Silico-tuberculosis and associated risk factors in central province of Iran

Silico-tuberculosis: An updated review

Silico-Tuberculosis (silico-TB) is a severe combination of tuberculosis and silicosis, caused by occupational exposure to fine crystalline silica dust, which has become a global health concern. This comprehensive review compiles the updated knowledge regarding pathophysiology, clinical manifestations, important diagnostic techniques, treatment aspects, and challenges in understanding silico-TB. The review compiles the disease's history and epidemiology, highlighting a lack of data owing to poor monitoring and healthcare particularly in low- and middle-income countries like India. Further weak safety regulations, lack of preventative measures, and inadequate education increase the rates of silico-TB. The pathophysiology shows how silica particles impair the immune system and stimulate Th2 cells and M2 macrophages, which exacerbate TB, while inhibiting Th1 cells and M1 macrophages, which fight against the disease. Subsequently, it can be difficult to distinguish current TB from pre-existing silicosis. In cases where sputum and X-ray results are negative, chest CT scans may be helpful since radiographic screening identifies TB earlier than sputum assessment. Isoniazid, rifampicin, or both minimize the risk of active tuberculosis in people with silicosis. Consistent anti-tuberculosis drug therapy is recommended for 8-9 months to stop recurrence. The assessment recommends integrating silicosis and TB control initiatives to fight this combined health issue.

Silico-Tuberculosis Mimicking Malignancy

Silico-tuberculosis is the combination of silicosis and tuberculosis (TB). Symptoms of TB such as dyspnea, cough, and hemoptysis may precede the diagnosis of an endo-bronchial mass lesion on chest imaging. Among workers who were exposed to silica, TB was more common, and experiments indicated that silica inhibits alveolar macrophage activity and severe exposure induces apoptosis. Endobronchial neoplasms, which are tumors primarily affecting the bronchial lumen, are uncommon and may show up in a wide variety of different ways pathologically. Cough, chest discomfort, wheezing, hemoptysis, recurrent pneumonia, and weight loss are common complaints from people with endobronchial tumors. The requirement for additional bronchoscopy and imaging examination is raised when symptoms such as hemoptysis and obstructive pneumonia are present. Endobronchial silicosis lesions are uncommon and develop as a result of broncho lithiasis, the endoluminal erosion of peri bronchial adenopathy, or local bronchial wall silica-induced fibrosis. Endobronchial TB can present in a varied manner, diagnosis is often challenging as there is no specific radiological feature, and sputum acid-fast bacilli several times come out negative. However, a bronchoscopy with or without biopsy is a useful investigation in these cases. The following case is a rare manifestation of endobronchial TB as it mimicked malignancy, describing the difficulties in diagnosis and treating a patient who had both silicosis and endobronchial TB.

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.

Latent tuberculosis infection and infection-associated risk factors for miner workers with silicosis in eastern China

OBJECTIVES

Silicosis people are at high risk of developing pulmonary tuberculosis. Whether silica exposure increases the likelihood of latent tuberculosis infection (LTBI) was not well understood, and potential factors involved in LTBI risk among silicosis people were not evaluated before. Thus, LTBI among silicosis people and potential risk factors for LTBI among silicosis people were evaluated in this study.

METHODS

A cross-sectional study was undertaken for 130 miner workers with silicosis. The QFT-GIT was performed for LTBI detection.

RESULTS

The LTBI was high to 31.6% (36/114) for silicosis participants, and 13.1% (13/99) had a history of tuberculosis. Drinking was associated with LTBI risk (OR = 6.92, 95%CI, 1.47-32.66, P = 0.015). Meanwhile, tunneling work was associated with an increased risk of LTBI compared with other mining occupations (OR = 3.91,95%CI,1.20-12.70, P = 0.024).

CONCLUSIONS

The LTBI rate of silicosis participants was high and more than 10% had a history of tuberculosis. Drinking alcohol and tunneling were independent risk factors for LTBI in silicosis participants.

Predictors for Concurrent Diabetes in Tuberculosis Patients. Perspectives from Two Mining Districts of Eastern Tribal State Jharkhand, in India

Background

Tuberculosis and diabetes both diseases are present in large numbers in the country and we are major contributors to both globally. With the objective to understand the various traits of patients having both tuberculosis and diabetes and to ascertain various possible predictors for such occurrence based on the public health database we carried out this study. We seek answers to questions like they have any effects? Are they having any additive role to play?

Methods

One-year data from the NIKSHAY portal of both districts were analyzed to look for possible associations and other variable traits. Data were analyzed using standard methods to express data in frequency and percentage. Chi-square test was used to establish association, while step-wise approach was used to calculate univariate and multivariate logistic regression analysis for knowing various predictors. P-value of <0.05 was considered statistically significant.

Results

Concurrent diabetes in tuberculosis patients was close to 294 (6%) in the 4933 individuals. In total, 65.2% of the study population were male. Diagnosis of tuberculosis was made most of the time by chest X-ray (49.4%) followed by Microscopy ZN staining and cartridge-based nucleic acid amplification test (CBNAAT). Death was more among diabetics (4.4%) as compared to nondiabetics (3.5%).

Conclusion

Diabetes is increasing in tuberculosis patients; improvement in data quality is needed. More research is required to reveal various other reasons that make tuberculosis patients more prone to develop diabetes.

Occupational respiratory disorders in Iran: a review of prevalence and inducers

The link between occupational respiratory diseases (ORD) and exposure to harmful factors that are present in the workplace has been well shown. Factors such as physical activity, age and duration of occupational exposure playing important roles in ORD severity, should be identified in the workplace, their effects on workers health should be studied, and ultimately, exposure to them must be minimized. We carried out a literature review by searching PubMed, Scopus, and Web of Science databases to retrieve studies published from 1999 until the end of April 2023 reporting the prevalence and inducers of ORD in Iran. In Iranian workers, several ORD such as interstitial lung disease, silicosis, occupational asthma, pulmonary inflammatory diseases, chronic obstructive pulmonary diseases, and lung cancers have been reported. It was indicated that ORD mainly occur due to repeated and prolonged exposure to noxious agents in the workplace. We also extracted the prevalence of ORD in different regions of Iran from the retrieved reports. Based on our literature review, the prevalence of ORD among Iranian workers highlights the importance of regular assessment of the risk of exposure to noxious agents in the workplace to develop measures for preventing potential adverse effects.

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.

Risk of Silico-Tuberculosis in Miners: A Systematic Review and Meta-Analysis

Context

Tuberculosis (TB) and Silicosis are public health problems with high morbidity and mortality. They also exist as comorbidities and are highly prevalent among mine workers.

Aims

This study aims to estimate the risk of TB in miners with silicosis than in miners not having silicosis.

Methods and Material

This systematic review was conducted by literature search using PubMed, and EMBASE for studies published from 1st Jan 2017 till 20th July 2022. From the data obtained using relevant keywords for the search, a total of 345 articles were selected for screening after applying our inclusion-exclusion criteria and removing duplicates. PRISMA guidelines were followed. items JBI critical appraisal checklist for cross-sectional studies was used for assessment of the risk of bias. The odds ratio was used to estimate the strength of the association.

Results

After extensive screening, four studies have met our selection criteria. The meta-analysis of those studies revealed that the prevalence of TB in miners with silicosis is 27.11% while the prevalence of TB in miners with non-silicosis is 16.75%. The estimated pooled odds ratio (fixed effect model) is 1.34 (95% CI 1.01 - 1.76).

Conclusions

The present study reveals that there is an increased risk of TB in miners with Silicosis. Newer initiatives must be taken to prevent TB in miners.

Silicosis and tuberculosis: A systematic review and meta-analysis

INTRODUCTION

Silicosis mostly happens in workers with high silica exposure and may accompany the development of various diseases like tuberculosis, cancer, or autoimmune diseases. The term silico-tuberculosis describes a condition in which an individual is affected by both silicosis and tuberculosis at the same time. This systematic review and meta-analysis study was conducted to evaluate the risk of tuberculosis in silicosis patients and individuals exposed to silica dust.

METHODS

We performed a systematic search for relevant studies up to 6 September 2022 using PubMed/ Medline, and Embase with the following keywords in titles or abstracts: "silicosis" OR "silicoses" OR "pneumoconiosis" OR "pneumoconioses" AND "tuberculosis". Cohort and case-control studies containing relevant and original information about tuberculosis infection in silicosis patients were included for further analysis. Pooled estimates and 95% confidence intervals (CI) for the relative risk of tuberculosis in individuals with silicosis compared to those without; these were evaluated using the random effects model due to the estimated heterogeneity of the true effect sizes.

RESULTS

Out of 5352 potentially relevant articles, 7 studies were eligible for systematic review, of which 4 cohort studies were included for meta-analysis. The total population of all studies was 5884, and 90.63% were male. The mean age of participants was 47.7 years. Our meta-analysis revealed a pooled risk ratio of 1.35 (95%CI 1.18-1.53, I ²: 94.30%) which means an increased risk of silicosis patients and silica-exposed individuals to tuberculosis infection.

CONCLUSION

Silicosis and silica dust exposure increase the risk of tuberculosis. Therefore, we suggest that individuals with long-time silica exposure, like mine workers, be routinely considered for both silicosis and tuberculosis screening programs.

Silica-associated lung disease in developing countries

PURPOSE OF REVIEW

There is a considerable burden of silica-associated lung diseases in the developing world. This review summarizes the epidemiology of these diseases, especially silicosis and silico-tuberculosis, mitigative efforts and treatment, especially in the context of developing countries.

RECENT FINDINGS

In 2017, the highest incidence of silicosis was in China, India and Brazil among the developing countries. The prevalence of silicosis amongst exposed workers may vary from 4 to 55%; there is a risk of underestimation because of the 'healthy worker effect'. The permissible exposure limit for respirable silica adopted by governments in developing countries remains higher than the proposed 0.025 mg/m3. Silica exposure in informal or unorganized industries is challenging, as it falls outside statutory controls. Recent efforts on regulation and compensation by various governments in developing countries are encouraging but need proper implementation on the ground. Biomarkers such as club cell protein 16 and imaging methods such as computed tomography may offer earlier and easier detection of silicosis. Advanced silicosis remains incurable; novel treatments such as antifibrotics agents may be potentially effective.

SUMMARY

Silica-associated lung diseases are prevalent in developing countries. Efforts directed at preventing or minimizing exposure to respirable crystalline silica are required for mitigation.

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.

Mini-review: Silico-tuberculosis

Silicosis continues to be a serious health issue in many countries and its elimination by 2030 (a target set by WHO and the International Labour Organization in 1995) is virtually impossible. The risk to develop pulmonary tuberculosis for silicosis patients is higher than for non-silicosis people, and there is also an increased risk of both pulmonary and extrapulmonary tuberculosis in individuals exposed to silica. HIV coinfection adds further to the risk, and in some countries, such as South Africa, miners living with HIV are a considerable number. The diagnosis of active tuberculosis superimposed on silicosis is often problematic, especially in initial phases, and chest X-ray and smear examination are particularly important for the diagnosis of pulmonary tuberculosis. Treatment is difficult; directly observed therapy is recommended, a duration of at least eight months is probably needed, drug reactions are frequent and the risk of relapse higher than in non-silicosis patients. TB prevention in silicosis patients is essential and include active surveillance of the workers, periodic chest X-rays, tuberculin skin test or interferon-gamma releasing assay testing, and, importantly, adoption of measures to reduce the exposure to silica dust. Chemoprophylaxis is possible with different regimens and needs to be expanded around the world, but efficacy is unfortunately limited. Silico-tuberculosis is still a challenging health problem in many countries and deserves attention worldwide.

Silico-tuberculosis, silicosis and other respiratory morbidities among sandstone mine workers in Rajasthan- a cross-sectional study

BACKGROUND

Exposures to respirable crystalline silica causes silicosis, pulmonary tuberculosis, chronic obstructive pulmonary disease, lung cancer, autoimmune disorders and chronic renal disease. The aim of this study was to find out the prevalence of silico-tuberculosis, silicosis and other respiratory morbidities in sandstone mine workers in Jodhpur district of Rajasthan.

METHODS

It was a cross-sectional study done in sandstone mines in Jodhpur. A total of 15 mines were selected. The sample size was calculated and fixed to 174 mine workers. Chi-square and t-test were applied to draw inferences.

RESULTS

The mean age of the mine workers was 39.13 ± 11.09 years. Three fourth (75.3%) of the workers were working for more than ten years in mines. Around 30.0% had a history of tuberculosis. Abnormal spirometry was found in 89.2% of workers. Around 42% of mine workers were found with abnormal chest x-rays. Prevalence of silicosis was 37.3%, silico-tuberculosis was 7.4%, tuberculosis was 10.0%, and other respiratory diseases like emphysema and pleural effusion were diagnosed among 4.3% workers.

CONCLUSION

Prevalence of silico-tuberculosis, silicosis and other respiratory morbidities are high among sandstone mine workers.

Occupational exposure to silica and risk of heart disease: a systematic review with meta-analysis

OBJECTIVE

To search for evidence of the relationship between occupational silica exposure and heart disease.

DESIGN

A systematic review and meta-analysis.

BACKGROUND

Growing evidence suggests a relationship between occupational silica exposure and heart disease; however, the link between them is less clear.

DATA SOURCES

PubMed, ScienceDirect, Springer and EMBASE were searched for articles published between 1 January 1995 and 20 June 2019. Articles that investigated the effects of occupational silica exposure on the risk of heart disease were considered.

STUDY SELECTION

We included cohort studies, including prospective, retrospective and retroprospective studies.

DATA EXTRACTION AND SYNTHESIS

We extracted data using a piloted data collection form and conducted random-effects meta-analysis and exposure-response analysis. The meta-relative risk (meta-RR), a measure of the average ratio of heart disease rates in those with and without silica exposure, was used as an inverse variance-weighted average of relative risks from the individual studies. The Newcastle-Ottawa Quality Assessment Scale for cohort studies was used for study quality assessment.

OUTCOME MEASURE

We calculated the risk of heart diseases such as pulmonary heart disease, ischaemic heart disease and others.

RESULTS

Twenty cohort studies were included. The results suggest a significant increase in the risk of overall heart disease (meta-RR=1.08, 95% CI 1.03 to 1.13). Stronger evidence of association with pulmonary heart disease was found in the risk estimate of both categories of heart disease (meta-RR=1.24, 95% CI 1.08 to 1.43) and in the exposure-response analysis (meta-RR=1.39, 95% CI 1.19 to 1.62). Our subgroup analyses also revealed that the statistical heterogeneity among studies could be attributed mainly to the diversity in reference group, occupation and study quality score.

CONCLUSIONS

Silica-exposed workers are at an increased risk for overall heart disease, especially pulmonary heart disease. Further research is needed to better clarify the relationship between occupational silica exposure and ischaemic heart disease.

PROSPERO REGISTRATION NUMBER

CRD42019124673.

Active tuberculosis case finding in India - The way forward

Community based active case finding (ACF) for tuberculosis (TB) has seen resurrection in the current armamentarium of many TB managers in their fight toward eliminating TB. This article explores the accuracy and approximate cost of various ACF algorithms currently in vogue in India or those which could be useful, while inputting the sensitivity and specificity of screening and diagnostic tools as estimated from recently conducted community based surveys. This analysis informs that ACF may be prioritized to higher prevalence settings and the diagnostic algorithm for specific setting may be chosen taking into account the expected prevalence, estimated accuracy of the algorithm and resource availability. Further, chest X-ray cannot be used alone as a diagnostic tool and can be relied upon for this purpose when at least one of the three sputum specimen is smear positive. Accuracy of Xpert MTB/RIF as a diagnostic tool in community situations needs to be investigated further. The review brings out significant proportions of initial default and default during treatment among cases detected through ACF thus emphasizing the need for heightened efforts toward preventing the same. The article rounds off emphasizing priority to addressing barriers to speedy scale up of more sensitive diagnostic tools for health center based case finding including in private sector and ACF in high risk clinical groups for early and efficient case detection. It concludes by putting forth certain research areas that would strengthen future efforts.

Non-communicable diseases and tuberculosis: Anticipating the impending global storm

The epidemiological transitions that have occurred in low and middle income countries (LMIC) during the past decades have led to an increased prevalence on non-communicable diseases (NCDs) in these countries, where the burden of infectious diseases (IDs), especially tuberculosis (TB), remains high. Although the true dimensions of this comorbidity have not yet been fully understood, there is a growing amount of data, over the last 10 years, that suggest a clear association between NCDs and TB. In particular, there is a continuously increasing body of evidence that diabetes mellitus, chronic respiratory conditions, tobacco use, mental health illnesses and chronic kidney disease increase TB morbidity and mortality and vice versa. This bidirectional negative association between diseases may jeopardise the achievement of the Sustainable Development Goals (SDGs) specific TB targets, thus underlying the importance of integrated public health responses towards both epidemics. Population as well as individual based approaches are required, along with both strategic and operation integration on a global scale. This year's United Nations High Level Meetings (ΗLMs) presented a rare opportunity for the political foundations of the TB and NCD responses to be dug together, thus creating a potential breakthrough in the global response to both epidemics.