Occupational exposures and incidence of chronic bronchitis and related symptoms over two decades: the European Community Respiratory Health Survey

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.

[Pesticide exposure and chronic respiratory diseases]

INTRODUCTION

Pesticides are used worldwide, mainly in agriculture as a means of controlling pests and protecting crops. That said, the entire world population is ultimately subject to pesticide exposure (consumption of fruits and vegetables, living near treated fields…), with varying degrees of toxicity involved.

STATE OF THE ART

In recent decades, epidemiological studies have contributed to the identification of chemical pesticide families with detrimental effects on human health: cognitive disorders, Parkinson's disease, prostate cancer… and impairment in respiratory functioning. Current scientific evidence points to the implication of the active substances in insecticides, herbicides and fungicides in chronic respiratory diseases, two examples being chronic obstructive pulmonary disease (COPD) in exposed workers, and asthmatic wheezing in children during prenatal or postnatal exposure.

PERSPECTIVES

The safety of individuals exposed to pesticides is of key importance in public health. Further epidemiological investigations are needed to identify the chemical families affecting certain populations.

CONCLUSIONS

The scientific literature suggests strong links between pesticide exposure and respiratory health. Whether it be environmental or occupational, pesticide exposure can lead to respiratory disorders and symptoms of varying severity.

Chronic Bronchitis in Children and Adults: Definitions, Pathophysiology, Prevalence, Risk Factors, and Consequences

The complex nature of chronic bronchitis (CB) and changing definitions have contributed to challenges in understanding its aetiology and burden. In children, CB is characterised by persistent airway inflammation often linked to bacterial infections and is therefore termed "protracted bacterial bronchitis" (PBB). Longitudinal studies suggest that CB in childhood persists into adulthood in a subgroup. It can also be associated with future chronic respiratory diseases including asthma, bronchiectasis, and chronic obstructive pulmonary disease (COPD). Adult CB is traditionally associated with smoking, occupational exposures, and lower socioeconomic status. The interplay between risk factors, childhood CB, adult CB, and other chronic respiratory diseases is intricate, requiring comprehensive longitudinal studies for a clearer understanding of the natural history of CB across the lifespan. Such longitudinal studies have been scarce to date given the logistic challenges of maintaining them over time. In this review, we summarise current evidence on the evolution of the definitions, pathophysiology, risk factors, and consequences of childhood and adulthood chronic bronchitis.

A nested case-control study of the effects of dust exposure, smoking on COPD in coal workers

BACKGROUND

Chronic obstructive pulmonary disease (COPD) represents a prevalent ailment, progressively surging within the ranks of coal mine laborers. The current study endeavors to elucidate the effects of dust exposure and smoking on COPD incidence amongst coal mine workers, while concurrently devising preventive strategies for this affliction.

METHOD

A nested case-control study was conducted encompassing 1,416 participants aged ≥ 18 years, spanning the duration from (2017-2018) until 2020. A meticulous matching process yielded a cohort of 708 COPD patients, each paired with a control subject, forming a harmonious 1:1 ratio. Multiple logistic regression analysis was employed to scrutinize the associations between smoking, dust exposure with COPD among coal workers.

RESULTS

The COPD prevalence within the cohort of coal workers under investigation amounted to 22.66%, with an accompanying incidence density of 0.09/person-year. Following meticulous adjustment for confounding variables, it was discerned that cumulative dust exposure within the range of 47.19 ~ (OR: 1.90, 95% CI: 1.05, 3.44), 101.27 ~ (OR: 1.99, 95% CI: 1.17, 3.39), as well as smoking indices of 72 ~ (OR: 1.85, 95% CI: 1.19, 2.88), 145 ~ (OR: 1.74, 95% CI: 1.17, 2.61), 310 ~ (OR: 1.85, 95% CI: 1.23, 2.77) engender an escalated vulnerability to COPD among coal workers. Furthermore, interaction analysis discerned an absence of both multiplicative and additive interactions between dust exposure, smoking, and COPD occurrence amidst coal workers.

CONCLUSION

Dust exposure and smoking were unequivocally identified as precipitating risk factors for COPD incidence within the population of coal workers, albeit devoid of any discernible interaction between these two causal agents.

Association of Occupational Exposures and Chronic Obstructive Pulmonary Disease Morbidity

OBJECTIVE

The aim of the study is to determine whether aggregate measures of occupational exposures are associated with chronic obstructive pulmonary disease (COPD) outcomes in the Subpopulations and Intermediate Outcome Measures in COPD study cohort.

METHODS

Individuals were assigned to six predetermined exposure hazard categories based on self-reported employment history. Multivariable regression, adjusted for age, sex, race, current smoking status, and smoking pack-years determined the association of such exposures to odds of COPD and morbidity measures. We compared these with the results of a single summary question regarding occupational exposure.

RESULTS

A total of 2772 individuals were included. Some exposure estimates, including "gases and vapors" and "dust and fumes" exposures resulted in associations with effect estimates over two times the estimated effect size when compared with a single summary question.

CONCLUSIONS

Use of occupational hazard categories can identify important associations with COPD morbidity while use of single-point measures may underestimate important differences in health risks.

Chronic rhinosinusitis associated with chronic bronchitis in a five-year follow-up: the Telemark study

Background

Chronic rhinosinusitis (CRS) is associated with generalised airway inflammation. Few studies have addressed the relationship between CRS and chronic bronchitis (CB).

Methods

This prospective study over a five-year period aims to investigate the risk of developing CB in subjects reporting CRS at the beginning of the study. A random sample of 7393 adult subjects from Telemark County, Norway, answered a comprehensive respiratory questionnaire in 2013 and then 5 years later in 2018. Subjects reporting CB in 2013 were excluded from the analyses. New cases of CB in 2018 were analysed in relation to having CRS in 2013 or not.

Results

The prevalence of new-onset CB in 2018 in the group that reported CRS in 2013 was 11.8%. There was a significant increase in the odds of having CB in 2018 in subjects who reported CRS in 2013 (OR 3.8, 95% CI 2.65–5.40), adjusted for age, sex, BMI, smoking and asthma.

Conclusion

In this large population sample, CRS was associated with increased odds of developing CB during a five-year follow-up. Physicians should be aware of chronic bronchitis in patients with CRS.

Challenges in Diagnosing Occupational Chronic Obstructive Pulmonary Disease

Occupational chronic obstructive pulmonary disease (oCOPD) represents 15–20% of the global burden of this disease. Even if industrial bronchitis has long been known, new occupational hazards continue to emerge and enlarge the number of people exposed to risk. This review discusses the challenges related to the early detection of oCOPD, in the context of new exposures and of limited usage of methods for an efficient disease occupational screening. It underlines that a better translation into clinical practice of the new methods for lung function impairment measurements, imaging techniques, or the use of serum or exhaled breath inflammation biomarkers could add significant value in the early detection of oCOPD. Such an approach would increase the chance to stop exposure at an earlier moment and to prevent or at least slow down the further deterioration of the lung function as a result of exposure to occupational (inhaled) hazards.

Cumulative Occupational Exposures and Lung-Function Decline in Two Large General-Population Cohorts

Rationale: Few longitudinal studies have assessed the relationship between occupational exposures and lung-function decline in the general population with a sufficiently long follow-up.Objectives: To examine the potential association in two large cohorts: the ECRHS (European Community Respiratory Health Survey) and the SAPALDIA (Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults).Methods: General-population samples of individuals aged 18 to 62 were randomly selected in 1991-1993 and followed up approximately 10 and 20 years later. Spirometry (without bronchodilation) was performed at each visit. Coded complete job histories during follow-up visits were linked to a job-exposure matrix, generating cumulative exposure estimates for 12 occupational exposures. Forced expiratory volume in 1 second (FEV₁) and forced vital capacity (FVC) were jointly modeled in linear mixed-effects models, fitted in a Bayesian framework, taking into account age and smoking.Results: A total of 40,024 lung-function measurements from 17,833 study participants were analyzed. We found accelerated declines in FEV₁ and the FEV₁/FVC ratio for exposure to biological dust, mineral dust, and metals (FEV₁ = -15.1 ml, -14.4 ml, and -18.7 ml, respectively; and FEV₁/FVC ratio = -0.52%, -0.43%, and -0.36%, respectively; per 25 intensity-years of exposure). These declines were comparable in magnitude with those associated with long-term smoking. No effect modification by sex or smoking status was identified. Findings were similar between the ECRHS and the SAPALDIA cohorts.Conclusions: Our results greatly strengthen the evidence base implicating occupation, independent of smoking, as a risk factor for lung-function decline. This highlights the need to prevent or control these exposures in the workplace.

Cough Sound Detection and Diagnosis Using Artificial Intelligence Techniques: Challenges and Opportunities

Coughing is a common symptom of several respiratory diseases. The sound and type of cough are useful features to consider when diagnosing a disease. Respiratory infections pose a significant risk to human lives worldwide as well as a significant economic downturn, particularly in countries with limited therapeutic resources. In this study we reviewed the latest proposed technologies that were used to control the impact of respiratory diseases. Artificial Intelligence (AI) is a promising technology that aids in data analysis and prediction of results, thereby ensuring people's well-being. We conveyed that the cough symptom can be reliably used by AI algorithms to detect and diagnose different types of known diseases including pneumonia, pulmonary edema, asthma, tuberculosis (TB), COVID19, pertussis, and other respiratory diseases. We also identified different techniques that produced the best results for diagnosing respiratory disease using cough samples. This study presents the most recent challenges, solutions, and opportunities in respiratory disease detection and diagnosis, allowing practitioners and researchers to develop better techniques.

The coexistence of asthma and COPD: risk factors, clinical history and lung function trajectories

RATIONALE

Patients with concomitant features of asthma and chronic obstructive pulmonary disease (COPD) have a heavy disease burden.

OBJECTIVES

Using data collected prospectively in the European Community Respiratory Health Survey, we compared the risk factors, clinical history, and lung function trajectories from early adulthood to the late sixties of middle aged subjects having asthma+COPD (n=179), past (n=263) or current (n=808) asthma alone, COPD alone (n=111), or none of these (n=3477).

METHODS

Interview data and prebronchodilator FEV₁ and FVC were obtained during three clinical examinations in 1991-1993, 1999-2002, and 2010-2013. Disease status was classified in 2010-2013, when the subjects were aged 40-68, according to the presence of fixed airflow obstruction (postbronchodilator FEV₁/FVC below the lower limit of normal), a lifetime history of asthma, and cumulative exposure to tobacco or occupational inhalants. Previous lung function trajectories, clinical characteristics, and risk factors of these phenotypes were estimated.

MAIN RESULTS

Subjects with asthma+COPD reported maternal smoking (28.2%) and respiratory infections in childhood (19.1%) more frequently than subjects with COPD alone (20.9 and 14.0%, respectively). Subjects with asthma+COPD had an impairment of lung function at age 20 that tracked over adulthood, and more than half of them had asthma onset in childhood. Subjects with COPD alone had the highest lifelong exposure to tobacco smoking and occupational inhalants, and they showed accelerated lung function decline during adult life.

CONCLUSIONS

The coexistence between asthma and COPD seems to have its origins earlier in life compared to COPD alone. These findings suggest that prevention of this severe condition, which is typical at older ages, should start in childhood.

Structural airway imaging metrics are differentially associated with persistent chronic bronchitis

BACKGROUND

Chronic bronchitis (CB) is strongly associated with cigarette smoking, but not all smokers develop CB. We aimed to evaluate whether measures of structural airway disease on CT are differentially associated with CB.

METHODS

In smokers between ages 45 and 80 years, and with Global Initiative for Obstructive Lung Disease stages 0-4, CB was defined by the classic definition. Airway disease on CT was quantified by (i) wall area percent (WA%) of segmental airways; (ii) Pi10, the square root of the wall area of a hypothetical airway with 10 mm internal perimeter; (iii) total airway count (TAC) and (iv) airway fractal dimension (AFD), a measure of the complex branching pattern and remodelling of airways. CB was also assessed at the 5-year follow-up visit.

MEASUREMENTS AND MAIN RESULTS

Of 8917 participants, 1734 (19.4%) had CB at baseline. Airway measures were significantly worse in those with CB compared with those without CB: WA% 54.5 (8.8) versus 49.8 (8.3); Pi10 2.58 (0.67) versus 2.28 (0.59) mm; TAC 156.7 (81.6) versus 177.8 (91.1); AFD 1.477 (0.091) versus 1.497 (0.092) (all p<0.001). On follow-up of 5517 participants at 5 years, 399 (7.2%) had persistent CB. With adjustment for between-visits changes in smoking status and lung function, greater WA% and Pi10 were associated with significantly associated with persistent CB, adjusted OR per SD change 1.75, 95% CI 1.56 to 1.97; p<0.001 and 1.66, 95% CI 1.42 to 1.86; p<0.001, respectively. Higher AFD and TAC were associated with significantly lower odds of persistent CB, adjusted OR per SD change 0.76, 95% CI 0.67 to 0.86; p<0.001 and 0.69, 95% CI 0.60 to 0.80; p<0.001, respectively.

CONCLUSIONS

Higher baseline AFD and TAC are associated with a lower risk of persistent CB, irrespective of changes in smoking status, suggesting preserved airway structure can confer a reserve against CB.

Airborne occupational exposures and the risk of developing respiratory symptoms and airway obstruction in the Lifelines Cohort Study

OBJECTIVES

To date, only a few studies have investigated the associations between occupational exposures and respiratory outcomes longitudinally in the general population. We investigated the associations between occupational exposures and the development of respiratory symptoms and airway obstruction in the Lifelines Cohort Study.

METHODS

We included 35 739 occupationally active subjects with data on chronic cough, chronic phlegm, chronic bronchitis or airway obstruction at baseline and approximately 4.5 years follow-up. Exposures to biological dust, mineral dust, gases/fumes, pesticides, solvents and metals in the current job at baseline were estimated with the ALOHA+job-exposure matrix (JEM). Airway obstruction was defined as FEV1/FVC below the lower limit of normal. Logistic regression analysis adjusted for baseline covariates was used to investigate the associations.

RESULTS

At follow-up, 1888 (6.0%), 1495 (4.7%), 710 (2.5%) and 508 (4.5%) subjects had developed chronic cough, chronic phlegm, chronic bronchitis and airway obstruction, respectively. High exposure to biological dust was associated with a higher odds to develop chronic cough and chronic bronchitis. High exposure to pesticides was associated with a higher odds for the development of all respiratory symptoms and airway obstruction. In the multiple exposures analyses, only the association between pesticides exposure and respiratory symptoms remained.

CONCLUSIONS

Subjects exposed to high pesticides had a higher odds to develop respiratory symptoms on average 4.5 years later. Control measures should be taken to reduce pesticides exposure among the working population to prevent respiratory symptoms and airway obstruction.

Chronic productive cough and inhalant occupational exposure-a study of the general population

PURPOSE

Occupational inhalant exposures have been linked with a higher occurrence of chronic productive cough, but recent studies question the association.

METHODS

We included participants from two general population studies, the Copenhagen City General Population Study and the Copenhagen City Heart Study, to assess contemporary (year 2003-2017) and historical (1976-1983) occupational inhalant hazards. Job titles one year prior to study inclusion and an airborne chemical job-exposure matrix (ACE JEM) were used to estimate occupational exposure. The association between occupational exposures and self-reported chronic productive cough was studied using generalized estimating equations stratified by smoking status and cohort.

RESULTS

The population consisted of 5210 working individuals aged 20-65 from 1976 to 1983 and 64,279 from 2003 to 2017. In smokers, exposure to high levels of mineral dust, biological dust, gases & fumes and the composite variable vapours, gases, dusts or fumes (VGDF) were associated with chronic productive cough in both cohorts with odds ratios in the range of 1.2 (95% confidence interval, 1.0;1.4) to 1.6 (1.2;2.1). High levels of biological dust were only associated with an increased risk of a chronic productive cough in the 2003-2017 cohort (OR 1.5 (1.1;2.0)). In non-smokers, high levels of VGDF (OR 1.5 (1.0;2.3)) and low levels of mineral dust (OR 1.7 (1.1;2.4)) were associated with chronic productive cough in the 1976-1983 cohort, while no associations were seen in non-smokers in the 2003-2017 cohort.

CONCLUSION

Occupational inhalant exposure remains associated with a modestly increased risk of a chronic productive cough in smokers, despite declining exposure levels during the past four decades.

A 2019 Update on Occupational Lung Diseases: A Narrative Review

Occupational lung diseases (OLDs) are caused, aggravated or exacerbated by exposures at the workplace. OLDs encompass a wide range of respiratory diseases similar to that found outside the work environment. Occupational asthma is the most commonly diagnosed OLD. Other OLDs may include acute and chronic conditions, ranging from hypersensitivity pneumonitis to chronic obstructive pulmonary disease (COPD) to pulmonary fibrosis. Historically, research into OLDs has centered on diseases resulting from exposures relevant to high-income countries and more obvious hazardous occupations, such as silicosis in coal miners. Peer-reviewed publications in 2019 have broadened the focus to include low- and middle-income countries and once-overlooked occupations such as dry cleaning and animal husbandry. Technological advances and greater understanding of disease etiology have allowed researchers and clinicians to implement improved risk analysis, screening and mitigation strategies to not only treat disease once it occurs, but to identify at-risk populations and institute protections to prevent or limit the negative impacts of workplace hazards. As recognition of OLDs as a worldwide threat in a variety of occupations increases, research is allowing for the development of better treatments and preventive measures that advance workers’ rights and ensure their continued good health.

Association of birthplace and occupational exposures with chronic bronchitis in US Hispanics/Latinos, 2008-2011

OBJECTIVES

In the US, chronic bronchitis (CB) is common and is associated with substantial morbidity and mortality. Data on CB in the Hispanic/Latino population-a large, diverse US minority-are scarce. We aimed to test whether the prevalence of CB varies across Hispanic/Latino heritages and to identify CB risk factors, including occupational exposures, in this population.

METHODS

We analysed data from the Hispanic Community Health Study/Study of Latinos, a US population-based probability sample of participants aged 18-74 years (n=16 415) including those with Mexican, Puerto Rican, Dominican, Cuban, Central American and South American heritages. Participants who had a completed respiratory questionnaire and valid spirometric data were included in the analysis (n=13 259). CB, place of birth, heritage, occupational exposures and other risk factors were based on standardised questionnaires. The prevalence of CB was estimated using survey logistic regression-conditional marginal analysis.

RESULTS

The estimated (mean (95% CI)) overall adjusted prevalence of CB was 12.1% (9.3 to 15.6), with a large variation across heritages. Dominican heritage had a fivefold higher prevalence than South American heritage. US-born participants had a higher adjusted prevalence than their non-US-born counterparts (16.8% (12.5 to 22.1) vs 11.0% (8.5 to 14.10); p=0.022). Compared with non-exposed participants, those exposed to cleaning or disinfecting solutions had a higher adjusted prevalence of CB (12.6% (9.1 to 17.1) vs 11.8% (9.2 to 15.1); p=0.024).

CONCLUSIONS

The prevalence of CB was higher among Dominicans than other Hispanic/Latino heritages. CB was more prevalent among US-born participants and those exposed to cleaning and disinfecting solutions.

Atopy Modifies the Association Between Inhaled Corticosteroid Use and Lung Function Decline in Patients with Asthma

BACKGROUND

Inhaled corticosteroids (ICSs) are the mainstay of asthma treatment, but response to medication is variable. Patients with allergic inflammation generally show a better short-term response to ICSs; however, studies on predictors of long-term response are few.

OBJECTIVE

To assess whether allergic sensitization can modify the association between ICS use and lung function decline over 20 years in adult asthma.

METHODS

We used data from the 3 clinical examinations of the European Community Respiratory Health Survey. We measured ICS use (no use, and use for <1.3, 1.3-8, and >8 years) and FEV₁ decline among subjects with asthma over the 2 periods between consecutive examinations. We conducted a cohort study combining data of the 2 periods (906 observations from 745 subjects) to assess whether the association between ICS use and FEV₁ decline was modified by allergic sensitization (IgE > 0.35 kU/L for any of house-dust mite, timothy grass, cat, or Cladosporium).

RESULTS

FEV₁ decline was similar for non-ICS users, as well as ICS users for less than 1.3 years, with and without allergic sensitization. However, among subjects on ICSs for a longer period, sensitization was associated with an attenuated decline (P_interaction = .006): in the group treated for more than 8 years, FEV₁ decline was on average 27 mL/y (95% CI_{Bonferroni-adjusted}, 11-42) lower for subjects with sensitization compared with nonsensitized subjects.

CONCLUSIONS

Our study suggests that biomarkers of atopy can predict a more favorable long-term response to ICSs. Randomized controlled studies are needed to confirm these findings.

Environmental triggers for chronic cough

Cough is a physiological defense reflex for protecting the airways from aspiration and irritation. Thus, roles of environmental triggers are postulated in the pathogenesis of chronic cough. There are several lines of epidemiological evidence demonstrating the relationships between environmental irritant and pollutant exposure and chronic cough. However, positive findings from cross-sectional studies just reflect the protective nature of cough but may not properly address the true impact of environmental triggers. If harmful inhalation is repeated, cough may be seen as chronic but indeed is protective in nature. Therefore, long-term residual outcomes would be the key for understanding the effects of environmental triggers on chronic cough. The present review aims to summarize the associations between chronic cough and environmental pollutants or irritant exposure, with a focus on the long-term residual effects of (1) chronic persistent exposure and (2) acute high-intensity exposure on chronic cough, and also to examine (3) whether childhood irritant/pollutant exposure may increase the risk of chronic cough in adulthood.