Risk factors for chronic obstructive pulmonary disease among never-smokers in Korea

COPD Risk Factor Profiles in General Population and Referred Patients: Potential Etiotypes

Purpose

To identify the risk factors for chronic obstructive pulmonary disease (COPD) in view of potential etiotypes in a general population and referred COPD patients.

Patients and Methods

We performed a cross-sectional observational study utilizing two distinct datasets: a dataset of a general population including 2430 subjects with COPD from the Korea National Health and Nutrition Examination Survey (KNHANES) and another dataset of referral clinics including 579 patients with COPD from the Korean Obstructive Lung Disease (KOLD).

Results

The mean age of both groups was 67 years, and 71.2% and 93.8% were male in the COPD subjects from the KNHANES and the KOLD, respectively. The mean forced expiratory volume in 1 second of predicted value was 79.1% (KNHANES) and 55.4% (KOLD). The frequency of risk factors of cigarette smoking (C), infection (I), pollution (P), and asthma (A) was 54.6%, 9.4%, 10.7%, and 7.9%, respectively, in the KNHANES COPD subjects, and 88.4%, 26.6%, 41.6%, and 35.2%, respectively, in the KOLD COPD subjects. Risk factors were unidentified in 32.6% (KNHANES) and 3.1% (KOLD) of COPD subjects. Additionally, 14.1% and 66.2% of subjects with COPD had two or more risk factors in the KNHANES and KOLD, respectively.

Conclusion

The profiles of risk factors C, I, P, and A were identified and appeared to be different among the two COPD groups from a general population or referral clinics. In some of the COPD subjects, risk factors were not identified, so we should endeavour to find out unidentified COPD risk factors, especially in the general population.

Adherence to a Planetary Health Diet, Environmental Impacts, and Mortality in Chinese Adults

Importance

Although the EAT-Lancet Commission has recently proposed a planetary health diet (PHD) to promote human and environmental health, little is known about how PHD affects environment and mortality risk among an Asian population.

Objective

To investigate whether a PHD score is associated with environmental impacts and mortality outcomes in a Chinese cohort living in Singapore.

Design, Setting, and Participants

This cohort study used data from the Singapore Chinese Health Study. Eligible participants were without known cardiovascular disease and cancer at baseline; they were recruited between 1993 and 1998 and followed up using record linkage data until 2020. Data were analyzed from September 2022 to April 2023.

Exposures

PHD score was calculated based on the reference consumption of 14 dietary components in PHD and individual energy intake assessed using a validated food frequency questionnaire in this cohort.

Main Outcomes and Measures

Diet-related environmental impacts were estimated using a food frequency questionnaire. Mortality outcomes (all-cause, cardiovascular disease, cancer, and respiratory disease) were identified via linkage with a nationwide registry.

Results

A total of 57 078 participants were included in this study (mean [SD] age, 56.1 (7.9) years; 31 958 women [56.0%]). During a median (IQR) follow-up of 23.4 (18.7-26.2) years, 22 599 deaths occurred. Comparing the highest and lowest quintiles, higher PHD scores were associated with lower greenhouse gas emissions (β = -0.13 kg CO2 equivalent; 95% CI, -0.14 to -0.12 kg CO2 equivalent), but with higher total water footprint (β = 0.12 m3; 95% CI, 0.11-0.13 m3) and land use (β = 0.29 m2; 95% CI, 0.28-0.31 m2). In the adjusted multivariable model, compared with the lowest quintile, participants in the highest quintile of PHD score had lower risk of all-cause mortality (hazard ratio [HR], 0.85; 95% CI, 0.81-0.89), cardiovascular disease mortality (HR, 0.79; 95% CI, 0.73-0.85), cancer mortality (HR, 0.93; 95% CI, 0.86-1.00), and respiratory disease mortality (HR, 0.81; 95% CI, 0.74-0.89).

Conclusions and Relevance

In this study of Singapore Chinese adults, higher adherence to PHD was associated with reduced risk of chronic disease mortality. However, environmental impacts were uncertain, as higher adherence was associated with lower greenhouse gas emissions but higher total water footprint and land use.

Chronic Obstructive Pulmonary Disease and Work: The Continuing Narrative

It has long been recognized that harmful inhaled workplace exposures can contribute to the development of chronic obstructive pulmonary disease (COPD). This article, intended for the clinician, summarizes some of this evidence and some areas of controversy. Current estimates based on pooled epidemiological analyses of population-based studies identify that approximately 14% of the burden of COPD (and 13% of the burden of chronic bronchitis) is attributable to such exposures. In addition to these approaches, various studies implicate specific exposures as contributing. Certain of these relating to cadmium, coal, and respirable crystalline silica are discussed in more detail. Despite this amassed evidence to date supporting associations between COPD and workplace exposures, there have been surprisingly few studies that have attempted to assess the attribution by experts of an occupational cause in cases of COPD. One study, using hypothetical cases of COPD, noted that while expert physicians were willing to make such an occupational link, this was only likely in cases with light smoking histories and a priori defined heavy occupational exposures. Relatively recent data relating to computed tomography (CT) scan appearances may give the clinician a further guide. Several studies from populations have now linked potentially harmful occupational exposures specifically with the presence of emphysema on CT scanning. It will be of interest to see if this finding, along with other clinical attributes of cases such as smoking and family histories, exclusion of asthma, genetic data, and the nature of workplace exposures, will increase the future diagnosis by clinicians of occupational COPD. In the interim, while better diagnostic approaches are developed, we suggest that consideration of an occupational cause is an important part of the clinical investigation of cases of COPD. Finally, we suggest that evidence-based workplace preventive strategies for occupational COPD should be informed by knowledge of which exposures are most important to reduce, and whether and when intervention to reduce exposure at an individual worker level is warranted.

Chronic Obstructive Pulmonary Disease Prevalence and Associated Risk Factors in Adults Aged 40 Years and Older in Southeast China: A Cross-Sectional Study During 2019-2020

Purpose

Chronic obstructive pulmonary disease (COPD) is one of many major public health problems in China, and its prevalence and associated risk factors in the southeast of China need to be determined to facilitate disease control and prevention.

Methods

A multistage stratified cluster sampling method was used to select 5486 participants aged ≥ 40 years from nine COPD monitoring districts in Fujian Province during 2019–2020. Participants were interviewed using a laptop-based questionnaire and underwent pulmonary function tests. COPD was diagnosed according to the 2019 Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria.

Results

Final analysis was conducted using data from 4999 participants with qualified post-bronchodilator results. The prevalence of COPD was 11.6% (95% confidence interval [CI]: 10.5–12.7). Risk factors for COPD in the logistic regression model were being male (odds ratio [OR] = 2.83, 95% CI: 2.01–3.98), > 70 years old (OR = 16.16, 95% CI: 8.14–32.08), having a low body mass index (BMI) (OR = 1.81, 95% CI: 1.13–2.89), parental history of respiratory disease (OR = 1.78, 95% CI: 1.50–2.10), being a current (OR = 2.82, 95% CI: 1.83–4.36) or former (OR = 2.47, 95% CI: 1.45–4.19) smoker, and indoor exposure to biomass (OR = 1.28, 95% CI: 1.05–1.58).

Conclusion

The estimated prevalence of COPD in southeast China is high. COPD was strongly associated with sex, aging, a low BMI, parental history of respiratory diseases, smoking, and indoor exposure to biomass in adults aged ≥ 40 years. The government should urgently implement comprehensive measures to reduce the risk factors for COPD.

Chronic obstructive pulmonary disease in never-smokers: risk factors, pathogenesis, and implications for prevention and treatment

Chronic obstructive pulmonary disease (COPD) was traditionally thought to be caused by tobacco smoking. However, recognition of the importance of non-smoking-related risk factors for COPD has increased over the past decade, with evidence on the burden, risk factors, and clinical presentations of COPD in never-smokers. About half of all COPD cases worldwide are due to non-tobacco-related risk factors, which vary by geographical region. These factors include air pollution, occupational exposures, poorly controlled asthma, environmental tobacco smoke, infectious diseases, and low socioeconomic status. Impaired lung growth during childhood, caused by a range of early-life exposures, is associated with an increased risk of COPD. Potential mechanisms for the pathogenesis of COPD in never-smokers include inflammation, oxidative stress, airway remodelling, and accelerated lung ageing. Compared with smokers who develop COPD, never-smokers with COPD have relatively mild chronic respiratory symptoms, little or no emphysema, milder airflow limitation, and fewer comorbidities; however, exacerbations can still be frequent. Further research-including epidemiological, translational, clinical, and implementation studies-is needed to address gaps in understanding and to advance potential solutions to reduce the burden of COPD in never-smokers.

Risk factors for chronic obstructive pulmonary disease in never‐smokers: A systematic review

Introduction

Relatively little is known about the risk factors for chronic obstructive pulmonary disease (COPD) in never‐smokers, and these factors have not yet been fully characterised. This study therefore sought to analyse COPD risk factors in never‐smokers by conducting a systematic review of the literature on the topic.

Materials and methods

We performed a search in PubMed (Medline) and Embase from 2000 onwards, to locate studies on COPD in never‐smokers. For literature search and evidence synthesis purposes, we used the PRISMA guidelines and drew up a specific quality scale to quantify the evidence of each study included.

Results

The bibliographic search retrieved a total of 557 papers, 20 of which fulfilled the designated inclusion criteria (two case–control studies, four cohort studies and 14 cross‐sectional studies). These studies were undertaken in Europe, the United States, Latin America, Asia and Africa. The risk factors for never‐smokers were varied and ranged from exposure to biomass, occupational exposure and passive smoking to having a history of asthma, tuberculosis or respiratory infections during childhood. The effect of residential radon was unclear. The highest risk was obtained for previous respiratory diseases of any type, with a magnitude much higher than that observed for other risk factors.

Conclusions

There are few studies on COPD risk factors in never‐smokers. More purpose‐designed studies in this subpopulation are thus called for, including well‐designed studies to specifically assess if indoor radon has any role on COPD onset.

Association of Body Mass Index with Risk of Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis

The association between body mass index (BMI) and chronic obstructive pulmonary disease (COPD) remains controversial. Therefore, a meta-analysis was conducted to further evaluate the relationship. A comprehensive literature search was performed in PubMed, Web of Science, EMBASE, China National Knowledge Infrastructure (CNKI), and Wanfang databases to identify eligible articles until July 15, 2020. Random effect model (REM) was used to compute the pooled results with 95% confidence intervals (CIs). We conducted meta-regression and subgroup analysis to explore potential sources of heterogeneity. Publication bias was evaluated by funnel plots and Egger's test. Thirty articles with 1,578,449 participants were included in the meta-analysis. The pooled OR of COPD was 1.96 (95% CI: 1.78-2.17) for the underweight group, 0.80 (95% CI: 0.73-0.87) for overweight group, and 0.86 (95% CI: 0.73-1.02) for obesity group. After further excluding 5 studies of high between-study heterogeneity in sensitivity analysis, the pooled OR of COPD was 0.77 (95% CI: 0.68-0.86) for the obesity group. This meta-analysis indicated that BMI was associated with COPD. Specifically, underweight might increase the risk of COPD; overweight and obesity might reduce the risk of COPD.

Analysis of Risk Factors Affecting The Occurrence of Chronic Obstructive Pulmonary Disease in Indonesia

Background: Chronic obstructive pulmonary disease (COPD) is a lung disease caused by the occurrence of airflow limitation in the lungs and also causes 60% of all deaths in Indonesia. Purpose: This study aimed to analyze the risk factors that affect the incidence of COPD in Indonesia. Methods: This study was conducted in July–August 2019 in Indonesia as an analytic research study with a cross-sectional design, using data from the Indonesia Family Life Survey-5. The sample consisted of respondents aged >15 years, giving a total of 34,231 respondents. Data analysis was partially carried out using the chi-square test to analyze the relationships between the variables. Results: The majority of respondents were female, were aged <40 years, and had a low level of education. Risk factors for the development of COPD included, among others, an age of >40 years (p = 0.02; PR = 1.20; 95% CI = 1.02–1.41), male gender (p = 0.01; PR = 1.26; 95% CI = 1.07–1.49), smoking (p = 0.01; PR = 1.22 ; 95% CI = 1.03–1.44), first smoking age < 40 years (p = 0.02; PR = 1.22; 95% CI = 1.03–1.44), residence in urban areas (p = 0.01; PR = 1.43; 95% CI = 1.20–1.70), being underweight (p = 0.01; PR = 2.17; 95% CI = 1.76–2.66). Conclusions: The risk factors that affect the incidence of COPD include being aged >40 years, being male, smoking, taking up smoking when aged <40 years, urban residence, and being underweight.

COPD in the major nonsmoking adult: A systematic review and meta-analysis

Chronic Obstructive Pulmonary Disease (COPD) main cause is attributed to active smokers, but there's a small percentage that comes from risk factors that have been less considered. The aim of this research was to identify the risk factors and the clinical presentation of the population over 64 years of age that lead to the development of COPD. A systematic review and a meta-analysis was performed. From the 92 studies interpreted, we identified seven studies on the presence of COPD in nonsmokers older adults, having a universe of 14,920 patients. The primary risk factor to trigger the development of COPD was secondhand smoking. The study defined the most common risk factors that currently trigger COPD development among nonsmokers and provided an insight into the potential clinical differences between nonsmokers and smokers.

Use of the COPD Assessment Test (CAT) to screen for COPD in dairy farmers: AIRBAg study

OBJECTIVES

People at risk of chronic obstructive pulmonary disease (COPD) can benefit from appropriate medical management before severe symptoms appear. This study assesses the value of the COPD Assessment Test (CAT) questionnaire for screening dairy farmers, who tend to be slow or reluctant to seek health care.

METHODS

During the time period 2012-2017, 2089 randomly selected dairy farmers in Brittany (France) were invited to complete self-administered questionnaires (including the CAT) and to undergo an occupational health check-up using an electronic mini-spirometer and conventional spirometry. Those showing symptoms suggestive of COPD and/or a ratio FEV₁ /FEV₆ < 80% were sent to a pulmonologist for a further check-up, including spirometry with a reversibility test. Multivariate logistic models based on CAT scores and socio-demographic or work-related factors were developed to predict COPD.

RESULTS

The 1231 farmers who underwent the occupational health check-up included 1203 who met the inclusion/exclusion criteria. Pulmonologist identified 16 (1.3%) cases of COPD. A multivariate logistic regression model (covariates: CAT sum score, on-farm time, BMI, smoking status, free-stall mulching) provided an area under the receiver-operating characteristic curve (AUC) of 0.87 (95% CI: 0.75-0.98). Using a cut-off of 0.007 gave a sensitivity of 93.8% and a specificity of 62.4%. Another model that included CAT breathlessness and the same covariates performed marginally better (AUC = 0.88, 95% CI: 0.77-0.98).

CONCLUSION

Our predictive models can both benefit dairy farmers by providing early diagnosis and management of their COPD and avoid unnecessary, costly spirometry during the screening process.

Association between adiposity measures and COPD risk in Chinese adults

Bodyweight and fat distribution may be related to COPD risk. Limited prospective evidence linked COPD to abdominal adiposity. We investigated the association of body mass index (BMI) and measures of abdominal adiposity with COPD risk in a prospective cohort study.The China Kadoorie Biobank recruited participants aged 30-79 years from 10 areas across China. Anthropometric indexes were objectively measured at the baseline survey during 2004-2008. After exclusion of participants with prevalent COPD and major chronic diseases, 452 259 participants were included and followed-up until the end of 2016. We used Cox models to estimate adjusted hazard ratios relating adiposity to risk of COPD hospitalisation or death.Over an average of 10.1 years of follow-up, 10 739 COPD hospitalisation events and deaths were reported. Compared with subjects with normal BMI (18.5-<24.0 kg·m-2), underweight (BMI <18.5 kg·m-2) individuals had increased risk of COPD, with adjusted hazard ratio 1.78 (95% CI 1.66-1.89). Overweight (BMI 24.0-<28.0 kg·m-2) and obesity (BMI ≥28.0 kg·m-2) were not associated with an increased risk after adjustment for waist circumference. A higher waist circumference (≥85 cm for males and ≥80 cm for females) was positively associated with COPD risk after adjustment for BMI. Additionally, waist-to-hip ratio and waist-to-height ratio were positively related to COPD risk.Abdominal adiposity and underweight were risk factors for COPD in Chinese adults. Both BMI and measures of abdominal adiposity should be considered in the prevention of COPD.

COPD: How can evidence from randomised controlled trials apply to patients treated in everyday clinical practice?

OBJECTIVES

To evaluate the degree to which evidence from large clinical trials can be applied to patients treated in a local hospital cohort of COPD outpatients.

METHODS

The authors selected seventeen RCTs identified in a systematic way from GOLD 2019 consensus document, and applied their inclusion and exclusion criteria to a real-world cohort of a previous cross-sectional study of 303 COPD outpatients included consecutively.

RESULTS

When the inclusion criteria of the 17 RCTs were applied to a real-world cohort of COPD outpatients, only a small portion of them were eligible to participate in the referred trials, from 4.29% to 60.07%. However, when both the inclusion and the exclusion criteria were applied, only as little as 3.63% to as much as 40.59% of patients were eligible to participate. Hence, only a small fraction of patients from this cohort could benefit from the findings of these RCTs.

CONCLUSIONS

There is a need to complement the efficacy evidence provided by large RCTs according to the extent to which their results, designed to target significant patient populations, can be applied to typical patients treated in routine clinical practice.

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.

Functional variations of the TLR4 gene in association with chronic obstructive pulmonary disease and pulmonary tuberculosis

Objective

Chronic obstructive pulmonary disease (COPD) and pulmonary tuberculosis (PTB) share a number of common risk factors, including innate immunity-related genetic factors. In the present study, we compared the role of genetic variations of the TLR4 gene in susceptibility to COPD and PTB and illuminated the underlying molecular mechanism of functional single-nucleotide polymorphisms (SNPs).

Methods

A population-based case control study was performed in a Chinese Han population and included 152 COPD cases, 1601 PTB cases and 1727 controls. Five SNPs in the TLR4 gene (rs10759932, rs2737190, rs7873784, rs11536889, and rs10983755) were genotyped using TaqMan allelic discrimination technology. We estimated the effects of SNPs using the odds ratio (OR) together with 95% confidence interval (CI). Dual-luciferase reporter vectors expressing different genotypes of SNPs were constructed and transfected into the human HEK 293 T cell line to explore their effects on potential transcription activity.

Results

After Bonferroni correction, the genetic polymorphisms of all five SNPs remained significantly associated with COPD, while rs10759932 and rs2737190 were also associated with PTB. Compared with rs10759932-TT, individuals carrying TC (OR: 0.42, 95% CI: 0.28–0.64) or CC (OR: 0.24, 95% CI: 0.09–0.63) had a significantly reduced risk of COPD. However, individuals carrying TC (OR: 1.28, 95% CI: 1.11–1.49) or CC (OR: 1.26, 95% CI: 0.98–1.62) had an increased risk of PTB. The OR (95% CI) for allele rs10759932-C was 0.45 (0.32–0.62) for COPD and 1.18 (1.07–1.32) for PTB. For rs2737190, heterozygous AG was related to a decreased risk of COPD (OR: 0.32, 95% CI: 0.21–0.49) and an increased risk of PTB (OR: 1.30, 95% CI: 1.11–1.52). The dual-luciferase reporter assay showed decreased transcription activity caused by rs10759932-C and rs2737190-G.

Conclusion

Genetic polymorphisms of rs10759932 and rs2737190 in TLR4 are significantly related to both COPD and PTB but with inverse effects. The altered transcription activity caused by mutations in these two loci may partly explain the observed relationship.

Respiratory Sound Based Classification of Chronic Obstructive Pulmonary Disease: a Risk Stratification Approach in Machine Learning Paradigm

This article investigates the classification of normal and COPD subjects on the basis of respiratory sound analysis using machine learning techniques. Thirty COPD and 25 healthy subject data are recorded. Total of 39 lung sound features and 3 spirometry features are extracted and evaluated. Various parametric and nonparametric tests are conducted to evaluate the relevance of extracted features. Classifiers such as support vector machine (SVM), k-nearest neighbor (KNN), logistic regression (LR), decision tree and discriminant analysis (DA) are used to categorize normal and COPD breath sounds. Classification based on spirometry parameters as well as respiratory sound parameters are assessed. Maximum classification accuracy of 83.6% is achieved by the SVM classifier while using the most relevant lung sound parameters i.e. median frequency and linear predictive coefficients. Further, SVM classifier and LR classifier achieved classification accuracy of 100% when relevant lung sound parameters, i.e. median frequency and linear predictive coefficient are combined with the spirometry parameters, i.e. forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV₁). It is concluded that combining lung sound based features with spirometry data can improve the accuracy of COPD diagnosis and hence the clinician's performance in routine clinical practice. The proposed approach is of great significance in a clinical scenario wherein it can be used to assist clinicians for automated COPD diagnosis. A complete handheld medical system can be developed in the future incorporating lung sounds for COPD diagnosis using machine learning techniques.

Characterisation of morbidity in a COPD hospital cohort

OBJECTIVES

To characterise the morbidity of COPD out-patients based on symptoms, acute exacerbations, FEV₁ and comorbidities, and to explore the association between different patients' characteristics such as social, demographic, clinical history or exposure.

METHODS

Stable COPD outpatients over 40 years old diagnosed according to GOLD criteria were included consecutively; the exclusion criteria were only refusal to participate and inability to understand clinical questionnaires. A survey of demographic and clinical data was conducted. Symptoms were evaluated using the CAT and mMRC questionnaires. The number of COPD acute exacerbations reported in the previous year was assessed, and spirometry performed on all participants according to ATS/ERS recommendations. Different variables were collected and then related to each other.

RESULTS

We studied 303 COPD outpatients, all Caucasians, 79.5% males and mostly elderly. 65.7% of participants reported having low monthly income and 87.8% a low education level. Tobacco smoking was the most common exposure identified but a substantial proportion of COPD patients were non-smokers (26%). Frequent acute exacerbations were reported by 38.0% of patients. The mean post-bronchodilator FEV₁ was 53.2%. The distribution of patients according to GOLD 2017 stage and classification was respectively 9.9%, 41.9%, 35.0% and 13.2% from 1 to 4 and 23.1%, 39.6%, 2.3% and 35.0% from GOLD A to D. Only 29 patients (9.5%) presented no comorbid conditions, and the most common were hypertension, heart diseases and dyslipidaemia.

CONCLUSIONS

Our data confirms COPD as a complex and heterogeneous disorder, with a significant morbidity due to the nature of symptoms, frequent comorbidities and exacerbations. A substantial proportion of COPD patients were never-smokers, mainly women, calling attention to the need for COPD recognition in these cases. COPD in women, in never-smokers and in patients with a previous diagnosis of asthma presented some specific characteristics. Some patient characteristics are associated with frequent acute exacerbations. FEV₁ was strongly related both to symptoms and exacerbations.

Taurine treatment decreases inflammation and oxidative stress in lungs of adult mice exposed to cigarette smoke

Taurine is the major free amino acid found in mammalian cells and is known to be an antioxidant and membrane-stabilizing agent. This study aimed to evaluate the effects of taurine on oxidative stress and inflammatory response in the lungs of mice exposed to cigarette smoke. Fifty male C57BL/6 mice were divided into 5 groups: control group (CG), vehicle group (VG), taurine group (TG), cigarette smoke group (CSG), and cigarette smoke + taurine group (CSTG). For five consecutive days, CSG and CSTG were exposed to 4 cigarettes 3 times a day. Taurine administration was able to reduce total leukocytes in bronchoalveolar lavage fluid in CSTG compared to CSG. There was an increase in antioxidant superoxide dismutase and catalase activity in CSG compared to that in CG and TG, and a decrease in CSTG compared to CSG. There was an increase in the concentration of TNF and IL-17 in CSG and CSTG compared to CG and TG. There was an increase in the concentration of IL-22 in CSG compared to CG and TG, and a decrease in CSTG compared to CSG. The administration of taurine has been shown to reduce the inflammation and oxidative stress induced by short-term exposure to cigarette smoke.

Prevalence of lung cancer in patients with interstitial lung disease is higher than in those with chronic obstructive pulmonary disease

We aimed to explore lung cancer prevalence in interstitial lung disease (ILD) patients with or without connective tissue disorder (CTD) and idiopathic pulmonary fibrosis (IPF) in comparison with chronic obstructive pulmonary disorder (COPD).We evaluated lung cancer prevalence associated with ILD and IPF using Korean Health Insurance Review and Assessment Service (HIRA) data from January to December 2011. This database (HIRA-NPS-2011-0001) was sampled using random sampling of outpatients; 1,375,842 sample cases were collected, and 670,258 (age ≥ 40 ys) were evaluated. Patients with ILDs, IPF, CTD, or COPD were identified using the International Classification of Disease-10 diagnostic codes.Lung cancer prevalence rates per 100,000 persons for the sample population and those with ILD, IPF, CTD-ILD, and COPD were 420, 7334, 7404, 7272, and 4721, respectively. Lung cancer prevalence was significantly higher in those with ILD than in those with COPD (P < .01).More attention should be paid to lung cancer development in those with ILD as well as COPD.

Cross-Sectional Study of Chronic Obstructive Pulmonary Disease Prevalence Among Smokers, Ex-Smokers, and Never-Smokers in Almaty, Kazakhstan: Study Protocol

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is significantly underdiagnosed in Kazakhstan, and there is no previously conducted study on COPD prevalence in the country.

OBJECTIVE

The purpose of this study is to assess the prevalence of COPD among individuals aged 40 to 59 years based on results of spirometry before and after bronchodilator, presence of structural changes in the lungs (emphysema, inflammatory changes, and thickening of the walls of the large and small airways) detected by computer tomography, and the symptoms of COPD. The study has 3 study groups: smokers of conventional cigarettes, those who had quit smoking 1 to 5 years ago, and those who haven't smoked cigarettes.

METHODS

This is an observational study with a cross-sectional design among individuals aged 40 to 59 years in Almaty, Kazakhstan. The sample of 900 individuals of both sexes contains 500 smokers, 200 ex-smokers, and 200 never-smokers. Study measures include spirometry, chest computed tomography, electrocardiography, physical exams, laboratory testing of serum, anthropometry, and 6-minute walk test. Data are collected by computer-assisted personal interviewing with tablets. The questionnaire was designed to explore possible COPD risk factors including history of smoking, current smoking, level of smoking exposure (in pack-years), passive smoking, occupational and environmental hazards, and covariates: age, gender, ethnicity, education, occupation, and self-reported morbidity. COPD Assessment Test (CAT) is used to collect information about COPD symptoms.

RESULTS

We have completed the participant recruitment and study procedures. Currently, we are working on data processing and data analysis. The authors anticipate the preliminary results should be available by September 2017. Study results will be published in peer-reviewed scientific journals.

CONCLUSIONS

This is the first study in Kazakhstan that assesses prevalence of COPD and its comorbidities in the adult population aged 40 to 59 years. The results of the study will be useful for improving COPD preventive measures, better COPD screening, identification, and registration. Findings of the study will also contribute to global knowledge on the epidemiology of COPD.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02926534; https://clinicaltrials.gov/ct2/show/NCT02926534 (Archived by WebCite at http://www.webcitation.org/6rjwGsPOZ).

The role of acute and chronic respiratory colonization and infections in the pathogenesis of COPD

COPD is a major global concern, increasingly so in the context of ageing populations. The role of infections in disease pathogenesis and progression is known to be important, yet the mechanisms involved remain to be fully elucidated. While COPD pathogens such as Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pneumoniae are strongly associated with acute exacerbations of COPD (AECOPD), the clinical relevance of these pathogens in stable COPD patients remains unclear. Immune responses in stable and colonized COPD patients are comparable to those detected in AECOPD, supporting a role for chronic colonization in COPD pathogenesis through perpetuation of deleterious immune responses. Advances in molecular diagnostics and metagenomics now allow the assessment of microbe-COPD interactions with unprecedented personalization and precision, revealing changes in microbiota associated with the COPD disease state. As microbial changes associated with AECOPD, disease severity and therapeutic intervention become apparent, a renewed focus has been placed on the microbiology of COPD and the characterization of the lung microbiome in both its acute and chronic states. Characterization of bacterial, viral and fungal microbiota as part of the lung microbiome has the potential to reveal previously unrecognized prognostic markers of COPD that predict disease outcome or infection susceptibility. Addressing such knowledge gaps will ultimately lead to a more complete understanding of the microbe-host interplay in COPD. This will permit clearer distinctions between acute and chronic infections and more granular patient stratification that will enable better management of these features and of COPD.

The Definition of Past Tuberculosis Affects the Magnitude of Association between Pulmonary Tuberculosis and Respiratory Dysfunction: Korea National Health and Nutrition Examination Survey, 2008-2012

Tuberculosis (TB) is associated with an increased risk of chronic lung impairment. The aim of this study was to compare the clinical characteristics and lung functions according to definition of past TB. We used the population-based, Korea National Health and Nutrition Examination Survey (KNHANES) (2008-2012) to analyze 13,522 subjects age 40 years or older who underwent spirometry and chest X-ray (CXR). Subjects with TB lesions on CXR (with or without a history of TB) were older, more likely to be male, ever smokers, and of low socioeconomic status than subjects with only a history of TB or without evidence of TB. Airflow obstruction (AFO) was associated with only a history of TB (odds ratio [OR] 1.53, 95% confidence interval [CI] 0.95-2.46), only TB lesion on CXR (OR 2.37, 95% CI 1.80-3.12), and both a history and TB lesions on CXR (OR 4.47, 95% CI 3.07-6.51) after adjustment for gender, age, body mass index, education, income, and smoking amount (P for trend < 0.001). Spirometric restriction was associated with only a history of TB (OR 1.29, 95% CI 0.80-2.08), only TB lesions on CXR (OR 2.03, 95% CI 1.49-2.76), and both a history and TB lesions on CXR (OR 2.65, 95% CI 1.74-4.05) after adjustment for the above variables (P for trend < 0.001). How to define past TB in population study affects the magnitude of association between past TB and respiratory dysfunction. Without considering TB lesions on CXR, the association between TB and respiratory dysfunction could be underestimated.

Prevalence and Risk Factors of Chronic Obstructive Pulmonary Disease among Nonsmokers: Fifth Korea National Health and Nutrition Examination Survey (2010-2012)

OBJECTIVES

The purpose of this study was to determine the prevalence of COPD among non-smoking adults, and to investigate the risk factors that affect disease occurrence.

METHODS

The data from the 5th Korea national health and nutrition examination survey (KNHNES) has been used, and 5,489 non-smoking adults aged between 40 to 79 years with diagnosable FEV1/FVC were selected therefrom as the subjects of this study.

RESULTS

The prevalence of COPD in non-smokers was observed to be 6.9%. The development of the COPD showed statistically significant difference among groups; males showed about 2.54 times (95% CI: 1.410∼146.612) higher rates compared to females, subjects aged 70-79 showed about 3.08 times (95% CI: 1.823∼11.437) higher rates compared to those aged 40-49, subjects whose education level was elementary school or less showed about 5.36 times (95% CI: 1.341∼21.393) higher rates compared to those who are college or more, and subjects who are middle school showed about 4.72 times (95% CI: 1.374∼16.217) higher rates compared to the college or more.

CONCLUSION

It is confirmed that development of the COPD in non-smokers reach significance. For the prevention of the disease, there is a need to identify COPD-related risk factors in males and the elderly and provide appropriate nursing intervention, and to develop health-related education programs for those with low educational background to take in order to promote the improvement of lung health.

Differences in chronic obstructive pulmonary disease phenotypes between non-smokers and smokers

INTRODUCTION AND OBJECTIVES

Although tobacco smoking is a major risk factor for chronic obstructive pulmonary disease (COPD), more than one-fourth of COPD patients are non-smokers. In this cross-sectional study, the differences in COPD phenotypes between non-smokers and smokers in male subjects were investigated and were focused on structural lung changes using a quantitative assessment of computed tomography (CT) images.

METHODS

They divided male participants with COPD, from a Korean cohort near a cement plant, into non-smokers and smokers by a cutoff of a 5 pack-year smoking history. Clinical characteristics, including age, body mass index (BMI), spirometry results, history of biomass smoke exposure, and CT measurements, were compared between the two groups. Emphysema index (EI) and mean wall area percentage (MWA %) were used to evaluate the structural lung changes on volumetric CT scans.

RESULTS

The non-smoker group (n = 49) had younger patients and had a greater BMI than the smoker group (n = 113) (P < .05). Spirometry results, including post-bronchodilator forced expiratory volume in 1 s, were comparable between the two groups. More smokers had emphysema than non-smokers (EI 10.0 vs. 6.5, P < .001), but after accounting the potential confounders in model analysis, the difference was borderline significance (P = .051). In the subgroup of biomass smoke-exposed subjects, MWA% was significantly greater in smokers than in non-smokers (MWA 69.1 vs. 65.3, P = .03), while EI was not statistically different (EI 7.1 vs. 10.4, P = .52).

CONCLUSIONS

Non-smoker males with COPD were younger and had a greater BMI than the smokers. Tobacco smoke exposure seemed to be associated with an emphysema-predominant phenotype, while biomass smoke exposure exhibited a significant interaction with tobacco smoking in an airway-predominant phenotype.

Defining and targeting health disparities in chronic obstructive pulmonary disease

The global burden of chronic obstructive pulmonary disease (COPD) continues to grow in part due to better outcomes in other major diseases and in part because a substantial portion of the worldwide population continues to be exposed to inhalant toxins. However, a disproportionate burden of COPD occurs in people of low socioeconomic status (SES) due to differences in health behaviors, sociopolitical factors, and social and structural environmental exposures. Tobacco use, occupations with exposure to inhalant toxins, and indoor biomass fuel (BF) exposure are more common in low SES populations. Not only does SES affect the risk of developing COPD and etiologies, it is also associated with worsened COPD health outcomes. Effective interventions in these people are needed to decrease these disparities. Efforts that may help lessen these health inequities in low SES include 1) better surveillance targeting diagnosed and undiagnosed COPD in disadvantaged people, 2) educating the public and those involved in health care provision about the disease, 3) improving access to cost-effective and affordable health care, and 4) markedly increasing the efforts to prevent disease through smoking cessation, minimizing use and exposure to BF, and decreasing occupational exposures. COPD is considered to be one the most preventable major causes of death from a chronic disease in the world; therefore, effective interventions could have a major impact on reducing the global burden of the disease, especially in socioeconomically disadvantaged populations.

COPD in Nonsmokers: Reports from the Tunisian Population-Based Burden of Obstructive Lung Disease Study

BACKGROUND

It's currently well known that smoking and increasing age constitute the most important risk factors for chronic obstructive pulmonary disease (COPD). However, little is known about COPD among nonsmokers. The present study aimed to investigate prevalence, risk factors and the profiles of COPD among nonsmokers based on the Tunisian Burden of Obstructive Lung Disease (BOLD) study.

METHODS

807 adults aged 40 years+ were randomly selected from the general population. We collected information about history of respiratory disease, risk factors for COPD and quality of life. Post-bronchodilator spirometry was performed for assessment of COPD. COPD diagnostic was based on the post-bronchodilator FEV1/FVC ratio, according to the Global Initiative for Obstructive Lung Disease (GOLD) guidelines. The lower limit of normal (LLN) was determined as an alternative threshold for the FEV1/FVC ratio.

RESULTS AND CONCLUSIONS

Among 485 nonsmokers, 4.7% met the criteria for GOLD grade I and higher COPD. These proportions were similar even when the LLN was used as a threshold. None of the nonsmokers with COPD reported a previous doctor diagnosis of COPD compared to 7.1% of smokers. Nonsmokers accounted for 45.1% of the subjects fulfilling the GOLD spirometric criteria of COPD. Nonsmokers were predominately men and reported more asthma problems than obstructed smokers. Among nonsmokers significantly more symptoms and higher co-morbidity were found among those with COPD. Increasing age, male gender, occupational exposure, lower body mass index and a previous diagnosis of asthma are associated with increased risk for COPD in nonsmokers. This study confirms previous evidence that nonsmokers comprise a substantial proportion of individuals with COPD. Nonsmokers with COPD have a specific profile and should, thus, receive far greater attention to prevent and treat chronic airway obstruction.

Long-term effects of pneumonia in young children

Each year an estimated 120 million episodes of pneumonia occur in children younger than 5 years of age, resulting in one million deaths globally. Within this age group the lungs are still developing by increasing alveoli numbers and airway dimensions. Pneumonia during this critical developmental period may therefore adversely affect the lung's structure and function, with increased risk of subsequent chronic lung disease. However, there are few longitudinal studies of pneumonia in otherwise healthy children that extend into adulthood to help address this important question. Birth cohort, longitudinal, case-control and retrospective studies have reported restrictive and obstructive lung function deficits, asthma, bronchiectasis, and chronic obstructive pulmonary disease. In particular, severe hospitalised pneumonia had the greatest risk for long-term sequelae. Most studies, however, were limited by incomplete follow-up, some reliance upon parental recall, risk of diagnostic misclassification, and potential confounders such as nutrition, social deprivation, and pre-existing small airways or lungs. More long-term studies measuring lung function shortly after birth are needed to help disentangle the complex relationships between pneumonia and later chronic lung disease, while also addressing host responses, types of infection, and potential confounding variables. Meanwhile, parents of young children with pneumonia need to be advised about the importance of symptom resolution, post-pneumonia. In addition, paying attention to factors associated with optimising lung growth such as good nutrition, minimising exposure to air pollution, avoiding cigarette smoke, and decreasing the risk of preventable infections through good hygiene and having their children fully vaccinated should be emphasised. Finally, in the developing world and for disadvantaged communities in developed countries, public health policies leading to good quality housing and heating, hygiene, education, and improving socio-economic status are also essential.

Prevalence and risk factors for COPD in greenhouse farmers: a large, cross-sectional survey of 5,880 farmers from northeast China

Background

COPD is one of the most common chronic diseases, and more and more farmers who were frequently exposed to greenhouse environments were diagnosed with COPD. However, little information is available on the prevalence of COPD among the greenhouse farmers. This study was conducted to assess the prevalence of COPD and investigate the potential risk factors for COPD among the Chinese greenhouse farmers.

Methods

Cross-sectional studies involving a sample of greenhouse farmers living in northeast China were performed via stratified-cluster-random sampling. All subjects were interviewed using a uniform questionnaire and underwent pulmonary function tests between 2006 and 2009, based on the diagnostic criteria of the Global Initiative for Chronic Obstructive Lung Disease. Multiple logistic regression analysis was conducted to examine the risk factors for COPD.

Results

Of the 5,880 greenhouse farmers from northeast China who were originally selected for this study, 5,420 questionnaires were completed. The overall prevalence of COPD in greenhouse farmers was 17.5%. The COPD prevalence was significantly higher in elderly subjects (≥50 years), current smokers, in those with lower body mass index (≤18.5 kg/m²) and less education, in those who were exposed to mushroom, flowers and poultry, and in those living in mountain and coastal region. Multiple logistic regression analysis revealed that age over 50 years old (odds ratio [OR]=298.69, 95% confidence interval [CI]=121.57–733.84), smoking (OR=2.18, 95% CI=1.84–2.59), planting mushroom and flowers (OR=1.46 and 1.53, 95% CI=1.13–1.87 and 1.24–1.95), and living in mountain and coastal region (OR=1.68 and 1.35, 95% CI=1.37–2.06 and 1.10–1.65) were associated with the development of COPD among greenhouse farmers.

Conclusion

In northeast China, COPD is highly prevalent among greenhouse farmers, and advanced age, smoking, planting mushroom, and flowers, as well as living in mountain and coastal regions, are potential risk factors for this disease.