Correlates of COPD and chronic bronchitis in nonsmokers: data from a cross-sectional study

Prevalence of chronic obstructive pulmonary disease in Indian nonsmokers: a systematic review & meta-analysis

INTRODUCTION

Nonsmokers with chronic obstructive pulmonary disease (COPD) are neglected despite constituting half of all cases in studies from the developed world. Herein, we systematically reviewed the prevalence of COPD among nonsmokers in India.

CONTENT

We searched Embase, Scopus, and PubMed databases for studies examining the prevalence of COPD among nonsmokers in India. We used the Joanna Briggs Institute (JBI) checklist to assess included studies' quality. Meta-analysis was performed using random-effects model.

SUMMARY

Seven studies comprising 6,903 subjects were included. The quality of the studies ranged from 5/9 to 8/9. The prevalence of COPD varied between 1.6 and 26.6 %. Studies differed considerably in demographics and biomass exposure profiles of subjects. Among the four studies that enrolled both middle-aged and elderly Indian nonsmokers not screened based on biomass fuel exposure, the pooled prevalence of COPD was 3 % (95 % CI, 2-3 %; I2=50.52 %, p=0.11). The pooled prevalence of COPD among biomass fuel-exposed individuals was 10 % (95 % CI, 2-18 %; I2=98.8 %, p<0.001).

OUTLOOK

Limited evidence suggests a sizable burden of COPD among nonsmokers and biomass fuel-exposed individuals in India. More epidemiological studies of COPD in nonsmokers are needed from low and middle-income countries.

Secondhand Smoke Exposure and the Risk of Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis

Background

Many studies have shown that active smoking leads to an increasing incidence of chronic obstructive pulmonary disease (COPD). However, studies interested in the effects of secondhand smoke exposure (SHS exposure) on COPD were less or underappreciated.

Methods

A systematic review and meta-analysis was conducted to investigate the association between SHS exposure and the risk of COPD. Three databases (PubMed, Embase and Web of Science) were searched to obtain data. After assessing the study quality, stratified analyses were performed according to the region, gender, and duration of exposure. Cochran's Q and I² were utilized for heterogeneity assessment. To assess publication bias, we used a funnel plot and Egger's test.

Results

A total of 15 studies (6 cross-sectional studies, 6 case-control studies, and 3 cohort studies) with 25,592 participants were involved in this meta-analysis. This study showed that SHS exposure was associated with an increased risk of COPD (odds ratio (OR): 2.25, 95% CI: 1.40-3.62, I² = 98%, p < 0.01 for heterogeneity based on a random-effects analysis model), especially in those with a longer time exposure of more than 5 years was 4.38 (95% CI: 1.28-15.00, I² = 89%, p < 0.01 for heterogeneity based on a random-effects analysis model). In addition, SHS exposure also increases the risk of COPD in women (odds ratio (OR): 2.02, 95% CI: 1.52-2.67, I² = 0%, p = 0.89 for heterogeneity based on a random-effects analysis model).

Conclusion

The findings suggest that SHS exposure is associated with the risk of COPD, especially for individuals with a long time exposed.

Trial Registry

Prospero CRD42022329421.

Impact of early life exposures on COPD in adulthood: A systematic review and meta-analysis

Early life represents a critical period for the development and growth of the lungs. Adverse exposures in this stage may drive the development of chronic obstructive pulmonary disease (COPD). Thus, we quantitatively evaluated the impact of different early life exposures on COPD in adulthood. The PubMed, Embase and Cochrane Library electronic databases were searched for articles published from January 2001 to October 2020. A total of 30 studies (795,935 participants) met the criteria and were included in the review. We found a significant association of COPD with childhood serious respiratory infections, pneumonia or bronchitis (pooled adjusted OR [aOR], 2.23 [95% CI, 1.63-3.07]). The probability of COPD was increased 3.45-fold for children with than without asthma (pooled aOR, 3.45 [95% CI, 2.37-5.02]). In addition, the probability of COPD was associated with maternal smoking (pooled aOR, 1.42 [95% CI, 1.17-1.72]), any child maltreatment (pooled aOR, 1.30 [95% CI, 1.18-1.42]) and low birth weight (pooled aOR, 1.58 [95% CI, 1.08-2.32]) but not childhood environmental tobacco smoke exposure (pooled aOR, 1.15 [0.83-1.61]) or premature birth (pooled aOR, 1.17 [95% CI, 0.87-1.58]). Furthermore, subgroup analyses revealed that probability was increased for only women with childhood physical abuse, sexual abuse and exposure to intimate partner violence. Factors resulting in COPD in adults could trace back to early life. Childhood respiratory disease, maltreatment, maternal smoking and low birth weight increase the risk of COPD. Promising advances in prevention strategies for early life exposures could markedly decrease the risk of COPD.

Unmet need in the management of chronic obstructive pulmonary disease in the Middle East and Africa region: An expert panel consensus

Chronic obstructive pulmonary disease (COPD) has a significant impact on healthcare systems and health-related quality of life. Increased prevalence of smoking is an important factor contributing to high burden of COPD in the Middle East and Africa (MEA). Several other factors including sedentary lifestyle, urbanization, second-hand smoke, air pollution, and occupational exposure are also responsible for the upsurge of COPD in the MEA. Frequent COPD exacerbations accelerate disease progression, progressively deteriorate the lung function, and negatively affect quality of life. This consensus is based on review of the published evidence, international and regional guidelines, and insights provided by the expert committee members from the MEA region. Spirometry, though the gold standard for diagnosis, is often unavailable and/or underutilized leading to underdiagnosis of COPD in primary care settings. Low adherence to the treatment guidelines and delayed use of appropriate combination therapy including triple therapy are additional barriers in management of COPD in MEA. It is necessary to recognize COPD as a screenable condition and develop easy and simple screening tools to facilitate early diagnosis. Knowledge of the disease symptomatology at patient and physician level and adherence to the international or regional guidelines are important to create awareness about harmful effects of smoking and develop national guidelines to focus on prevention on COPD. Implementation of vaccination program and pulmonary rehabilitation are equally valuable to manage patients with COPD at local and regional level. We present recommendations made by the expert panel for improved screening, diagnosis, and management of COPD in MEA.

Chronic Cough Due to Stable Chronic Bronchitis: CHEST Expert Panel Report

BACKGROUND

Chronic cough due to chronic bronchitis (CB) causes significant impairment in quality of life, and effective treatment strategies are needed. We conducted a systematic review on the management of chronic cough due to CB to update the recommendations and suggestions of the American College of Chest Physicians (CHEST) 2006 guideline on this topic.

METHODS

This systematic review asked three questions: (1) What are the clinical features of the history that suggest a patient's cough-phlegm syndrome is due to CB? (2) Can treatment of stable CB improve or eliminate chronic cough? (3) Can therapy that targets chronic cough due to CB prevent or reduce the occurrence of acute CB exacerbations? Studies of adult patients with CB were included and assessed for relevance and quality. Based on the systematic review, guideline suggestions were developed and voted on by using the CHEST organization methodology.

RESULTS

The search strategy used an assortment of descriptors and assessments to identify studies of chronic cough due to CB.

CONCLUSIONS

The evidence supporting the management of chronic cough due to CB is limited overall and of low quality. This article provides guidance on treatment by presenting suggestions based on the best currently available evidence and identifies gaps in our knowledge and areas for future research.

A Small Molecule BH3-mimetic Suppresses Cigarette Smoke-Induced Mucous Expression in Airway Epithelial Cells

Cigarette smoke (CS) exposure is one of the primary risk factors associated with the chronic mucous hypersecretion (CMH). The antiapoptotic protein, Bcl-2 sustains hyperplastic mucous cells, and the airway epithelium of ex-smokers with CMH as well as mice exposed to chronic CS showed increased Bcl-2 expression. Therefore, we investigated whether Bcl-2 plays a role in CS-induced mucous expression. Primary airway epithelial cells (AECs) of murine and human origin were treated with CS extract (CSE), and there was a concentration- and time-dependent increase in secretory mucin (MUC5AC), mucous regulator (SPDEF) and Bcl-2 expression. Using differentiated human AECs cultured on air-liquid interface, EGFR and ERK1/2 pathways were interrogated. Bcl-2 activity was blocked using a small molecule BH3 mimetic ABT-263 that disrupts the Bcl-2 interaction with pro-apoptotic proteins. The ABT-263 treatment resulted in the downregulation of CSE-induced mucus expression and disrupted the EGFR-signaling while inducing the apoptosis and the pro-apoptotic protein, Bik expression. This strategy significantly suppressed the mainstream CS-induced mucous phenotype in a 3-D human airway epithelium model. Therefore, the present study suggests that CS induces Bcl-2 expression to help promote mucous cell survival; and small molecule BH3 mimetics targeting Bcl-2 could be useful in suppressing the CS-induced mucous response.

Epidemiological evidence relating environmental smoke to COPD in lifelong non-smokers: a systematic review

Background: Some evidence suggests environmental tobacco smoke (ETS) might cause chronic obstructive pulmonary disease (COPD). We reviewed available epidemiological data in never smokers. Methods: We identified epidemiological studies providing estimates of relative risk (RR) with 95% confidence interval (CI) for various ETS exposure indices. Confounder-adjusted RRs for COPD were extracted, or derived using standard methods. Meta-analyses were conducted for each exposure index, with tests for heterogeneity and publication bias. For the main index (spouse ever smoked or nearest equivalent), analyses investigated variation in RR by location, publication period, study type, sex, diagnosis, study size, confounder adjustment, never smoker definition, and exposure index definition. Results: Twenty-eight relevant studies were identified; nine European or Middle Eastern, nine Asian, eight American and two from multiple countries. Five were prospective, seven case-control and 16 cross-sectional. The COPD definition involved death or hospitalisation in seven studies, GOLD stage 1+ criteria in twelve, and other definitions in nine. For the main index, random-effects meta-analysis of 33 heterogeneous (p<0.001) estimates gave a RR of 1.20 (95%CI 1.08-1.34). Higher estimates for females (1.59,1.16-2.19, n=11) than males (1.29,0.94-1.76, n=7) or sexes combined (1.10,0.99-1.22, n=15 where sex-specific not available), and lower estimates for studies of 150+ cases (1.08,0.97-1.20, n=13) partly explained the heterogeneity. Estimates were higher for Asian studies (1.34,1.08-1.67, n=10), case-control studies (1.55,1.04-2.32, n=8), and COPD mortality or hospitalisation (1.40,1.12-1.74, n=11). Some increase was seen for severer COPD (1.29,1.10-1.52, n=7). Dose-response evidence was heterogeneous. Evidence for childhood (0.88,0.72-1.07, n=2) and workplace (1.12,0.77-1.64, n=4) exposure was limited, but an increase was seen for overall adulthood exposure (1.20,1.03-1.39, n=17). We discuss study weaknesses that may bias estimation of the association of COPD with ETS. Conclusions: Although the evidence suggests ETS increases COPD, study weaknesses and absence of well-designed large studies precludes reliable inference of causality. More definitive evidence is required.

Epidemiological evidence relating environmental smoke to COPD in lifelong non-smokers: a systematic review

Background: Some evidence suggests environmental tobacco smoke (ETS) might cause chronic obstructive pulmonary disease (COPD). We reviewed available epidemiological data in never smokers. Methods: We identified epidemiological studies providing estimates of relative risk (RR) with 95% confidence interval (CI) for various ETS exposure indices. Confounder-adjusted RRs for COPD were extracted, or derived using standard methods. Meta-analyses were conducted for each exposure index, with tests for heterogeneity and publication bias. For the main index (spouse ever smoked or nearest equivalent), analyses investigated variation in RR by location, publication period, study type, sex, diagnosis, study size, confounder adjustment, never smoker definition, and exposure index definition. Results: Twenty-eight relevant studies were identified; nine European or Middle Eastern, nine Asian, eight American and two from multiple countries. Five were prospective, seven case-control and 16 cross-sectional. The COPD definition involved death or hospitalisation in seven studies, GOLD stage 1+ criteria in twelve, and other definitions in nine. For the main index, random-effects meta-analysis of 33 heterogeneous (p<0.001) estimates gave a RR of 1.20 (95%CI 1.08-1.34). Higher estimates for females (1.59,1.16-2.19, n=11) than males (1.29,0.94-1.76, n=7) or sexes combined (1.10,0.99-1.22, n=15 where sex-specific not available), and lower estimates for studies of 150+ cases (1.08,0.97-1.20, n=13) partly explained the heterogeneity. Estimates were higher for Asian studies (1.34,1.08-1.67, n=10), case-control studies (1.55,1.04-2.32, n=8), and COPD mortality or hospitalisation (1.40,1.12-1.74, n=11). Some increase was seen for severer COPD (1.29,1.10-1.52, n=7). Dose-response evidence was heterogeneous. Evidence for childhood (0.88,0.72-1.07, n=2) and workplace (1.12,0.77-1.64, n=4) exposure was limited, but an increase was seen for overall adulthood exposure (1.20,1.03-1.39, n=17). We discuss study weaknesses that may bias estimation of the association of COPD with ETS. Conclusions: Although the evidence suggests ETS increases COPD, study weaknesses and absence of well-designed large studies precludes reliable inference of causality. More definitive evidence is required.

Joint statement for the diagnosis, management, and prevention of chronic obstructive pulmonary disease for Gulf Cooperation Council countries and Middle East-North Africa region, 2017

Smoking and subsequent development of COPD is an ever-increasing epidemic in Arabian Gulf and Middle East countries, with no signs of decline. The important fact to be highlighted is that this COPD epidemic of increasing incidence and prevalence is mostly unrecognized by patients, due to the common attribution of symptoms to "smoker's cough", and the underdiagnosis and undertreatment by physicians because the common signs and symptoms masquerade as asthma. Consequently, there are long-term adverse effects of missing the diagnosis. The purpose of this review article is to focus upon the status of COPD in Arabian Gulf and Middle East countries, stressing the increasing burden of smoking and COPD, to emphasize the specific factors leading to rise in prevalence of COPD, to bring to light the underdiagnosis and undermanagement of COPD, and to treat COPD in conformity with standard guidelines with local and regional modifications. This review ends with suggestions and recommendations to the health department to formulate policies and to generate awareness among the general public about the side effects of smoking and consequences of COPD.

Occupational and Environmental Contributions to Chronic Cough in Adults: Chest Expert Panel Report

BACKGROUND

In response to occupational and environmental exposures, cough can be an isolated symptom reflecting exposure to an irritant with little physiological consequence, or it can be a manifestation of more significant disease. This document reviews occupational and environmental contributions to chronic cough in adults, focusing on aspects not previously covered in the 2006 ACCP Cough Guideline or our more recent systematic review, and suggests an approach to investigation of these factors when suspected.

METHODS

MEDLINE and TOXLINE literature searches were supplemented by articles identified by the cough panel occupational and environmental subgroup members, to identify occupational and environmental aspects of chronic cough not previously covered in the 2006 ACCP Cough Guideline. Based on the literature reviews and the Delphi methodology, the cough panel occupational and environmental subgroup developed guideline suggestions that were approved after review and voting by the full cough panel.

RESULTS

The literature review identified relevant articles regarding: mechanisms; allergic environmental causes; chronic cough and the recreational and involuntary inhalation of tobacco and marijuana smoke; nonallergic environmental triggers; laryngeal syndromes; and occupational diseases and exposures. Consensus-based statements were developed for the approach to diagnosis due to a lack of strong evidence from published literature.

CONCLUSIONS

Despite increased understanding of cough related to occupational and environmental triggers, there remains a gap between the recommended assessment of occupational and environmental causes of cough and the reported systematic assessment of these factors. There is a need for further documentation of occupational and environmental causes of cough in the future.

The Risk Factors and Characteristics of COPD Among Nonsmokers in Korea: An Analysis of KNHANES IV and V

PURPOSE

Chronic obstructive pulmonary disease (COPD) is increasing in prevalence and mortality. This study evaluated the prevalence, risk factors, characteristics, and health-related quality of life (HRQoL) of COPD among nonsmokers in Korea.

METHODS

This was a population-based cross-sectional study using data obtained from the Fourth and Fifth Korean National Health and Nutrition Examination Survey, which was conducted from 2007 to 2011.

RESULTS

A total of 15,063 participants completely answered the questionnaire and performed the spirometry. Among them, 59.6 % were nonsmokers and 40.4 % were smokers. The prevalence of nonsmoker COPD was 7.1 %. On multivariate analysis, age ≥65 years (OR, 2.93; 95 % CI, 2.44-3.51), male sex (OR, 2.98; 95 % CI, 2.40-3.71), living in rural area (OR, 1.26; 95 % CI, 1.05-1.51), lower body mass index (BMI) (<18.5 kg/m(2)) (OR, 3.00; 95 % CI, 1.78-5.01), self-reported asthma (OR, 2.72; 95 % CI, 2.05-3.60), and self-reported tuberculosis (OR, 4.73; 95 % CI, 3.63-6.17) showed a significantly higher risk of nonsmoker COPD. Analysis of nonsmoker and smoker COPD revealed that there are more females in nonsmoker COPD patients (73.9 vs. 6.9 %, P < 0.001). Nonsmoker COPD patients presented with impaired mobility, pain/discomfort, and anxiety/depression functions as well as a lower mean EuroQol Five-Dimension Questionnaire utility score, which showed HRQoL.

CONCLUSIONS

The burden of nonsmoker COPD was considerable. Older age, male sex, lower BMI, self-reported asthma, and self-reported tuberculosis were risk factors for nonsmoker COPD and there were differences between nonsmoker and smoker COPD in terms of sex, comorbidities, and HRQoL.

Burden of smoking among adults with COPD, chronic bronchitis, and emphysema in urban China

OBJECTIVE

Tobacco, widely used in China, poses a major risk for chronic obstructive pulmonary disease (COPD). This study assessed health outcomes of COPD-diagnosed smokers vs. never smokers and examined treatment patterns of patients attempting to quit smoking in urban China.

METHODS

National Health and Wellness Survey (NHWS) 2010 and 2012 China data were analysed. Respondents self-reporting diagnosis with COPD, chronic bronchitis, or emphysema were categorised: quit attempters (current smokers 'trying to quit' or non-smokers 'in the process of quitting'), smokers (including quit attempters) and those who never smoked. Respondents reported smoking cessation treatment utilisation; health status: SF-36v2-based scores and SF-6D health utilities; Work Productivity and Activity Impairment questionnaire-based metrics; and resource utilisation. Regression modelling assessed health outcomes, controlling for covariates.

RESULTS

Among 1421 (3.6%) diagnosed respondents, 51.6% never smoked and 35.5% smoked (of whom, 43.8% were attempting to quit). After adjustments, smokers vs. never smokers had significantly lower health utilities, lower mental/physical health status and greater absenteeism, presenteeism, overall work impairment, activity impairment, emergency room visits, hospitalisations and provider visits. Quit attempters were diagnosed an average 6.9 years (SD = 7.7) previously, with 25.3% reporting moderate/severe COPD. Most-reported main causes of COPD were: smoking (57.5%), illnesses/conditions (53.8%) and pollutants (44.3%). Among quit attempters, 82.8% smoked currently. Use of prescription cessation treatments was reported by 12.7%.

CONCLUSIONS

Smokers experienced poorer health outcomes, reinforcing importance of prevention in mitigating disease burden. Among quit attempters, few reported using prescription cessation treatments. Given the high burden imposed by smoking in China, effective interventions may be beneficial.

Subjects with COPD and productive cough have an increased risk for exacerbations and death

BACKGROUND

Chronic bronchitis is related to worse general health status, exacerbations and mortality among subjects with COPD. Also less longstanding cough and phlegm may be related to worse prognosis in COPD but this has rarely been evaluated in population-based studies.

AIM

To evaluate the relationship between productive cough, exacerbations and mortality among subjects with and without COPD.

METHOD

All subjects with COPD (n = 993) were identified together with sex- and age matched reference subjects without obstructive lung function impairment from four population-based cohorts in 2002-04. Baseline spirometry and structured interview including data on exacerbations last 12 months were used in this study (n = 1986) together with mortality data collected until February 2012.

RESULTS

Productive cough was more common in COPD than non-COPD (42.8 vs. 23.5%, p < 0.001), more common in men than women, but associated to exacerbations in both sexes. COPD-subjects with productive cough had the highest risk for exacerbations in both sexes and they had a significantly increased risk for death (HR 1.48, 95% CI 1.13-1.94) also when adjusted for sex, age, BMI, smoking habits and heart disease.

CONCLUSION

Productive cough was common and increased the risk for exacerbations in both sexes, in both COPD and non-COPD. COPD-subjects with productive cough had the highest risk for exacerbations and a significantly higher risk for death also after adjustment for common risk factors.

Biomarkers of progression of chronic obstructive pulmonary disease (COPD)

Disease progression of chronic obstructive pulmonary disease (COPD) is variable, with some patients having a relatively stable course, while others suffer relentless progression leading to severe breathlessness, frequent acute exacerbations of COPD (AECOPD), respiratory failure and death. Radiological markers such as CT emphysema index, bronchiectasis and coronary artery calcification (CAC) have been linked with increased mortality in COPD patients. Molecular changes in lung tissue reflect alterations in lung pathology that occur with disease progression; however, lung tissue is not routinely accessible. Cell counts (including neutrophils) and mediators in induced sputum have been associated with lung function and risk of exacerbations. Examples of peripheral blood biological markers (biomarkers) include those associated with lung function (reduced CC-16), emphysema severity (increased adiponectin, reduced sRAGE), exacerbations and mortality [increased CRP, fibrinogen, leukocyte count, IL-6, IL-8, and tumor necrosis factor α (TNF-α)] including increased YKL-40 with mortality. Emerging approaches to discovering markers of gene-environment interaction include exhaled breath analysis [volatile organic compounds (VOCs), exhaled breath condensate], cellular and systemic responses to exposure to air pollution, alterations in the lung microbiome, and biomarkers of lung ageing such as telomere length shortening and reduced levels of sirtuins. Overcoming methodological challenges in sampling and quality control will enable more robust yet easily accessible biomarkers to be developed and qualified, in order to optimise personalised medicine in patients with COPD.

Chronic obstructive pulmonary disease prevalence among nonsmokers by occupation in the United States

OBJECTIVE

To examine the prevalence of chronic obstructive pulmonary disease (COPD) among nonsmokers by occupation in the United States.

METHODS

The 1997 to 2004 National Health Interview Survey data for working adults aged 25 years or more were used to estimate the COPD prevalence and to examine change in COPD prevalence between 1997 to 2000 and 2001 to 2004 by occupational groups.

RESULTS

During 1997 to 2004, COPD prevalence was 2.8%. The COPD prevalence was highest in financial records processing (4.6%) occupations. There was a slight increase in COPD prevalence during the two survey periods from 2.8% during 1997 to 2000 compared with 2.9% during 2001 to 2004.

CONCLUSIONS

No significant changes in the COPD prevalence between the two periods were found. Nevertheless, the elevated COPD prevalence in certain occupational groups suggests that other risk factors play a role in developing COPD.

Lung cancer correlates in Lebanese adults: a pilot case--control study

BACKGROUND

Lung cancer is one of the most prevalent types of cancers. However, there are no epidemiological studies concerning lung cancer and its risk factors in Lebanon. This study was carried out to determine the association between lung cancer and its most common risk factors in a sample of the Lebanese population.

METHODS

A hospital-based case-control study was conducted. Patients were recruited in a tertiary health care center. A questionnaire in Arabic was designed to assess the possible risk factors for lung cancer.

RESULTS

For females, cigarette smoking (ORa=9.76) and using fuel for heating (ORa=9.12) were found to be the main risk factors for lung cancer; for males, cigarette smoking (ORa=156.98), living near an electricity generator (ORa=13.26), consuming low quantities of fruits and vegetables (ORa=10.54) and a family history of cancer (ORa=8.75) were associated with lung cancer. Waterpipe smoking was significantly correlated with lung cancer in the bivariate analysis.

CONCLUSION

In this pilot study, it was found that in addition to smoking, outdoor and indoor pollution factors were potential risk factors of lung cancer. Additional studies would be necessary to confirm these findings.