Environmental exposure to asbestos: from geology to mesothelioma

Epidemiology of Asbestosis between 2010-2014 and 2015-2019 Periods in Colombia: Descriptive Study

Background

Asbestosis is a prevalent worldwide problem, but scarce data sourced from developing countries are available. We describe the sociodemographic characteristics and patterns in the occurrence of care provided for asbestosis in Colombia during the periods 2010-2014 and 2015-2019 to establish the behavior, trends, and variables associated with concentrations among people attended by asbestosis.

Methods

A retrospective descriptive study was carried out with data from the Integrated Social Protection Information System (SISPRO) for two 5-year periods. People attended by asbestosis (ICD-10: J61) were identified; the frequency of patient visits, sociodemographic characteristics, case distribution patterns, and trends in both five-year periods were described, as was the crude frequency (cFr, 95% CI) of asbestosis (1,000,000 people/year) in both five-year periods (cFr ratio, 95% CI).

Results

During the period 2010-2019, 765 people attended by asbestosis were identified; there were 308 people attended by asbestosis between 2010-2014 (cFr: 2.20, 1.96-2.47), and ther were 457 people attended by asbestos between 2015-2019 (cFr: 3.14, 2.92-3.50). In both periods, the estimated cFr in men was nine times the estimated cFr in women. The cFr increased in the 2015-2019 period (cFr_ratio: 1.23, 1.06-1.43). Compared with the 2010-2014 period, the cFr of asbestosis increased in women (cFr_ratio: 1.44, 1.03-2.01), in the Andean (cFr_ratio: 1.61, 1.35-1.95) and Caribbean regions (cFr_ratio: 1. 66, 1.21-2.30), in the urban area (cFr_ratio: 1.24, 1.05-1.48), and in the age groups 45-59 years (cFr_ratio: 1.34, 1.001-1.79) and ≥60 years (cFr_ratio: 1.43, 1.13-1.83).

Discussion

During two five-year periods, the cFr of asbestosis was higher in men; between the first and second five-year periods, it increased significantly, especially in urbanized geographic areas and in populations aged ≥45 years. The estimates possibly reflect the effect of disease latency or the expected impact of public health policies to monitor asbestos exposure and complications.

Malignant mesothelioma in Sub-Saharan Africa: A case report from Lubumbashi, DR Congo

Although asbestos has been used throughout Africa in the past decades, no reports of asbestos-related malignant mesothelioma are available from sub-Saharan Africa, except from South Africa and Zimbabwe. We present a case of a 39-year-old man who died from a histologically proven malignant mesothelioma of the peritoneum in Lubumbashi, DR Congo. No occupational exposure to asbestos could be found in his history. In view of his young age, we speculated that he had been exposed to asbestos as a child, which was highly plausible because he had grown up in one of the numerous mining estates of the region. The houses of these estates were often built with asbestos-containing materials, notably roofs made of corrugated asbestos-cement. The possibility of past domestic or environmental exposure to asbestos was substantiated by the identification of chrysotile and crocidolite fibres in samples of asbestos-cement collected from the home where the patient had lived as a child. To our knowledge, this is the first report of malignant mesothelioma from a country in the Central African region. We expect that heightened awareness and improved diagnosis will lead to the detection of more asbestos-related diseases in Africa.

Case series: rheumatological manifestations attributed to exposure to Libby Asbestiform Amphiboles

An increased risk for Systemic Autoimmune Diseases (SAID) has been reported in Libby, Montana, where extensive exposures to fibrous amphiboles occurred due to mining and use of asbestos-laden vermiculite. In addition, positive antinuclear autoantibody tests are associated with exposure to Libby Asbestiform Amphiboles (LAA) in both humans and mice. Among 6603 subjects who underwent health screening at the Center for Asbestos Related Diseases (CARD, Libby MT), 13.8% were diagnosed with an autoimmune disease, with prevalence values for the most common SAID being significantly higher than expected in the United States. Among the CARD screening population, serological and clinical profiles are diverse, representing symptoms and autoantibodies reflective of systemic lupus erythematosus (SLE), scleroderma, rheumatoid arthritis, and other rheumatic syndromes, including undifferentiated connective tissue disease (UCTD). Based upon screening of medical records by physicians with rheumatology expertise, the evolving nature of rheumatological disease in these patients is often atypical, with mixed diagnostic criteria and with a 1:1 male-to-female ratio. Through the Libby Epidemiology Research Program, cases were identified that illustrate clinical autoimmune outcomes with LAA exposure. Our goal was to better characterize SAID in Libby, MT in order to improve recognition of autoimmune outcomes associated with this exposure. In view of recent discoveries of widespread exposure to fibrous minerals in several areas of the U.S. and globally, it is critical to evaluate rheumatologic manifestations in other cohorts so that screening, surveillance, and diagnostic procedures are able to detect and recognize potential autoimmune outcomes of asbestos exposure.

ABBREVIATIONS

ANA, antinuclear autoantibody; ARD, Asbestos-Related Diseases; ATSDR, Agency for Toxic Substances & Disease Registry; CARD, Center for Asbestos Related Diseases; CCP, Cyclic citrullinated peptide antibody; CREST, limited cutaneous form of scleroderma; CT, computed tomography; DIP, Distal Interphalangeal Joint; DLCO, Diffusing Capacity of the Lung for CO₂; DMARD, Disease Modifying Anti-Rheumatic Drugs; ENA, Extractable Nuclear Antigen antibodies; FVC, Forced Vital Capacity; LAA, Libby Asbestiform Amphiboles; LERP, Libby Epidemiology Research Program; MCP, Metacarpal Phalangeal Joint; PIP, Proximal Interphalangeal Joint; PIP, rheumatoid arthritis; RV, Residual Volume; SAID, Systemic autoimmune diseases; SLE, systemic lupus erythematosus; SSc, Systemic Sclerosis; TLC, Total Lung Capacity.

Comparative health effects in mice of Libby amphibole asbestos and a fibrous amphibole from Arizona

This project developed from studies demonstrating that Libby Amphibole Asbestos (LAA) causes a non-typical set of health outcomes not generally reported for asbestos, including systemic autoimmunity and an unusual and devastating lamellar pleural thickening that progresses to severe pulmonary dysfunction and death. Further, mineral fiber mixtures with some similarities to LAA have recently been discovered in southern Nevada and northwestern Arizona, where the material exists in extensive recreational areas and is present in yards, roads, parking lots and school yards. The objective was to compare the health outcomes in mice exposed to either LAA or the fibrous amphiboles collected in Arizona at the Lake Mead National Recreational Area at very low doses to represent environmental exposures. In this study, the fibrous amphibole asbestos sample from Arizona (AzA) is composed of winchite (69%), actinolite (22%), and non-amphibole minerals (9%) and has a mean aspect ratio of 16.7±0.9. Fibrous amphibole asbestos from Libby (LAA) is composed of winchite (70%), richterite (9%), tremolite (5%), and non-amphibole minerals (16%) with a mean aspect ratio of 8.4±0.7. C57BL/6 mice were exposed by oropharyngeal aspiration to fiber suspensions at a very low dose of 3μg/mouse. After seven months, both LAA- and AzA-exposed mice had indices of chronic immune dysfunction related to a T_H17 cytokine profile, with B cell activation, autoantibody production and proteinuria, suggesting kidney involvement. In addition, both exposures led to significant lung and pleural fibrosis. These data suggest that there is risk of pulmonary disease and autoimmune outcomes with environmental exposure to amphibole asbestos, and that this is not limited to Libby, Montana.

Environmental asbestos exposure and risk of mesothelioma

Mesothelioma is commonly considered an occupational disease occurring as a result of asbestos exposure in the workplace. Several avenues for environmental asbestos exposures have been described and may be associated with asbestos related disease, including mesothelioma. Worker take-home asbestos, or para-occupational exposure, has been well documented and is the most commonly reported pathway for asbestos exposure among mesothelioma cases that do not have history of occupational asbestos exposure. Observational studies have evaluated several communities with elevated mesothelioma incidence and environmental exposures attributed to local asbestos-related industries. Potential, but uncertain, mesothelioma risk also may be associated with general population asbestos exposure through contact with asbestos-containing commercial products, particularly housing materials that can be easily disturbed through normal activity. Finally, studies have described elevated mesothelioma incidence in several areas where populations are exposed to naturally occurring asbestos materials. These various environmental asbestos exposure pathways are poorly understood, and further studies should be pursued to evaluate their respective importance for population mesothelioma risk.

Elemental analysis of histological specimens: a method to unmask nano asbestos fibers

There is recent mounting evidence that nanoparticles may have enhanced toxicological potential in comparison to the same material in the bulk form. The aim of this study was to develop a new method for unmask asbestos nanofibers from Formalin-Fixed, Paraffin-Embedded tissue. There is an increasing amount of evidence that nanoparticles may enhance toxicological potential in comparison to the same material in the bulk form. The aim of this study was to develop a new method to unmask asbestos nanofibers from Formalin-Fixed Paraffin-Embedded (FFPE) tissue. For the first time, in this study we applied Energy Dispersive X-ray (EDX) microanalysis through transmission electron microscopy to demonstrate the presence of asbestos nanofibers in histological specimens of patients with possible occupational exposure to asbestos. The diagnostic protocol was applied to 10 randomly selected lung cancer patients with no history of previous asbestos exposure. We detected asbestos nanofibers in close contact with lung cancer cells in two lung cancer patients with previous possible occupational exposure to asbestos. We were also able to identify the specific asbestos iso-type, which in one of the cases was the same rare variety used in the workplace of the affected patient. By contrast, asbestos nanofibers were not detected in lung cancer patients with no history of occupational asbestos exposure. The proposed technique can represent a potential useful tool for linking the disease to previous workplace exposure in uncertain cases. Furthermore, Formalin-Fixed Paraffin-Embedded (FFPE) tissues stored in the pathology departments might be re-evaluated for possible etiological attribution to asbestos in the case of plausible exposure. Since diseases acquired through occupational exposure to asbestos are generally covered by workers' insurance in most countries, the application of the protocol used in this study may have also relevant social and economic implications.

[Asbestos and respiratory diseases]

Previous occupational asbestos exposure (more rarely environmental or domestic exposure) may induce various pleural and/or pulmonary, benign or malignant diseases, sometimes with a very long latency for malignant mesothelioma (MM). Asbestos has been widely extracted and used in Western countries and in emerging or developing countries, resulting in a peak of MM incidence in France around 2020 and likely in a world pandemic of asbestos-induced diseases. These patients have mostly benign respiratory diseases (pleural plugs) but may also be diagnosed with lung cancer or malignant pleural mesothelioma, and have a global poor outcome. New therapeutic tools (targeted therapies, immunotherapy…) with first promising results are developed. However, it is crucial to obtain a full ban of asbestos use worldwide, and to do a regular follow-up of asbestos-exposed subjects, mostly if they are already diagnosed with benign respiratory diseases. Finally, new cancers (larynx and ovary) were recently added to the list of asbestos-induced tumors.

Asbestosis and environmental causes of usual interstitial pneumonia

PURPOSE OF REVIEW

Recent epidemiologic investigations suggest that occupational and environmental exposures contribute to the overall burden of idiopathic pulmonary fibrosis (IPF). This article explores the epidemiologic and clinical challenges to establishing exposure associations, the current literature regarding exposure disease relationships and the diagnostic work-up of IPF and asbestosis patients.

RECENT FINDINGS

IPF patients demonstrate a histopathologic pattern of usual interstitial pneumonia. In the absence of a known cause or association, a usual interstitial pneumonia pattern leads to an IPF diagnosis, which is a progressive and often terminal fibrotic lung disease. It has long been recognized that asbestos exposure can cause pathologic and radiographic changes indistinguishable from IPF. Several epidemiologic studies, primarily case control in design, have found that a number of other exposures that can increase risk of developing IPF include cigarette smoke, wood dust, metal dust, sand/silica and agricultural exposures. Lung mineralogic analyses have provided additional support to causal associations. Genetic variation may explain differences in disease susceptibility among the population.

SUMMARY

An accumulating body of literature suggests that occupational and environmental exposure can contribute to the development of IPF. The impact of exposure on the pathogenesis and clinical course of disease requires further study.

High-risk mesothelioma relation to meteorological and geological condition and distance from naturally occurring asbestos

OBJECTIVES

Very few studies have investigated the incidence and risk of malignant mesothelioma (MM) associated with distinct sources of asbestos exposure, especially exposure to naturally occurring asbestos (NOA).

METHODS

Subjects were MM, lung, and breast cancer patients who were diagnosed and followed in Diyarbakir Province between 2008 and 2013. The birthplaces of patients were displayed on a geologic map. Geological and meteorological effects on MM were analyzed by logistic regression.

RESULTS

A total of 180 MM, 368 breast, and 406 lung cancer patients were included. The median distance from birthplace to ophiolites was 6.26 km for MM, 31.06 km for lung, and 34.31 km for breast cancer (p < 0.001). The majority of MM cases were seen within 20 km from NOA areas. The MM incidence inside of NOA was 1059/100.000, and out of NOA was 397/100.000; this difference was significant (p = 0.014). The largest concentration of MM residential areas was within ± 30° (34 residential areas 36.6%) of the dominant wind direction. Most MM patients were found in or near the dominant wind direction, especially in the acute angle defined by the dominant wind direction. MM incidence was directly proportional to {[area of NOA (km(2))] * [cosine α of wind direction angle]} and was inversely proportional to the square of the distance (R = 0.291, p = 0.023).

CONCLUSIONS

MM was higher near NOA and in the downwind direction. MM incidence and risk were affected by geological and meteorological factors.

Occupational and environmental exposures and cancers in developing countries

BACKGROUND

Over the past few decades, there has been a decline in cancers attributable to environmental and occupational carcinogens of asbestos, arsenic, and indoor and outdoor air pollution in high-income countries. For low- to middle-income countries (LMICs), however, these exposures are likely to increase as industrialization expands and populations grow.

OBJECTIVE

The aim of this study was to review the evidence on the cancer risks and burdens of selected environmental and occupational exposures in less-developed economies.

FINDINGS

A causal association has been established between asbestos exposure and mesothelioma and lung cancer. For arsenic exposure, there is strong evidence of bladder, skin, lung, liver, and kidney cancer effects. Women are at the highest risk for lung cancer due to indoor air pollution exposure; however, the carcinogenic effect on the risk for cancer in children has not been studied in these countries. Cancer risks associated with ambient air pollution remain the least studied in LMICs, although reported exposures are higher than World Health Organization, European, and US standards. Although some associations between lung cancer and ambient air pollutants have been reported, studies in LMICs are weak or subject to exposure misclassification. For pulmonary cancers, tobacco smoking and respiratory diseases have a positive synergistic effect on cancer risks.

CONCLUSIONS

A precise quantification of the burden of human cancer attributable to environmental and occupational exposures in LMICs is uncertain. Although the prevalence of carcinogenic exposures has been reported to be high in many such countries, the effects of the exposures have not been studied due to varying country-specific limitations, some of which include lack of resources and government support.