Effect of occupational exposures on decline of lung function in early chronic obstructive pulmonary disease

Effects of occupational exposure to dust, gas, vapor and fumes on chronic bronchitis and lung function

Background

Chronic obstructive pulmonary disease (COPD) is one of the leading causes of mortality worldwide, and therefore the identification of the modifiable risk factors [such as exposure to vapors, gases, dust and fumes (VGDF)] for accelerate disease progression has important significance.

Methods

We conducted COPD surveillance in six cities of southern China between 2014 and 2019. We recorded the diagnosis of chronic bronchitis, respiratory symptoms, occupational exposure to VGDF and other covariates by using a structured questionnaire. Logistic regression and multivariate linear regression model were adopted for analysis. We performed sensitivity analyses based on two methods of propensity score (PS) methods to evaluate the robustness of our results.

Results

A total of 7,418 participants were included. Cough [odds ratios (ORs): 1.60, 95% confidence interval (CI): 1.22 to 2.08] and phlegm (OR: 1.49, 95% CI: 1.19 to 1.85) correlated significantly with exposure to dust. There was an increased risk of cough (OR: 1.53, 95% CI: 1.11 to 2.07) for occupational exposure to gas/vapor/fume. Dual exposure to dust and gas/vapor/fume was associated with a significantly increased risk of chronic bronchitis (OR: 1.74, 95% CI: 1.20 to 2.52), cough (OR: 1.43, 95% CI: 1.15 to 1.79) and phlegm (OR: 1.49, 95% CI: 1.24 to 1.79). In 5,249 participants with complete data of spirometry, gas/vapor/fume was associated with a decreased ratio of forced expiratory volume in one second and forced vital capacity (FEV1/FVC) (β: -1.05, 95% CI: -1.85 to -0.26) and maximal mid-expiratory flow (MMEF) (β: -0.15, 95% CI: -0.23 to -0.07). Dual exposure to dust and gas/vapor/fume was significantly associated with decreased FEV1/FVC (β: -0.74, 95% CI: -1.28 to -0.20) and MMEF (β: -0.06, 95% CI: -0.12 to -0.01). Results of sensitivity analysis were not materially changed.

Conclusions

VGDF exposure is associated with chronic bronchitis, respiratory symptoms and decreased lung function, suggesting that VGDF contributes to the pathogenesis and progression of COPD.

Bronchoalveolar Lavage Fluid from Chronic Obstructive Pulmonary Disease Patients Increases Neutrophil Chemotaxis Measured by a Microfluidic Platform

Chronic obstructive pulmonary disease (COPD) is a persistent and progressive respiratory disorder characterized by expiratory airflow limitation caused by chronic inflammation. Evidence has shown that COPD is correlated with neutrophil chemotaxis towards the airways, resulting in neutrophilic airway inflammation. This study aimed to evaluate neutrophil chemotaxis in bronchoalveolar lavage fluid (BALF) from COPD patients using a high-throughput nine-unit microfluidic platform and explore the possible correlations between neutrophil migratory dynamics and COPD development. The results showed that BALF from COPD patients induced stronger neutrophil chemotaxis than the Control BALF. Our results also showed that the chemotactic migration of neutrophils isolated from the blood of COPD patients was not significantly different from neutrophils from healthy controls, and neutrophil migration in three known chemoattractants (fMLP, IL-8, and LTB4) was not affected by glucocorticoid treatment. Moreover, comparison with clinical data showed a trend of a negative relationship between neutrophil migration chemotactic index (C. I.) in COPD BALF and patient's spirometry data, suggesting a potential correlation between neutrophil migration and the severity of COPD. The present study demonstrated the feasibility of using the microfluidic platform to assess neutrophil chemotaxis in COPD pathogenesis, and it may serve as a potential marker for COPD evaluation in the future.

Awareness of Chronic Obstructive Pulmonary Disease and Its Risk Factors Among the Adult Population of the Qassim Region, Saudi Arabia

BACKGROUND

Epidemiological studies are crucial in appraising the occurrence of chronic obstructive pulmonary disease (COPD) in a specific region, establishing benchmarks, and devising effective preventive measures. It is against this background that the study aims to evaluate adult awareness of COPD and its risk factors among adults in the Qassim Region, Saudi Arabia.

METHOD

This observational cross-sectional study was conducted in the Qassim Region and involved consenting adults who voluntarily participated. Between 20 May and 4 June 2023, a self-administered online survey was distributed through social media platforms, utilizing an anonymous, self-explanatory questionnaire to evaluate participants' awareness of COPD.

RESULTS

In our study, a total of 1,306 participants were enrolled, of which 27.6% (n=360) reported having ever heard of COPD. Among all respondents, 21.3% (n=278) stated that they study or work in medical-related fields, and out of them, 60.4% (n=168) had prior awareness of COPD. Upon excluding participants associated with medical-related fields, the overall awareness level decreased to 18.7%. The majority of respondents fell within the age range of 18 to 29 years, of whom 34.5% had ever heard of COPD. Regarding smoking habits, the majority were cigarette smokers (38.4%), and of all cigarette smokers, 22.4% had heard of COPD. The second highest proportion of smokers (35.8%) were electronic smokers, and among them, 24.1% were aware of COPD. The lowest proportion of smokers (25.8%) were shisha smokers, with 25.6% of them having heard of COPD. Among the 1,306 respondents, only 27.5% (n=360) had ever heard of COPD. When asked about the organ affected by COPD, 81% (n=292) of those who were aware of the condition correctly responded that it affects the lungs. On the other hand, 8.9% (n=32) incorrectly selected "heart" as the affected organ, while 2.5% (n=9) chose "I don't know," and none selected "throat."

CONCLUSION

The Qassim Region in Saudi Arabia exhibits a reduced level of COPD awareness among the general population. It is imperative to urgently address this situation and enhance awareness for improved COPD diagnosis and treatment. Considering the region's high prevalence of COPD and associated risk factors, it becomes vital to strengthen educational curricula and integrate COPD awareness into public forums and awareness campaigns. Moreover, conducting additional national research would be instrumental in assisting policymakers in developing effective preventive and therapeutic strategies.

The association of forced expiratory volume in one second with occupational exposures in a longitudinal study of adults in a rural community in Iowa

PURPOSE

The Keokuk County Rural Health Study (KCRHS) is a longitudinal population-based study conducted in rural Iowa. A prior analysis of enrollment data identified an association of airflow obstruction with occupational exposures only among cigarette smokers. The current study used spirometry data from all three rounds to investigate whether level of forced expiratory volume in one second (FEV1) and longitudinal change in FEV1 were associated with occupational vapor-gas, dust, and fumes (VGDF) exposures, and whether these associations were modified by smoking.

METHODS

This study sample comprised 1071 adult KCRHS participants with longitudinal data. A job-exposure matrix (JEM) was applied to participants' lifetime work histories to assign exposures to occupational VGDF. Mixed regression models of pre-bronchodilator FEV1 (millimeters, ml) were fit to test for associations with occupational exposures while adjusting for potential confounders.

RESULTS

Mineral dust had the most consistent association with change in FEV1, including ever/never ( - 6.3 ml/year) and nearly every level of duration, intensity, and cumulative exposure. Because 92% of participants with mineral dust also had organic dust exposure, the results for mineral dust may be due to a combination of the two. An association of FEV1 level with fumes was observed for high intensity ( - 91.4 ml) among all participants, and limited to cigarette smokers with results of  - 104.6 ml ever/never exposed,  - 170.3 ml high duration, and  - 172.4 ml high cumulative.

CONCLUSION

The current findings suggest that mineral dust, possibly in combination with organic dust, and fumes exposure, especially among cigarette smokers, were risk factors for adverse FEV1 results.

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.

Ever and cumulative occupational exposure and lung function decline in longitudinal population-based studies: a systematic review and meta-analysis

OBJECTIVES

Adverse occupational exposures can accelerate age-related lung function decline. Some longitudinal population-based studies have investigated this association. This study aims to examine this association using findings reported by longitudinal population-based studies.

METHODS

Ovid Medline, PubMed, Embase, and Web of Science were searched using keywords and text words related to occupational exposures and lung function and 12 longitudinal population-based studies were identified using predefined inclusion criteria. The quality of the studies was assessed using the Newcastle-Ottawa Scale. Lung function decline was defined as annual loss of forced expiratory volume in 1 s (FEV₁), forced vital capacity (FVC) or the ratio (FEV₁/FVC). Fixed and random-effects meta-analyses were conducted to calculate pooled estimates for ever and cumulative exposures. Heterogeneity was assessed using the I² test, and publication bias was evaluated using funnel plots.

RESULTS

Ever exposures to gases/fumes, vapours, gases, dusts, fumes (VGDF) and aromatic solvents were significantly associated with FEV₁ decline in meta-analyses. Cumulative exposures for these three occupational agents observed a similar trend of FEV₁ decline. Ever exposures to fungicides and cumulative exposures to biological dust, fungicides and insecticides were associated with FEV₁ decline in fixed-effect models only. No statistically significant association was observed between mineral dust, herbicides and metals and FEV₁ decline in meta-analyses.

CONCLUSION

Pooled estimates from the longitudinal population-based studies have provided evidence that occupational exposures are associated with FEV₁ decline. Specific exposure control and respiratory health surveillance are required to protect the lung health of the workers.

Impact of Previous Occupational Exposure on Outcomes of Chronic Obstructive Pulmonary Disease

Occupational exposures have been regarded as a risk factor for the development of chronic obstructive pulmonary disease (COPD). However, there is little knowledge regarding the effect of occupational exposure on the treatment outcomes of COPD. Therefore, the aim of this study was to evaluate the question of whether occupational exposure can have a potential impact on COPD outcomes. Methods: Information regarding self-reported occupational exposure for 312 patients with COPD from the Korean Obstructive Lung Disease (KOLD) Cohort were included. A comparison of the rate of acute exacerbation, annual lung function change, and quality of life according to the presence or absence of occupational exposure was performed. Results: Seventy-six patients (24.4%) had experienced occupational exposure; chemical materials were most common. At enrollment, a higher COPD-specific version of the St. George Respiratory Questionnaire total score (39.7 ± 18.8 vs. 33.1 ± 17.6, p = 0.005) and a higher exacerbation history in the past year (30.3% vs. 17.5%, p = 0.017) were observed for patients with occupational exposure compared to those without occupational exposure. Furthermore, in the follow-up period, after adjusting for potential confounders, a higher frequency of acute exacerbation (odd ratio, 1.418; 95% confidence interval, 1.027–1.956; p = 0.033) and a more rapid decline in forced expiratory volume in 1 s (p = 0.009) was observed for COPD patients with occupational exposure compared to those without occupational exposure. Conclusions: In the KOLD cohort, worse outcomes in terms of exacerbation rate and change in lung function were observed for COPD patients with occupational exposure compared to those without occupational exposure. These findings suggest that occupational exposure not only is a risk factor for COPD but also might have a prognostic impact on COPD.

Occupational COPD-The most under-recognized occupational lung disease?

Chronic obstructive pulmonary disease (COPD) is caused by exposure to noxious particles and gases. Smoking is the main risk factor, but other factors are also associated with COPD. Occupational exposure to vapours, gases, dusts and fumes contributes to the development and progression of COPD, accounting for a population attributable fraction of 14%. Workplace pollutants, in particular inorganic dust, can initiate airway damage and inflammation, which are the hallmarks of COPD pathogenesis. Occupational COPD is still underdiagnosed, mainly due to the challenges of assessing the occupational component of the disease in clinical settings, especially if other risk factors are present. There is a need for specific education and training for clinicians, and research with a focus on evaluating the role of occupational exposure in causing COPD. Early diagnosis and identification of occupational causes is very important to prevent further decline in lung function and to reduce the health and socio-economic burden of COPD. Establishing details of the occupational history by general practitioners or respiratory physicians could help to define the occupational burden of COPD for individual patients, providing the first useful interventions (smoking cessation, best therapeutic management, etc.). Once patients are diagnosed with occupational COPD, there is a wide international variation in access to specialist occupational medicine and public health services, along with limitations in workplace and income support. Therefore, a strong collaboration between primary care physicians, respiratory physicians and occupational medicine specialists is desirable to help manage COPD patients' health and social issues.

Chronic Obstructive Pulmonary Disease and U.S. Workers: Prevalence, Trends, and Attributable Cases Associated With Work

INTRODUCTION

Chronic obstructive pulmonary disease is the fourth leading cause of death in the U.S. Workplace exposures are important modifiable contributors to the burden of chronic obstructive pulmonary disease. Among U.S. workers, 19% of chronic obstructive pulmonary disease cases are attributable to workplace exposures. This study examines the trends in chronic obstructive pulmonary disease prevalence during 2012-2018 among workers and assesses the population attributable fraction for chronic obstructive pulmonary disease associated with work by smoking status, industry, and occupation.

METHODS

The 2012-2018 National Health Interview Survey data for workers aged ≥18 years employed during the 12 months before the interview were analyzed in 2019. Annual trends were examined using the Poisson regression model. Multivariate logistic regression was used to calculate adjusted prevalence ORs.

RESULTS

During 2012-2018, an estimated age-adjusted annual average of 4.1% of workers had chronic obstructive pulmonary disease, and prevalence varied by industry and occupation. Overall, chronic obstructive pulmonary disease prevalence increased by an estimated annual average of 1.5% (p<0.05). The prevalence trends increased significantly among workers in the merchant wholesale nondurable and the arts, entertainment, and recreation industries and among financial specialists; supervisors, other food services workers; supervisors, building grounds workers, and maintenance workers; personal care and services workers; supervisors and office and administrative support workers; and motor-vehicle operators and material moving workers. The proportion of chronic obstructive pulmonary disease cases attributable to work was 27.3% among all workers and 24.0% among never smokers.

CONCLUSIONS

Public health efforts to increase the awareness and understanding of chronic obstructive pulmonary disease associated with occupational risk factors are needed to prevent chronic obstructive pulmonary disease among workers, especially among those employed in industries and occupations with increasing prevalence trends.

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.

Occupation, socioeconomic status and chronic obstructive respiratory diseases - The EpiLung study in Finland, Estonia and Sweden

OBJECTIVE

To study occupational groups and occupational exposure in association with chronic obstructive respiratory diseases.

METHODS

In early 2000s, structured interviews on chronic respiratory diseases and measurements of lung function as well as fractional expiratory nitric oxide (F_ENO) were performed in adult random population samples of Finland, Sweden and Estonia. Occupations were categorized according to three classification systems. Occupational exposure to vapours, gases, dusts and fumes (VGDF) was assessed by a Job-Exposure Matrix (JEM). The data from the countries were combined.

RESULTS

COPD, smoking and occupational exposure were most common in Estonia, while asthma and occupations requiring higher educational levels in Sweden and Finland. In an adjusted regression model, non-manual workers had a three-fold risk for physician-diagnosed asthma (OR 3.18, 95%CI 1.07-9.47) compared to professionals and executives, and the risk was two-fold for healthcare & social workers (OR 2.28, 95%CI 1.14-4.59) compared to administration and sales. An increased risk for physician-diagnosed COPD was seen in manual workers, regardless of classification system, but in contrast to asthma, the risk was mostly explained by smoking and less by occupational exposure to VGDF. For F_ENO, no associations with occupation were observed.

CONCLUSIONS

In this multicenter study from Finland, Sweden and Estonia, COPD was consistently associated with manual occupations with high smoking prevalence, highlighting the need to control for tobacco smoking in studies on occupational associations. In contrast, asthma tended to associate with non-manual occupations requiring higher educational levels. The occupational associations with asthma were not driven by eosinophilic inflammation presented by increased F_ENO.

Insights from Twitter About Public Perceptions of Asthma, COPD, and Exposures

OBJECTIVE

The aim of this study was to analyze tweets concerning asthma and chronic obstructive pulmonary disease (COPD).

METHODS

Approximately 40,000 tweets containing asthma or COPD were analyzed. Lexical analysis ranked terms and domains of interest, compared COPD with asthma tweets, evaluated co-occurrence of terms within tweets, and assessed differences by source (personal, institutional, or retweet). The frequency of indicator terms relevant to occupational health was determined.

RESULTS

Many tweets address community pollution and effects on children, but there is much less interest in work-related factors and occupational regulatory agencies. Environment is considered much more relevant for asthma than COPD.

CONCLUSION

Although epidemiologic studies demonstrate a major burden of occupational factors upon both diseases, significantly improved outreach is needed to overcome inadequate public interest. Social media represent a valuable resource for assessing perceptions about work-related disease and potentially discovering new associations.

Diagnosis and Treatment of Early Chronic Obstructive Lung Disease (COPD)

Chronic obstructive lung disease (COPD) is responsible for substantial rates of mortality and economic burden, and is one of the most important public-health concerns. As the disease characteristics include irreversible airway obstruction and progressive lung function decline, there has been a great deal of interest in detection at the early stages of COPD during the “at risk” or undiagnosed preclinical stage to prevent the disease from progressing to the overt stage. Previous studies have used various definitions of early COPD, and the term mild COPD has also often been used. There has been a great deal of recent effort to establish a definition of early COPD, but comprehensive evaluation is still required, including identification of risk factors, various physiological and radiological tests, and clinical manifestations for diagnosis of early COPD, considering the heterogeneity of the disease. The treatment of early COPD should be considered from the perspective of prevention of disease progression and management of clinical deterioration. There has been a lack of studies on this topic as the definition of early COPD has been proposed only recently, and therefore further clinical studies are needed.

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.

Early COPD: current evidence for diagnosis and management

Chronic obstructive pulmonary disease (COPD) affects one-tenth of the world's population and has been identified as a major global unmet health need by the World Health Organisation, which predicts that within 10 years, COPD will become the third leading cause of death. Despite active research, there have been no recent major strides in terms of disease modifying treatment for COPD; smoking cessation remains the only intervention known to alter disease progression and improve mortality. As established COPD is a key driver of disease burden, earlier diagnosis coupled with disease-modifying intervention carries promise as a route to address this global health priority. The concept of early COPD is emerging as an area of focus for research and consideration of new treatment modalities, as it has been hypothesised that intervention at this stage may potentially halt or reverse the disease process. However, at present, a globally accepted criteria for defining early COPD does not exist. Several studies propose small airways disease as the earliest stage in the development of COPD, and this has been demonstrated to be a precursor to development of emphysema and to correlate with subsequent development of airflow obstruction. However, treatment strategies for early disease, which pre-date the development of airflow obstruction, remain uncertain. This review addresses the rationale and current evidence base for the diagnosis and treatment of early COPD and highlights the challenges of implementing trials and clinical pathways to address COPD earlier in the life course, particularly in the absence of a universally accepted definition of COPD.The reviews of this paper are available via the supplemental material section.

Association of air pollutants, airborne occupational exposures, and chronic rhinosinusitis disease severity

BACKGROUND

Previous work has shown that chronic rhinosinusitis (CRS) severity may be associated with particulate matter 2.5 (PM_2.5 ) and black carbon (BC) in CRS patients without nasal polyps (CRSsNP). Data regarding occupational exposures, however, are lacking. We assessed the impact of PM_2.5 , BC, as well as occupational airborne exposure on CRS disease severity.

METHODS

Patients with CRS with nasal polyps (CRSwNP), CRSsNP, and aspirin-exacerbated respiratory disease (AERD) were identified from an institutionwide database. Spatial modeling from 37 pollutant monitoring sites in Allegheny County was used to estimate exposures. Patient occupations using the 2010 Standard Occupation Classification (SOC10) and airborne occupation exposures to vapors, gases, dusts, fumes, fibers and mists (VGDFFiM) or diesel fumes were recorded. Disease severity was measured by modified Lund-Mackay score (LMS), systemic corticosteroid therapy, and incidence of functional endoscopic sinus surgery (FESS).

RESULTS

Two hundred thirty-four patients were included (CRSwNP, n = 113; CRSsNP, n = 96; AERD, n = 25). The prevalence of AERD among those with CRSwNP was 18%. Patients exposed to VGDFFiM or diesel fumes required higher steroid doses vs nonexposed patients (p = 0.015 and p = 0.03, respectively); patients with VGDFFiM levels >5% were more likely to undergo FESS vs nonexposed patients (p = 0.0378). There was no difference in PM_2.5 and BC with regard to disease severity and FESS between CRSwNP, CRSsNP, and AERD patients. Steroid use was significantly higher in CRSwNP and AERD vs CRSsNP (p = 0.001). LMS was significantly higher in AERD as compared with CRSwNP and CRSsNP (p = 0.001).

CONCLUSION

Occupational airborne exposure to VGDFFiM correlated with increased prevalence of FESS and need for corticosteroids in CRS patients. There was no difference in PM_2.5 and BC levels and disease severity outcome measures between CRS subtypes in this subset.

Occupational exposure to solvents and lung function decline: A population based study

RATIONALE

While cross-sectional studies have shown associations between certain occupational exposures and lower levels of lung function, there was little evidence from population-based studies with repeated lung function measurements.

OBJECTIVES

We aimed to investigate the associations between occupational exposures and longitudinal lung function decline in the population-based Tasmanian Longitudinal Health Study.

METHODS

Lung function decline between ages 45 years and 50 years was assessed using data from 767 participants. Using lifetime work history calendars completed at age 45 years, exposures were assigned according to the ALOHA plus Job Exposure Matrix. Occupational exposures were defined as ever exposed and cumulative exposure -unit- years. We investigated effect modification by sex, smoking and asthma status.

RESULTS

Compared with those without exposure, ever exposures to aromatic solvents and metals were associated with a greater decline in FEV₁ (aromatic solvents 15.5 mL/year (95% CI -24.8 to 6.3); metals 11.3 mL/year (95% CI -21.9 to - 0.7)) and FVC (aromatic solvents 14.1 mL/year 95% CI -28.8 to - 0.7; metals 17.5 mL/year (95% CI -34.3 to - 0.8)). Cumulative exposure (unit years) to aromatic solvents was also associated with greater decline in FEV₁ and FVC. Women had lower cumulative exposure years to aromatic solvents than men (mean (SD) 9.6 (15.5) vs 16.6 (14.6)), but greater lung function decline than men. We also found association between ever exposures to gases/fumes or mineral dust and greater decline in lung function.

CONCLUSIONS

Exposures to aromatic solvents and metals were associated with greater lung function decline. The effect of aromatic solvents was strongest in women. Preventive strategies should be implemented to reduce these exposures in the workplace.

Occupational Exposures and Computed Tomographic Imaging Characteristics in the SPIROMICS Cohort

RATIONALE

Quantitative computed tomographic (CT) imaging can aid in chronic obstructive pulmonary disease (COPD) phenotyping. Few studies have identified whether occupational exposures are associated with distinct CT imaging characteristics.

OBJECTIVES

To examine the association between occupational exposures and CT-measured patterns of disease in the SPIROMICS (Subpopulations and Intermediate Outcome Measures in COPD Study).

METHODS

Participants underwent whole-lung multidetector helical CT at full inspiration and expiration. The association between occupational exposures (self-report of exposure to vapors, gas, dust, or fumes [VGDF] at the longest job) and CT metrics of emphysema (percentage of total voxels < -950 Hounsfield units at total lung capacity), large airways (wall area percent [WAP] and square-root wall area of a single hypothetical airway with an internal perimeter of 10 mm [Pi10]), and small airways (percent air trapping [percent total voxels < -856 Hounsfield units at residual volume] and parametric response mapping of functional small-airway abnormality [PRM fSAD]) were explored by multivariate linear regression, and for central airway measures by generalized estimating equations to account for multiple measurements per individual. Models were adjusted for age, sex, race, current smoking status, pack-years of smoking, body mass index, and site. Airway measurements were additionally adjusted for total lung volume.

RESULTS

A total of 2,736 participants with available occupational exposure data (n = 927 without airflow obstruction and 1,809 with COPD) were included. The mean age was 64 years, 78% were white, and 54% were male. Forty percent reported current smoking, and mean (SD) pack-years was 49.3 (26.9). Mean (SD) post-bronchodilator forced expiratory volume in 1 second (FEV1) was 73 (27) % predicted. Forty-nine percent reported VGDF exposure. VGDF exposure was associated with higher emphysema (β = 1.17; 95% confidence interval [CI], 0.44-1.89), greater large-airway disease as measured by WAP (segmental β = 0.487 [95% CI, 0.320-0.654]; subsegmental β = 0.400 [95% CI, 0.275-0.527]) and Pi10 (β = 0.008; 95% CI, 0.002-0.014), and greater small-airway disease was measured by air trapping (β = 2.60; 95% CI, 1.11-4.09) and was nominally associated with an increase in PRM fSAD (β = 1.45; 95% CI, 0.31-2.60). These findings correspond to higher odds of percent emphysema, WAP, and air trapping above the 95th percentile of measurements in nonsmoking control subjects in individuals reporting VGDF exposure.

CONCLUSIONS

In an analysis of SPIROMICS participants, we found that VGDF exposure in the longest job was associated with an increase in emphysema, and in large- and small-airway disease, as measured by quantitative CT imaging.

An Official American Thoracic Society Workshop Report: Presentations and Discussion of the Sixth Jack Pepys Workshop on Asthma in the Workplace

The Sixth Jack Pepys Workshop on Asthma in the Workplace focused on six key themes regarding the recognition and assessment of work-related asthma and airway diseases: (1) cleaning agents and disinfectants (including in swimming pools) as irritants and sensitizers: how to evaluate types of bronchial reactions and reduce risks; (2) population-based studies of occupational obstructive diseases: use of databanks, advantages and pitfalls, what strategies to deal with biases and confounding?; (3) damp environments, dilapidated buildings, recycling processes, and molds, an increasing problem: mechanisms, how to assess causality and diagnosis; (4) diagnosis of occupational asthma and rhinitis: how useful are recombinant allergens (component-resolved diagnosis), metabolomics, and other new tests?; (5) how does exposure to gas, dust, and fumes enhance sensitization and asthma?; and (6) how to determine probability of occupational causality in chronic obstructive pulmonary disease: epidemiological and clinical, confirmation, and compensation aspects. A summary of the presentations and discussion is provided in this proceedings document. Increased knowledge has been gained in each topic over the past few years, but there remain aspects of controversy and uncertainty requiring further research.

Occupational airborne exposure in relation to Chronic Obstructive Pulmonary Disease (COPD) and lung function in individuals without childhood wheezing illness: A 50-year cohort study

BACKGROUND

Evidence from longitudinal population-based studies relating occupational exposure to the full range of different forms of airborne pollutants and lung function and airway obstruction is limited.

OBJECTIVE

To relate self-reported COPD and lung function impairment to occupational exposure to different forms of airborne chemical pollutants in individuals who did not have childhood wheeze.

METHODS

A prospective cohort study was randomly selected in 1964 at age 10-15 years and followed up in 1989, 1995, 2001 and 2014 (aged 58-64) by spirometry and respiratory questionnaire. Occupational histories were recorded in 2014 and occupational exposures assigned using an airborne chemical job exposure matrix. The risk of COPD and lung function impairment was analyzed in subjects, who did not have childhood wheeze, using logistic and linear regression and linear mixed effects models.

RESULTS

237 subjects without childhood wheeze (mean age 60.6 years, 47% male) were analyzed. There was no association between any respiratory outcomes and exposure to gases, fibers, mists or mineral dusts and no consistent associations with exposure to fumes. Reduced FEV₁ was associated with longer duration (years) of exposure to any of the six main pollutant forms - vapors, gases, dusts, fumes, fibers and mists (VGDFFiM) with evidence of a dose-response relationship (p-trend=0.004). Exposure to biological dusts was associated with self-reported COPD and FEV₁<Lower Limit of Normal (LLN) (adjusted odds ratio [95%CI] 4.59 [1.15,18.32] and 3.54 [1.21,10.35] respectively), and reduced FEF_25-75% (adjusted regression coefficients [95% CIs] -9.11 [-17.38, -0.84] respectively). Exposure to vapors was associated with self-reported COPD and FEV₁<LLN (adjOR 6.46 [1.18,35.37] and 4.82 [1.32,17.63]). Longitudinal analysis demonstrated reduced FEV₁ and FEF_25-75% associated with exposure to biological dusts or vapors.

CONCLUSIONS

People with no history of childhood wheezing who have been occupationally exposed to biological dusts or vapors or had longer duration of lifetime exposure to any VGDFFiM are at a higher risk of reduced lung function at age 58-64 years. Occupational exposure to biological dusts or vapors also increased the risk of self-reported COPD.

Occupational chronic obstructive pulmonary disease: a standard of care

BACKGROUND

Consistent evidence from population studies report that 10-15% of the total burden of chronic obstructive pulmonary disease (COPD) is associated with workplace exposures. This proportion of COPD could be eliminated if harmful workplace exposures were controlled adequately.

AIMS

To produce a standard of care for clinicians, occupational health professionals, employers and employees on the identification and management of occupational COPD.

METHODS

A systematic literature review was used to identify published data on the prevention, identification and management of occupational COPD. Scottish Intercollegiate Guidance Network grading and the Royal College of General Practitioner three star grading system were used to grade the evidence.

RESULTS

There are a number of specific workplace exposures that are established causes of COPD. Taking an occupational history in patients or workers with possible or established COPD will identify these. Reduction in exposure to vapours, gases, dusts and fumes at work is likely to be the most effective method for reducing occupational COPD. Identification of workers with rapidly declining lung function, irrespective of their specific exposure, is important. Individuals can be identified at work by accurate annual measures of lung function.

CONCLUSIONS

Early identification of cases with COPD is important so that causality can be considered and action taken to reduce causative exposures thereby preventing further harm to the individual and other workers who may be similarly exposed. This can be achieved using a combination of a respiratory questionnaire, accurate lung function measurements and control of exposures in the workplace.

Lymphocyte Kv1.3-channels in the pathogenesis of chronic obstructive pulmonary disease: novel therapeutic implications of targeting the channels by commonly used drugs

In patients with chronic obstructive pulmonary disease (COPD), over-activated T-lymphocytes produce pro-inflammatory cytokines and proliferate in situ in the lower airways and pulmonary parenchyma, contributing substantially to the pathogenesis of the disease. Despite our understanding of the molecular mechanisms by which lymphocytes are activated, we know little about the physiological mechanisms. T-lymphocytes predominantly express delayed rectifier K⁺-channels (Kv1.3) in their plasma membranes and these channels play crucial roles in inducing the lymphocyte activation and proliferation. In the pathogenesis of chronic inflammatory diseases, such as chronic kidney disease (CKD) or inflammatory bowel disease (IBD), these channels, which are overexpressed in proliferating lymphocytes within the inflamed organs, are responsible for the progression of the diseases. Since the over-activation of cellular immunity is also mainly involved in the pathogenesis of COPD, this disease could share similar pathophysiological features as those of CKD or IBD. From a literature review including ours, it is highly likely that the Kv1.3-channels are overexpressed or over-activated in T-lymphocytes isolated from patients with COPD, and that the overexpression of the channels would contribute to the development or progression of COPD. The involvement of the channels leads to novel therapeutic implications of potentially useful Kv1.3-channel inhibitors, such as calcium channel blockers, macrolide antibiotics, HMG-CoA reductase inhibitors and nonsteroidal anti-inflammatory drugs, in the treatment of COPD.

Occupational exposure to asthmagens and adult onset wheeze and lung function in people who did not have childhood wheeze: A 50-year cohort study

BACKGROUND

There are few prospective studies that relate the development of adult respiratory disease with exposure to occupational asthmagens.

OBJECTIVE

To evaluate the risk of adult onset wheeze (AOW) and obstructive lung function associated with occupational exposures over 50years.

METHODS

A population-based randomly selected cohort of children who had not had asthma or wheezing illness, recruited in 1964 at age 10-15years, was followed-up in 1989, 1995, 2001 and 2014 by spirometry and respiratory questionnaire. Occupational histories were obtained in 2014 and occupational exposures determined with an asthma-specific job exposure matrix. The risk of AOW and lung function impairment was analysed in subjects without childhood wheeze using logistic regression and linear mixed effects models.

RESULTS

All 237 subjects (mean age: 61years, 47% male, 52% ever smoked) who took part in the 2014 follow-up had completed spirometry. Among those who did not have childhood wheeze, spirometry was measured in 93 subjects in 1989, in 312 in 1995 and in 270 subjects in 2001 follow-up. For longitudinal analysis of changes in FEV1 between 1989 and 2014 spirometry records were available on 191 subjects at three time points and on 45 subjects at two time points, with a total number of 663 records. AOW and FEV1<LLN were associated with occupational exposure to food-related asthmagens (adjusted odds ratios (adjORs) 95% CI: 2.7 [1.4, 5.1] and 2.9 [1.1, 7.7]) and biocides/fungicides (adjOR 95% CI: 1.8 [1.1, 3.1] and 3.4 [1.1, 10.8]), with evident dose-response effect (p-trends<0.05). Exposure to food-related asthmagens was also associated with reduced FEV1, FVC and FEF25-75% (adjusted regression coefficients 95% CI: -7.2 [-12.0, -2.4], -6.2 [-10.9, -1.4], and -13.3[-23.4, -3.3]). Exposure to wood dust was independently associated with AOW, obstructive lung function and reduced FEF25-75%. Excess FEV1 decline of 6-8ml/year was observed with occupational exposure to any asthmagen, biocides/fungicides and food-related asthmagens (p<0.05).

CONCLUSIONS

This longitudinal study confirmed previous findings of increased risks of adult onset wheezing illness with occupational exposure to specific asthmagens. A novel finding was the identification of food-related asthmagens and biocides/fungicides as potential new occupational risk factors for lung function impairment in adults without childhood wheeze.

Development of an occupational airborne chemical exposure matrix

BACKGROUND

Population-based studies of the occupational contribution to chronic obstructive pulmonary disease generally rely on self-reported exposures to vapours, gases, dusts and fumes (VGDF), which are susceptible to misclassification.

AIMS

To develop an airborne chemical job exposure matrix (ACE JEM) for use with the UK Standard Occupational Classification (SOC 2000) system.

METHODS

We developed the ACE JEM in stages: (i) agreement of definitions, (ii) a binary assignation of exposed/not exposed to VGDF, fibres or mists (VGDFFiM), for each of the individual 353 SOC codes and (iii) assignation of levels of exposure (L; low, medium and high) and (iv) the proportion of workers (P) likely to be exposed in each code. We then expanded the estimated exposures to include biological dusts, mineral dusts, metals, diesel fumes and asthmagens.

RESULTS

We assigned 186 (53%) of all SOC codes as exposed to at least one category of VGDFFiM, with 23% assigned as having medium or high exposure. We assigned over 68% of all codes as not being exposed to fibres, gases or mists. The most common exposure was to dusts (22% of codes with >50% exposed); 12% of codes were assigned exposure to fibres. We assigned higher percentages of the codes as exposed to diesel fumes (14%) compared with metals (8%).

CONCLUSIONS

We developed an expert-derived JEM, using a strict set of a priori defined rules. The ACE JEM could also be applied to studies to assess risks of diseases where the main route of occupational exposure is via inhalation.

Occupational exposures are associated with worse morbidity in patients with chronic obstructive pulmonary disease

RATIONALE

Links between occupational exposures and morbidity in individuals with established chronic obstructive pulmonary disease (COPD) remain unclear.

OBJECTIVES

To determine the impact of occupational exposures on COPD morbidity.

METHODS

A job exposure matrix (JEM) determined occupational exposure likelihood based on longest job in current/former smokers (n = 1,075) recruited as part of the Subpopulations and Intermediate Outcomes in COPD Study, of whom 721 had established COPD. Bivariate and multivariate linear regression models estimated the association of occupational exposure with COPD, and among those with established disease, the occupational exposure associations with 6-minute-walk distance (6MWD), the Modified Medical Research Council Dyspnea Scale (mMRC), the COPD Assessment Test (CAT), St. George's Respiratory Questionnaire (SGRQ), 12-item Short-Form Physical Component (SF-12), and COPD exacerbations requiring health care utilization, adjusting for demographics, current smoking status, and cumulative pack-years.

MEASUREMENTS AND MAIN RESULTS

An intermediate/high risk of occupational exposure by JEM was found in 38% of participants. In multivariate analysis, those with job exposures had higher odds of COPD (odds ratio, 1.44; 95% confidence interval, 1.04-1.97). Among those with COPD, job exposures were associated with shorter 6MWDs (-26.0 m; P = 0.006); worse scores for mMRC (0.23; P = 0.004), CAT (1.8; P = 0.003), SGRQ (4.5; P = 0.003), and SF-12 Physical (-3.3; P < 0.0001); and greater odds of exacerbation requiring health care utilization (odds ratio, 1.55; P = 0.03).

CONCLUSIONS

Accounting for smoking, occupational exposure was associated with COPD risk and, for those with established disease, shorter walk distance, greater breathlessness, worse quality of life, and increased exacerbation risk. Clinicians should obtain occupational histories from patients with COPD because work-related exposures may influence disease burden.

Association between occupational exposure and lung function, respiratory symptoms, and high-resolution computed tomography imaging in COPDGene

RATIONALE

Although occupational exposure to dust and fumes is considered a risk factor for chronic obstructive pulmonary disease, this determination has been limited by reliance on spirometry alone to assess disease severity in predominantly male populations.

OBJECTIVES

To determine the effect of occupational exposure on lung function, respiratory symptoms, and findings of emphysema and airway wall thickness measured using quantitative computed tomography in men and women.

METHODS

COPDGene is a multicenter study of current and former smokers that underwent standardized volumetric chest computed tomography scans to assess airways, % emphysema, and % gas trapping. Spirometry and a respiratory questionnaire including occupational history were also analyzed in 9,614 subjects (4,496 women). Logistic regression and analysis of covariance was used to assess associations with exposure.

MEASUREMENTS AND MAIN RESULTS

Occupational exposure to both dust and fumes was reported by 47.9% of men and 20.1% of women. Adjusting for age, race, body mass index, education, and current and lifetime smoking, the odds ratios for persons with dust and fume exposures for chronic cough, chronic phlegm, persistent wheeze, and Global Initiative for Chronic Obstructive Lung Disease stages 2 and higher chronic obstructive pulmonary disease were significantly elevated and similar for men (1.83, 1.84, 2.0, 1.61, respectively) and women (1.65, 1.82, 1.98, 1.90, respectively). The % predicted FEV1 was similarly lower in those with exposure in men (70.7 ± 0.8 vs. 76.0 ± 0.9; P < 0.001) and women (70.5 ± 0.8 vs. 77.2 ± 0.8; P < 0.001). Percent emphysema and gas trapping was greater in those exposed to dust and fumes in men and women. In men, but not in women, persons with exposure had a greater mean square root wall area of 10-mm internal perimeter airways.

CONCLUSIONS

Occupational exposure to dust and fumes in men and women is similarly associated with airflow obstruction, respiratory symptoms, more emphysema, and gas trapping in men and women.

Chronic obstructive pulmonary disease hospitalisations and mortality in Victoria: analysis of variations by socioeconomic status

OBJECTIVE

This paper analysed chronic obstructive pulmonary disease (COPD) hospitalisations, unplanned readmissions and deaths in Victoria to identify associations with socioeconomic status (SES).

METHODS

The data was taken from the Victorian Admitted Episodes Dataset, the Victorian Health Information Surveillance System, the Victorian Burden of Disease Study and the Australian Bureau of Statistics' Index of Relative Socioeconomic Disadvantage.

RESULTS

COPD separations have a greater variation by SES than all separations. The average age-standardised separation rate (10.43) for the top percentile Local Government Areas (LGA) was 5.8 times that of the bottom percentile LGAs (1.80). The top percentile group was the lowest SES group (effect size = 0.93). There were significant negative correlations between the age-standardised COPD separation rates and SES across LGAs (r = -0.60) and Regions (r = -0.89). Analysis of readmissions (r = -0.49), mortality data (r = -0.51) and the burden of disease data (r = -0.39) also showed significant inverse associations between COPD and SES.

CONCLUSIONS AND IMPLICATIONS

Victorians living in the most disadvantaged areas have a greater burden from COPD, highlighting a need to prioritise public health services interventions to improve outcomes.

Complete mitochondrial genome sequence of a chronic obstructive pulmonary disease Rattus norvegicus C57CE strain

We sequenced a chronic obstructive pulmonary disease Rattus norvegicus C57CE strain mitochondrial genome for the first time (GenBank Accession No. KM114607). Its mitogenome was 16,307 bp and coding 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes. This genome will provide definite information for genetic perspective into this disease.

Lifetime occupational exposure to dusts, gases and fumes is associated with bronchitis symptoms and higher diffusion capacity in COPD patients

BACKGROUND

Occupational exposure to dusts, gases and fumes has been associated with reduced FEV1 and sputum production in COPD patients. The effect of occupational exposure on other characteristics of COPD, especially those reflecting emphysema, has not been studied in these patients.

METHODS

We studied 338 patients hospitalized for a first exacerbation of COPD in 9 Spanish hospitals, obtaining full occupational history in a face-to-face interview; job codes were linked to a job exposure matrix for semi-quantitative estimation of exposure to mineral/biological dust, and gases/fumes for each job held. Patients underwent spirometry, diffusing capacity testing and analysis of gases in stable conditions. Quality of life, dyspnea and chronic bronchitis symptoms were determined with a questionnaire interview. A high- resolution CT scan was available in 133 patients.

RESULTS

94% of the patients included were men, with a mean age of 68(8.5) years and a mean FEV1% predicted 52 (16). High exposure to gases or fumes was associated with chronic bronchitis, and exposure to mineral dust and gases/fumes was associated with higher scores for symptom perception in the St. George's questionnaire. No occupational agent was associated with a lower FEV1. High exposure to all occupational agents was associated with better lung diffusion capacity, in long-term quitters. In the subgroup with CT data, patients with emphysema had 18% lower DLCO compared to those without emphysema.

CONCLUSIONS

In our cohort of COPD patients, high exposure to gases or fumes was associated with chronic bronchitis, and high exposure to all occupational agents was consistently associated with better diffusion capacity in long-term quitters.

Combined effect of smoking and occupational exposure to dusts, gases or fumes on the incidence of COPD

To assess risk factors related to the development of chronic obstructive pulmonary disease (COPD) including smoking and occupational exposure (OE) to dusts, gases or fumes, we performed a longitudinal 11-year follow-up postal survey. The original study population was a random population sample of 8000 inhabitants of Helsinki aged 20 to 69 years in 1996. Participants of the first postal questionnaire were invited to this follow-up survey in 2007 with 4302 (78%) answers obtained. Cumulative incidence of COPD in 11 years was 3.43% corresponding to an incidence rate of 3.17/1000/year after exclusion of those with self-reported physician-diagnosed COPD and ever COPD in 1996. Smoking and age, but not gender, were associated with incident COPD. Reported family history of COPD increased the cumulative incidence to 8.55% vs 3.04% among those without a family history (p < 0.001). In multivariate analysis, significant independent risk factors for incident COPD were: current smoking in 1996 (OR 4.40 [95% CI 2.89-6.71]), age over 50 (OR 3.42 [95% CI 2.22-5.26]), family history of COPD (OR 2.08 [1.27-3.43]), ever asthma (OR 2.28 [1.35-3.86]), and self-reported OE (OR 2.14 [1.50-3.05]). Occupational exposure to dusts, gases or fumes, assessed both based on self-reported exposure and a job exposure matrix using reported professions, was an independent risk factor for incident COPD. Smoking and OE together yielded an additive effect on incidence of COPD.

Variations in FEV₁ decline over time in chronic obstructive pulmonary disease and its implications

PURPOSE OF REVIEW

This article reviews findings from longitudinal observational studies in both general and chronic obstructive pulmonary disease (COPD) populations, as well as from intervention trials in COPD, in which the annual rate of decline in forced expired volume in 1  s (FEV₁) has been measured. The purpose of the review is to describe the individual variability in rates of decline in FEV₁ within these populations, explore the factors contributing to this variability and discuss its implications.

RECENT FINDINGS

Individual rates of decline in FEV₁ have been found to vary considerably across participants with COPD in both observational cohorts and intervention trials from decreases as rapid as 150-200  ml per year to increases of up to approximately 150  ml per year, with mean rates of decline ranging from 33 to 69  ml per year. Aside from technical and biologic (e.g., time of day, season, weather, fatigue) sources of variation, other influential factors have included smoking status (most notably current versus former smoking), baseline smoking intensity, baseline lung function, airway hyperresponsiveness, exacerbation frequency, and, variably, age and sex. The presence of emphysema may also be a determinant, as well as certain biomarkers and gene variants.

SUMMARY

The wide distribution of individual rates of decline in FEV₁ includes especially rapid and slow declines. Future research is needed to identify biomarkers that both are predictive of a rapid decline within individuals who might then be targeted for special intervention and might also serve as surrogate endpoints in interventional trials.

Dust exposure is associated with increased lung function loss among workers in the Norwegian silicon carbide industry

OBJECTIVES

To investigate the relationship between dust exposure and annual change in lung function among employees in Norwegian silicon carbide (SiC) plants using a quantitative job exposure matrix (JEM) regarding total dust.

METHODS

All employees, 20-55 years of age by inclusion (n=456), were examined annually for up to 5 years (1499 examinations). Spirometry was performed at each examination, and a questionnaire encompassing questions of respiratory symptoms, smoking status, job and smoking history, and present job held was completed. A JEM was constructed based on 1970 personal total dust exposure measurements collected during the study period. The association between lung function and total dust exposure was investigated using linear mixed models.

RESULTS

The annual change in forced expiratory volume (FEV) in one second per squared height, FEV1/height(2), per mg/m(3) increase in dust exposure was -2.3 (95% CI -3.8 to -0.79) (mL/m(2))×year(-1). In an employee of average height (1.79 m) and exposure (1.4 mg/m(3)) the estimated contribution to the annual change in FEV1 associated with dust was 10.4 mL/year. The annual change in FEV1/height(2) in current, compared with non-smokers was -1.9 (-7.2 to 3.4) (mL/m(2))×year(-1). The estimated overall annual decline in FEV1 among current and non-smokers in the highest exposed group was -91.2 (-124.3 to -58.1) (mL/m(2))×year(-1) and -49.0 (-80.2 to -17.8) (mL/m(2))×year(-1), respectively.

CONCLUSIONS

Dust exposure, expressed by a quantitative JEM, was found to be associated with an increased yearly decline in FEV1 in employees of Norwegian SiC plants.

Dust is in the air: effects of occupational exposure to mineral dust on lung function in a 9-year study

BACKGROUND

Occupational mineral dust exposure is a well-known risk factor for numerous respiratory and systemic diseases. The aim of the present longitudinal study was to assess the influence of work-associated dust exposure on spirometric results. Furthermore, the impact of implementation of stricter limit values for occupational contact with quartz dust on lung function was evaluated.

METHODS

Anthropometric data (age, gender, BMI), smoking behavior, and lung function parameters (FVC, FEV1, MEF50) from 7,204 medical examinations of 3,229 female and male workers during the years 2002-2010 were examined following Austrian standards for occupational medicine and the guidelines of the European Respiratory Society. Analysis of data was performed using models of multiple linear regression.

RESULTS

Lung function decrease over time was associated with smoking habits and duration of occupational dust exposure. Specifically, occupational quartz exposure negatively influenced the annual lung function parameters (FVC, -6.68 ml; FEV1, -6.71 ml; and MEF50, -16.15 ml/s, all p < 0.001). Thus, an overadditive effect of smoking and work-related contact with quartz was found regarding decline in MEF50 (p < 0.05). Implementation of stricter occupational limit values for dust exposure resulted in a highly significant deceleration of the annual decrease in respiratory function (p = 0.001).

CONCLUSIONS

Individual smoking habits and occupational dust exposure had a negative impact on lung function. To reduce the risk of loss of respiratory capacity, smoking cessation is especially recommended to workers exposed to quartz dust. Moreover, stricter limit values could prevent chronic occupational damage to the respiratory system.

Rationale for earlier treatment in COPD: a systematic review of published literature in mild-to-moderate COPD

COPD is progressive and typically begins many years before a definite diagnosis is made. As the rate of decline in lung function may be faster in the initial stages of the disease, early intervention could be beneficial to control symptoms and affect disease progression and outcomes. A systematic review of published literature relating to mild-to-moderate COPD (patients with FEV(1) ≥50% predicted) was performed to evaluate the level of impairment and natural history or disease progression over time, and impact of interventions on the outcomes of patients with early-stage disease. Of the 79 published articles included in this analysis, 31 reported randomized controlled trials; the remaining 48 articles reported studies of non-randomized and/or observational design. Nine of the randomized controlled trials were ≥6 months' duration, enabling assessment of outcomes over time. Most of the randomized controlled trials were in patients with moderate COPD (GOLD stage II); few included patients with the mildest stages of the disease (i.e., stage I). The results show that even patients with milder or moderate COPD can have substantial limitations and physical impairment, which worsen over time. Encouragement of smoking cessation, in conjunction with management of symptoms and treating activity limitation and exacerbations by appropriate non-pharmacologic and pharmacologic management at the earliest possible stage, could positively affect the impact and progression of the disease.

Smoking cessation and environmental hygiene

Although there are nonmodifiable genetic risk factors for COPD, most known risk factors for development and progression of COPD can be corrected. Continued efforts to encourage smoking cessation and measures to reduce exposure to SHS, outdoor air pollution, biomass smoke, and occupational and related amateur exposures will have a significant impact on worldwide health.

Understanding the natural progression in %FEV1 decline in patients with cystic fibrosis: a longitudinal study

BACKGROUND

Forced expiratory volume in 1 s as a percentage of predicted (%FEV1) is a key outcome in cystic fibrosis (CF) and other lung diseases. As people with CF survive for longer periods, new methods are required to understand the way %FEV1 changes over time. An up to date approach for longitudinal modelling of %FEV1 is presented and applied to a unique CF dataset to demonstrate its utility at the clinical and population level.

METHODS AND FINDINGS

The Danish CF register contains 70,448 %FEV1 measures on 479 patients seen monthly between 1969 and 2010. The variability in the data is partitioned into three components (between patient, within patient and measurement error) using the empirical variogram. Then a linear mixed effects model is developed to explore factors influencing %FEV1 in this population. Lung function measures are correlated for over 15 years. A baseline %FEV1 value explains 63% of the variability in %FEV1 at 1 year, 40% at 3 years, and about 30% at 5 years. The model output smooths out the short-term variability in %FEV1 (SD 6.3%), aiding clinical interpretation of changes in %FEV1. At the population level significant effects of birth cohort, pancreatic status and Pseudomonas aeruginosa infection status on %FEV1 are shown over time.

CONCLUSIONS

This approach provides a more realistic estimate of the %FEV1 trajectory of people with chronic lung disease by acknowledging the imprecision in individual measurements and the correlation structure of repeated measurements on the same individual over time. This method has applications for clinicians in assessing prognosis and the need for treatment intensification, and for use in clinical trials.

Association between occupational exposure and the clinical characteristics of COPD

Background

The contribution of occupational exposures to COPD and their interaction with cigarette smoking on clinical pattern of COPD remain underappreciated. The aim of this study was to explore the contribution of occupational exposures on clinical pattern of COPD.

Methods

Cross-sectional data from a multicenter tertiary care cohort of 591 smokers or ex-smokers with COPD (median FEV1 49%) were analyzed. Self-reported exposure to vapor, dust, gas or fumes (VDGF) at any time during the entire career was recorded.

Results

VDGF exposure was reported in 209 (35%) subjects aged 31 to 88 years. Several features were significantly associated with VDGF exposure: age (median 68 versus 64 years, p < 0.001), male gender (90% vs 76%; p < 0.0001), reported work-related respiratory disability (86% vs 7%, p < 0.001), current wheezing (71% vs 61%, p = 0.03) and hay fever (15.5% vs 8.5%, p < 0.01). In contrast, current and cumulative smoking was less (p = 0.01) despite similar severity of airflow obstruction.

Conclusion

In this patient series of COPD patients, subjects exposed to VDGF were older male patients who reported more work-related respiratory disability, more asthma-like symptoms and atopy, suggesting that, even in smokers or ex-smokers with COPD, occupational exposures are associated with distinct patients characteristics.

Time trend in hospitalised chronic lower respiratory diseases among Danish building and construction workers, 1981-2009: a cohort study

OBJECTIVES

To show trends in age-standardised hospital admission ratios (SHR) for chronic lower respiratory diseases, estimated for Danish construction workers over three time periods (1981-1990, 1991-2000, 2001-2009).

DESIGN

Within consecutive cohorts of all male building and construction workers in Denmark, selected occupations: bricklayers, carpenters, electricians, painters, plumbers and 'other construction workers' were followed up for hospitalisation due to chronic lower respiratory diseases. SHR was calculated for each occupation and time period. Time trend was calculated for construction workers at large using Poisson regression.

SETTING

Denmark.

PARTICIPANTS

All gainfully employed male building and construction workers aged 20 or more.

PRIMARY AND SECONDARY OUTCOME MEASURES

Age-standardised and gender-standardised hospitalisation ratios (SHR).

RESULTS

The number of hospitalised construction workers at large was reduced from 1134 in the first 10-year period to 699 in the last 9-year period. Among all Danish males, it was, however, even more reduced as reflected in the expected number that was down from 1172 to 617. Hence, SHR increased from 97 during 1981-1990, 100 during 1991-2000 to 113 during 2001-2009. It means that SHR increased with an average rate of 0.76% per year (95% CI 0.28 to 1.24) during the study period. A low SHR=72 (95% CI 60 to 87) was found among carpenters in 1981-1990. From 2001 to 2009, high SHRs were found among painters (SHR=147; 95% CI 111 to 192) and plumbers (SHR=132; 95% CI 101 to 171). In general, the selected groups of construction workers had, however, a low or average SHR due to chronic lower respiratory diseases.

CONCLUSIONS

The number of hospitalised workers, suffering from chronic lower respiratory diseases, was reduced over time for construction workers, but for all economically active men, it was reduced even more. Therefore, SHR due to chronic lower respiratory diseases increased over time in the construction industry at large.

Health outcomes associated with lung function decline and respiratory symptoms and disease in a community cohort

BACKGROUND

In workplace respiratory disease prevention, a thorough understanding is needed of the relative contributions of lung function loss and respiratory symptoms in predicting adverse health outcomes.

METHODS

Copenhagen City Heart Study respiratory data collected at 4 examinations (1976-2003) and morbidity and mortality data were used to investigate these relationships. With 15 or more years of follow-up for a hospital diagnosis of chronic obstructive pulmonary disease (COPD) morbidity, COPD or coronary heart disease (CHD) mortality, and all-cause mortality, risks for these outcomes were estimated in relation to asthma, chronic bronchitis, shortness of breath, and lung function level at examination 2 (1981-1983) or lung function decline established from examinations 1 (1976-1978) to 2 using 4 measures (FEV(1) slope, FEV(1) relative slope, American College of Occupational and Environmental Medicine's Longitudinal Normal Limit [LNL], or a limit of 90 milliliters per year [ml/yr]). These risks were estimated by hazard ratios (HR) and 95% confidence intervals (CI) adjusted for age, height-adjusted baseline forced expiratory volume in 1 second (FEV(1)/height(2)), and height.

RESULTS

For COPD morbidity, the increasing trend in the HR (95% CI) by quartiles of the FEV(1) slope reached a maximum of 3.77 (2.76-5.15) for males, 6.12 (4.63-8.10) for females, and 4.14 (1.57-10.90) for never-smokers. Significant increasing trends were also observed for mortality, with females at higher risk.

CONCLUSION

Lung function decline was associated with increased risk of COPD morbidity and mortality emphasizing the need to monitor lung function change over time in at-risk occupational populations.

Systematic review of the evidence relating FEV1 decline to giving up smoking

BACKGROUND

The rate of forced expiratory volume in 1 second (FEV1) decline ("beta") is a marker of chronic obstructive pulmonary disease risk. The reduction in beta after quitting smoking is an upper limit for the reduction achievable from switching to novel nicotine delivery products. We review available evidence to estimate this reduction and quantify the relationship of smoking to beta.

METHODS

Studies were identified, in healthy individuals or patients with respiratory disease, that provided data on beta over at least 2 years of follow-up, separately for those who gave up smoking and other smoking groups. Publications to June 2010 were considered. Independent beta estimates were derived for four main smoking groups: never smokers, ex-smokers (before baseline), quitters (during follow-up) and continuing smokers. Unweighted and inverse variance-weighted regression analyses compared betas in the smoking groups, and in continuing smokers by amount smoked, and estimated whether beta or beta differences between smoking groups varied by age, sex and other factors.

RESULTS

Forty-seven studies had relevant data, 28 for both sexes and 19 for males. Sixteen studies started before 1970. Mean follow-up was 11 years. On the basis of weighted analysis of 303 betas for the four smoking groups, never smokers had a beta 10.8 mL/yr (95% confidence interval (CI), 8.9 to 12.8) less than continuing smokers. Betas for ex-smokers were 12.4 mL/yr (95% CI, 10.1 to 14.7) less than for continuing smokers, and for quitters, 8.5 mL/yr (95% CI, 5.6 to 11.4) less. These betas were similar to that for never smokers. In continuing smokers, beta increased 0.33 mL/yr per cigarette/day. Beta differences between continuing smokers and those who gave up were greater in patients with respiratory disease or with reduced baseline lung function, but were not clearly related to age or sex.

CONCLUSION

The available data have numerous limitations, but clearly show that continuing smokers have a beta that is dose-related and over 10 mL/yr greater than in never smokers, ex-smokers or quitters. The greater decline in those with respiratory disease or reduced lung function is consistent with some smokers having a more rapid rate of FEV1 decline. These results help in designing studies comparing continuing smokers of conventional cigarettes and switchers to novel products.