Explore the vast range of titles available.

ObjectivesChronic bronchitis (CB) is an important chronic obstructive pulmonary disease (COPD)-related phenotype, with distinct clinical features and prognostic implications. Occupational exposures have been previously associated with increased risk of CB but few studies have examined this association prospectively using objective exposure assessment. We examined the effect of occupational exposures on CB incidence in the European Community Respiratory Health Survey.MethodsPopulation samples aged 20–44 were randomly selected in 1991–1993, and followed up twice over 20 years. Participants without chronic cough or phlegm at baseline were analysed. Coded job histories during follow-up were linked to the ALOHA Job Exposure Matrix, generating occupational exposure estimates to 12 categories of chemical agents. Their association with CB incidence over both follow-ups was examined with Poisson models using generalised estimating equations.Results8794 participants fulfilled the inclusion criteria, contributing 13 185 observations. Only participants exposed to metals had a higher incidence of CB (relative risk (RR) 1.70, 95% CI 1.16 to 2.50) compared with non-exposed to metals. Mineral dust exposure increased the incidence of chronic phlegm (RR 1.72, 95% CI 1.43 to 2.06). Incidence of chronic phlegm was increased in men exposed to gases/fumes and to solvents and in women exposed to pesticides.ConclusionsOccupational exposures are associated with chronic phlegm and CB, and the evidence is strongest for metals and mineral dust exposure. The observed differences between men and women warrant further investigation.

Moderate and severe exacerbations are incompletely prevented by maximal inhalation therapy in patients with severe chronic obstructive pulmonary disease. To determine whether roflumilast reduces moderate and/or severe chronic obstructive pulmonary disease exacerbations in patients at risk for exacerbations despite treatment with inhaled corticosteroid/long-acting β2-agonist with or without a long-acting muscarinic antagonist (LAMA). In this 52-week, phase 4, double-blind, placebo-controlled RE(2)SPOND (Roflumilast Effect on Exacerbations in Patients on Dual [LABA/ICS] Therapy) trial (NCT01443845), participants aged 40 years or older with severe/very severe chronic obstructive pulmonary disease, chronic bronchitis, two or more exacerbations and/or hospitalizations in the previous year, and receiving inhaled corticosteroid/long-acting β2-agonist with or without LAMA daily for 3 or more months were equally randomized to once-daily roflumilast, 500 μg (n = 1,178), or placebo (n = 1,176). Stratification was based on LAMA use. Although rate of moderate or severe exacerbations per patient per year (primary endpoint) was reduced by 8.5% with roflumilast versus placebo, the between-group difference was not statistically significant (rate ratio, 0.92; 95% confidence interval, 0.81-1.04; P = 0.163). However, roflumilast improved lung function, and in a post hoc analysis roflumilast significantly reduced the rate of moderate or severe exacerbations in participants with a history of more than three exacerbations and/or one or more hospitalizations in the prior year. Adverse event-related discontinuations occurred in 11.7% roflumilast-treated and 5.4% placebo-treated participants. Deaths occurred in 2.5% roflumilast and 2.1% placebo participants. Roflumilast failed to statistically significantly reduce moderate and/or severe exacerbations in the overall population. Roflumilast improved lung function and reduced exacerbations in participants with frequent exacerbations and/or hospitalization history. The safety profile of roflumilast was consistent with that of previous studies. Clinical trial registered with www.clinicaltrials.gov (NCT01443845).

Abstract Chronic bronchitis (CB) is a common but variable phenomenon in chronic obstructive pulmonary disease (COPD). It has numerous clinical consequences, including an accelerated decline in lung function, greater risk of the development of airflow obstruction in smokers, a predisposition to lower respiratory tract infection, higher exacerbation frequency, and worse overall mortality. CB is caused by overproduction and hypersecretion of mucus by goblet cells, which leads to worsening airflow obstruction by luminal obstruction of small airways, epithelial remodeling, and alteration of airway surface tension predisposing to collapse. Despite its clinical sequelae, little is known about the pathophysiology of CB and goblet cell hyperplasia in COPD, and treatment options are limited. In addition, it is becoming increasingly apparent that in the classic COPD spectrum, with emphysema on one end and CB on the other, most patients lie somewhere in the middle. It is known now that many patients with severe emphysema can develop CB, and small airway pathology has been linked to worse clinical outcomes, such as increased mortality and lesser improvement in lung function after lung volume reduction surgery. However, in recent years, a greater understanding of the importance of CB as a phenotype to identify patients with a beneficial response to therapy has been described. Herein we review the epidemiology of CB, the evidence behind its clinical consequences, the current understanding of the pathophysiology of goblet cell hyperplasia in COPD, and current therapies for CB.

ObjectivesCharacterise inhalational exposures during deployment to Afghanistan and Southwest Asia and associations with postdeployment respiratory symptoms.MethodsParticipants (n=1960) in this cross-sectional study of US Veterans (Veterans Affairs Cooperative Study ‘Service and Health Among Deployed Veterans’) completed an interviewer-administered questionnaire regarding 32 deployment exposures, grouped a priori into six categories: burn pit smoke; other combustion sources; engine exhaust; mechanical and desert dusts; toxicants; and military job-related vapours gas, dusts or fumes (VGDF). Responses were scored ordinally (0, 1, 2) according to exposure frequency. Factor analysis supported item reduction and category consolidation yielding 28 exposure items in 5 categories. Generalised linear models with a logit link tested associations with symptoms (by respiratory health questionnaire) adjusting for other covariates. OR were scaled per 20-point score increment (normalised maximum=100).ResultsThe cohort mean age was 40.7 years with a median deployment duration of 11.7 months. Heavy exposures to multiple inhalational exposures were commonly reported, including burn pit smoke (72.7%) and VGDF (72.0%). The prevalence of dyspnoea, chronic bronchitis and wheeze in the past 12 months was 7.3%, 8.2% and 15.6%, respectively. Burn pit smoke exposure was associated with dyspnoea (OR 1.22; 95% CI 1.06 to 1.47) and chronic bronchitis (OR 1.22; 95% CI 1.13 to 1.44). Exposure to VGDF was associated with dyspnoea (OR 1.29; 95% CI 1.14 to 1.58) and wheeze (OR 1.18; 95% CI 1.02 to 1.35).ConclusionExposures to burn pit smoke and military occupational VGDF during deployment were associated with an increased odds of chronic respiratory symptoms among US Veterans.

Abstract Rationale In vitro studies, animal experiments, and human exposure studies have shown how ambient air pollution increases the risk of atopic diseases. However, results derived from observational studies are inconsistent. Objectives To assess the relationship between individual-based exposure to traffic-related air pollutants and allergic disease outcomes in a prospective birth cohort study during the first 6 years of life. Methods We studied 2,860 children at the age of 4 years and 3,061 at the age of 6 years to investigate atopic diseases and allergic sensitization. Long-term exposure to particulate matter (PM2.5), PM2.5 absorbance, and long-term exposure to nitrogen dioxide (NO2) was assessed at residential addresses using geographic information systems based regression models and air pollution measurements. The distance to the nearest main road was used as a surrogate for traffic-related air pollutants. Measurements and Main Results Strong positive associations were found between the distance to the nearest main road and asthmatic bronchitis, hay fever, eczema, and sensitization. A distance-dependent relationship could be identified, with the highest odds ratios (ORs) for children living less than 50 m from busy streets. For PM2.5 absorbance, statistically significant effects were found for asthmatic bronchitis (OR, 1.56; 95% confidence interval [CI], 1.03–2.37), hay fever (OR, 1.59; 95% CI, 1.11–2.27), and allergic sensitization to pollen (OR, 1.40; 95% CI, 1.20–1.64). NO2 exposure was associated with eczema, whereas no association was found for allergic sensitization. Conclusions This study provides strong evidence for increased risk of atopic diseases and allergic sensitization when children are exposed to ambient particulate matter.

Limited evidence links air pollution exposure to chronic cough and sputum production. Few reports have investigated the association between long-term exposure to air pollution and classically defined chronic bronchitis. Our objective was to estimate the association between long-term exposure to particulate matter (diameter <10 μm, PM ; <2.5μm, PM ), nitrogen dioxide (NO ), and both incident and prevalent chronic bronchitis. We estimated annual average PM , PM , and NO concentrations using a national land-use regression model with spatial smoothing at home addresses of participants in a prospective nationwide U.S. cohort study of sisters of women with breast cancer. Incident chronic bronchitis and prevalent chronic bronchitis, cough and phlegm, were assessed by questionnaires. Among 47,357 individuals with complete data, 1,383 had prevalent chronic bronchitis at baseline, and 647 incident cases occurred over 5.7-y average follow-up. No associations with incident chronic bronchitis were observed. Prevalent chronic bronchitis was associated with PM [adjusted odds ratio (aOR) per interquartile range (IQR) difference (5.8 μg/m )=1.07; 95% confidence interval (CI): 1.01, 1.13]. In never-smokers, PM was associated with prevalent chronic bronchitis (aOR=1.18 per IQR difference; 95% CI: 1.04, 1.34), and was associated with prevalent chronic bronchitis (aOR=1.10; 95% CI=1.01, 1.20), cough (aOR=1.10; 95% CI: 1.05, 1.16), and phlegm (aOR=1.07; 95% CI: 1.01, 1.14); interaction -values (nonsmokers vs. smokers) <0.05. PM exposure was related to chronic bronchitis prevalence. Among never-smokers, PM and NO exposure was associated with chronic bronchitis and component symptoms. Results may have policy ramifications for PM regulation by providing evidence for respiratory health effects related to long-term PM exposure. https://doi.org/10.1289/EHP2199.

BackgroundOver half the world is exposed daily to the smoke from combustion of solid fuels. Chronic obstructive pulmonary disease (COPD) is one of the main contributors to the global burden of disease and can be caused by biomass smoke exposure. However, studies of biomass exposure and COPD show a wide range of effect sizes. The aim of this systematic review was to quantify the impact of biomass smoke on the development of COPD and define reasons for differences in the reported effect sizes.MethodsA systematic review was conducted of studies with sufficient statistical power to calculate the health risk of COPD from the use of solid fuel, which followed standardised criteria for the diagnosis of COPD and which dealt with confounding factors. The results were pooled by fuel type and country to produce summary estimates using a random effects model. Publication bias was also estimated.ResultsThere were positive associations between the use of solid fuels and COPD (OR=2.80, 95% CI 1.85 to 4.0) and chronic bronchitis (OR=2.32, 95% CI 1.92 to 2.80). Pooled estimates for different types of fuel show that exposure to wood smoke while performing domestic work presents a greater risk of development of COPD and chronic bronchitis than other fuels.ConclusionDespite heterogeneity across the selected studies, exposure to solid fuel smoke is consistently associated with COPD and chronic bronchitis. Efforts should be made to reduce exposure to solid fuel by using either cleaner fuel or relatively cleaner technology while performing domestic work.

Background This study aimed to assess associations of outdoor air pollution on prevalence of chronic bronchitis symptoms in adults in five cohort studies (Asthma-E3N, ECRHS, NSHD, SALIA, SAPALDIA) participating in the European Study of Cohorts for Air Pollution Effects (ESCAPE) project. Methods Annual average particulate matter (PM10, PM2.5, PMabsorbance, PMcoarse), NO2, nitrogen oxides (NOx) and road traffic measures modelled from ESCAPE measurement campaigns 2008–2011 were assigned to home address at most recent assessments (1998–2011). Symptoms examined were chronic bronchitis (cough and phlegm for ≥3 months of the year for ≥2 years), chronic cough (with/without phlegm) and chronic phlegm (with/without cough). Cohort-specific cross-sectional multivariable logistic regression analyses were conducted using common confounder sets (age, sex, smoking, interview season, education), followed by meta-analysis. Results 15 279 and 10 537 participants respectively were included in the main NO2 and PM analyses at assessments in 1998–2011. Overall, there were no statistically significant associations with any air pollutant or traffic exposure. Sensitivity analyses including in asthmatics only, females only or using back-extrapolated NO2 and PM10 for assessments in 1985–2002 (ECRHS, NSHD, SALIA, SAPALDIA) did not alter conclusions. In never-smokers, all associations were positive, but reached statistical significance only for chronic phlegm with PMcoarse OR 1.31 (1.05 to 1.64) per 5 µg/m3 increase and PM10 with similar effect size. Sensitivity analyses of older cohorts showed increased risk of chronic cough with PM2.5abs (black carbon) exposures. Conclusions Results do not show consistent associations between chronic bronchitis symptoms and current traffic-related air pollution in adult European populations.

ObjectivesWe aimed to estimate the prevalence of chronic bronchitis (CB), examine its association with occupational exposure to irritants assessed by self-reporting or the Nordic job exposure matrix (N-JEM) stratified by smoking status and estimate the population-attributable fraction (PAF) of CB from occupational exposure.MethodsA two-phased, cross-sectional design was used to analyse a random sample collected in 2013 and 2018 of the population aged 16–55 years in Telemark County, Norway. CB was defined as cough and sputum production for ≥3 months over 2 consecutive years. The participants’ occupational histories were categorised using the International Standard Classification of Occupations and linked to the N-JEM. Self-reported occupational exposure was also assessed. Logistic regression was performed with adjustments for age, sex and smoking status and yielded ORs, 95% CIs and associated PAFs.ResultsOf the 20 282 participants, 5.3% reported CB symptoms. CB was associated with the frequency of self-reported occupational exposure to vapours, gas, dust and fumes (VGDF), with increasing ORs ranging from 1.6 (95% CI 1.3 to 1.9) for seldom to 3.6 (95% CI 2.9 to 4.5) for daily exposure. Among ever-smokers, the N-JEM ‘irritants’ category was associated with CB (OR 1.4; 95% CI 1.1 to 1.8) to a similar degree as in the group that reported VGDF exposure (OR 2.1; 95% CI 1.7 to 2.5). The PAFs for CB from VGDF exposure were 41% overall, 49% among ever-smokers and 37% among never-smokers.ConclusionsOccupational exposure to VGDF was associated with CB, when self-reported and for smokers when assessed by the N-JEM. Workplace exposure contributed to more than one third of the overall CB burden.

Respiratory health is closely related to immune system function, and diet can also influence immune homeostasis. Diet, an important part of a healthy lifestyle, is also linked to respiratory health. We aimed to explore the relationship between different dietary patterns and the risk of chronic respiratory diseases (CRDs), including chronic bronchitis (CB), emphysema, and asthma. A total of 23,042 adults from the United States were selected from the National Health and Nutrition Examination Survey (NHANES) dataset between 2007 and 2018. Diet quality was assessed using 2-day, 24-hour dietary recall data and quantified as the Healthy Eating Index-2020 (HEI-2020), the Dietary Inflammation Index (DII), the Mediterranean Dietary Index (MEDI), and the Dietary Approaches to Stop Hypertension Index (DASHI). Binary logistic regression models, restricted cubic splines (RCS), and the weighted quartile sum (WQS) models were used to assess the relationship between diet quality and the risk of CB, emphysema, and asthma. In logistic regression analyses of the four dietary indices with the three chronic respiratory diseases, it was consistently observed that higher dietary quality scores were linked to a reduced risk of respiratory disease. These consistent trends were also evident in the assessments of the dose-response relationship between dietary quality score and the risk of respiratory disease. Furthermore, evaluations of the combined effects of dietary components across different dietary indices in the risk of chronic respiratory disease yielded results consistent with the logistic regression models. Notably, high-quality protein, minerals, and fiber-rich fruits and vegetables emerged as the food groups making the most significant contributions to health across different dietary indices. Low-quality diets, lacking in high-quality protein, minerals, and fruits and vegetables rich in dietary fiber, are associated with a higher risk of chronic respiratory disease, regardless of the dietary index used to measure diet quality.