Focusing on Coal Workers' Lung Diseases: A Comparative Analysis of China, Australia, and the United States

Prevalence and associations between occupational diseases, emotional exhaustion, and dust mask anxiety among coal miners in Northern China

This study examined the prevalence and associations between occupational-related diseases, emotional exhaustion, and dust mask anxiety among coal miners in Northern China. The study sampled 506 miners from two coal mines in Northern China. Descriptive (frequency, percentages, and chi-square tests) and inferential (complementary log-log logistic regression) analyses were carried out to assess prevalence and associations. The prevalence of coal mining-related pulmonary diseases was 94%, with 40% and 37% reporting pneumoconiosis and bronchitis respectively. Emphysema and tuberculosis were less prevalent with a total prevalence of 5% while 12% of the miners reported two, three, or four of these diseases. For cardiovascular diseases, 66% of the miners reported 3H (hypertension, hyperlipemia, and hyperglycemia) while heart disease and cerebral infarction were reported by 6% and 2% of the miners respectively. Also, 5% and 2% of the miners reported two or all three of 3H, heart condition, and cerebral infarction. The overall prevalence of cardiovascular diseases was 81% while 82% and 63% of the miners reported experiencing some frequency of emotional exhaustion and dust mask anxiety respectively. The study also identified associations between mining-related diseases, emotional exhaustion, dust mask anxiety, and other demographic, personal habits and work-related factors. Miners with pulmonary diseases were more likely to experience emotional exhaustion and dust mask anxiety. Contrariwise, miners with cardiovascular diseases were less likely to experience dust mask anxiety. Factors such as age, engaging in physical exercises, rhinitis, source of pressure and shift system were also associated with emotional exhaustion and dust mask anxiety. These findings highlight the prevalence of occupational diseases, emotional exhaustion, and dust mask anxiety among coal miners in China. The study emphasizes the need for interventions to address health risks, improve work conditions, and support miners' well-being in the coal mining industry.

A nested case-control study of the effects of dust exposure, smoking on COPD in coal workers

BACKGROUND

Chronic obstructive pulmonary disease (COPD) represents a prevalent ailment, progressively surging within the ranks of coal mine laborers. The current study endeavors to elucidate the effects of dust exposure and smoking on COPD incidence amongst coal mine workers, while concurrently devising preventive strategies for this affliction.

METHOD

A nested case-control study was conducted encompassing 1,416 participants aged ≥ 18 years, spanning the duration from (2017-2018) until 2020. A meticulous matching process yielded a cohort of 708 COPD patients, each paired with a control subject, forming a harmonious 1:1 ratio. Multiple logistic regression analysis was employed to scrutinize the associations between smoking, dust exposure with COPD among coal workers.

RESULTS

The COPD prevalence within the cohort of coal workers under investigation amounted to 22.66%, with an accompanying incidence density of 0.09/person-year. Following meticulous adjustment for confounding variables, it was discerned that cumulative dust exposure within the range of 47.19 ~ (OR: 1.90, 95% CI: 1.05, 3.44), 101.27 ~ (OR: 1.99, 95% CI: 1.17, 3.39), as well as smoking indices of 72 ~ (OR: 1.85, 95% CI: 1.19, 2.88), 145 ~ (OR: 1.74, 95% CI: 1.17, 2.61), 310 ~ (OR: 1.85, 95% CI: 1.23, 2.77) engender an escalated vulnerability to COPD among coal workers. Furthermore, interaction analysis discerned an absence of both multiplicative and additive interactions between dust exposure, smoking, and COPD occurrence amidst coal workers.

CONCLUSION

Dust exposure and smoking were unequivocally identified as precipitating risk factors for COPD incidence within the population of coal workers, albeit devoid of any discernible interaction between these two causal agents.

Uncovering mechanisms of Baojin Chenfei formula treatment for silicosis by inhibiting inflammation and fibrosis based on serum pharmacochemistry and network analysis

BACKGROUND

Baojin Chenfei formula (BCF), a Chinese herbal formula, has significant effects on improving the clinical symptoms of patients with silicosis. However, its active compounds and the underlying mechanisms have not yet fully been elucidated.

PURPOSE

This study aimed to explore the underlying mechanisms of BCF in treating silicosis.

METHODS

The rat model of silicosis was developed via a single intratracheal instillation of SiO₂ suspension to examine the therapeutic impacts of BCF on silicosis. Subsequently, the active compounds, targets, and mechanisms of BCF were analyzed based on serum pharmacochemistry and network analysis. Finally, the underlying mechanisms of representative compounds of BCF were validated in vitro experiments.

RESULTS

BCF significantly alleviated SiO₂-induced silicosis in rats, evidenced by improved lung function, decreased pathological injury, and reduced inflammatory response and fibrosis. 19 active compounds were identified from the rat serum samples after BCF gavage. Subsequently, 299 targets for these 19 compounds in BCF and 257 genes related to silicosis were collected. 26 overlapping targets, including AKT1, TNF, IL6, MAPK3, EGFR, and others, were obtained from the intersection of the 299 BCF-related targets and 257 silicosis-associated genes. These overlapping targets mainly corresponded to glycyrrhetic acid and paeoniflorin and were mainly associated with positive regulation of smooth muscle cell proliferation, positive regulation of MAP kinase activity, and inflammatory response. In vitro experiments also demonstrated that the representative compounds of BCF (glycyrrhetic acid and paeoniflorin) could suppress inflammatory response by the MAPK pathway, and also inhibited fibroblast activation by the EGFR-PI3K-AKT pathway.

CONCLUSION

Active compounds of BCF, such as glycyrrhetic acid and paeoniflorin, could suppress inflammatory response by the MAPK pathway and suppress fibroblast activation by the EGFR-PI3K-AKT pathway. These might be the mechanisms of BCF in treating silicosis.

Genetic susceptibility in pneumoconiosis in China: a systematic review

OBJECTIVE

Pneumoconiosis, encompassing coal workers' pneumoconiosis (CWP), silicosis and asbestosis, is one of the most common occupational diseases in China. Previous studies revealed significant associations between genetic variations and pneumoconiosis risk among individuals in different countries. With the known variability of genetic makeup between ethnicities, susceptibility to pneumoconiosis due to genetic differences is likely to be ethnicity-specific. The present review aimed at providing a comprehensive overview on the association between genetic polymorphisms and susceptibility of pneumoconiosis, specifically among people in China.

METHODS

The literature search was performed in seven English and Chinese databases using keywords related to the review aim. An appraisal of the methodological quality of the included studies was conducted using the assessment tool derived from the Strengthening the Reporting of Genetic Association Studies (STREGA) statement.

RESULTS

Forty-five studies were included in this review. Genotypes of specific genes which are associated with the risk of CWP, silicosis and asbestosis were reported. Our findings showed that genes encoding inflammatory cytokines have been examined extensively, and they demonstrated an association between these genes and pneumoconiosis risk. Gene-environment interactions in pneumoconiosis susceptibility were also reported by a number of studies.

CONCLUSIONS

This review summarised the evidence demonstrating the association between genetic polymorphisms and pneumoconiosis susceptibility among people in China, and that various genotypes could modify their risk to develop pneumoconiosis. The findings prompt that identification of individuals at high pneumoconiosis risk through genetic screening and strategies limiting their exposure to dust could be a potential strategy for the control of this occupational disease in China.

Co-occurrence of pneumoconiosis with COPD, pneumonia and lung cancer

BACKGROUND

Pneumoconiosis is a well-documented occupational disease that is linked to conditions such as chronic obstructive pulmonary disease (COPD), pneumonia and congestive heart failure. Pneumoconiosis prevalence has decreased in the United States, but it remains implicated in tens of thousands of deaths worldwide per year.

AIMS

To provide a recent update on associations of pneumoconiosis and smoking status with various pulmonary diseases in the United States.

METHODS

The CDC's National Vital Statistics System was analysed on the entity axis using ICD-10 codes for pulmonary disease and potential lung injury with a cohort of those aged 15 and older during the years 2010-2019. The cases of evaluated diseases were scaled to rates per 100 000 and compared through analysis of variance.

RESULTS

Pneumoconiosis and smoking history were each associated with an increased rate of COPD, but combined, were associated with an even higher rate of COPD than either factor alone. Smoking history was associated with an increased rate of lung cancer, but pneumoconiosis status was only linked to increased lung cancer prevalence in non-smokers. Both pneumoconiosis and smoking were associated with an increased rate of pneumonia, but combined, had no deviation from the pneumonia rate in those with pneumoconiosis alone. Finally, pneumoconiosis status was associated with decreased rates of non-lung cancers and sepsis.

CONCLUSIONS

Although pneumoconiosis has become less common in the United States through regulatory and industrial shifts, it is still a significant risk factor for co-occurring pulmonary diseases and will likely remain relevant as international demands for mining, construction and manufacturing change.

Prevalence of coal worker's pneumoconiosis: a systematic review and meta-analysis

Global prevalence trend and regional differences of coal worker's pneumoconiosis (CWP) remain unclear. This study aimed to provide systematic and comprehensive evidence for the global prevalence of CWP. Literature research for studies that reported prevalence of CWP was conducted in PubMed, CNKI, and Web of Science. The identified studies were strictly screened according to predetermined inclusion and exclusion criteria. The pooled prevalence of CWP in different periods and regions was calculated. A total of 37 studies were included after screening, and data from the Coal Workers' Health Surveillance Program was additionally included in the meta-analysis. The global pooled prevalence of CWP decreased from 23.33% (95% confidence interval [CI]: 18.03%, 28.62%) before 1970 to 6.00% (95% CI: 4.11%, 7.90%) in 1981-1990, but indicated a rebound (10.35%, 95% CI: 8.08%, 12.62%) in 1991-2000 and finally dropped to 2.29% (95% CI: 2.06%, 2.51%) in 2011-2020. In the recent 30 years, the top three pooled prevalence of CWP was found in Europe, China, and the USA, respectively. Few articles have reported the prevalence in developing regions, but available evidence indicated that the prevalence in developing regions was much higher than that in developed regions. Higher pooled prevalence was observed in studies which reported larger number of miners in collieries, older average age of miners, underground collieries, and longer dust exposure time. The global prevalence of CWP indicates a rebound in 1990s, but the overall trend is downward in the recent 60 years. The prevention and treatment of CWP should be currently emphasized in developing countries.

Proportions distribution of pneumoconiosis stages in China: a study based on a meta-analysis and field investigation

Occupational pneumoconiosis is the most serious work-related disease in China. In this paper, pneumoconiosis stages distribution was obtained to study the stages severity of occupational pneumoconiosis patients in China. A meta-analysis was conducted among screening the published literature on the pneumoconiosis epidemiology in China by Stata 15.0. Moreover, a field survey was conducted on 510 migrant workers suffering from pneumoconiosis in four provinces of China, and the results were analyzed by simple linear analysis and ordinal logistic regression analysis. The stage I, II and III pneumoconiosis accounted for 0.71, 0.21, 0.08, respectively, by the results of meta-analysis. The publication bias of these articles is not obvious based on the Egger's test and funnel plots. There was no significant linear correlation between the distribution of pneumoconiosis stages and the economic status and medical conditions in this study. Migrant workers pneumoconiosis stage I, II and III accounted for 0.14, 0.2, 0.66 respectively, which was significantly correlated with length of work and provinces. In China, migrant workers lack effective occupational health protection so that they have higher occupational health risks than urban workers. Therefore, occupational health protection for migrant workers in the occupational health management system needs to be strengthened.

Understanding the pathogenesis of occupational coal and silica dust-associated lung disease

Workers in the mining and construction industries are at increased risk of respiratory and other diseases as a result of being exposed to harmful levels of airborne particulate matter (PM) for extended periods of time. While clear links have been established between PM exposure and the development of occupational lung disease, the mechanisms are still poorly understood. A greater understanding of how exposures to different levels and types of PM encountered in mining and construction workplaces affect pathophysiological processes in the airways and lungs and result in different forms of occupational lung disease is urgently required. Such information is needed to inform safe exposure limits and monitoring guidelines for different types of PM and development of biomarkers for earlier disease diagnosis. Suspended particles with a 50% cut-off aerodynamic diameter of 10 µm and 2.5 µm are considered biologically active owing to their ability to bypass the upper respiratory tract's defences and penetrate deep into the lung parenchyma, where they induce potentially irreversible damage, impair lung function and reduce the quality of life. Here we review the current understanding of occupational respiratory diseases, including coal worker pneumoconiosis and silicosis, and how PM exposure may affect pathophysiological responses in the airways and lungs. We also highlight the use of experimental models for better understanding these mechanisms of pathogenesis. We outline the urgency for revised dust control strategies, and the need for evidence-based identification of safe level exposures using clinical and experimental studies to better protect workers' health.

Effects of occupational hazards and occupational stress on job burn-out of factory workers and miners in Urumqi: a propensity score-matched cross-sectional study

OBJECTIVE

This study was designed to explore the impact of occupational hazards and occupational stress on job burn-out among factory workers and miners. This study also aimed to provide a scientific basis for the prevention and control of job burn-out among factory workers and miners.

DESIGN

A cross-sectional study based on the factory Workers and Miners of Urumqi, Xinjiang. Demographic biases, that is, confounding factors, were eliminated by the propensity score-matched analysis method.

PARTICIPANTS

An electronic questionnaire was used to survey 7500 eligible factory workers and miners in Urumqi, the capital of Xinjiang, and 7315 complete questionnaires were returned.

PRIMARY OUTCOME MEASURES

A general demographic questionnaire, the Effort-Reward Imbalance (ERI) and the Chinese Maslach Burnout Inventory.

RESULTS

The total rate of burn-out was 86.5%. Noise (OR 1.34, 95% CI 1.09 to 1.64) and ERI (OR 2.16, 95% CI 1.78 to 2.61) were the risk factors for job burn-out among factory workers and miners (p<0.001).

CONCLUSION

The job burn-out rate of factory workers and miners was high, and the noise and occupational stress factors among occupational hazard factors will affect the likelihood of job burn-out of factory workers and miners. We should control the impact of occupational hazards on factory workers and miners and reduce occupational stress to alleviate workers' job burn-out.

Thermogravimetric analysis of respirable coal mine dust for simple source apportionment

Resurgence of coal mine dust lung diseases in the central Appalachian region of the United States and elsewhere has spurred a range of efforts to better understand respirable coal mine dust (RCMD) exposures and sources. Thermogravimetric analysis (TGA) of RCMD samples can enable the dust mass to be fractionated into three main components: coal, non-carbonate minerals, and carbonates. These are expected to approximate, respectively, the three primary dust sources in many underground mines: the coal seam being mined, the surrounding rock strata (i.e., typically dominated by non-carbonate minerals) being drilled or mined along with the coal, and the rock dust products (i.e., typically made from carbonate-rich limestone or dolostone) being applied in the mine to mitigate explosibility hazards. As proof of concept, TGA was applied to respirable dust samples that were laboratory-generated from real source materials representing 15 mines. Except in the case of two mines, compositional results were generally consistent with expectations. TGA was also applied to RCMD samples collected in standard locations of 23 mines (including the 15 mines represented by the dust source materials). Results showed significantly different compositions with respect to sampling location and geographic region (i.e., within and outside of central Appalachia). To further interpret the RCMD results, a simple source apportionment model was built using the dust compositions yielded from the source materials analysis. Model results indicated that, on average, about twice as much dust was sourced from mining into rock strata than from mining the target coal seam. This finding is particularly important for mines extracting relatively large amounts of rock along with the coal or for mines that frequently encounter high-silica rock strata.

Occupational Dust Exposure and Respiratory Protection of Migrant Interior Construction Workers in Two Chinese Cities

Migrant interior construction workers are increasing in China. Construction workers are at an increased risk of work-related illness (WRI) due to prolonged exposure to and inhalation of dust. Dust concentrations in the air can be reduced significantly with effective respiratory protection measures. We assessed the dust exposure and factors associated with respiratory protection of migrant interior construction workers. The total dust concentration in the workplace ranged from 0.07 to 335.27 mg/m³, with a total dust exceedance rate of 50.00%. The respiratory dust loading ranged from 0.03 to 220.27 mg/m³, with a respiratory dust exceedance rate of 71.42 %. The highest total dust concentration occurred when masons were polishing cement walls. We performed a questionnaire survey of 296 persons in two cities in China, in which 87.84% had no respiratory protection or only one protection measure. Gender, workplace, respiratory disease, and protective attitude all had an effect on the level of respiratory protection. The dust exposure in most jobs exceeds hygiene standards. The respiratory protection of migrant interior construction workers in China is inadequate.

Pulmonary Capacity, Blood Composition and Metabolism among Coal Mine Workers in High- and Low-Altitude Aboveground and Underground Workplaces

(1) Background: While previous studies revealed how underground mining might adversely affect the cardiopulmonary functions of workers, this study further investigated the differences between under- and aboveground mining at both high and low altitudes, which has received little attention in the literature. (2) Methods: Seventy-one healthy male coal mine workers were recruited, who had worked at least 5 years at the mining sites located above the ground at high (>3900 m; n = 19) and low (<120 m; n = 16) altitudes as well as under the ground at high (n = 20) and low (n = 16) altitudes. Participants’ heart rates, pulmonary functions, total energy expenditure and metabolism were measured over a 5-consecutive-day session at health clinics. (3) Results: Combining the results for both above- and underground locations, workers at high-altitude mining sites had significantly higher peak heart rate (HR), minimum average HR and training impulse as well as energy expenditure due to all substances and due to fat than those at low-altitude sites. They also had significantly higher uric acid, total cholesterol, creatine kinase and N-osteocalcin in their blood samples than the workers at low-altitude mining sites. At underground worksites, the participants working at high-altitude had a significantly higher average respiratory rate than those at low-altitude regions. (4) Conclusion: In addition to underground mining, attention should be paid to high-altitude mining as working under a hypoxia condition at such altitude likely presents physiological challenges.

Lung function among residents from the largest coal region in Brazil

Coal mining and burning activities in coal-fired power plants are among the most polluting activities in developing countries. In Brazil, the Candiota coal deposit concentrates 40% of the national mineral coal. Although, previous studies indicate several negative health outcomes to residents of this coal region, there is no information about lung function. Thus, this study aimed to evaluate lung function by spirometry among residents from the largest coal mining region of Brazil and its related factors. It was carried out a cross-sectional study with 300 male adults residing in four cities from this region. Socioeconomic, demographic, life style, and health conditions were collected through a structured questionnaire, and lung function was assessed by spirometry. Almost 18% of the residents have disorders in pulmonary function. There was significant statistical difference in the spirometry main parameters between the cities. Candiota city (host city of coal exploration activities) have the highest prevalence of obstructive ventilatory disorder. Curiously, upper economic class had significant higher risk of altered lung function (P<0.001), as well as inappropriate sewage destination (P<0.001). Residents of Candiota city had 20% higher risk of altered lung function. Regarding air quality, the PM₁₀, SO₂, and NO₂ of the region were 20.6± 3.9, 7.0± 2.2, and 6.0± 1.6, respectively. Two air quality stations exceed the limit of 20 μg/m³ to PM₁₀ proposed by Brazilian legislation and WHO, and three stations had PM₁₀ quite close to the limit. This study points out the need for urgent action to protect residents from this coal mining region.

Structural Model Construction and Optimal Characterization of High-Volatile Bituminous Coal Molecules

The structural characteristics of coal at the molecular level are important for its efficient use. Bituminous coal from the Baozigou Coal Mine is investigated, using elemental analysis, ¹³C nuclear magnetic resonance, X-ray photoelectron spectroscopy, and Fourier transform infrared. The molecular structure was determined. The aromatic compounds of bituminous coal molecules are primarily two- and three-ring structures, and the aliphatic structures are primarily in the form of methyl, ethyl side chains, and naphthenic hydrocarbons. The ratio of aromatic bridge carbon to peripheral carbon in the molecular structure is 0.279. Oxygen atoms in the form of carbonyl, phenolic hydroxyl and C-O, and nitrogen atoms in pyrroles. Thus, the average structure model of bituminous coal macromolecules was constructed; the molecular formula was C₁₆₉H₁₂₈O₁₀N₂S, and the molecular weight was 2378. The aromatic structural units in the macromolecular structure of coal include four naphthalenes, three anthracenes, two tetracenes, and heteroatoms in the form of three carbonyl groups, one phenolic hydroxyl group, one pyrrole, and one pyridine. The structure optimization and annealing kinetic simulation of a single macromolecular structure model were performed. Chemical bonds such as bridge bonds and aliphatic bonds were found to be twisted, and π-π interactions between the aromatic sheets in the molecule produced adjacent aromatic sheets. This arrangement tends to be approximately parallel, and the total energy decreases from 6713.401 to 2667.595 kJ/mol, among which the bond stretching energy and van der Waals energy dominate. We used 20 bituminous coal macromolecular models to construct aggregated structural models. After optimization by molecular dynamics simulation, the macromolecules were constrained by the surrounding molecules, and the sheet-like aromatic carbon structures that were originally approximately parallel were distorted. The macromolecular structure model of bituminous coal constructed in this study provides a theoretical model basis for the optimal surfactant.

Sputum Microbiota in Coal Workers Diagnosed with Pneumoconiosis as Revealed by 16S rRNA Gene Sequencing

Coal worker’s pneumoconiosis (CWP) is an occupationally induced progressive fibrotic lung disease. This irreversible but preventable disease currently affects millions across the world, mainly in countries with developed coal mining industries. Here, we report a pilot study that explores the sputum microbiome as a potential non-invasive bacterial biomarker of CWP status. Sputum samples were collected from 35 former and active coal miners diagnosed with CWP and 35 healthy controls. Sequencing of bacterial 16S rRNA genes was used to study the taxonomic composition of the respiratory microbiome. There was no difference in alpha diversity between CWP and controls. The structure of bacterial communities in sputum samples (β diversity) differed significantly between cases and controls (pseudo-F = 3.61; p = 0.004). A significant increase in the abundance of Streptococcus (25.12 ± 11.37 vs. 16.85 ± 11.35%; p = 0.0003) was detected in samples from CWP subjects as compared to controls. The increased representation of Streptococcus in sputum from CWP patients was associated only with the presence of occupational pulmonary fibrosis, but did not depend on age, and did not differ between former and current miners. The study shows, for the first time, that the sputum microbiota of CWP subjects differs from that of controls. The results of our present exploratory study warrant further investigations on a larger cohort.

Elucidation of alveolar macrophage cell response to coal dusts: Role of ferroptosis in pathogenesis of coal workers' pneumoconiosis

Causal factors underlying coal workers' pneumoconiosis (CWP) have been variously attributed to the presence of carbon, crystalline silica and reduced iron (Fe) minerals, especially pyrite and Fe/Si-amorphous compounds. The aim of this research was to assess the role of iron in CWP and, more specifically, the cytotoxicity of coal dusts with different elemental composition towards alveolar macrophages (AMs). Survival rate of AMs, alteration in the production of pro-inflammatory cytokine TNF-α, MDA (the lipid peroxidation product) and intracellular GSH were assessed using commercial assay kits. The quantitative interaction between iron and GSH was investigated by developing a numerical model. The presence of various reduced Fe minerals (viz. pyrite and siderite) in coal dusts exhibited a consistently acute adverse impact on the viability of AMs and enhanced the production of TNF-α. The presence of the clinically available Fe chelator deferiprone (DFP) and the cytosolic antioxidant glutathione (GSH) significantly increased the viability of AMs exposed to Fe bearing coal dusts, suggesting coal dusts containing reduced Fe minerals were likely contributors to the initial stages of AM cytotoxicity via a ferroptosis related pathway. Chemical kinetic modeling indicated that these results may be attributed to an enhanced consumption of GSH as a result of Fe redox cycling. Fe^IIGSH and GS^• produced from the interaction between ferric Fe and GSH facilitated the production of O₂^•- which further oxidized GSH via a direct reaction between GSH and GS^• or GSO^•. These results suggest that coal dusts containing reduced Fe minerals and Fe compounds may elevate acute inflammation levels in AMs, indicating that crystalline silica may not be the only hazard of concern in mining environments.

Cost-effectiveness of comprehensive preventive measures for coal workers' pneumoconiosis in China

Background

Coal workers’ pneumoconiosis (CWP) remains one of the most severe occupational diseases in China. Despite the implementation of CWP comprehensive preventive measures, the unreasonable allocation of investment by coal enterprises limits the effect of preventing CWP, especially when the health resources are inadequate. This study aims to evaluate the cost-effectiveness of comprehensive measures for CWP from the perspective of coal enterprises.

Methods

Comprehensive measures and two primary interventions (engineering controls and individual protective equipment) were selected. A time-dependent Markov model was developed to evaluate cost and quality-adjusted life-years (QALYs). The input data were collected from the survey and literature. A hypothetical null situation, in which the currently implemented interventions were eliminated, was used as a comparator based on the generalised cost-effectiveness analysis (GCEA) recommended by the World Health Organization (WHO). The primary outcomes of the model were reported in terms of incremental cost-effectiveness ratios (ICERs). Uncertainty was verified using one-way and probabilistic sensitivity analyses.

Results

The QALYs of the comprehensive measures, engineering controls, and individual protective equipment were 17.60, 17.50, and 16.85 years, respectively. Compared with null, the ICERs of the interventions were 65,044.73, 30,865.15, and 86,952.41 RMB/QALY, respectively. Individual protective equipment was dominated by an ICER of -11,416.02 RMB/QALY compared to engineering controls. Sensitivity analysis suggested the robustness of the results.

Conclusions

The comprehensive preventive measures for CWP that are currently implemented in Chinese state-owned mines are cost-effective. In comprehensive measures, engineering controls are more cost-effective than individual protective equipment. Investment in engineering controls should be increased to improve the cost-effectiveness of preventing CWP.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-022-07654-7.

Occupational Dust Hazards and Risk Assessment of Coal-Fired Thermal Power Plants of Different Capacities - China, 2017-2019

What is already known about this topic?

Silica dust and coal dust are the main occupational hazards in coal-fired thermal power plants, which mainly exist in coal transportation workplaces, combustion milling workplaces, and ash removal workplaces.

What is added by this report?

The overall environmental and personal dust exposure levels decrease with an increase in the capacity of coal-fired thermal power plants, the overall dust hazard risk level of the workforce in coal-fired is Medium.

What are the implications for public health practice?

Dust management should be conducted in the coal-fired thermal power plant in 300 million watt units because it has the highest dust exposure level, and ash removal workplaces and combustion milling workplaces are key control points for dust hazards.

Genome-wide mRNA profiling identifies the NRF2-regulated lymphocyte oxidative stress status in patients with silicosis

BACKGROUND

The immunomodulatory abnormalities of silicosis are related to the lymphocyte oxidative stress state. The potential effect of antioxidant therapy on silicosis may depend on the variation in nuclear factor erythroid 2-related factor 2 (NRF2)-regulated antioxidant genes in peripheral blood mononuclear cells (PBMCs). As NRF2 is a redox-sensitive transcription factor, its possible roles and underlying mechanism in the treatment of silicosis need to be clarified.

METHODS

Ninety-two male patients with silicosis and 87 male healthy volunteers were randomly selected. PBMCs were isolated from fresh blood from patients with silicosis and healthy controls. The lymphocyte oxidative stress state was investigated by evaluating NRF2 expression and NRF2-dependent antioxidative genes in PBMCs from patients with silicosis. Key differentially expressed genes (DEGs) and signaling pathways were identified utilizing RNA sequencing (RNA-Seq) and bioinformatics technology. Gene set enrichment analysis was used to identify the differences in NRF2 signaling networks between patients with silicosis and healthy controls.

RESULTS

The number of monocytes was significantly higher in patients with silicosis than that of healthy controls. Furthermore, RNA-Seq findings were confirmed using quantitative polymerase chain reaction and revealed that NRF2-regulated DEGs were associated with glutathione metabolism, transforming growth factor-β, and the extracellular matrix receptor interaction signaling pathway in PBMCs from patients with silicosis. The top 10 hub genes were identified by PPI analysis: SMAD2, MAPK3, THBS1, SMAD3, ITGB3, integrin alpha-V (ITGAV), von Willebrand factor (VWF), BMP4, CD44, and SMAD7.

CONCLUSIONS

These findings suggest that NRF2 signaling regulates the lymphocyte oxidative stress state and may contribute to fibrogenic responses in human PBMCs. Therefore, NRF2 might serve as a novel preventive and therapeutic candidate for silicosis.

MicroRNA-205-5p targets E2F1 to promote autophagy and inhibit pulmonary fibrosis in silicosis through impairing SKP2-mediated Beclin1 ubiquitination

Silicosis is an occupational disease characterized by extensive pulmonary fibrosis, and the underlying pathological process remains uncertain. Herein, we explored the molecular mechanism by which microRNA‐205‐5p (miR‐205‐5p) affects the autophagy of alveolar macrophages (AMs) and pulmonary fibrosis in mice with silicosis through the E2F transcription factor 1 (E2F1)/S‐phase kinase‐associated protein 2 (SKP2)/Beclin1 axis. Alveolar macrophages (MH‐S cells) were exposed to crystalline silica (CS) to develop an in vitro model, and mice were treated with CS to establish an in vivo model. Decreased Beclin1 and increased SKP2 and E2F1 were identified in mice with silicosis. We silenced or overexpressed miR‐205‐5p, E2F1, SKP2 and Beclin1 to investigate their potential roles in pulmonary fibrosis in vivo and autophagy in vitro. Recombinant adenovirus mRFP‐GFP‐LC3 was transduced into the MH‐S cells to assay autophagic flow. Knocking down Beclin1 promoted pulmonary fibrosis and suppressed the autophagy. Co‐immunoprecipitation and ubiquitination assays suggested that SKP2 induced K48‐linked ubiquitination of Beclin1. Furthermore, chromatin immunoprecipitation‐PCR revealed the site where E2F1 bound to the SKP2 promoter between 1638 bp and 1645 bp. As shown by dual‐luciferase reporter gene assay, the transfection with miR‐205‐5p mimic inhibited the luciferase activity of the wild‐type E2F1 3′untranslated region, suggesting that miR‐205‐5p targeted E2F1. Additionally, miR‐205‐5p overexpression increased autophagy and reduced the pulmonary fibrosis, while overexpression of E2F1 or SKP2 or inhibition of Beclin1 could annul this effect. The current study elucidated that miR‐205‐5p targeted E2F1, thereby inhibiting SKP2‐mediated Beclin1 ubiquitination to promote macrophage autophagy and inhibit pulmonary fibrosis in mice with silicosis.

Alpha-lipoic acid attenuates silica-induced pulmonary fibrosis by improving mitochondrial function via AMPK/PGC1α pathway activation in C57BL/6J mice

Silicosis is characterized by pulmonary interstitial fibrosis that arises as a result of chronic exposure to silica. The few available treatments only delay its progression. As α-lipoic acid (ALA) has been shown to have various beneficial effects, including mitoprotective, antioxidant, and anti-inflammatory effects, we hypothesized that it may exhibit therapeutic effects in pulmonary fibrosis. Therefore, in the present study, we used a murine model of silicosis to investigate whether supplementation with exogenous ALA could attenuate silica-induced pulmonary fibrosis by improving mitochondrial function. ALA was administered to the model mice via continuous intragastric administration for 28 days, and then the antioxidant and mitoprotective effects of ALA were evaluated. The results showed that ALA decreased the production of reactive oxygen species, protected mitochondria from silica-induced dysfunction, and inhibited extracellular matrix deposition. ALA also decreased hyperglycemia and hyperlipidemia. Activation of the mitochondrial AMPK/PGC1α pathway might be responsible for these ALA-mediated anti-fibrotic effects. Exogenous ALA blocked oxidative stress by activating NRF2. Taken together, these findings demonstrate that exogenous ALA effectively prevents the progression of silicosis in a murine model, likely by stimulating mitochondrial biogenesis and endogenous antioxidant responses. Therefore, ALA can potentially delay the progression of silica-induced pulmonary fibrosis.

Associations of musculoskeletal disorders with occupational stress and mental health among coal miners in Xinjiang, China: a cross-sectional study

BACKGROUND

Musculoskeletal disorders (MSDs), a common type of occupational diseases, have become the main cause of absenteeism and early retirement in the occupational population, as well as a major risk factor for occupational disability. The purpose of this study was to investigate the effects of occupational stress and mental health on MSDs in coal miners in Xinjiang, China, to provide a theoretical basis for reducing the incidence of MSDs in coal miners and improving their physical and mental health.

METHODS

In this study, stratified cluster random sampling was used to randomly select six coal mining companies in Xinjiang, and 1675 coal miners were surveyed by questionnaire. The status of occupational stress, mental health and MSDs among coal miners was investigated by means of the Effort-Reward Imbalance questionnaire (ERI), Symptom Checklist-90(SCL-90), and Musculoskeletal disorders scale (MSDs) questionnaire.

RESULTS

The prevalence of MSDs among coal miners was higher, and there were statistical differences among different sexes, ages, working years, shifts, types of work, educational level and monthly income (P < 0.001). The prevalence of MSDs in different body parts in the occupational stress group and mental disorder group was higher than that in the normal group. The results of multivariate logistic regression analysis showed that females had an increased risk of developing MSDs (OR = 2.23, 95% CI.:1.50,3.33). The risk of MSDs was higher with age < 30 years (30-39 years,OR = 2.39, 95% CI.,1.68,3.40; 40-49 years,OR = 2.15, 95% CI.:1.52,3.04; 50-60 years:OR = 3.25, 95% CI.:2.09,5.07), and the longer the working years, the higher the risk of MSDs (OR = 1.90, 95% CI.:1.38,2.62). The two shifts group (OR = 2.18, 95% CI.:1.59,2.98) had an increased risk of developing MSDs compared with the fixed day shift group. The risk of MSDs was lower in heading drivers (OR = 0.41, 95% CI.:0.29,0.60,) and transport workers (OR = 0.30, 95% CI.:0.20,0.43). The higher the education level, the lower the risk of MSDs (high school: OR = 0.46, 95% CI.:0.34,0.62, junior college and above: OR = 0.12, 95% CI.:0.08,0.17), and the higher the monthly income, the lower the risk of MSDs (OR = 0.50, 95% CI.:0.34,0.74). Occupational stress (OR = 1.32, 95% CI.:1.05,1.67) and mental disorder(OR = 2.94, 95% CI.:2.25,3.84) increased the risk of MSDs. A Bayesian network diagram showed that occupational stress and MSDs have direct effects on mental disorders, and occupational stress can have indirect effects on mental disorders through MSDs.

CONCLUSION

Our research shows that MSDs are common among coal miners. Occupational stress and psychological disorders can increase the incidence of MSDs.

Proceedings from the CIHLMU occupational safety and health symposium 2019 "Protecting workers' health: global challenges and opportunities in work-related respiratory diseases"

The international CIH^LMU Occupational Safety and Health Symposium 2019 was held on 16th March, 2019 at the Ludwig-Maximilians-Universität Munich, Germany. About 60 participants from around the world representing occupational health and safety professionals, students, instructors from several institutions in Germany and abroad, attended the symposium.

The main objective of the symposium was to create awareness on global challenges and opportunities in work-related respiratory diseases. One keynote lecture and six presentations were made. While the keynote lecture addressed issues on occupational diseases in the twenty-first century, the six presentations were centered on: Prevention and control of work-related respiratory diseases, considerations; Occupational health and safety in Mining: Respiratory diseases; The prevention of TB among health workers is our collective responsibility; Compensation and prevention of occupational diseases and discussion on how artificial intelligence can support them: Overview of international approaches; Work-related Asthma: Evidence from high-income countries; and The role of imaging in the diagnosis of work- related respiratory diseases. A panel discussion was conducted following the presentations on the importance and challenges of data acquisition which is needed to have a realistic picture of the occupational safety and health status of workers at different levels. The current summary is an attempt to share the proceedings of the symposium.

N-Acetyl-Seryl-Asparyl-Lysyl-Proline regulates lung renin angiotensin system to inhibit epithelial-mesenchymal transition in silicotic mice

Silicosis is a major public health concern with various contributing factors. The renin-angiotensin system (RAS)is a critical regulator in the pathogenesis of this disease. We focused on two key RAS enzymes, angiotensin-converting enzyme (ACE) and angiotensin-converting enzyme 2 (ACE2), to elucidate the activation of the ACE-angiotensin II (Ang II)-angiotensin II receptor 1 (AT1) axis and the inhibition of the ACE2-angiotensin-(1-7) [Ang-(1-7)]-Mas receptor axis in C57BL/6mice following SiO₂ treatment. Silica exposure caused nodule formation, pulmonary interstitial fibrosis, epithelial-mesenchymal transition (EMT), abnormal deposition of extracellular matrix, and impaired lung function in mice. These effects were attenuated by the inhibition of ACE (captopril), blockade of the AT1(losartan), or systemic knockdown of the Ace gene. These effects were exacerbated by the inhibition of ACE2 (MLN-4760), blockade of the Mas (A779), or knockdown of the Ace2 gene. N-Acetyl-Seryl-Asparyl-Lysyl-Proline (Ac-SDKP), an anti-fibrotic peptide, ameliorated the silica-exposure-induced pathological changes by targeting the RAS system by activating the protective ACE2-Ang-(1-7)-Mas axis and inhibiting the deleterious ACE-Ang II-AT1 axis, thereby exerting a protective effect. This was confirmed in mouse lung type II epithelial cells (MLE-12) pretreated with Ang II and/or gene silencing separately targeting Ace and Ace2.The effects of Ac-SDKP were similar to those produced by Ace gene silencing and were partly attenuated by Ace2 deficiency. These findings suggested that RAS plays critical roles in the pathomechanism of silicosis fibrosis and that Ac-SDKP regulates lung RAS to inhibit EMT in silicotic mice and MLE-12 cells.

Coal mining and lung disease in the 21st century

PURPOSE OF REVIEW

To review the impact of coal mining and resurgence of coal workers' pneumoconiosis (CWP) in 21st century and effect of ambient air pollution on lung function.

RECENT FINDINGS

At the beginning of 21st century, statistics by National Institute for Occupational Safety and Health showed a steep rise in pneumoconiosis. This was followed by numerous epidemiologic and pathologic studies that confirmed increasing CWP prevalence as well as disease in younger miners and those with a shorter mining tenure. Recent studies have demonstrated that poor dust control in mines, a relative shift in composition of the coal mine dust, small sized mines and increase in surface mining are all possible contributors to this resurgence. There is also growing literature evaluating the effects of worsening air pollution on health, including decreasing lung function and development of emphysema, worsening quality of life measures and lung cancer.

SUMMARY

This irreversible but preventable disease currently haunts approximately 60 000 miners across United States and millions across the world. Its resurgence despite the strict dust regulations is a setback from the public health standpoint. The continued reliance on coal for energy will continue to place coal miners at danger of developing disease as well as the world.

Silica dust exposure induces autophagy in alveolar macrophages through switching Beclin1 affinity from Bcl-2 to PIK3C3

Increased deposition of silica dust in pulmonary interstitial tissues leads to silicosis, in which autophagy plays a defensive role in silica dust-associated stress response and cell death. Our previous studies revealed that silica dust exposure contributed to autophagy in pulmonary macrophages in vivo, while the specific regulatory mechanism is still unclear. This study aimed to figure out the regulatory mechanism as well as the role of autophagy in the pathogenesis of experimental silicosis. We used 3-methyladenine (3-MA) and ABT-737 to suppress the expression of phosphatidylinositol 3-kinase catalytic subunit type 3 (PIK3C3) and B cell leukemia/lymphoma 2 (Bcl-2), two critical initiators of autophagy, and detected and evaluated the autophagy in NR8383 cells with or without silica dust exposure. We found that exposure of silica dust increased autophagy in NR8383 cells and elevated the expression of Beclin1 and PIK3C3, but it reduced the expression of Bcl-2. The relationship among Beclin1, PIK3C3, and Bcl-2 were then investigated using immunoprecipitation analysis, and we found that suppression of PIK3C3 and/or Bcl-2 using 3-MA and/or ABT-737 could alter the autophagy induced by silica dust in NR8383 cells, and the complexes of Beclin1/PIK3C3 and Beclin1/Bcl-2 were both downregulated, which may be that inhibition of PIK3C3 and Bcl-2 altered the affinity of Beclin1 with PIK3C3 and Bcl-2 and lead to the silence of PIK3C3 signaling. These findings indicate that silica dust exposure induces autophagy via changing the connectivity of Beclin1 from Bcl-2 to PIK3C3.

Trends in global, regional and national incidence of pneumoconiosis caused by different aetiologies: an analysis from the Global Burden of Disease Study 2017

OBJECTIVES

Pneumoconiosis remains a major global occupational health hazard and illness. Accurate data on the incidence of pneumoconiosis are critical for health resource planning and development of health policy.

METHODS

We collected data for the period between 1990 and 2017 on the annual incident cases and the age-standardised incidence rates (ASIR) of pneumoconiosis aetiology from the Global Burden of Disease Study 2017. We calculated the average annual percentage changes of ASIR by sex, region and aetiology in order to determine the trends of pneumoconiosis.

RESULTS

Globally, the number of pneumoconiosis cases increased by a measure of 66.0%, from 36 186 in 1990 to 60 055 in 2017. The overall ASIR decreased by an average of 0.6% per year in the same period. The number of pneumoconiosis cases increased across the five sociodemographic index regions, and there was a decrease in the ASIR from 1990 to 2017. The ASIR of silicosis, coal workers' pneumoconiosis and other pneumoconiosis decreased. In contrast, measures of the ASIR of asbestosis displayed an increasing trend. Patterns of the incidence of pneumoconiosis caused by different aetiologies were found to have been heterogeneous for analyses across regions and among countries.

CONCLUSION

Incidence patterns of pneumoconiosis which were caused by different aetiologies varied considerably across regions and countries of the world. The patterns of incidence and temporal trends should facilitate the establishment of more effective and increasingly targeted methods for prevention of pneumoconiosis and reduce associated disease burden.

Overexpression of endogenous lipoic acid synthase attenuates pulmonary fibrosis induced by crystalline silica in mice

Oxidative stress and inflammatory processes are proposed to mediate the development of silicosis. However, antioxidant therapy has not produced consistent results during the treatment of silicosis. α-Lipoic acid synthesized by lipoic acid synthase is a powerful anti-oxidant and helps protect mitochondria. Thus far, the effect of endogenous α-Lipoic acid on silicosis has not been elucidated yet. We established an experimental model of silicosis with wildtype and Lias^H/H mice, a new antioxidant mouse model which has overexpressed Lias gene (∼150 %) relative to its wild type counterpart. We systemically examined main pathological changes of pulmonary fibrosis, and explored α-lipoic acid effects on oxidative stress, inflammatory and pulmonary fibrosis biomarkers in silica-instillated mice. In Lias^H/H mice over-expression of lipoic acid alleviated the severity of major pathological alterations in the early stage of pulmonary fibrosis induced by silica compared with wild type mice. Silica significantly increased oxidative stress in both wild type and Lias^H/H mice. The antioxidant defense was strengthen including increased NRF2 and LIAS production in Lias^H/H mice. Relieved oxidative stress resulted in decreased inflammatory response and secretion of chemokines. Lias^H/H mice reduced chronic inflammatory response and inhibition of NF-κB activity after silica instillation. The Lias^H/H mouse model overexpression of lipoic acid synthase gene retarded the development of silica-induced pulmonary fibrosis. Strengthen antioxidant defense by increased lipoic acid synthase is a potential strategy for protection against silica-induced pulmonary fibrosis.

Prediction of the length of service at the onset of coal workers' pneumoconiosis based on neural network

Three environmental parameters, i.e. dust concentrations, dust dispersion, and free silica content, were introduced into the traditional indices of the neural network model in order to construct a new prediction index and explore a new method for preventing the incidence of pneumoconiosis with intelligent accuracy and universality. Data of the pneumoconiosis patients from Huabei Mining Group (HBMG) of China from 1980 to 2017 were collected. SPSS22.0 was used to develop the combined models based on Back Propagation (BP) neural network model, Radial Basis Function (RBF) neural network model, and Multiple Linear Regression (MLR) model. The paired sample t-test was performed between the real and predicted values. According to this model, it was predicted that 382 coal workers in HBMG were likely to suffer from pneumoconiosis in 2022 and the incidence rate was 4.48%. It is necessary to take prevention measures and transfer these workers from their current positions. In four combined models, the BP-MLR combined model achieved the optimal error parameters and the most accurate prediction. This study provided a scientific basis for effective control and prevention of the incidence of the pneumoconiosis.