosis. The overall number of excess cases was about 194 (211 against 17.24 expected). In the remaining adjacent (No. 8) and surrounding (No. 17) municipalities (32,000 people) there were 7 cases (1 men, 6 women, 8.85 expected).

CONCLUSION

The mesothelioma burden related to the asbestos cement factory is still high on factory workers, their families, and residents in Broni and Stradella towns.