Global and national burden and trends of mortality and disability-adjusted life years for silicosis, from 1990 to 2019: results from the Global Burden of Disease study 2019

Relationship between cumulative silica exposure and silicosis: a systematic review and dose-response meta-analysis

BACKGROUND

Silicosis, a chronic respiratory disease caused by crystalline silica exposure, is a persistent global lung health issue. No systematic review of the relationship between cumulative respirable crystalline silica (RCS) exposure and silicosis exists. UK exposure limits are currently under review. We therefore performed a systematic review and dose-response meta-analysis of this relationship.

METHODS

Web of Science, Medline and Embase were searched on 24 February 2023. Studies of radiographic, autopsy or death certificate silicosis, with an estimated average follow-up of over 20 years since first employment, were included. Cumulative silicosis risk methods were compared. The relative risks (RR) of silicosis at increasing cumulative exposures were calculated and used to estimate the absolute risk reduction (ARR).

RESULTS

Eight eligible studies, including 10 cohorts, contributed 8792 cases of silicosis among 65 977 participants. Substantial differences in cumulative risk estimates between methodologies exist. Using the same method, we observed higher cumulative silicosis risks among mining compared with non-mining cohorts. A reduction from 4 to 2 mg/m³-years in cumulative RCS exposure corresponded to substantial risk reductions among miners (RR 0.23 (95% CI 0.18 to 0.29, I2=92.9%) with an ARR of 323 (95% CI 298 to 344) per 1000) and non-miners (RR 0.55 (95% CI 0.36 to 0.83, I2=77.0%) with an ARR of 23 (95% CI 9 to 33) per 1000).

CONCLUSION

Despite significant heterogeneity, our findings support a reduction in permissible exposure limits from 0.1 mg/m3 to 0.05 mg/m³, particularly among mining populations. Further research is needed among non-miners as only two studies were eligible.

Tetrandrine Alleviates Silica-induced Pulmonary Fibrosis Through PI3K/AKT Pathway: Network Pharmacology Investigation and Experimental Validation

Tetrandrine (TET) is a bisbenzylisoquinoline alkaloid derived from Stephania tetrandra S. Moor, known for its potential use in attenuating the progression of silicosis. However, the precise effects and underlying mechanisms of TET remain controversial. In this study, we aimed to elucidate the pharmacological mechanism of TET using a network pharmacology approach, while also evaluating its effect on silica-induced lung fibrosis in mice and TGF-β1-stimulated pulmonary fibroblasts in vitro. We employed network pharmacology to unravel the biological mechanisms through which TET may exert its therapeutic effects on pulmonary fibrosis and silicosis. In a silica-induced mouse model of lung fibrosis, TET was administered orally either during the early or late stage of fibrotic progression. Additionally, we examined the effects of TET on fibroblasts stimulated by TGF-β1 in vitro. Through the analysis, we identified a total of 101 targets of TET, 7,851 genes associated with pulmonary fibrosis, and 80 overlapping genes. These genes were primarily associated with key pathways such as epidermal growth factor receptor tyrosine kinase inhibitor resistance, the vascular endothelial growth factor signaling pathway, and the phosphatidylinositol 3 kinase (PI3K)-protein kinase B (PKB or AKT) signaling pathway. Furthermore, molecular docking analysis revealed the binding of TET to AKT1, the catalytic subunit of phosphatidylinositol-3 kinase, and KDR. In vivo experiments demonstrated that TET significantly alleviated silica-induced pulmonary fibrosis and reduced the expression of fibrotic markers. Moreover, TET exhibited inhibitory effects on the migration, proliferation, and differentiation of TGF-β1-induced lung fibroblasts in vitro. Notably, TET mitigated silica-induced pulmonary fibrosis by suppressing the PI3K/AKT pathway. In conclusion, our findings suggest that TET possesses the ability to suppress silica-induced pulmonary fibrosis by targeting the PI3K/AKT signaling pathway. These results provide valuable insights into the therapeutic potential of TET in the treatment of pulmonary fibrosis and silicosis.

Framework for implementing collaborative TB-silicosis activities in India: insights from an expert panel

Tuberculosis (TB) treatment is more challenging for patients with silicosis, as it complicates the diagnosis of both diseases and increases mortality risk. Silicosis, an incurable occupational disease, confounds the diagnosis of TB and vice versa, making it more difficult to accurately identify and treat either condition. Moreover, TB appears to accelerate the progression of silicosis. Exposure to silica dust, a common cause of silicosis, can also trigger latent TB to become active TB. This correspondence outlines a proposed framework for implementing collaborative TB-silicosis activities in India, aimed at improving early diagnosis and management for both diseases. An expert panel of medical professionals developed this framework through online consultations in October and November 2022. The panel's goal was to establish a consensus on integrating TB-silicosis activities, with a focus on early detection and proper management. The framework suggests testing all patients with silicosis for active TB and screening workers exposed to silica dust for latent TB infection. It also recommends that patients with TB who have a history of occupational exposure to silica dust should be tested for silicosis. Reliable diagnostic tools, such as chest X-rays, are emphasized, providing guidance on their use for both diseases. The proposed collaborative TB-silicosis framework offers a structured approach to identifying and managing these two diseases, contributing to the global goal of eliminating silicosis by 2030 and aligning with the World Health Organization's targets for reducing TB incidence and mortality. It recommends specific strategies for implementation, including testing, referral systems, and workplace-based interventions. The framework also underscores the need for coordinated efforts among stakeholders, including the ministries of health, labor, industry, and environment. This correspondence provides valuable insights into how India can successfully implement collaborative TB-silicosis activities, serving as a model for other regions with similar challenges.

Trigonelline hydrochloride attenuates silica-induced pulmonary fibrosis by orchestrating fibroblast to myofibroblast differentiation

BACKGROUND

Silicosis represents a paramount occupational health hazard globally, with its incidence, morbidity, and mortality on an upward trajectory, posing substantial clinical dilemmas due to limited effective treatment options available. Trigonelline (Trig), a plant alkaloid extracted mainly from coffee and fenugreek, have diverse biological properties such as protecting dermal fibroblasts against ultraviolet radiation and has the potential to inhibit collagen synthesis. However, it's unclear whether Trig inhibits fibroblast activation to attenuate silicosis-induced pulmonary fibrosis is unclear.

METHODS

To evaluate the therapeutic efficacy of Trig in the context of silicosis-related pulmonary fibrosis, a mouse model of silicosis was utilized. The investigation seeks to elucidated Trig's impact on the progression of silica-induced pulmonary fibrosis by evaluating protein expression, mRNA levels and employing Hematoxylin and Eosin (H&E), Masson's trichrome, and Sirius Red staining. Subsequently, we explored the mechanism underlying of its functions.

RESULTS

In vivo experiment, Trig has been demonstrated the significant efficacy in mitigating SiO2-induced silicosis and BLM-induced pulmonary fibrosis, as evidenced by improved histochemical staining and reduced fibrotic marker expressions. Additionally, we showed that the differentiation of fibroblast to myofibroblast was imped in Trig + SiO2 group. In terms of mechanism, we obtained in vitro evidence that Trig inhibited fibroblast-to-myofibroblast differentiation by repressing TGF-β/Smad signaling according to the in vitro evidence. Notably, our finding indicated that Trig seemed to be safe in mice and fibroblasts.

CONCLUSION

In summary, Trig attenuated the severity of silicosis-related pulmonary fibrosis by alleviating the differentiation of myofibroblasts, indicating the development of novel therapeutic approaches for silicosis fibrosis.

Daphnetin alleviates silica-induced pulmonary inflammation and fibrosis by regulating the PI3K/AKT1 signaling pathway in mice

Silicosis is a hazardous occupational disease caused by inhalation of silica, characterized by persistent lung inflammation that leads to fibrosis and subsequent lung dysfunction. Moreover, the complex pathophysiology of silicosis, the challenges associated with early detection, and the unfavorable prognosis contribute to the limited availability of treatment options. Daphnetin (DAP), a natural lactone, has demonstrated various pharmacological properties, including anti-inflammatory, anti-fibrotic, and pulmonary protective effects. However, the effects of DAP on silicosis and its molecular mechanisms remain uncover. This study aimed to evaluate the therapeutic effects of DAP against pulmonary inflammation and fibrosis using a silica-induced silicosis mouse model, and investigate the potential mechanisms and targets through network pharmacology, proteomics, molecular docking, and cellular thermal shift assay (CETSA). Here, we found that DAP significantly alleviated silica-induced lung injury in mice with silicosis. The results of H&E staining, Masson staining, and Sirius red staining indicated that DAP effectively reduced the inflammatory response and collagen deposition over a 28-day period following lung exposure to silica. Furthermore, DAP reduced the number of TUNEL-positive cells, increased the expression levels of Bcl-2, and decreased the expression of Bax and cleaved caspase-3 in the mice with silicosis. More importantly, DAP suppressed the expression levels of NLRP3 signaling pathway-related proteins, including NLRP3, ASC, and cleaved caspase-1, thereby inhibiting silica-induced lung inflammation. Further studies demonstrated that DAP possesses the ability to inhibit the epithelial mesenchymal transition (EMT) induced by silica through the inhibition of the TGF-β1/Smad2/3 signaling pathway. The experimental results of proteomic analysis found that the PI3K/AKT1 signaling pathway was the key targets of DAP to alleviate lung injury induced by silica. DAP significantly inhibited the activation of the PI3K/AKT1 signaling pathway induced by silica in lung tissues. The conclusion was also verified by the results of molecular and CETSA. To further verify this conclusion, the activity of PI3K/AKT1 signaling pathway was inhibited in A549 cells using LY294002. When the A549 cells were pretreated with LY294002, the protective effect of DAP on silica-induced injury was lost. In conclusion, the results of this study suggest that DAP alleviates pulmonary inflammation and fibrosis induced by silica by modulating the PI3K/AKT1 signaling pathway, and holds promise as a potentially effective treatment for silicosis.

Issue 3-The occupational burden of respiratory diseases, an update

INTRODUCTION AND AIMS

Workplace exposures are widely known to cause specific occupational diseases such as silicosis and asbestosis, but they also can contribute substantially to causation of common respiratory diseases. In 2019, the American Thoracic Society (ATS) and the European Respiratory Society (ERS) published a joint statement on the occupational burden of respiratory diseases. Our aim on this narrative review is to summarise the most recent evidence published after the ATS/ERS statement as well as to provide information on traditional occupational lung diseases that can be useful for clinicians and researchers.

RESULTS

Newer publications confirm the findings of the ATS/ERS statement on the role of workplace exposure in contributing to the aetiology of the respiratory diseases considered in this review (asthma, COPD, chronic bronchitis, idiopathic pulmonary fibrosis, hypersensitivity pneumonitis, infectious pneumonia). Except for COPD, chronic bronchitis and infectious pneumonia, the number of publications in the last 5 years for the other diseases is limited. For traditional occupational lung diseases such as silicosis and asbestosis, there are old as well as novel sources of exposure and their burden continues to be relevant, especially in developing countries.

CONCLUSIONS

Occupational exposure remains an important risk factor for airways and interstitial lung diseases, causing occupational lung diseases and contributing substantially in the aetiology of common respiratory diseases. This information is critical for public health professionals formulating effective preventive strategies but also for clinicians in patient care. Effective action requires shared knowledge among clinicians, researchers, public health professionals, and policy makers.

Incidence, mortality, and disability-adjusted life years due to silicosis worldwide, 1990-2019: evidence from the global burden of disease study 2019

Silicosis is an occupational lung disease because of exposure to silica dust in the workplace. Evidence on the spatiotemporal change of silicosis burden worldwide remains limited. This study utilized data extracted from the Global Burden of Disease Study 2019 to examine the numbers and age-standardized rates of incidence (ASIR), mortality (ASMR), and disability-adjusted life years (DALYs) caused by silicosis between 1990 and 2019. Average annual percentage changes (AAPCs) were calculated to evaluate the temporal trends of age-standardized indicators by sex, region, and socio-demographic index (SDI) since 1990. Results indicated an increase in new silicosis cases globally, rising by 64.61% from 84,426 in 1990 to 138,971 in 2019, with a sustained high number of DALYs attributed to this disease. Although the global age-standardized rates of incidence, mortality, and DALYs of silicosis have decreased since 1990, the number of new cases has increased in 168 countries and territories, and the ASIR of silicosis has also risen in 118 countries and territories, primarily in developing countries. Since 1990, the burden of silicosis among the elderly has significantly increased. Countries with higher SDI experienced a more rapid decline in the silicosis burden. Silicosis remains a public health problem that requires significant attention. Programs for prevention and elimination of this public health issue need to be established in more countries and territories. Protecting young workers from silica dust exposure is crucial to prevent the onset of silicosis in their later years and to reduce the disease burden among older workers.

Implementation and Cost Analysis of a Novel Silicosis Case-Finding Program For Mine Workers in Rural Rwanda

Little is known about the burden of silicosis in Africa, despite extensive mining and construction operations in the region putting numerous people at risk. The implementation experience and costs of case-finding for occupational lung disease in resource-limited settings are also currently unknown. We describe the first-ever silicosis case-finding project in rural Rwanda using chest X-ray, symptom questionnaires, and spirometry. This was coupled with routine noncommunicable disease case-finding for diabetes and hypertension. We performed an ingredient-based analysis of the costs of all case-finding activities. In 2022, over 25 days, 1,032 mine workers were included in the program, of which 1,014 (98.3%) completed silicosis case-finding activities. The total cost of the program was estimated to be US$38,656, representing a cost of US$37.49 per person. We conclude that conducting large-scale occupational lung disease case-finding is clinically and economically feasible in resource-limited settings and can be effectively integrated with routine noncommunicable disease case-finding.

Respirable Silica Dust Exposure of Migrant Workers Informing Regulatory Intervention in Engineered Stone Fabrication

Background

Silicosis among workers who fabricate engineered stone products in micro or small-sized enterprises (MSEs) was reported from several countries. Workplace exposure data of these workers at high risk of exposure to respirable crystalline silica (RCS) dust are limited.

Methods

We surveyed workers performing cutting, shaping and polishing tasks at 6 engineered stone fabricating MSEs in Sydney, Australia prior to regulatory intervention. Personal exposure to airborne RCS dust in 34 workers was measured, work practices were observed using a checklist and worker demography recorded.

Results

Personal respirable dust measurements showed exposures above the Australian workplace exposure standard (WES) of 0.1 mg/m3 TWA-8 hours for RCS in 85% of workers who performed dry tasks and amongst 71% using water-fed tools. Dust exposure controls were inadequate with ineffective ventilation and inappropriate respiratory protection. All 34 workers sampled were identified as overseas-born migrants, mostly from three linguistic groups.

Conclusions

Workplace exposure data from this survey showed that workers in engineered stone fabricating MSEs were exposed to RCS dust levels which may be associated with a high risk of developing silicosis. The survey findings were useful to inform a comprehensive regulatory intervention program involving diverse hazard communication tools and enforcing improved exposure controls. We conclude that modest occupational hygiene surveys in MSEs, with attention to workers' demographic factors can influence the effectiveness of intervention programs. Occupational health practitioners should address these potential determinants of hazardous exposures in their workplace surveys to prevent illness such as silicosis in vulnerable workers.

Autoimmune findings in patients with silicosis in Spain

Background

Occupational exposure to silica is related to autoimmune diseases and features of autoimmunity, mainly autoantibodies. The study objectives were to estimate the prevalence of silicosis with associated autoimmune findings or diagnosed autoimmune diseases in Spain, and to assess the clinical and functional characteristics of affected patients.

Methods

This is a multicentre prospective study in patients diagnosed with silicosis. Autoantibodies analysed were antinuclear antibodies, isotypes IgA, IgM and IgG, rheumatoid factor, anticyclic citrullinated peptide, anti-Scl70, anti-Ro, and anti-LA. Pulmonary function tests were performed.

Results

Autoimmunity was assessed in 105 patients. Autoimmune findings were recorded in 29 (27%) patients, including antinuclear antibodies (n=21), anti-Ro (n=7), rheumatoid factor (n=5) and anti-Scl70 (n=3). Autoimmune disease was diagnosed in 16 (15%) patients, mainly rheumatoid arthritis (n=7) and systemic lupus erythematosus (n=4). Patients with silicosis and autoimmune findings had a lower mean time of exposure to silica and showed a trend toward lower values in pulmonary function tests.

Conclusions

Autoimmune findings and diagnosis of autoimmune diseases were frequent in patients with silicosis in Spain.

Burden of silica-attributed pneumoconiosis and tracheal, bronchus & lung cancer for global and countries in the national program for the elimination of silicosis, 1990-2019: a comparative study

BACKGROUND

In industries worldwide, crystalline silica is pervasive and poses risks of pneumoconiosis and respiratory malignancies, with the latter being a knowledge gap in disease burden research that this study aims to address. By integrating both diseases, we also seek to provide an in-depth depiction of the silica-attributed disease burden.

METHODS

Data from the Global Burden of Disease 2019 were extracted to analyze the disease burden due to silica exposure. The trends of age-standardized mortality rate (ASMR) and age-standardized DALY rate (ASDR) from 1990 to 2019, as well as the age-specific number and rate of deaths and disability-adjusted life years (DALYs) in 1990 and 2019, were presented using GraphPad Prism software. The average annual percentage changes (AAPCs) on ASMR and ASDR were calculated using joinpoint regression models.

RESULTS

The global trends of disease burden due to silica exposure from 1990 to 2019 showed a significant decrease, with AAPCs on ASMR and ASDR of -1.22 (-1.38, -1.06) and - 1.18 (-1.30, -1.05), respectively. Vietnam was an exception with an unprecedented climb in ASMR and ASDR in general over the years. The age-specific deaths and DALYs mainly peaked in the age group 60-64. In comparison to 1990, the number of deaths and DALYs became higher after 45 years old in 2019, while their rates stayed consistently lower in 2019. Males experienced an elevated age-specific burden than females. China's general age-standardized burden of pneumoconiosis and tracheal, bronchus & lung (TBL) cancer ranked at the forefront, along with the highest burden of pneumoconiosis in Chilean males and South African females, as well as the prominent burden of TBL cancer in Turkish males, Thai females, and overall Vietnamese. The age-specific burden of TBL cancer surpassed that of pneumoconiosis, and a delay was presented in the pneumoconiosis pinnacle burden compared to the TBL cancer. Besides, the burden of pneumoconiosis indicated a sluggish growth trend with advancing age.

CONCLUSION

Our research highlights the cruciality of continuous enhancements in occupational health legislation for countries seriously suffering from industrial silica pollution and the necessity of prioritizing preventive measures for male workers and elderly retirees.

Silico-tuberculosis amidst COVID-19 pandemic: global scenario and Indian perspective

Inhalation of crystalline silica-rich dust particles can result in the deadly occupational lung disorder called silicosis. The risk of contracting tuberculosis (TB) and the potential for lung cancer increase due to silicosis. This review article aims to bring to light the state of silicosis and TB scenario in the world and India for evaluating hurdles in the present and future to achieve the elimination road map and assess these conditions in the backdrop of the COVID-19 pandemic. A patient with silicosis has a 2.8-2.9 times higher risk of developing pulmonary TB and 3.7 times that of extrapulmonary TB. Incidences of missed cases when TB was misdiagnosed with silicosis due to indifferent clinical manifestations of the two in the initial stages are not uncommon. The duration of silica exposure and silicosis severity are directly related to the propensity to develop TB. As per a study, an average gap of 7.6 years has been noticed in a South African population for silico-tuberculosis to develop post-silicosis. In a study done on mine workers at Jodhpur, Rajasthan, it was seen that there is no definitive relation between patients with silicosis and the possibility of having COVID-19. There is a significant need to integrate the Silicosis control program with the TB elimination program for the government. A few steps can include assessing the workplaces, periodic monitoring of the workers' health, active case surveillance, identification of hotspots, and introducing reforms to curb the spread of dust and particulate matter from industrialised areas be taken in this regard.

Occupational interstitial lung diseases

Millions of workers are exposed to substances known to cause occupational interstitial lung diseases (ILDs), particularly in developing countries. However, the burden of the disease is likely to be underestimated due to under-recognition, under-reporting or both. The diagnosis of occupational ILD requires a high level of suspicion and a thorough occupational history, as occupational and non-occupational ILDs may be clinically, functionally and radiologically indistinguishable, leading to delayed diagnosis and inappropriate management. A potential occupational aetiology should always be considered in the differential diagnosis of ILD, as removal from the workplace exposure, with or without treatment, is a key therapeutic intervention and may lead to significant improvement. In this article, we provide an overview of the 'traditional' inorganic dust-related ILDs but also address idiopathic pulmonary fibrosis and the immunologically mediated chronic beryllium disease, sarcoidosis and hypersensitivity pneumonitis, with emphasis on the importance of surveillance and prevention for reducing the burden of these conditions. To this end, health-care professionals should be specifically trained about the importance of occupational exposures as a potential cause of ILD.

Animal models of silicosis: fishing for new therapeutic targets and treatments

Silicosis as an occupational lung disease has been present in our lives for centuries. Research studies have already developed and implemented many animal models to study the pathogenesis and molecular basis of the disease and enabled the search for treatments. As all experimental animal models used to date have their advantages and disadvantages, there is a continuous search for a better model, which will not only accelerate basic research, but also contribute to clinical aspects and drug development. We review here, for the first time, the main animal models developed to date to study silicosis and the unique advantages of the zebrafish model that make it an optimal complement to other models. Among the main advantages of zebrafish for modelling human diseases are its ease of husbandry, low maintenance cost, external fertilisation and development, its transparency from early life, and its amenability to chemical and genetic screening. We discuss the use of zebrafish as a model of silicosis, its similarities to other animal models and the characteristics of patients at molecular and clinical levels, and show the current state of the art of inflammatory and fibrotic zebrafish models that could be used in silicosis research.

Preliminary Study on the Effect and Molecular Mechanism of Tetrandrine in Alleviating Pulmonary Inflammation and Fibrosis Induced by Silicon Dioxide

This study aims to explore the molecular mechanism of tetrandrine (Tet) in alleviating pulmonary inflammation and fibrosis induced by silica (SiO2) from the perspective of autophagy. C57BL/6J mice were selected as experimental animals, and SiO2 was exposed by intranasal instillation. Tet was intervened by oral gavage. The mice were euthanized on the 7th and 42nd day of SiO2 exposure, and lung tissues were collected for histopathological, molecular biological, immunological, and transmission electron microscopy analysis. The results showed that SiO2 exposure could lead to significant lung inflammation and fibrosis, while Tet could significantly reduce SiO2 exposure-induced lung inflammation and fibrosis. Molecular mechanism research indicated that, compared with SiO2 expose group, Tet intervention could significantly reduce the expression levels of inflammatory cytokines and fibrosis markers (TNF-α, IL-1β, MCP-1, TGF-β1, HYP, Col-I, and Fn), and regulate the expression of key molecules ATG7, microtubule-associated protein 1 light chain 3B (LC3B), and P62 in the autophagy pathway to improve the blocking of autophagic flux, promote the recovery of autophagic lysosomal system function, and inhibit apoptosis. In summary, Tet can alleviate silica-induced lung inflammation and fibrosis, which may be achieved by regulating the expression of key molecules in the autophagy process and associated apoptotic pathway.

IL33-mediated NPM1 promotes fibroblast-to-myofibroblast transition via ERK/AP-1 signaling in silica-induced pulmonary fibrosis

Silicosis is a global occupational pulmonary disease due to the accumulation of silica dust in the lung. Lacking effective clinical drugs makes the treatment of this disease quite challenging in clinics largely because the pathogenic mechanisms remain obscure. Interleukin 33 (IL33), a pleiotropic cytokine, could promote wound healing and tissue repair via the receptor ST2. However, the mechanisms governing the involvement of IL33 in silicosis progression remain to be further explored. Here, we demonstrated that the IL33 levels in the lung sections were significantly overexpressed after bleomycin and silica treatment. Chromatin immunoprecipitation assay, knockdown, and reverse experiments were performed in lung fibroblasts to prove gene interaction following exogenous IL33 treatment or cocultured with silica-treated lung epithelial cells. Mechanistically, we illustrated that silica-stimulated lung epithelial cells secreted IL33 and further promoted the activation, proliferation, and migration of pulmonary fibroblasts by activating the ERK/AP-1/NPM1 signaling pathway in vitro. And more, treatment with NPM1 siRNA-loaded liposomes markedly protected mice from silica-induced pulmonary fibrosis in vivo. In conclusion, the involvement of NPM1 in the progression of silicosis is regulated by the IL33/ERK/AP-1 signaling axis, which is the potential therapeutic target candidate in developing novel antifibrotic strategies for pulmonary fibrosis.

Current status, trends, and predictions in the burden of silicosis in 204 countries and territories from 1990 to 2019

Background

Silicosis, a severe lung disease caused by inhaling silica dust, predominantly affects workers in industries such as mining and construction, leading to a significant global public health challenge. The purpose of this study is to analyze the current disease burden of silicosis and to predict the development trend of silicosis in the future the world by extracting data from the GBD database.

Methods

We extracted and analyzed silicosis prevalence, incidence, mortality, and disability-adjusted life years (DALYs) data from the Global Burden of Disease 2019 program for 204 countries and territories from 1990 to 2019. The association between the Sociodemographic Index (SDI) and the burden of age-standardized rates (ASRs) of DALYs has been examined at the regional level. Jointpoint regression analysis has been also performed to evaluate global burden trends of silicosis from 1990 to 2019. Furthermore, Nordpred age-period-cohort analysis has also been projected to predict future the burden of silicosis from 2019 to 2044.

Results

In 2019, global ASRs for silicosis prevalence, incidence, mortality, and DALYs were 5.383, 1.650, 0.161, and 7.872%, respectively which are lower than that in 1990. The populations of 45-59 age group were more susceptible to silicosis, while those aged 80 or above suffered from higher mortality and DALY risks. In 2019, the most impacted nations by the burden of silicosis included China, the Democratic People's Republic of Korea, and Chile. From 1990 to 2019, most regions observed a declining burden of silicosis. An "M" shaped association between SDI and ASRs of DALYs for silicosis was observed from 1990 to 2019. The age-period-cohort analysis forecasted a decreasing trend of the burden of silicosis from 2019 to 2044.

Conclusion

Despite the overall decline in the global silicosis burden from 1990 to 2019, some regions witnessed a notable burden of this disease, emphasizing the importance of targeted interventions. Our results may provide a reference for the subsequent development of appropriate management strategies.

Challenges and opportunities for silicosis prevention and control: need for a national health program on silicosis in India

BACKGROUND

Silicosis has been one of the most serious occupational public health problems worldwide for many decades. The global burden of silicosis is largely unknown, although it is thought to be more prevalent in low and medium-income countries. Individual studies among workers exposed to silica dust in various industries, however, reveal a high prevalence of silicosis in India. This paper is an updated review of the novel challenges and opportunities for silicosis prevention and control in India.

MAIN BODY

The unregulated informal sector employs workers on contractual appointment thereby insulating the employers from legislative provisions. Due to a lack of awareness of the serious health risks and low-income levels, symptomatic workers tend to disregard the symptoms and continue working in dusty environments. To prevent any future dust exposure, the workers must be moved to an alternative job in the same factory where they will not be exposed to silica dust. Government regulatory bodies, on the other hand, must guarantee that factory owners relocate workers to another vocation as soon as they exhibit signs of silicosis. Technological advances such as artificial intelligence and machine learning might assist industries in implementing effective and cost-saving dust control measures. A surveillance system needs to be established for the early detection and tracking of all patients with silicosis. A pneumoconiosis elimination program encompassing health promotion, personal protection, diagnostic criteria, preventive measures, symptomatic management, prevention of silica dust exposure, treatment, and rehabilitation is felt important for wider adoption.

CONCLUSION

Silica dust exposure and its consequences are fully preventable, with the benefits of prevention considerably outweighing the benefits of treating patients with silicosis. A comprehensive national health program on silicosis within the public health system would strengthen surveillance, notification, and management of workers exposed to silica dust in India.

The evaluation analysis on the airborne dust regional pollution of the anchor drilling operation in the tunnel

The anchor drilling operations generate massive airborne dust particles in the tunnel heading face that raises the pneumoconiosis morbidity and explosion risk. In this paper, a full-scale tunnel physical model is constructed to study the effect of the wind velocity and drilling site position on the airborne dust regional pollution scope based on the actual anchor drilling craft. The research indicates that the four extensive vortex areas keep the dust suspension at 14 m from the heading face and make the deposition dust particle refloat. The average respirable dust rate reaches the maximum value at section 5 m and presents a gradual decline as the dust particle migrates along the outlet direction. Raising the wind velocity contributes to alleviating the airborne dust pollution in the anchor drilling operation. As the wind velocity increases from 3 to 24 m/s, the high dust concentration area and number higher than 200 mg/m³ pose overall decrease trends, and the average dust concentration displays a linear decrease until 26.14-58.65 mg/m³ around the anchor worker head. Moving the drilling site positions closer to the exhaust air duct aggravates the airborne dust pollution in the front breathing zone. As the anchor drilling operation switches from the return air side to the supply air side, the dust concentration area ascends by 59.4-84.4% in the personnel respiratory space.

The therapeutic effect of exosomal lncRNA MSTRG.91634.7 on mitochondrial dysfunction during SiO2-induced lung fibrosis

Long-term silica (SiO₂) exposure led to irreversible lung fibrosis, in which epithelial-mesenchymal transition (EMT) played an essential role. A novel lncRNA MSTRG.91634.7 in the peripheral exosomes of silicosis patients was reported in our previous study, which could remold the pathological process of silicosis. However, whether its regulatory role on the development of silicosis was related to EMT process is unclear, and its mechanism remains to be further studied. In this study, up-regulating lncRNA MSTRG91634.7 restricted SiO₂-activated EMT and restored mitochondrial homeostasis binding to PINK1 in vitro. Moreover, overexpressing PINK1 could inhibit SiO₂-activated EMT in pulmonary inflammation and fibrosis in mice. Meanwhile, PINK1 contributed to restoring the SiO₂-induced mitochondrial dysfunction in mice lung. Our results revealed that exosomal lncRNA MSTRG.91634.7 from macrophages could restore mitochondrial homeostasis to restrict the SiO₂-activated EMT by binding to PINK1 during pulmonary inflammation and fibrosis due to SiO₂ exposure.

Activation of AMPK signalling by Metformin: Implication an important molecular mechanism for protecting against mice silicosis via inhibited endothelial cell-to-mesenchymal transition by regulating oxidative stress and apoptosis

Inhalation of silica particles (SiO₂) causes oxidative stress-induced inflammation and cell apoptosis, ultimately resulting in irreversible pulmonary fibrosis, Unfortunately, effective treatment or preventative measures have yet to be fully established. Metformin (Met), a relatively safe and effective medication for treating diabetes, may hold promise as protective agent against early-stage pulmonary fibrosis in mice through the activation of autophagy and inhibition of endothelial cell to mesenchymal transition (EndoMT). Here, we investigated whether Met could reduce silicosis in mice by regulating inflammation, oxidative stress, and apoptosis, and to identify the underlying protective effect on endothelial cells. First, through pathological observation, we found that 21 consecutive days of Met (100 mg/kg) administration is optimal against silicosis. Next, using haematoxylin-eosin and Masson's trichrome staining and immunoblotting, we found that Met effectively blunted the inflammatory response and collagen deposition at 56 days after exposure to SiO₂. We also demonstrated that Met effectively activates AMPK signalling and markedly relieves oxidative stress, the mitochondrial apoptotic pathway and EndoMT induced by SiO₂ exposure both in vivo and in vitro. Overall, Met can alleviate SiO₂-induced pulmonary fibrosis by regulating oxidative stress and the mitochondrial apoptotic pathway. The current study provides a rationale for the clinical treatment of SiO₂-induced pulmonary fibrosis.

A mixed-methods study on impact of silicosis on tuberculosis treatment outcomes and need for TB-silicosis collaborative activities in India

Globally, silicosis and tuberculosis (TB) have been targeted for elimination by 2030. The study's objectives were to determine the association of silicosis with unfavorable TB treatment outcomes, as well as to explore experts' perspectives on improving treatment outcomes among silico-tuberculosis patients. A retrospective cohort study evaluated TB treatment outcomes in Khambhat block, the western part of India, between 138 patients with silico-tuberculosis and 2610 TB patients without silicosis in February-March 2022. 'Unfavorable TB treatment outcomes' was defined as a patient stopping treatment for at least one month, a positive sputum smear at the end of treatment, or, a patient dying while on treatment. During April-July 2022, fifteen in-depth interviews with experts in the field of silicosis/tuberculosis were audio-recorded, transcribed, and analyzed to generate codes (thematic analysis). On multivariable logistic regression analysis, patients with silico-tuberculosis had a 2.3 (95% CI 1.6-3.4) times higher odds of unfavorable treatment outcomes. The experts recommended collaborative TB-silicosis activities for improving treatment outcomes of patients with silico-tuberculosis. I conclude from the study's findings that silicosis is associated with unfavorable TB treatment outcomes in this study setting. All patients with silicosis should be screened for TB and treated according to national TB program guidelines. All patients with TB who have a history of occupational dust exposure should be evaluated for silicosis and provided appropriate pulmonary/vocational rehabilitation.

Biomonitoring Exposure and Early Diagnosis in Silicosis: A Comprehensive Review of the Current Literature

Silicosis is a particular form of lung fibrosis attributable to occupational exposure to crystalline silica. The occupational exposure to crystalline silica also increases the risk of chronic obstructive pulmonary disease (COPD), cancer and lung infections, especially pulmonary tuberculosis. Silicosis is currently diagnosed in previously exposed workers by standard chest X-ray, when lesions are visible and irreversible. Therefore, it would be necessary to find specific and non-invasive markers that could detect silicosis in earlier stages, before the occurrence of X-ray opacities. In this narrative review, we present several diagnostic, monitoring and predictive biomarkers with high potential in the management of silicosis, such as: pro- and anti-inflammatory cytokines (TNF (Tumour necrosis factor-α), IL-1 (Interleukin-1), IL-6, IL-10), CC16 (Clara cell 16, an indirect marker of epithelial cell destruction), KL-6 (Krebs von den Lungen 6, an indirect marker of alveolar epithelial damage), neopterin (indicator of cellular immunity) and MUC5B gene (Mucin 5B, a gel-forming mucin in mucus). Studies have shown that all the aforementioned markers have a high potential for early diagnosis or evaluation of progression in silicosis and represent promising alternatives to radiology. We consider that a multicentric study is needed to evaluate these biomarkers in correlation with occupational history, histopathological examination, imaging signs and pulmonary functions tests on large groups of subjects to better evaluate the accuracy of the presented biomarkers.

A rare case of silicosis with hepatitis B infection

Introduction

Silicosis is a type of diffuse interstitial lung disease caused by inhalation of crystalline silicon dioxide. The number of silicosis cases have been rapidly increasing over the years. Complete cure is not possible so early diagnosis and prevention is required.

Case presentation

Our patient came with chief complaints of productive cough, breathlessness progressing to MRC grade 4 and fever. He worked in a flour mill for 15 years and has been symptomatic for the past 4-5 years. Chest examination showed tracheal deviation to the right, bilateral decreased breath sounds and fine crepitations. Chest X ray showed multiple tiny nodular opacities in all lung zones. Pulmonary function test confirmed restrictive lung disease. On CT scan, miliary mottled densities were noted bilaterally along with fibrosis in upper lobes and ground glass appearance in lower lobes. Echocardiography revealed mild pericardial effusion and Abdominal Ultrasound revealed coarse liver texture, splenomegaly and right sided pleural effusion. Patient was also Hepatitis B positive.Patient was treated with Prednisolone, Entecavir, Moxaclav along with symptomatic management.

Discussion

Male gender, HIV infection, Smoking, Occupation, Age at first exposure, Duration of exposure and Concentration of inhaled silica dust are the risk factors of silicosis. Individuals with Silicosis are at high risk of developing Tuberculosis and Hepatitis B infection. Pulmonary function test, HRCT and Lung biopsies help in diagnosis of Silicosis. Serological markers and Liver Function Test helps in diagnosis of Hepatitis B infection. Early diagnosis and prevention is essential for better prognosis and Lung transplant is the only definitive management. Complications like progressive fibrosis, infections, cor pulmonale and pneumothorax may result due to Silicosis.

Conclusion

Silicosis is a rare chronic inflammatory condition which leads to an immunosuppressed state and may predispose individuals to opportunistic conditions like Hepatitis B. Therefore, early identification of risk factors and clinical features is required.

FcεRI deficiency alleviates silica-induced pulmonary inflammation and fibrosis

Silicosis is one of the most important occupational diseases worldwide, caused by inhalation of silica particles or free crystalline silicon dioxide. As a disease with high mortality, it has no effective treatment and new therapeutic targets are urgently needed. Recent studies have identified FCER1A, encoding α-subunit of the immunoglobulin E (IgE) receptor FcεRI, as a candidate gene involved in the biological pathways leading to respiratory symptoms. FcεRI is known to be important in allergic asthma, but its role in silicosis remains unclear. In this study, serum IgE concentrations and FcεRI expression were assessed in pneumoconiosis patients and silica-exposed mice. The role of FcεRI was explored in a silica-induced mouse model using wild-type and FcεRI-deficient mice. The results showed that serum IgE concentrations were significantly elevated in both pneumoconiosis patients and mice exposed to silica compared with controls. The mRNA and protein expression of FcεRI were also significantly increased in the lung tissue of patients and silica-exposed mice. FcεRI deficiency significantly attenuated the changes in lung function caused by silica exposure. Silica-induced elevations of IL-1β, IL-6, and TNF-α were significantly attenuated in the lung tissue and bronchoalveolar lavage fluid (BALF) of FcεRI-deficient mice compared with wild-type controls. Additionally, FcεRI-deficient mice showed a significantly lower score of pulmonary fibrosis than wild-type mice following exposure to silica, with significantly lower hydroxyproline content and expression of fibrotic genes Col1a1 and Fn1. Immunofluorescent staining suggested FcεRI mainly on mast cells. Mast cell degranulation took place after silica exposure, as shown by increased serum histamine levels and β-hexosaminidase activity, which were significantly reduced in FcεRI-deficient mice compared with wild-type controls. Together, these data showed that FcεRI deficiency had a significant protective effect against silica-induced pulmonary inflammation and fibrosis. Our findings provide new insights into the pathophysiological mechanisms of silica-induced pulmonary fibrosis and a potential target for the treatment of silicosis.