Occupational Contributions to Interstitial Lung Disease

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.

Interstitial lung disease: a review of classification, etiology, epidemiology, clinical diagnosis, pharmacological and non-pharmacological treatment

Interstitial lung diseases (ILDs) refer to a heterogeneous and complex group of conditions characterized by inflammation, fibrosis, or both, in the interstitium of the lungs. This results in impaired gas exchange, leading to a worsening of respiratory symptoms and a decline in lung function. While the etiology of some ILDs is unclear, most cases can be traced back to factors such as genetic predispositions, environmental exposures (including allergens, toxins, and air pollution), underlying autoimmune diseases, or the use of certain medications. There has been an increase in research and evidence aimed at identifying etiology, understanding epidemiology, improving clinical diagnosis, and developing both pharmacological and non-pharmacological treatments. This review provides a comprehensive overview of the current state of knowledge in the field of interstitial lung diseases.

Interstitial lung disease related to occupational hard metal exposure: two case reports

BACKGROUND

Hard metal lung disease (HMLD) is a relatively less known occupational interstitial lung disease, and instances of HMLD resulting from para-occupational exposure are rarely reported.

CASE PRESENTATION

This paper presents two cases of interstitial lung disease caused by exposure to hard metal. The first case involves a 37-year-old Taiwanese man who had worked at a grinder station for hard metal materials for 12 years without respiratory protective equipment. He experienced a dry cough and exertional dyspnea, and his chest imaging and pathology findings were consistent with the features of usual interstitial pneumonia. Analysis of his lung tissue revealed the presence of tungsten and cobalt. The second case involves a 68-year-old Taiwanese woman, the mother of the first patient, who had hand-washed her son's workwear. She experienced a dry cough and had similar imaging findings to her son. After her son left his job, they both exhibited improved symptoms and lung functions with nintedanib treatment. These findings suggest a diagnosis of HMLD and interstitial lung disease resulting from para-occupational exposure to hard metal dust.

CONCLUSIONS

The diagnosis of HMLD relies on obtaining a detailed occupational exposure history. If HMLD is diagnosed, discontinuing exposing to hard metal dusts can lead to improved lung function.

Global Trends in Occupational Lung Disease

Lung diseases caused by workplace exposure are too often mis- or underdiagnosed due in part to nonexistent or inadequate health surveillance programs for workers. Many of these diseases are indistinguishable from those that occur in the general population and are not recognized as being caused at least in part by occupational exposures. More than 10% of all lung diseases are estimated to result from workplace exposures. This study reviews recent estimates of the burden of the most important occupational lung diseases using data published by United Nations specialized agencies as well as the Global Burden of Disease studies. We focus on occupational chronic respiratory disease of which chronic obstructive lung disease and asthma are the most significant. Among occupational cancers, lung cancer is the most common, and is associated with more than 10 important workplace carcinogens. Classic occupational interstitial lung diseases such as asbestosis, silicosis, and coal workers' pneumoconiosis still comprise a substantial burden of disease in modern industrial societies, while other occupational causes of pulmonary fibrosis and granulomatous inflammation are frequently misclassified as idiopathic. Occupational respiratory infections gained prominence during the severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) pandemic, eclipsing influenza and tuberculosis and other less common workplace infectious agents. The most significant risks are workplace exposures to particulate matter, gases, and fumes as well as occupational carcinogens and asthmagens. We present data on the burden of disease measured by deaths attributable to occupational respiratory disease as well as disability-adjusted years of life lost. Where available, prevalence and incidence data are also presented. These diseases are unique in that they are theoretically 100% preventable if appropriate exposure controls and workplace medical surveillance are implemented. This remains a continuing challenge globally and requires steadfast commitment on the part of government, industry, organized labor, and the medical profession.

Machine operator's lung outbreak due to Eikenella corrodens

BACKGROUND

Outbreaks of hypersensitivity pneumonitis (HP) are not uncommon in workplaces where metalworking fluids (MWFs) are used. The recirculation of MWFs leads to microbiological contamination, which is responsible for outbreaks. Most outbreak reports come from USA and the UK; however, no similar reports have been published from Central Europe.

AIMS

To describe an outbreak of MWF-associated HP in workers from a compressor assembly manufacturing facility in Slovak Republic and to identify the potential antigens responsible for the outbreak.

METHODS

We investigated the history of worker's symptoms, physical examinations, lung function tests, radiographic scans and lung biopsies. The MWF samples were analysed for different strains of bacteria and fungi. Antigen extracts were produced from the microorganisms isolated from MWFs, and positive precipitin reactions were evaluated.

RESULTS

MWF-associated HP was diagnosed in 21 men and 6 women. All workers had work-related dyspnoea and cough with abnormal pulmonary diffusing capacity. Twenty-four cases had evidence of interstitial lung disease. Four cases were classified as having fibrotic HP. Nineteen microbial isolates (12 bacteria and 7 fungi) were cultured from the MWFs. Twenty-five cases had a positive response to at least one isolate. Eikenella corrodens and Bacillus subtilis were the most frequently reacting antigens (in 15 and 12 workers, respectively).

CONCLUSIONS

Despite decreasing reports of MWF-associated HP outbreaks over the past several decades, we describe one of the largest outbreaks in Europe. While the bacterium E. corrodens was found in the MWF samples, its relationship to the disease should be further investigated.

Sex and gender in interstitial lung diseases

Sex and gender differences influence key domains of research, lung health, healthcare access and healthcare delivery. In interstitial lung diseases (ILDs), mouse models of pulmonary fibrosis are clearly influenced by sex hormones. Additionally, short telomeres, a biomarker of telomere regulation gene mutations, are impacted by sex, while heritability unexplained by genetic variation may be attributable to gendered environmental factors that drive epigenetic control. Diseases like idiopathic pulmonary fibrosis, hypersensitivity pneumonitis, occupational ILDs, connective tissue-associated ILDs and lymphangioleiomyomatosis have different prevalence and prognosis between men and women. These differences arise from a complex interplay between biological sex and sociocultural gender influencing genetics, epigenomic modifiers, hormones, immune function, response to treatment and interaction with healthcare systems. Much work remains to be done to systematically integrate sex and gender analysis into relevant domains of science and clinical care in ILD, from strategic considerations for establishing research priorities to guidelines for establishing best clinical practices. Accounting for sex and gender in ILD is essential to the practice of individualised, patient-centred medicine.

Master Clinician and Public Health Practitioner: Selected Occupational and Environmental Pulmonary Cases

Occupational and environmental exposures contribute to the development and progression of most lung diseases, yet their impact is greatly under-recognized in clinical practice. Clinicians caring for patients with respiratory diseases should maintain a high index of suspicion for occupational and environmental contributing factors. Mastering occupational and environmental medicine clinical decision making requires specialized clinical skills. These skills include obtaining an appropriate work and exposure history; making an assessment of the magnitude and relevance of exposures and their contribution to a patient's respiratory disease; utilizing appropriate resources for evaluation and management of exposure-related disease; and considering socioeconomic and public health factors.