A systematic review of occupational exposure to coal dust and the risk of interstitial lung diseases

Identification of core carcinogenic elements based on the age-standardized mortality rate of lung cancer in Xuanwei Formation coal in China

In this study, the core carcinogenic elements in Xuanwei Formation coal were identified. Thirty-one samples were collected based on the age-standardized mortality rate (ASMR) of lung cancer; Si, V, Cr, Co, Ni, As, Mo, Cd, Sb, Pb, and rare earth elements and yttrium (REYs) were analyzed and compared; multivariate statistical analyses (CA, PCA, and FDA) were performed; and comprehensive identification was carried out by combining multivariate statistical analyses with toxicology and mineralogy. The final results indicated that (1) the high-concentration Si, Ni, V, Cr, Co, and Cd in coal may have some potential carcinogenic risk. (2) The concentrations of Cr, Ni, As, Mo, Cd, and Pb meet the zoning characteristics of the ASMR, while the Si concentration is not completely consistent. (3) The REY distribution pattern in Longtan Formation coal is lower than that in Xuanwei Formation coal, indicating that the materials of these elements in coal are different. (5) The heatmap divides the sampling sites into two clusters and subtypes in accordance with carcinogenic zoning based on the ASMR. (6) PC1, PC2, and PC3 explain 62.629% of the total variance, identifying Co, Ni, As, Cd, Mo, Cr, and V. (7) Fisher discriminant analysis identifies Ni, Si, Cd, As, and Co based on the discriminant function. (8) Comprehensive identification reveals that Ni is the primary carcinogenic element, followed by Co, Cd, and Si in combination with toxicology. (9) The paragenesis of Si (nanoquartz), Ni, Co, and Cd is an interesting finding. In other words, carcinogenic elements Ni, Co, Cd, and Si and their paragenetic properties should receive more attention.

The prevalences and levels of occupational exposure to dusts and/or fibres (silica, asbestos and coal): A systematic review and meta-analysis from the WHO/ILO Joint Estimates of the Work-related Burden of Disease and Injury

BACKGROUND

The World Health Organization (WHO) and the International Labour Organization (ILO) are developing joint estimates of the work-related burden of disease and injury (WHO/ILO Joint Estimates), with contributions from a large number of individual experts. Evidence from human, animal and mechanistic data suggests that occupational exposure to dusts and/or fibres (silica, asbestos and coal dust) causes pneumoconiosis. In this paper, we present a systematic review and meta-analysis of the prevalences and levels of occupational exposure to silica, asbestos and coal dust. These estimates of prevalences and levels will serve as input data for estimating (if feasible) the number of deaths and disability-adjusted life years that are attributable to occupational exposure to silica, asbestos and coal dust, for the development of the WHO/ILO Joint Estimates.

OBJECTIVES

We aimed to systematically review and meta-analyse estimates of the prevalences and levels of occupational exposure to silica, asbestos and coal dust among working-age (≥ 15 years) workers.

DATA SOURCES

We searched electronic academic databases for potentially relevant records from published and unpublished studies, including Ovid Medline, PubMed, EMBASE, and CISDOC. We also searched electronic grey literature databases, Internet search engines and organizational websites; hand-searched reference lists of previous systematic reviews and included study records; and consulted additional experts.

STUDY ELIGIBILITY AND CRITERIA

We included working-age (≥ 15 years) workers in the formal and informal economy in any WHO and/or ILO Member State but excluded children (< 15 years) and unpaid domestic workers. We included all study types with objective dust or fibre measurements, published between 1960 and 2018, that directly or indirectly reported an estimate of the prevalence and/or level of occupational exposure to silica, asbestos and/or coal dust.

STUDY APPRAISAL AND SYNTHESIS METHODS

At least two review authors independently screened titles and abstracts against the eligibility criteria at a first stage and full texts of potentially eligible records at a second stage, then data were extracted from qualifying studies. We combined prevalence estimates by industrial sector (ISIC-4 2-digit level with additional merging within Mining, Manufacturing and Construction) using random-effects meta-analysis. Two or more review authors assessed the risk of bias and all available authors assessed the quality of evidence, using the ROB-SPEO tool and QoE-SPEO approach developed specifically for the WHO/ILO Joint Estimates.

RESULTS

Eighty-eight studies (82 cross-sectional studies and 6 longitudinal studies) met the inclusion criteria, comprising > 2.4 million measurements covering 23 countries from all WHO regions (Africa, Americas, Eastern Mediterranean, South-East Asia, Europe, and Western Pacific). The target population in all 88 included studies was from major ISCO groups 3 (Technicians and Associate Professionals), 6 (Skilled Agricultural, Forestry and Fishery Workers), 7 (Craft and Related Trades Workers), 8 (Plant and Machine Operators and Assemblers), and 9 (Elementary Occupations), hereafter called manual workers. Most studies were performed in Construction, Manufacturing and Mining. For occupational exposure to silica, 65 studies (61 cross-sectional studies and 4 longitudinal studies) were included with > 2.3 million measurements collected in 22 countries in all six WHO regions. For occupational exposure to asbestos, 18 studies (17 cross-sectional studies and 1 longitudinal) were included with > 20,000 measurements collected in eight countries in five WHO regions (no data for Africa). For occupational exposure to coal dust, eight studies (all cross-sectional) were included comprising > 100,000 samples in six countries in five WHO regions (no data for Eastern Mediterranean). Occupational exposure to silica, asbestos and coal dust was assessed with personal or stationary active filter sampling; for silica and asbestos, gravimetric assessment was followed by technical analysis. Risk of bias profiles varied between the bodies of evidence looking at asbestos, silica and coal dust, as well as between industrial sectors. However, risk of bias was generally highest for the domain of selection of participants into the studies. The largest bodies of evidence for silica related to the industrial sectors of Construction (ISIC 41-43), Manufacturing (ISIC 20, 23-25, 27, 31-32) and Mining (ISIC 05, 07, 08). For Construction, the pooled prevalence estimate was 0.89 (95% CI 0.84 to 0.93, 17 studies, I2 91%, moderate quality of evidence) and the level estimate was rated as of very low quality of evidence. For Manufacturing, the pooled prevalence estimate was 0.85 (95% CI 0.78 to 0.91, 24 studies, I2 100%, moderate quality of evidence) and the pooled level estimate was rated as of very low quality of evidence. The pooled prevalence estimate for Mining was 0.75 (95% CI 0.68 to 0.82, 20 studies, I2 100%, moderate quality of evidence) and the pooled level estimate was 0.04 mg/m3 (95% CI 0.03 to 0.05, 17 studies, I2 100%, low quality of evidence). Smaller bodies of evidence were identified for Crop and animal production (ISIC 01; very low quality of evidence for both prevalence and level); Professional, scientific and technical activities (ISIC 71, 74; very low quality of evidence for both prevalence and level); and Electricity, gas, steam and air conditioning supply (ISIC 35; very low quality of evidence for both prevalence and level). For asbestos, the pooled prevalence estimate for Construction (ISIC 41, 43, 45,) was 0.77 (95% CI 0.65 to 0.87, six studies, I2 99%, low quality of evidence) and the level estimate was rated as of very low quality of evidence. For Manufacturing (ISIC 13, 23-24, 29-30), the pooled prevalence and level estimates were rated as being of very low quality of evidence. Smaller bodies of evidence were identified for Other mining and quarrying (ISIC 08; very low quality of evidence for both prevalence and level); Electricity, gas, steam and air conditioning supply (ISIC 35; very low quality of evidence for both prevalence and level); and Water supply, sewerage, waste management and remediation (ISIC 37; very low quality of evidence for levels). For coal dust, the pooled prevalence estimate for Mining of coal and lignite (ISIC 05), was 1.00 (95% CI 1.00 to 1.00, six studies, I2 16%, moderate quality of evidence) and the pooled level estimate was 0.77 mg/m3 (95% CI 0.68 to 0.86, three studies, I2 100%, low quality of evidence). A small body of evidence was identified for Electricity, gas, steam and air conditioning supply (ISIC 35); with very low quality of evidence for prevalence, and the pooled level estimate being 0.60 mg/m3 (95% CI -6.95 to 8.14, one study, low quality of evidence).

CONCLUSIONS

Overall, we judged the bodies of evidence for occupational exposure to silica to vary by industrial sector between very low and moderate quality of evidence for prevalence, and very low and low for level. For occupational exposure to asbestos, the bodies of evidence varied by industrial sector between very low and low quality of evidence for prevalence and were of very low quality of evidence for level. For occupational exposure to coal dust, the bodies of evidence were of very low or moderate quality of evidence for prevalence, and low for level. None of the included studies were population-based studies (i.e., covered the entire workers' population in the industrial sector), which we judged to present serious concern for indirectness, except for occupational exposure to coal dust within the industrial sector of mining of coal and lignite. Selected estimates of the prevalences and levels of occupational exposure to silica by industrial sector are considered suitable as input data for the WHO/ILO Joint Estimates, and selected estimates of the prevalences and levels of occupational exposure to asbestos and coal dust may perhaps also be suitable for estimation purposes. Protocol identifier: https://doi.org/10.1016/j.envint.2018.06.005. PROSPERO registration number: CRD42018084131.

The dependence of particle size on cell toxicity for modern mining dust

Progressive massive pulmonary fibrosis among coal miners has unexpectedly increased. It would likely due to the greater generation of smaller rock and coal particles produced by powerful equipment used in modern mines. There is limited understanding of the relationship between micro- or nanoparticles with pulmonary toxicity. This study aims to determine whether the size and chemical characteristics of typical coal-mining dust contribute to cellular toxicity. Size range, surface features, morphology, and elemental composition of coal and rock dust from modern mines were characterized. Human macrophages and bronchial tracheal epithelial cells were exposed to mining dust of three sub- micrometer and micrometer size ranges at varying concentrations, then assessed for cell viability and inflammatory cytokine expression. Coal had smaller hydrodynamic size (180–3000 nm) compared to rock (495–2160 nm) in their separated size fractions, more hydrophobicity, less surface charge, and consisted of more known toxic trace elements (Si, Pt, Fe, Al, Co). Larger particle size had a negative association with in-vitro toxicity in macrophages (p < 0.05). Fine particle fraction, approximately 200 nm for coal and 500 nm for rock particles, explicitly induced stronger inflammatory reactions than their coarser counterparts. Future work will study additional toxicity endpoints to further elucidate the molecular mechanism causing pulmonary toxicity and determine a dose–response curve.

Investigation of respirable coal mine dust (RCMD) and respirable crystalline silica (RCS) in the U.S. underground and surface coal mines

Dust is an inherent byproduct of mining activities that raises notable health and safety concerns. Cumulative inhalation of respirable coal mine dust (RCMD) and respirable crystalline silica (RCS) can lead to obstructive lung diseases. Despite considerable efforts to reduce dust exposure by decreasing the permissible exposure limits (PEL) and improving the monitoring techniques, the rate of mine workers with respiratory diseases is still high. The root causes of the high prevalence of respiratory diseases remain unknown. This study aimed to investigate contributing factors in RCMD and RCS dust concentrations in both surface and underground mines. To this end, a data management approach is performed on MSHA's database between 1989 and 2018 using SQL data management. In this process, all data were grouped by mine ID, and then, categories of interests were defined to conduct statistical analysis using the generalized estimating equation (GEE) model. The total number of 12,537 and 9050 observations for respirable dust concentration are included, respectively, in the U.S. underground and surface mines. Several variables were defined in four categories of interest including mine type, geographic location, mine size, and coal seam height. Hypotheses were developed for each category based on the research model and were tested using multiple linear regression analysis. The results of the analysis indicate higher RCMD concentration in underground compared to RCS concentration which is found to be relatively higher in surface coal mines. In addition, RCMD concentration is seen to be higher in the Interior region while RCS is higher in the Appalachia region. Moreover, mines of small sizes show lower RCMD and higher RCS concentrations. Finally, thin-seam coal has greater RCMD and RCS concentrations compared to thicker seams in both underground and surface mines. In the end, it is demonstrated that RCMD and RCS concentrations in both surface and underground mines have decreased. Therefore, further research is needed to investigate the efficacy of the current mass-concentration-based monitoring system.

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.

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.

Computer-Aided Diagnosis of Coal Workers' Pneumoconiosis in Chest X-ray Radiographs Using Machine Learning: A Systematic Literature Review

Computer-aided diagnostic (CAD) systems can assist radiologists in detecting coal workers' pneumoconiosis (CWP) in their chest X-rays. Early diagnosis of the CWP can significantly improve workers' survival rate. The development of the CAD systems will reduce risk in the workplace and improve the quality of chest screening for CWP diseases. This systematic literature review (SLR) amis to categorise and summarise the feature extraction and detection approaches of computer-based analysis in CWP using chest X-ray radiographs (CXR). We conducted the SLR method through 11 databases that focus on science, engineering, medicine, health, and clinical studies. The proposed SLR identified and compared 40 articles from the last 5 decades, covering three main categories of computer-based CWP detection: classical handcrafted features-based image analysis, traditional machine learning, and deep learning-based methods. Limitations of this review and future improvement of the review are also discussed.

Prolonged Inhalation Exposure to Coal Dust on Irradiated Rats and Consequences

The purposes of this study were to research immune system changes and liver and lung tissues in irradiated rats after prolonged exposure to coal dust. A study was carried out on 30 male Wistar rats that were divided into 3 groups: group I, intact animals; group II, exposure to coal dust and 0.2 Gy γ-irradiation; and group III, combined exposure to 6 Gy γ-irradiation and coal dust. The combination of a low and sublethal dose of γ-irradiation with coal dust leads to a significant change in immunity at the remote period. Particularly, the increase in radioactivity at the combined effect causes weakening of phagocytosis, and reduction in T lymphocytes by a factor of 2, immunoglobulin imbalance, and cytokine dysfunction develop secondary immune failure. During prolonged inhalation with coal dust of irradiated animals with the dose of 0.2 Gy, fibrosis and perivascular sclerosis of the bronchial wall of the lungs are formed, and perivascular fibrosis is formed in the liver. The increase in exposure dose up to 6 Gy in combination with coal, in the distant period, caused pulmonary hypertension amid hypertrophy of light arterial vessels and fibrous changes in arteriole, and destructive changes and collection necrosis develop in liver parenchyma. In the case of dust radiation synergy, the increase in doses leads to a significant immune deficiency, which occurs according to the “dose effect” principle; increases damage to animal tissues; and leads to liver tissue necrosis, pulmonary fibrosis, and pulmonary hypertension.

Occupational Disease as the Bane of Workers' Lives: A Study of Its Incidence in Slovakia. Part 2

The main objective of this article is to monitor the development of the number of occupational diseases related to selected physical factors in the working environment (noise, vibration and dust). Each region of Slovakia has its own specific social and economic conditions. Due to the existence of a strong correlation between the several regional variables observed, principal component analysis (PCA) was used to determine the new variables. Cluster analysis was used to group regions with similar characteristics. A dendrogram was created using the average linkage method, which illustrated the similarity of the regions studied. The value of the cophenetic correlation coefficient (CC = 0.90) confirms the validity of the average linkage method. The result of the cluster analysis is the grouping of the eight regions into five homogenic groups (clusters). An analysis of the data shows that Slovakia’s regional differences significantly influence the incidence of occupational diseases in individual regions. It is shown that, in Slovakia, the development of the number of occupational diseases has seen a favourable trend in the long term.

Characterization of nano-to-micron sized respirable coal dust: Particle surface alteration and the health impact

Chemical and physical properties of coal dust particles significantly influence the inhalation of respirable coal dust by miners, causing several lung diseases such as coal workers' pneumoconiosis (CWP) and silicosis. Multiple experimental techniques, including proximate/ultimate analyses, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), laser diffraction, and low-pressure CO₂ and N₂ adsorption, were used to investigate the chemical and physical properties of micron-/nano-coal particles comprehensively. Compared to the micron-scale coal dust, the nano-coal dust (prepared by cryogenic ballmill) shows the increase of carbon content and aromaticity and a decrease of oxygen content along with the reduction of oxygen-containing functional groups. Pore volume and surface area estimated by low-pressure CO₂ and N₂ adsorption have more than five-time increase for the nano-coal dust. The reduction of oxygen functional groups suggests the dropped wetting behavior of coal nanoparticles. The significantly increased pore volume and surface area in coal nanoparticles could be caused by the enhanced pore interconnectivity on the particle surface and the alteration of coal macromolecules. Weaker wettability and the highly enhanced surface area suggest potentially more significant toxicity of nano-coal dust inhaled by coal miners.

Respirable Coal Mine Dust: A Review of Respiratory Deposition, Regulations, and Characterization

In the late 1990s, despite years of efforts to understand and reduce coal worker’s pneumoconiosis (CWP) prevalence from more than 30% in 1970 to less than 4.2%, the level of occurrence among the US coal miners increased unexpectedly. The recent resurgence of lung diseases has raised concerns in the scientific and regulatory communities. In 2014, the United States Mine Safety and Health Administration (MSHA) issued a new dust rule changing the respirable coal mine dust (RCMD) exposure limits, measurement technology, and sampling protocol. The analysis for probable causes for the substantial increase in the CWP incidence rate is rather complicated. This paper aims to conduct a review of RCMD respiratory deposition, health effects, monitoring, regulations, and particle characteristics. The primary sources of RCMD along with the health risks from potential exposure are highlighted, and the current RCMD exposure regulations of the major coal producer countries are compared. A summary of RCMD characterization studies from 1972 to the present is provided. A review of the literature revealed that numerous factors, including geological and mining parameters, advancements in mining practices, particle characteristics, and monitoring approaches are considered to contribute to the recent resurgence of RCMD lung diseases. However, the root causes of the problem are still unknown. The effectiveness of the new dust rules in the United States will probably take years to be correctly assessed. Therefore, future research is needed to understand the relationship between RCMD particle characteristics and lung deposition, and the efficacy of current monitoring practices to measure the true dose of RCMD exposure.

Review of Respirable Coal Mine Dust Characterization for Mass Concentration, Size Distribution and Chemical Composition

Respirable coal mine dust (RCMD) exposure is associated with black lung and silicosis diseases in underground miners. Although only RCMD mass and silica concentrations are regulated, it is possible that particle size, surface area, and other chemical constituents also contribute to its adverse health effects. This review summarizes measurement technologies for RCMD mass concentrations, morphology, size distributions, and chemical compositions, with examples from published efforts where these methods have been applied. Some state-of-the-art technologies presented in this paper have not been certified as intrinsically safe, and caution should be exerted for their use in explosive environments. RCMD mass concentrations are most often obtained by filter sampling followed by gravimetric analysis, but recent requirements for real-time monitoring by continuous personal dust monitors (CPDM) enable quicker exposure risk assessments. Emerging low-cost photometers provide an opportunity for a wider deployment of real-time exposure assessment. Particle size distributions can be determined by microscopy, cascade impactors, aerodynamic spectrometers, optical particle counters, and electrical mobility analyzers, each with unique advantages and limitations. Different filter media are required to collect integrated samples over working shifts for comprehensive chemical analysis. Teflon membrane filters are used for mass by gravimetry, elements by energy dispersive X-ray fluorescence, rare-earth elements by inductively coupled plasma-mass spectrometry and mineralogy by X-ray diffraction. Quartz fiber filters are analyzed for organic, elemental, and brown carbon by thermal/optical methods and non-polar organics by thermal desorption-gas chromatography-mass spectrometry. Polycarbonate-membrane filters are analyzed for morphology and elements by scanning electron microscopy (SEM) with energy dispersive X-ray, and quartz content by Fourier-transform infrared spectroscopy and Raman spectroscopy.

Association between Coalmine Dust and Mortality Risk of Lung Cancer: A Meta-Analysis

Background

Evidence on the carcinogenicity of coalmine dust in occupational settings is still conflicting. Therefore, we conducted this research to evaluate the mortality risk of lung cancer for coalminers exposed to occupational dust when compared to population with no or low dust exposure.

Methods

Databases of PubMed and Chinese National Knowledge Infrastructure as well as reference lists were searched updated to September 18, 2020. The enrolled articles should report lung cancer mortality risk for coalminers exposed to occupational dust. Basic information was extracted such as the author and publication year, area and ethnicity, the type and estimates of outcome, duration of follow-up, and the study design. The checklists from Agency for Healthcare Research and Quality and the Newcastle-Ottawa Scale were used for the assessment of quality and bias risk for descriptive studies, cohort studies, and case control studies, respectively. The overall relative risks were calculated while Begg's and Egger's tests and sensitivity analysis were performed to explore potential heterogeneity sources. Metaregression and subgroup analyses were also conducted to give more detailed information for the correlation between dust exposure and lung cancer mortality.

Results

A total of 19 articles with 22 different studies (descriptive study, case control study, and cohort study) including 8909 observed deaths from 1964 to 2017 were enrolled with a significant heterogeneity (I ² = 95%, P < 0.001). The pooled relative risk of mortality from lung cancer was 1.16 (1.03-1.30) for coalminers. Results of metaregression analysis indicated that the high heterogeneity among these enrolled studies might be caused by the ethnicity differences (P = 0.011). Subgroup analysis also indicated that the pooled estimate for Asian population in China was 4.94 (3.95-6.17) with I ² = 39.3% and P = 0.192. All these results suggested that exposure to occupational dust would significantly increase the mortality risk of lung cancer, especially for Asian population in China, which should be measured and controlled more strictly. Discussion. This systematic review and meta-analysis provides high-quality evidence that exposure to occupational dust might increase the mortality risk of lung cancer, especially for Asian populations in China. The magnitude of this effect is of major public health importance in view of the ubiquitous existence of coalmining industry in China and even in the world. However, these pooled estimates should be interpreted cautiously because of the high heterogeneity among these publications. Other. This study was supported by the National Key Research and Development Program of China (Grant No. 2016YFC1302501).

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.

The health of communities living in proximity of geothermal plants generating heat and electricity: A review

Since the 1990s, in areas with natural geothermal manifestations studies on the association between exposure to pollutants and health effect have become increasingly relevant. These emissions consist of water vapor mixed with carbon dioxide, hydrogen sulfide (H₂S), methane and, to a lesser extent, rare gases and trace elements in volatile forms. Considering the indications of the World Health Organization and the growth in the use of geothermal energy for energy production, this review aims to report studies exploring the health status of the populations living in areas where geothermal energy is used to produce heat and electricity. Studies on the health effects of the general population exposed to emissions from both natural geothermal events and plants using geothermal energy at domestic or commercial level have been considered between 1999 and 2019. Studies were classified into those based on health indicators and those based on proxy-individual level exposure metrics. Both statistically significant results (p<0.05) and interesting signals were commented. The 19 studies selected (New Zealand, Iceland and Italy) provide heterogeneous results, with an increased risk for several tumor sites. Exposure to H₂S low concentrations is positively associated with an increment of respiratory symptoms, anti-asthma drugs use, mortality for respiratory diseases and lung cancer. Exposure to H₂S high levels is inversely related to cancer mortality but associated with an increase in hospitalization for respiratory diseases, central nervous system disorders and cardiovascular diseases. The results indicate that the health of populations residing in areas rich in geothermal emissions presents some critical elements to be explored. The two major limitations of the studies are the ecological design and the inadequate exposure assessment. The authors suggested the prosecution and the systematization of health surveillance and human biomonitoring activities associated with permanent control of atmospheric emissions from both industrial and natural plants.

Focusing on the premature death of redeployed miners in China: an analysis of cause-of-death information from non-communicable diseases

Background

Reducing premature deaths is an important step towards achieving the World Health Organization’s sustainable development goal. Redeployed miners are more prone to disease or premature death due to the special occupational characteristics. Our aims were to describe the deaths of redeployed miners, assess the losses due to premature death and identify their main health problems. All the records of individuals were obtained from Fuxin Mining Area Social Security Administration Center. Year of life lost (YLL) and average year of life lost were used to assess the loss due to premature death. YLL rates per 1000 individuals were considered to compare deaths from different populations.

Results

Circulatory system diseases contributed the most years of life lost in the causes of death, followed by neoplasms. But average year of life lost in neoplasms was 6.85, higher than circulatory system diseases, 5.63. Cerebrovascular disease and ischemic heart disease were the main causes of death in circulatory system diseases. And average years of life lost in cerebrovascular disease and ischemic heart disease were 5.85 and 5.62, higher than those in other circulatory system diseases. Lung cancer was the principal cause of death in neoplasms. Average year of life lost in liver cancer was 7.92, the highest in neoplasms.

Conclusions

For redeployed miners, YLL rates per 1000 individuals in cerebrovascular disease, ischemic heart disease and lung cancer were higher than those in other populations, especially in men. It is important to attach importance to the health of redeployed miners, take appropriate measures to reduce premature death and achieve the sustainable development goal. Our findings also contribute to a certain theoretical reference for other countries that face or will face the same problem.

Electronic supplementary material

The online version of this article (10.1186/s12992-019-0450-5) contains supplementary material, which is available to authorized users.

Pharmacological management of progressive-fibrosing interstitial lung diseases: a review of the current evidence

A proportion of patients with interstitial lung diseases (ILDs) are at risk of developing a progressive-fibrosing phenotype, which is associated with a deterioration in lung function and early mortality. In addition to idiopathic pulmonary fibrosis (IPF), fibrosing ILDs that may present a progressive phenotype include idiopathic nonspecific interstitial pneumonia, connective tissue disease-associated ILDs, hypersensitivity pneumonitis, unclassifiable idiopathic interstitial pneumonia, ILDs related to other occupational exposures and sarcoidosis. Corticosteroids and/or immunosuppressive therapies are sometimes prescribed to patients with these diseases. However, this treatment regimen may not be effective, adequate on its own or well tolerated, suggesting that there is a pressing need for efficacious and better tolerated therapies. Currently, the only approved treatments to slow disease progression in patients with IPF are nintedanib and pirfenidone. Similarities in pathobiological mechanisms leading to fibrosis between IPF and other ILDs that may present a progressive-fibrosing phenotype provide a rationale to suggest that nintedanib and pirfenidone may be therapeutic options for patients with the latter diseases.

This review provides an overview of the therapeutic options currently available for patients with fibrosing ILDs, including fibrosing ILDs that may present a progressive phenotype, and explores the status of the randomised controlled trials that are underway to determine the efficacy and safety of nintedanib and pirfenidone.

Aside from IPF, there are no proven therapies for other ILDs with a progressive-fibrosing phenotype that are effective and have tolerable adverse effects. Clinical studies evaluating the benefits of antifibrotic therapy in these populations are underway.http://ow.ly/40yL30mOs0q

WHO/ILO work-related burden of disease and injury: Protocol for systematic reviews of occupational exposure to dusts and/or fibres and of the effect of occupational exposure to dusts and/or fibres on pneumoconiosis

BACKGROUND

The World Health Organization (WHO) and the International Labour Organization (ILO) are developing a joint methodology for estimating the national and global work-related burden of disease and injury (WHO/ILO joint methodology), with contributions from a large network of experts. In this paper, we present the protocol for two systematic reviews of parameters for estimating the number of deaths and disability-adjusted life years attributable to pneumoconiosis from occupational exposure to dusts and/or fibres, to inform the development of the WHO/ILO joint methodology.

OBJECTIVES

We aim to systematically review studies on occupational exposure to dusts and/or fibres (Systematic Review 1) and systematically review and meta-analyse estimates of the effect of occupational exposure to dusts and/or fibres on pneumoconiosis (Systematic Review 2), applying the Navigation Guide systematic review methodology as an organizing framework.

DATA SOURCES

Separately for Systematic Reviews 1 and 2, we will search electronic academic databases for potentially relevant records from published and unpublished studies, including Medline, EMBASE, Web of Science and CISDOC. We will also search electronic grey literature databases, Internet search engines and organizational websites; hand-search reference list of previous systematic reviews and included study records; and consult additional experts.

STUDY ELIGIBILITY AND CRITERIA

We will include working-age (≥15 years) study participants in the formal and informal economy in any WHO and/or ILO Member State but exclude children (<15 years) and unpaid domestic workers. Eligible risk factors will be dusts and/or fibres from: (i) asbestos; (ii) silica; and/or (iii) coal (defined as pure coal dust and/or dust from coal mining). Included outcomes will be (i) asbestosis; (ii) silicosis; (iii) coal worker pneumoconiosis; and (iv) unspecified pneumoconiosis. For Systematic Review 1, we will include quantitative prevalence studies of occupational exposure to dusts and/or fibres (i.e. no versus any exposure) stratified by country, sex, age and industrial sector or occupation. For Systematic Review 2, we will include randomized controlled trials, cohort studies, case-control studies and other non-randomized intervention studies with an estimate of any occupational exposure to dusts and/or fibres on the prevalence of, incidence of or mortality due to pneumoconiosis, compared with the theoretical minimum risk exposure level of no exposure.

STUDY APPRAISAL AND SYNTHESIS METHODS

At least two review authors will independently screen titles and abstracts against the eligibility criteria at a first stage and full texts of potentially eligible records at a second stage, followed by extraction of data from qualifying studies. At least two review authors will assess risk of bias and the quality of evidence, using the most suited tools currently available. For Systematic Review 2, if feasible, we will combine relative risks using meta-analysis. We will report results using the guidelines for accurate and transparent health estimates reporting (GATHER) for Systematic Review 1 and the preferred reporting items for systematic reviews and meta-analyses guidelines (PRISMA) for Systematic Review 2.

PROSPERO REGISTRATION NUMBER

CRD42018084131.