Asbestos-related diseases in mineworkers: a clinicopathological study

Exposure to insulating materials and risk of coronary artery diseases: a cross-sectional study

Background

Although previous reports link exposure to insulating materials with an increased risk of mesothelioma and chronic respiratory diseases, studies evaluating their associations with the risk of coronary artery diseases (CAD) are lacking.

Aims

We aimed at evaluating the associations between exposure to insulating materials and the 10-year risk of CAD among insulators.

Methods

In this cross-sectional study, we recruited 643 adults (≥18 years), full-time insulators from the Local 110 Heat and Frost Insulators and Allied Workers Union in Edmonton, Alberta. We obtained demographic information, personal and family history, and job-exposure history, including experience (years) and types of exposure to insulating materials. Clinical profiling including Framingham risk scores (FRS) was assessed.

Results

Of all insulators, 89% were men (mean ± SD age: 47 ± 12 years), 27% had a parental history of cardiac diseases, and 22% had a comorbid chronic respiratory disease. In total, 53% reported exposure to asbestos, while 61, 82, and 94% reported exposure to ceramic fibers, fiberglass, and mineral fibers, respectively. In single-exposure multivariable regression models adjusted for experience, marital status, and body mass index (BMI), asbestos was found to be associated with higher FRS (β: 1.004; 95%CI: 0.003-2.00). The association remained consistent in multi-exposure models and a higher association was found between asbestos exposure and FRS among insulators with comorbid chronic respiratory disease.

Conclusion

Our study demonstrates that apart from cancer and chronic respiratory diseases, asbestos exposure may also have a cardiac effect, thus warranting the need for systematic surveillance to protect workers from the adverse effects of these materials.

Mortality due to respiratory system disease and lung cancer among female workers exposed to chrysotile in Eastern China: A cross-sectional study

Female workers in the asbestos processing industry of Eastern China are at high risk of developing multiple types of cancer, and more data are urgently needed to better understand and address this issue. Death certificate data were selected from an asbestos processing city in China from 2005 to 2006. Information was investigated using the relatives of those individuals who had died as sources of information. Individuals were classified into one of three asbestos exposure levels. Standardized mortality ratio and 95% confidence interval were calculated. A total of 2,964 individual deaths were identified from 2005 to 2006; of these, 21.4% were occupationally exposed to asbestos. The main cause of death was circulatory system diseases (21.2%). The proportion of individuals with respiratory system diseases increased by age among each exposure subgroup (P_trend < 0.01). Among females, a significant trend was observed between increased asbestos exposure and mortality due to respiratory system diseases and lung cancer. Our study indicated that asbestos exposure was associated with excess mortality from lung cancer and respiratory diseases, particularly among female workers in an asbestos processing area in Eastern China.

Pathology for Thoracic Conditions in Low- and Middle-Income Countries

Pulmonary disease in low- and middle-income countries is highly diverse and dependent on the population, background epidemiology, environmental exposures, and smoking status. Credible evaluation of lung diseases requires skilled clinicians, imaging infrastructure, microbiology, and pathologic diagnostics, including imaging-guided cytology and biopsy. When these tools are available, improvement in patient outcomes is feasible. Pathologic diagnostics of lung lesions, including histology, immunohistochemistry, and molecular testing, are critical to properly stratify patient risk and determine exact therapies for each patient. A critical focus on research and directed interventions in lung cancer treatment specifically is needed to downstage this disease and improve patient outcome.

Breath analysis as a diagnostic and screening tool for malignant pleural mesothelioma: a systematic review

Malignant pleural mesothelioma (MPM) is a tumour related to a historical exposure to asbestos fibres. Currently, the definite diagnosis is made only by the histological examination of a biopsy obtained through an invasive thoracoscopy. However, diagnosis is made too late for curative treatment because of non-specific symptoms mainly appearing at advanced stage disease. Hence, due to its biologic aggressiveness and the late diagnosis, survival rate is low and the patients' outcome poor. In addition, radiological imaging, like computed tomographic scans, and blood biomarkers are found not to be sensitive enough to be used as an early diagnostic tool. Detection in an early stage is assumed to improve the patients' outcome but is hampered due to non-specific and late symptomology. Hence, there is a need for a new screening and diagnostic test which could improve the patients' outcome. Despite extensive research has focused on blood biomarkers, not a single has been shown clinically useful, and therefore research recently shifted to "breathomics" techniques to recognize specific volatile organic compounds (VOCs) in the breath of the patient as potential non-invasive biomarkers for disease. In this review, we summarize the acquired knowledge about using breath analysis for diagnosing and monitoring MPM and asbestos-related disorders (ARD). Gas chromatography-mass spectrometry (GC-MS), the gold standard of breath analysis, appears to be the method with the highest accuracy (97%) to differentiate MPM patients from at risk asbestos-exposed subjects. There have already been found some interesting biomarkers that are significantly elevated in asbestosis (NO, 8-isoprostane, leukotriene B4, α-Pinene…) and MPM (cyclohexane) patients. Regrettably, the different techniques and the plethora of studies suffer some limitations. Most studies are pilot studies with the inclusion of a limited number of patients. Nevertheless, given the promising results and easy sampling methods, we can conclude that breath analysis may become a useful tool in the future to screen for MPM, but further research is warranted.

Characterization of pulmonary responses in mice to asbestos/asbestiform fibers using gene expression profiles

Humans exposed to asbestos and/or asbestiform fibers are at high risk of developing many lung diseases including asbestosis, lung cancer, and malignant mesothelioma. However, the disease-causing potential and specific metabolic mechanisms and pathways associated with various asbestos/asbestiform fiber exposures triggering different carcinogenic and non-carcinogenic outcomes are still largely unknown. The aim of this this study was to investigate gene expression profiles and inflammatory responses to different asbestos/asbestiform fibers at the acute/sub-acute phase that may be related to delayed pathological outcomes observed at later time points. Mice were exposed to asbestos (crocidolite, tremolite asbestos), asbestiform fibers (erionite), and a low pathogenicity mineral fiber (wollastonite) using oropharyngeal aspiration. Similarities in inflammatory and tissue damage responses, albeit with quantitative differences, were observed at day 1 and 7 post treatment. Exposure to different fibers induced significant changes in regulation and release of a number of inflammatory cytokines/chemokines. Comparative analysis of changes in gene regulation in the lung on day 7 post exposure were interpretable in the context of differential biological responses that were consistent with histopathological findings at days 7 and 56 post treatment. Our results noted differences in the magnitudes of pulmonary responses and gene regulation consistent with pathological alterations induced by exposures to four asbestos/asbestiform fibers examined. Further comparative mechanistic studies linking early responses with the long-term endpoints may be instrumental to understanding triggering mechanisms underlying pulmonary carcinogenesis, that is lung cancer versus mesothelioma.