Occupational exposure and idiopathic pulmonary fibrosis: a multicentre case-control study in Korea

Occupational and environmental risk factors for idiopathic pulmonary fibrosis: A case-control study

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease of unknown etiology. The aim of this study was to evaluate the environmental and occupational risk factors of IPF.

METHODS

This hospital-based, case-control study included 206 patients with IPF selected from the Seoul National University Bundang Hospital Interstitial Lung Disease registry and 167 controls without lung disease. Data on occupation, lifestyle, transportation, and types of environmental and occupational dust exposure were obtained using a questionnaire. IPF diagnosis was confirmed based on the recent guidelines, and the possibility of hypersensitivity pneumonitis was excluded. Multiple logistic regression was performed to determine the risk factors for IPF.

RESULTS

After adjusting for age and sex, ever-smokers (odds ratio [OR], 2.35; 95 % confidence interval [CI]: 1.51-3.68) and individuals who smoked more than 30 pack-years (OR, 2.79; 95%CI: 1.70-4.68) showed an increased risk for IPF. Any occupational dust exposure (adjusted OR, 2.08; 95%CI: 1.19-3.72), especially exposure to chemicals (adjusted OR, 3.52; 99%CI: 1.56-9.05), was associated with IPF after adjusting for age, sex, and smoking.

CONCLUSIONS

Smoking and occupational dust exposure are associated with an increased risk for IPF. Both factors have dose and duration-dependent relationships with the risk for IPF.

Risk of hypersensitivity pneumonitis and other interstitial lung diseases following organic dust exposure

BACKGROUND

Organic dust is associated with hypersensitivity pneumonitis, and associations with other types of interstitial lung disease (ILD) have been suggested. We examined the association between occupational organic dust exposure and hypersensitivity pneumonitis and other ILDs in a cohort study.

METHODS

The study population included all residents of Denmark born in 1956 or later with at least 1 year of gainful employment since 1976. Incident cases of hypersensitivity pneumonitis and other ILDs were identified in the Danish National Patient Register 1994-2015. Job exposure matrices were used to assign individual annual levels of exposure to organic dust, endotoxin and wood dust from 1976 to 2015. We analysed exposure-response relations by different exposure metrics using a discrete-time hazard model.

RESULTS

For organic dust, we observed increasing risk with increasing cumulative exposure with incidence rate ratios (IRR) per 10 unit-years of 1.19 (95% CI 1.12 to 1.27) for hypersensitivity pneumonitis and 1.04 (95% CI 1.02 to 1.06) for other ILDs. We found increasing risk with increasing cumulative endotoxin exposure for hypersensitivity pneumonitis and other ILDs with IRRs per 5000 endotoxin units/m3-years of 1.55 (95% CI 1.38 to 1.73) and 1.09 (95% CI 1.00 to 1.19), respectively. For both exposures, risk also increased with increasing duration of exposure and recent exposure. No increased risks were observed for wood dust exposure.

CONCLUSION

Exposure-response relations were observed between organic dust and endotoxin exposure and hypersensitivity pneumonitis and other ILDs, with lower risk estimates for the latter. The findings indicate that organic dust should be considered a possible cause of any ILD.

TRIAL REGISTRATION NUMBER

j.no.: 1-16-02-196-17.

Occupational exposure to respirable crystalline silica and incident idiopathic interstitial pneumonias and pulmonary sarcoidosis: a national prospective follow-up study

BACKGROUND

Respirable crystalline silica is a well-known cause of silicosis but may also be associated with other types of interstitial lung disease. We examined the associations between occupational exposure to respirable crystalline silica and the risk of idiopathic interstitial pneumonias, pulmonary sarcoidosis and silicosis.

METHODS

The total Danish working population was followed 1977-2015. Annual individual exposure to respirable crystalline silica was estimated using a quantitative job exposure matrix. Cases were identified in the Danish National Patient Register. We conducted adjusted analyses of exposure-response relations between cumulative silica exposure and other exposure metrics and idiopathic interstitial pneumonias, pulmonary sarcoidosis and silicosis.

RESULTS

Mean cumulative exposure was 125 µg/m3-years among exposed workers. We observed increasing incidence rate ratios with increasing cumulative silica exposure for idiopathic interstitial pneumonias, pulmonary sarcoidosis and silicosis. For idiopathic interstitial pneumonias and pulmonary sarcoidosis, trends per 50 µg/m3-years were 1.03 (95% CI 1.02 to 1.03) and 1.06 (95% CI 1.04 to 1.07), respectively. For silicosis, we observed the well-known exposure-response relation with a trend per 50 µg/m3-years of 1.20 (95% CI 1.17 to 1.23).

CONCLUSION

This study suggests that silica inhalation may be related to pulmonary sarcoidosis and idiopathic interstitial pneumonias, though these findings may to some extent be explained by diagnostic misclassification. The observed exposure-response relations for silicosis at lower cumulative exposure levels than previously reported need to be corroborated in analyses that address the limitations of this study.

The Impact of Occupational Exposures on the Risk of Idiopathic Pulmonary Fibrosis: A Systematic Review and Meta-Analysis

Rationale: Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic pulmonary disorder of unknown etiology that is characterized by a usual interstitial pneumonia pattern. Previous meta-analyses have reported associations between occupational exposures and IPF, but higher-quality studies have been published in recent years, doubling the number of studied patients. Objectives: To provide a contemporary and comprehensive assessment of the relationship between occupational exposures and IPF. Methods: We searched PubMed, Embase, and Web of Science through July 2023 to identify all publications on occupational exposure and IPF. We conducted a meta-analysis of the occupational burden, odds ratio (OR), and population attributable fraction (PAF) of exposures. Five exposure categories were analyzed: vapors, gas, dust, and fumes (VGDF); metal dust; wood dust; silica dust; and agricultural dust. A comprehensive bias assessment was performed. The study protocol was registered in the International Prospective Register of Systematic Reviews (identifier CRD42021267808). Results: Our search identified 23,942 publications. Sixteen publications contained relative risks needed to calculate pooled ORs and PAFs, and 12 additional publications reported an occupational burden within a case series. The proportion of cases with occupational exposures to VGDF was 44% (95% confidence interval [CI], 36-53%), with a range of 8-17% within more specific exposure categories. The pooled OR was increased for VGDF at 1.8 (95% CI, 1.3-2.4), with a pooled PAF of 21% (95% CI, 15-28%). ORs and PAFs, respectively, were found to be 1.6 and 7% for metal dust, 1.6 and 3% for wood dust, 1.8 and 14% for agricultural dust, and 1.8 and 4% for silica dust. The pooled ORs and PAFs within specific exposure categories ranged from 1.6 to 1.8 and from 4% to 14%, respectively. We identified some publication bias, but it was not sufficient to diminish the association between occupational exposures and IPF based on sensitivity analysis and bias assessment. Conclusions: Our findings indicate that 21% of IPF cases (or approximately one in five) could be prevented by removal of occupational exposure (alongside a pooled OR of 1.8). Additionally, 44% of patients with IPF report occupational exposure to VGDF. This meta-analysis suggests that a considerable number of cases of IPF are attributable to inhaled occupational exposures and warrant increased consideration in the clinical care of patients and future prevention efforts.

Innovative Pre-Clinical Data Using Peptides to Intervene in the Evolution of Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive, relentless, and deadly disease. Little is known about its pathogenetic mechanisms; therefore, developing efficient pharmacological therapies is challenging. This work aimed to apply a therapeutic alternative using immunomodulatory peptides in a chronic pulmonary fibrosis murine model. BALB/c mice were intratracheally instilled with bleomycin (BLM) and followed for 30 days. The mice were treated with the immune modulatory peptides ToAP3 and ToAP4 every three days, starting on the 5th day post-BLM instillation. ELISA, qPCR, morphology, and respiratory function analyses were performed. The treatment with both peptides delayed the inflammatory process observed in the non-treated group, which showed a fibrotic process with alterations in the production of collagen I, III, and IV that were associated with significant alterations in their ventilatory mechanics. The ToAP3 and ToAP4 treatments, by lung gene modulation patterns, indicated that distinct mechanisms determine the action of peptides. Both peptides controlled the experimental IPF, maintaining the tissue characteristics and standard function properties and regulating fibrotic-associated cytokine production. Data obtained in this work show that the immune response regulation by ToAP3 and ToAP4 can control the alterations that cause the fibrotic process after BLM instillation, making both peptides potential therapeutic alternatives and/or adjuvants for IPF.

What role for asbestos in idiopathic pulmonary fibrosis? Findings from the IPF job exposures case-control study

BACKGROUND

Asbestos has been hypothesised as the cause of the recent global increase in the incidence of 'idiopathic' pulmonary fibrosis (IPF). Establishing this has important diagnostic and therapeutic implications. The association between occupational asbestos exposure and IPF, and interaction with a common (minor allele frequency of 9% in European populations) genetic variant associated with IPF, MUC5B rs35705950, is unknown.

METHODS

Multicentre, incident case-control study. Cases (n=494) were men diagnosed with IPF at 21 UK hospitals. Controls (n=466) were age-matched men who attended a hospital clinic in the same period. Asbestos exposure was assessed at interview using a validated job exposure matrix and a source-receptor model. The primary outcome was the association between asbestos exposure and IPF, estimated using logistic regression adjusted for age, smoking and centre. Interaction with MUC5B rs35705950 was investigated using a genetic dominant model.

RESULTS

327 (66%) cases and 293 (63%) controls ever had a high or medium asbestos exposure risk job; 8% of both cases and controls had cumulative exposure estimates ≥25 fibre ml⁻¹ years. Occupational asbestos exposure was not associated with IPF, adjusted OR 1.1 (95% CI 0.8 to 1.4; p=0.6) and there was no gene-environment interaction (p=0.3). Ever smoking was associated with IPF, OR 1.4 (95% CI 1 to 1.9; p=0.04) and interacted with occupational asbestos exposure, OR 1.9 (95% CI 1 to 3.6; p=0.04). In a further non-specified analysis, when stratifying for genotype there was significant interaction between smoking and work in an exposed job (p<0.01) for carriers of the minor allele of MUC5B rs35705950.

CONCLUSION

Occupational asbestos exposure alone, or through interaction with MUC5B rs35705950 genotype, was not associated with IPF. Exposure to asbestos and smoking interact to increase IPF risk in carriers of a common genetic variant, the minor allele of MUC5B rs35705950.

TRIAL REGISTRATION NUMBER

NCT03211507.

Role of the occupational disease consultant in the multidisciplinary discussion of interstitial lung diseases

BACKGROUND

Diffuse interstitial lung diseases (ILD) constitute a heterogeneous group of conditions with complex etiological diagnoses requiring a multidisciplinary approach. Much is still unknown about them, particularly their relationship with occupational exposures. The primary objective of this study was to investigate the distribution of occupational exposures according to type of ILD. The secondary objectives were to estimate the proportion of ILDs possibly related to occupational exposure and to evaluate the added value of the participation of an occupational disease consultant in ILD multidisciplinary discussions (MDD).

METHODS

From May to December 2020, all consecutive patients with ILD whose cases were reviewed during a MDD in a referral centre for ILD were prospectively offered a consultation with an occupational disease consultant.

RESULTS

Of the 156 patients with ILD whose cases were reviewed in MDD during the study period, 141 patients attended an occupational exposure consultation. Occupational exposure was identified in 97 patients. Occupational exposure to asbestos was found in 12/31 (38.7%) patients with idiopathic pulmonary fibrosis (IPF) and in 9/18 (50.0%) patients with unclassifiable fibrosis. Occupational exposure to metal dust was found in 13/31 (41.9%) patients with IPFs and 10/18 (55.6%) patients with unclassifiable fibrosis. Silica exposure was found in 12/50 (24.0%) patients with autoimmune ILD. The link between occupational exposure and ILD was confirmed for 41 patients after the specialist occupational consultation. The occupational origin had not been considered (n = 9) or had been excluded or neglected (n = 4) by the MDD before the specialised consultation. A total of 24 (17%) patients were advised to apply for occupational disease compensation, including 22 (15.6%) following the consultation. In addition, a diagnosis different from the one proposed by the MDD was proposed for 18/141 (12.8%) patients.

CONCLUSIONS

In our study, we found a high prevalence of occupational respiratory exposure with a potential causal link in patients with ILD. We suggest that a systematic specialised consultation in occupational medicine could be beneficial in the ILD diagnostic approach.

Idiopathic Pulmonary Fibrosis: What do we Know about the Role of Occupational and Environmental Determinants? A Systematic Literature Review and Meta-Analysis

The objectives of this systematic review of original articles published up until August 2021 and meta-analyses were to identify the links between occupational and non-occupational environmental exposures, types of occupations and idiopathic pulmonary fibrosis (IPF). Sixteen selected case-control studies were qualified as good level with Newcastle-Ottawa quality assessment scale. Sensitivity analyses highlighted the role of choice of control group, tobacco adjustment and diagnostic tools. Significantly increased risks of IPF were observed (OR (95%CI): for metals (1.42(1.05-1.92)), wood (OR:1.32(1.02-1.71)), and general dust (OR:1.32(1.08-1.63)) exposures. Subgroup analyses found a significantly elevated risk for: hardwood (OR:1.75 (1.13-2.70)), organic dusts (OR:1.72 (1.20-2.46)) and pesticides (OR:2.30 (1.30-4.08)), while no significant change was noted for softwoods and solvents. Smoking adjustments: general dust (1.45 (1.04-2.03)/organic dust (2.5 (1.49-4.22)/metals (1.87 (1.16-3)/wood dust OR: 1.16 (0.86-1.61)/pesticide exposure 2.4 (0.84-6.9) were calculated. Among agricultural workers, the risk was also increased (OR:2.06 (1.02-4.16)). Few environmental data were available and no significant associations detected. Thus, these meta-analyses highlighted the role of some occupational exposures in IPF occurrence. A more accurate and thorough assessment of exposures over the entire working life as well as on the duration and intensity of exposure and complex of multi-pollutant exposure is needed in future research and clinical practice.

Environmental and occupational exposures in interstitial lung disease

PURPOSE OF REVIEW

We highlight recent advances in the understanding of how environmental and occupational exposures increase the risk of developing interstitial lung disease (ILD), and how to evaluate a patient for potential exposures.

RECENT FINDINGS

A review of emerging literature suggests that environmental and occupational exposures can be directly causal, as in the case of the pneumoconioses and smoking-related ILDs, or one of many contributors to disease, as in the case of idiopathic pulmonary fibrosis (IPF). Regardless of the level of association, exposures are clearly prevalent across all ILD subtypes studied.

SUMMARY

Inhalational exposures are increasingly recognized as an important component in the development of ILDs, and novel exposure-disease associations continue to be discovered. These exposures represent potential opportunities for further understanding the pathobiology of disease and for the prevention of these often progressive and debilitating disorders. Prospective, comprehensive data collection regarding occupational and environmental exposures are needed in ILD patients to fully elucidate specific antigens and their relationships to disease incidence and outcomes. Systematically collected exposure information will also inform potential interventions to remediate exposures and thus mitigate the course of frequently progressive and fatal diseases.

Usual Interstitial Pneumonia Associated With Crystalline Silica Exposure in Pneumoconiosis: A Retrospective Cohort Study

OBJECTIVE

We aimed to identify a relation between the level of silica exposure and the associated increase in the risk of radiologic usual interstitial pneumonia (UIP) pattern.

METHODS

We selected data of 796 individuals with pneumoconiosis who had undergone a chest computed tomography (CT). We estimated the silica exposure by comparing their occupational history with the data silica dust exposure.

RESULTS

Individuals employed as stonemasons demonstrated a 2.30-fold increase in the risk of developing UIP than coal mine workers (odds ratio [OR], 2.30; 95% confidence interval [CI], 1.04 to 5.07). The high silica exposure group was associated with a 2.23-fold increase in the risk of developing UIP than the low silica exposure group (OR, 2.23; 95% CI, 1.07 to 4.69).

CONCLUSIONS

This study suggests that silica exposure is associated with an increased risk of developing UIP pattern, highlighting a dose-response relationship.

TGF‑β1: Gentlemanly orchestrator in idiopathic pulmonary fibrosis (Review)

Idiopathic pulmonary fibrosis (IPF) is a worldwide disease characterized by the chronic and irreversible decline of lung function. Currently, there is no drug to successfully treat the disease except for lung transplantation. Numerous studies have been devoted to the study of the fibrotic process of IPF and findings showed that transforming growth factor‑β1 (TGF‑β1) plays a central role in the development of IPF. TGF‑β1 promotes the fibrotic process of IPF through various signaling pathways, including the Smad, MAPK, and ERK signaling pathways. There are intersections between these signaling pathways, which provide new targets for researchers to study new drugs. In addition, TGF‑β1 can affect the fibrosis process of IPF by affecting oxidative stress, epigenetics and other aspects. Most of the processes involved in TGF‑β1 promote IPF, but TGF‑β1 can also inhibit it. This review discusses the role of TGF‑β1 in IPF.

Occupational exposures and idiopathic pulmonary fibrosis

PURPOSE OF REVIEW

A recent meta-analysis of data from international case-control studies reports a population attributable fraction of 16% for occupational factors in the cause of idiopathic pulmonary fibrosis (IPF). Smoking, genetic factors and other prevalent diseases only partly explain IPF, and so this review aims to summarize recent progress in establishing which occupational exposures are important in cause.

RECENT FINDINGS

IPF is a rare disease, although it is the commonest idiopathic interstitial pneumonia. Epidemiological study suggests that incidence of IPF is increasing, particularly in older men. There are significant associations with IPF and occupational exposures to organic dust, including livestock, birds and animal feed, metal dust, wood dust and silica/minerals. Estimates of effect vary between studies, and are influenced by the distribution of employment, study design and case definition. Inhalation of asbestos fibres is a known cause of usual interstitial pneumonia (as seen histologically in IPF), though there are significant linear relationships between asbestos consumption, and mortality from both IPF and mesothelioma, leading to the hypothesis that low-level asbestos exposure may cause IPF.

SUMMARY

Research must focus on exposure-response relationships between asbestos and other occupational inhaled hazards, and IPF. Funding bodies and policy makers should acknowledge the significant occupational burden on IPF.

Smoking, occupational exposures, and idiopathic pulmonary fibrosis among Swedish construction workers

BACKGROUND

Cigarette smoking and occupational exposures each have been reported to increase the risk of idiopathic pulmonary fibrosis (IPF), a disease previously considered of unknown origin. We investigated the risk of IPF mortality associated with combined smoking and occupational exposures.

METHODS

A registry study of Swedish construction workers (N = 389,132), linked baseline smoking and occupational data with registry data on cause of death and hospital care diagnoses. Occupation was classified by the likelihood of exposure to vapors, gases, dusts, or fumes using a job-exposure matrix. Those likely exposed to asbestos or silica were excluded from the analysis. Age-adjusted relative risks [RRs] were calculated using Poisson regression. Follow-up observation began at age 40 and ended at age 89.

RESULTS

Heavy smokers at baseline who were exposed to inorganic dusts during their working life had an increased risk of IPF mortality (RR 1.70; 95% confidence interval [CI] 1.11-2.60), while there was no statistically increased risk in the other exposure groups. There were dose-response relationships between smoking at baseline and IPF mortality among both unexposed and dust exposed workers, with similar risk for dust exposed and unexposed, except among baseline heavy smokers, where workers exposed to inorganic dust manifested the highest risk (RR 4.22; 95% CI 2.69-6.60). Excluding workers with chronic obstructive pulmonary disease or emphysema did not affect the results substantively.

CONCLUSION

A clear dose-response relationship was seen between smoking at baseline and IPF, supporting a causal relationship. Occupational exposure to inorganic dusts, excluding silica and asbestos, was associated with increased risk of IPF in baseline heavy current smokers.

Occupational and environmental risk factors of idiopathic pulmonary fibrosis: a systematic review and meta-analyses

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fibrosing interstitial lung disease of unknown cause. It has a high risk of rapid progression and mortality. We conducted a systematic review and meta-analysis to evaluate the risk factor of IPF. We searched Medline, Embase, and the Cochrane library from the earliest record to March, 2020. Case–control studies on occupational and environmental risk factors or on jobs with a risk of IPF were searched for. From 2490 relevant records, 12 studies were included. Any occupational or environmental exposure to metal dust (OR 1.83, 95% CI 1.15–2.91, I² = 54%), wood dust (OR 1.62 5% CI 1.04–2.53, I² = 5%) and pesticide (OR 2.07, 95% CI 1.24–3.45, I² = 0%) were associated with an increased risk of IPF. Farming or agricultural work (OR 1.88, 95% CI 1.17–3.04, I² = 67%) was also associated with an increased risk of IPF. Moreover, smoking increased IPF risk with an odds ratio of 1.39 (95% CI 1.01–1.91, I² = 29%). In conclusion, metal dust, wood dust, pesticide, occupational history of farming or agriculture and ever smoking increased the risk of IPF.

Proteomics in idiopathic pulmonary fibrosis: the quest for biomarkers

Idiopathic pulmonary fibrosis (IPF) is a debilitating chronic progressive and fibrosing lung disease that culminates in the destruction of alveolar integrity and dismal prognosis. Its etiology is unknown and pathophysiology remains unclear. While great advances have been made in elucidating the pathogenesis mechanism, considerable gaps related to information on pathogenetic pathways and key protein targets involved in the clinical course of the disease exist. These issues need to be addressed for better clinical management of this highly challenging disease. Omics approach has revolutionized the entire area of disease understanding and holds promise in its translation to clinical biomarker discovery. This review outlines the contribution of proteomics towards identification of important biomarkers in IPF in terms of their clinical utility, i.e. prognosis, differential diagnosis, disease progression and treatment monitoring. The major dysregulated pathways associated with IPF are also discussed. Based on numerous proteomics studies on human and animal models, it is proposed that IPF pathogenesis involves complex interactions of several pathways such as oxidative stress, endoplasmic reticulum stress, unfolded protein response, coagulation system, inflammation, abnormal wounding, fibroblast proliferation, fibrogenesis and deposition of extracellular matrix. These pathways and their key path-changing mediators need further validation in large well-planned multi-centric trials at various geographical locations for successful development of clinical biomarkers of this confounding disease.

Idiopathic pulmonary fibrosis: Molecular mechanisms and potential treatment approaches

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive disease with high mortality that commonly occurs in middle-aged and older adults. IPF, characterized by a decline in lung function, often manifests as exertional dyspnea and cough. Symptoms result from a fibrotic process driven by alveolar epithelial cells that leads to increased migration, proliferation, and differentiation of lung fibroblasts. Ultimately, the differentiation of fibroblasts into myofibroblasts, which synthesize excessive amounts of extracellular matrix proteins, destroys the lung architecture. However, the factors that induce the fibrotic process are unclear. Diagnosis can be a difficult process; the gold standard for diagnosis is the multidisciplinary conference. Practical biomarkers are needed to improve diagnostic and prognostic accuracy. High-resolution computed tomography typically shows interstitial pneumonia with basal and peripheral honeycombing. Gas exchange and diffusion capacity are impaired. Treatments are limited, although the anti-fibrotic drugs pirfenidone and nintedanib can slow the progression of the disease. Lung transplantation is often contraindicated because of age and comorbidities, but it improves survival when successful. The incidence and prevalence of IPF has been increasing and there is an urgent need for improved therapies. This review covers the detailed cellular and molecular mechanisms underlying IPF progression as well as current treatments and cutting-edge research into new therapeutic targets.

Occupational and environmental risk factors for idiopathic pulmonary fibrosis in Australia: case-control study

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF) is a lung disease of unknown cause characterised by progressive scarring, with limited effective treatment and a median survival of only 2-3 years. Our aim was to identify potential occupational and environmental exposures associated with IPF in Australia.

METHODS

Cases were recruited by the Australian IPF registry. Population-based controls were recruited by random digit dialling, frequency matched on age, sex and state. Participants completed a questionnaire on demographics, smoking, family history, environmental and occupational exposures. Occupational exposure assessment was undertaken with the Finnish Job Exposure Matrix and Australian asbestos JEM. Multivariable logistic regression was used to describe associations with IPF as ORs and 95% CIs, adjusted for age, sex, state and smoking.

RESULTS

We recruited 503 cases (mean±SD age 71±9 years, 69% male) and 902 controls (71±8 years, 69% male). Ever smoking tobacco was associated with increased risk of IPF: OR 2.20 (95% CI 1.74 to 2.79), but ever using marijuana with reduced risk after adjusting for tobacco: 0.51 (0.33 to 0.78). A family history of pulmonary fibrosis was associated with 12.6-fold (6.52 to 24.2) increased risk of IPF. Occupational exposures to secondhand smoke (OR 2.1; 1.2 to 3.7), respirable dust (OR 1.38; 1.04 to 1.82) and asbestos (OR 1.57; 1.15 to 2.15) were independently associated with increased risk of IPF. However occupational exposures to other specific organic, mineral or metal dusts were not associated with IPF.

CONCLUSION

The burden of IPF could be reduced by intensified tobacco control, occupational dust control measures and elimination of asbestos at work.

The Occupational Burden of Nonmalignant Respiratory Diseases. An Official American Thoracic Society and European Respiratory Society Statement

Rationale: Workplace inhalational hazards remain common worldwide, even though they are ameliorable. Previous American Thoracic Society documents have assessed the contribution of workplace exposures to asthma and chronic obstructive pulmonary disease on a population level, but not to other chronic respiratory diseases. The goal of this document is to report an in-depth literature review and data synthesis of the occupational contribution to the burden of the major nonmalignant respiratory diseases, including airway diseases; interstitial fibrosis; hypersensitivity pneumonitis; other noninfectious granulomatous lung diseases, including sarcoidosis; and selected respiratory infections. Methods: Relevant literature was identified for each respiratory condition. The occupational population attributable fraction (PAF) was estimated for those conditions for which there were sufficient population-based studies to allow pooled estimates. For the other conditions, the occupational burden of disease was estimated on the basis of attribution in case series, incidence rate ratios, or attributable fraction within an exposed group. Results: Workplace exposures contribute substantially to the burden of multiple chronic respiratory diseases, including asthma (PAF, 16%); chronic obstructive pulmonary disease (PAF, 14%); chronic bronchitis (PAF, 13%); idiopathic pulmonary fibrosis (PAF, 26%); hypersensitivity pneumonitis (occupational burden, 19%); other granulomatous diseases, including sarcoidosis (occupational burden, 30%); pulmonary alveolar proteinosis (occupational burden, 29%); tuberculosis (occupational burden, 2.3% in silica-exposed workers and 1% in healthcare workers); and community-acquired pneumonia in working-age adults (PAF, 10%). Conclusions: Workplace exposures contribute to the burden of disease across a range of nonmalignant lung conditions in adults (in addition to the 100% burden for the classic occupational pneumoconioses). This burden has important clinical, research, and policy implications. There is a pressing need to improve clinical recognition and public health awareness of the contribution of occupational factors across a range of nonmalignant respiratory diseases.

Idiopathic pulmonary fibrosis and occupational risk factors

Idiopathic pulmonary fibrosis (IPF) is a rare lung disease of unknown origin that rapidly leads to death. However, the rate of disease progression varies from one individual to another and is still difficult to predict. The prognosis of IPF is poor, with a median survival of three to five years after diagnosis, without curative therapies other than lung transplantation. The factors leading to disease onset and progression are not yet completely known. The current disease paradigm is that sustained alveolar epithelial micro-injury caused by environmental triggers (e.g., cigarette smoke, microaspiration of gastric content, particulate dust, viral infections or lung microbial composition) leads to alveolar damage resulting in fibrosis in genetically susceptible individuals. Numerous epidemiological studies and case reports have shown that occupational factors contribute to the risk of developing IPF. In this perspective, we briefly review the current understanding of the pathophysiology of IPF and the importance of occupational factors in the pathogenesis and prognosis of the disease. Prompt identification and elimination of occult exposure may represent a novel treatment approach in patients with IPF.

Comparing effectiveness of prognostic tests in idiopathic pulmonary fibrosis

Introduction: Idiopathic pulmonary fibrosis (IPF) is a debilitating and progressive fibrotic interstitial lung disease often resulting in death over several years. Prediction of disease course or survival remains of keen interest for clinicians and patients though a commonly used test or tool remain elusive. Areas covered: We undertook a comprehensive review of the published literature highlighting prognostic indicators and predictors of survival in IPF. Baseline and longitudinal clinical, functional, histopathologic, and radiologic findings have been extensively studied as prognostic predictors, both individually and in composite models. Recent approaches include automated quantifiable radiologic scoring, circulating biomarkers, and genetic polymorphisms or abnormalities. This review highlights individual and composite predictors and their relative utility in clinical practice and research studies. Expert opinion: There is a growing body of knowledge highlighting readily available individual and composite predictors of outcome, though none have come to the forefront for common clinical use. Recent advances include quantitative imaging analysis, circulating serologic markers, and genetic testing, which may be more standardized and less prone to lead-time bias or related complications and comorbidities.

The Role of Occupational and Environmental Exposures in the Pathogenesis of Idiopathic Pulmonary Fibrosis: A Narrative Literature Review

Idiopathic pulmonary fibrosis (IPF) is a chronic interstitial lung disease characterised by a progressive and irreversible decline in lung function, which is associated with poor long-term survival. The pathogenesis of IPF is incompletely understood. An accumulating body of evidence, obtained over the past three decades, suggests that occupational and environmental exposures may play a role in the development of IPF. This narrative literature review aims to summarise current understanding and the areas of ongoing research into the role of occupational and environmental exposures in the pathogenesis of IPF.

Occupational risk factors for idiopathic pulmonary fibrosis in Southern Europe: a case-control study

Background

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive fibrosing interstitial pneumonia of unknown cause associated with the histopathologic and/or radiologic pattern of usual interstitial pneumonia (UIP). Occupational risk factors have been proposed to be associated with UIP. The aim of this case-control study is to evaluate the relationship between UIP pattern and occupational exposure in Southern Europe.

Methods

Sixty nine cases with a UIP radiological pattern at CT-scan were selected from a clinical database of the University Hospital of Perugia, Umbria, between January 2010 and December 2013. Controls (n = 277) not reporting doctor diagnosed pulmonary fibrosis, were ascertained casually among general population from the same catching area of cases. Data were collected by a questionnaire used previously in a similar study. Logistic regression models, adjusted for gender, age and smoking, were performed to evaluate the association between UIP and occupational exposure.

Results

Farmers, veterinarians and gardeners (OR = 2.73, 95%CI = 1.47–5.10), metallurgical and steel industry workers (OR = 4.80, 95%CI = 1.50–15.33) were occupations associated with UIP. Metal dust and fumes and organic dust were risk factors for UIP. Increasing the length of occupational exposure in jobs at risk of pulmonary fibrosis, increased the risk of having UIP.

Conclusions

This case control study confirm partially the results from previous similar studies. Some discrepancies could be explained by the different geographical origins of the population under study, reflecting also different occupational exposures.

Electronic supplementary material

The online version of this article (10.1186/s12890-018-0644-2) contains supplementary material, which is available to authorized users.