Smoking duration alone provides stronger risk estimates of chronic obstructive pulmonary disease than pack-years

The association between smoking/vaping habits and self-reported respiratory symptoms

BACKGROUND

Smoking is well known for its harmful effect on the respiratory system, but whether vaping is less harmful is unknown. Therefore, the aim of this study was to assess the association of smoking/vaping habits with self-reported respiratory symptoms in vapers and cigarette smokers.

METHODS

An online survey was developed and shared on different vaping and smoking social media platforms and communities.

RESULTS

Out of the 891 respondents, 788 were vapers (77 pure vapers and 711 ex-smokers) and 103 were cigarette smokers. Smokers reported more frequently respiratory symptoms such as chest pain, wheezing and whistling, sputum production, cough, dry mouth, and smokers suffered from more shortness of breath, sore throat and disturbed sleep compared to vapers. The self-reported respiratory symptoms in vapers were mainly related to the nicotine strength of the product and number of puffs per use. There were no significant differences between pure vapers and vapers who were ex-smokers.

CONCLUSION

Self-reported severe respiratory symptoms were less frequent in vapers than smokers, irrespective of their smoking history. This suggests that vaping is less harmful than cigarette smoking.

Association of naples prognostic score and lung health: A population-based study

BACKGROUND

The Naples Prognostic Score (NPS) is a novel indicator of inflammatory and nutritional status, but its relationship to lung health is unknown.

OBJECTIVE

To evaluate the relationship of NPS to lung health problems.

METHODS

A total of 15,600 participants aged 20 years or older with an available assessment of chronic lung diseases were enrolled from the National Health and Nutrition Examination Survey 2007-2012. The NPS was calculated based on serum albumin, total cholesterol, neutrophil-to-lymphocyte ratio, and lymphocyte-to-monocyte ratio. Associations of NPS with chronic lung disease (diagnosed asthma, chronic bronchitis, and emphysema), respiratory symptoms (cough, phlegm production, wheeze, and exertional dyspnea), and spirometric measurements (FEV1, FVC, and obstructive or restrictive spirometry pattern) were evaluated. Kaplan-Meier survival analysis and multiple Cox regressions were used to assess the significance of NPS in relation to all-cause mortality and chronic lower respiratory diseases mortality in participants. Furthermore, to comprehensively assess the association between NSP and chronic lower respiratory diseases mortality, Fine-Gray subdistribution hazards model was performed to analyze non-chronic lower respiratory diseases mortality as a competitive risk.

RESULTS

People with a higher NPS score were associated with greater odds of asthma, chronic bronchitis, respiratory symptoms (including phlegm production, wheeze, and exertional dyspnea), and a greater risk of obstructive and restrictive spirometry. A higher NPS score was significantly associated with decreased FEV1 and FVC in both overall participants and those with lung health problems. Longitudinally, we found that those in the category with highest NPS were at greater risk of all-cause mortality and chronic lower respiratory diseases mortality in those with chronic lung disease, and respiratory symptoms.

CONCLUSIONS

An elevated NPS is associated with a host of adverse pulmonary outcomes. Prospective studies to define NPS as a biomarker for impaired lung health are warranted.

Pulmonary manifestations, treatments and outcomes of IgG4-related disease-a systematic literature review

Immunoglobulin G4-related disease (IgG4-RD) is a multisystem fibroinflammatory condition. A consistent feature of many cases is pulmonary infiltrates, or respiratory failure. This systematic literature review aims to summarise the pulmonary manifestations of IgG4-RD, including clinical outcomes and treatment. This review was registered on PROSPERO (CRD42023416410). Medline, Embase and Cochrane databases were searched for articles discussing IgG4-RD syndrome. Information was extracted on demographics, type and prevalence of pulmonary manifestations, treatment and clinical outcomes. Initially, after deduplication, 3123 articles were retrieved with 18 ultimately included. A pooled total of 724 patients with IgG4-RD were included, 68.6% male, mean age 59.4 years (SD 5.8) at disease onset. The most frequently described pulmonary manifestation was mediastinal lymphadenopathy (n = 186, 48.8%), followed by pulmonary nodules (n = 151, 39.6%) and broncho-vascular thickening (n = 85, 22.3%). Where treatment was reported, the majority of patients received glucocorticoids (n = 211, 93.4%). Other immunosuppressive therapy included cyclophosphamide (n = 31), azathioprine (n = 18), with mycophenolate mofetil (n = 6), rituximab (n = 6), methotrexate (n = 5) and other unspecified immunomodulators (50). Clinical outcomes were reported in 263 patients, where 196 patients had remission of their disease, 20 had relapse, 35 had stable disease, four had progression and eight patients died from complications of IgG4-RD. This systematic review summarises pulmonary manifestations, treatments and outcomes in patients with IgG4-RD. Pulmonary involvement in IgG4-RD is relatively common, leading to high levels of morbidity and mortality. Glucocorticoids remain the mainstay of treatment, but further work is required to explore the management of patients with pulmonary manifestations in association with IgG4-RD.

Association between prolonged dual use of cigarettes and E-cigarettes and psychosocial factors among U.S. Smokers: Secondary data analysis from the 2013 to 2019 PATH study

Objective

Dual use of combustible cigarettes and e-cigarettes is common among U.S. tobacco users, yet mis-perceptions about the harm of dual use persist, often oversimplifying its multifaceted exposure and health impacts. To address this gap, we evaluated the association of prolonged dual use (consecutive use for more than 1 year) with psychosocial factors, including perceptions of absolute and relative harm of e-cigarettes, social norms, and intentions to quit smoking, among U.S. adult smokers over time.

Methods

Using the data from Waves 1 to 5 (2013-2019) from the Population Assessment of Tobacco and Health (PATH) Study, we characterized dual use and prolonged dual use by sociodemographics and psychosocial factors among U.S. adult smokers. We examined the association between dual use, including prolonged dual use, and psychosocial factors over time using logistic regression.

Results

Dual use of smokers decreased from 19.8 % in 2013 to 16.4 % in 2019, and prolonged dual use among dual users decreased from 40.0 % in 2013 to 27.4 % in 2019. Prolonged dual users, independent of frequency of use, presented significantly higher cigarette dependence than temporary dual users. The perception of absolute e-cigarette harm (perceiving e-cigarettes as very or extremely harmful) was negatively associated with prolonged dual use. No significant association was found between prolonged dual use and perception of relative e-cigarette harm (perceiving e-cigarettes are less harmful than cigarettes) as well as with intentions to quit smoking and beliefs that most people disapprove of e-cigarette use.

Conclusion

Increased perceptions of absolute harm of e-cigarettes, rather than relative harm, appear to decrease prolonged dual use. Public health strategies should consider further emphasis in educating users of the absolute harm, as opposed to endorsing e-cigarette use as a harm reduction alternative, in their tobacco cessation efforts to further discourage dual use.

Untreated pulmonary sequestration with recurrent superinfection -supporting COPD development in a 42 year old male patient

BACKGROUND

Pulmonary sequestration is a congenital malformation in which nonfunctional lung tissue develops without connection to the bronchial system. The main complication is the occurrence of recurrent pneumonia.

CASE PRESENTATION

We describe the case of a patient who was incidentally diagnosed with PS as part of the diagnostic algorithm for community-acquired pneumonia. Due to the relatively late diagnosis, the recurrent bronchopulmonary was conducive to the development of COPD and pulmonary emphysema. For prognostic reasons, surgical resection was performed by posterolateral thoracotomy.

CONCLUSIONS

Although cigarette smoking is the main risk factor for developing COPD, recurring lung infections may have a synergistic effect. Sometimes recurrent infections are caused by a congenital malformation. Especially in adults who have had recurrent pneumonia since childhood.

Proposed Etiotypes for Chronic Obstructive Pulmonary Disease: Controversial Issues

The 2023 Global Initiative for Chronic Obstructive Lung Disease (GOLD) revised the definition of chronic obstructive pulmonary disease (COPD) to broadly include a variety of etiologies. A new taxonomy, composed of etiotypes, aims to highlight the heterogeneity in causes and pathogenesis of COPD, allowing more personalized management strategies and emphasizing the need for targeted research to understand and manage COPD better. However, controversy arises with including some diseases under the umbrella term of COPD, as their clinical presentations and treatments differ from classical COPD, which is smoking-related. COPD due to infection (COPD-I) and COPD due to environmental exposure (COPD-P) are classifications within the new taxonomy. Some disease entities in these categories show distinct clinical features and may not benefit from conventional COPD treatments, raising questions about their classification as COPD subtypes. There is also controversy regarding whether bronchiectasis with airflow limitations should be classified as an etiotype of COPD. This article discusses controversial issues associated with the proposed etiotypes for COPD in terms of COPD-I, COPD-P, and bronchiectasis. While the updated COPD definition by GOLD 2023 is a major step towards recognizing the disease's complexity, it also raises questions about the classification of related respiratory conditions. This highlights the need for further research to improve our understanding and approach to COPD management.

Coffee consumption was associated with a lower prevalence of airflow limitation in postmenopausal women

BACKGROUND

Several studies have suggested a potential correlation between menopause and airflow limitation. However, the presence of protective factors in postmenopausal women remains uncertain. Therefore, our study seeks to examine potential protective factors associated with a reduced prevalence of airflow limitation among postmenopausal women.

METHODS

Postmenopausal women were recruited from the Taiwan Biobank for this cross-sectional study. Airflow limitation was defined by a forced expiratory volume in the first second (FEV1)/forced vital capacity (FVC) ratio <0.7. The participants were categorized into two groups: non-coffee drinkers and coffee drinkers, and the association between coffee consumption and airflow limitation was examined using binary logistic regression models.

RESULTS

A total of 8149 women with available information were enrolled. Compared to the non-coffee drinkers, the coffee drinkers had a significantly lower prevalence of airflow limitation (7% vs. 5%). The odds ratio (OR) for airflow limitation was lower in the coffee drinkers than in the non-coffee drinkers (OR = 0.77; 95% confidence interval [CI] = 0.63 to 0.94) after adjusting for confounding factors. We also examined the association between daily coffee consumption in cups and airflow limitation. The women who consumed ≥2 cups of coffee per day had an OR of 0.74 (95% CI = 0.59 to 0.94) compared to those who did not consume coffee.

CONCLUSIONS

Our results suggest that habitual coffee consumption is associated with a reduction in the prevalence of airflow limitation in postmenopausal women, warranting further prospective studies to explore possible causal effects and mechanisms.

Productivity costs of lifelong smoking-the Northern Finland Birth Cohort 1966 study

BACKGROUND

Smoking is one of the leading causes of impaired health and mortality. Loss of paid and unpaid work and replacements due to morbidity and mortality result in productivity costs. Our aim was to investigate the productivity costs of lifelong smoking trajectories and cumulative exposure using advanced human capital method (HCM) and friction cost method (FCM).

METHODS

Within the Northern Finland Birth Cohort 1966 (NFBC1966), 10 650 persons were followed from antenatal period to age 55 years. The life course of smoking behaviour was assessed with trajectory modelling and cumulative exposure with pack-years. Productivity costs were estimated with advanced HCM and FCM models by using detailed, national register-based data on care, disability, mortality, education, taxation, occupation and labour market. A two-part regression model was used to predict productivity costs associated with lifelong smoking and cumulative exposure.

RESULTS

Of the six distinct smoking trajectories, lifetime smokers had the highest productivity costs followed by late starters, late adult quitters, young adult quitters and youth smokers. Never-smokers had the lowest productivity costs. The higher the number of pack-years, the higher the productivity costs. Uniform patterns were found in both men and women and when estimated with HCM and FCM. The findings were independent of other health behaviours.

CONCLUSIONS

Cumulative exposure to smoking is more crucial to productivity costs than starting or ending age of smoking. This suggests that the harmful effects of smoking depend on dose and duration of smoking and are irrespective of age when smoking occurred.

Evaluation of Salivary Biomarkers and Spirometry for Diagnosing COPD in Non-Smokers and Smokers of Polish Origin

Chronic obstructive pulmonary disease (COPD) is a prevalent respiratory condition with global implications. Accurate and timely diagnosis is critical; however, traditional diagnostic methods (based on spirometry) show limitations, prompting the search for predictive biomarkers and modern diagnostic techniques. This study explored the validation of COPD-related biomarkers (C-reactive protein, procalcitonin, neutrophil elastase, and alpha-1 antitrypsin) in saliva. A diverse cohort, including healthy non-smokers, healthy smokers, and COPD patients of Polish origin, underwent spirometry and marker analysis. The data correlated with clinical factors, revealing noteworthy relations. Firstly, salivary biomarker levels were compared with serum concentrations, demonstrating notable positive or negative correlations, depending on the factor. Further analysis within healthy individuals revealed associations between biomarker levels, spirometry, and clinical characteristics such as age, sex, and BMI. Next, COPD patients exhibited an enhanced concentration of biomarkers compared to healthy groups. Finally, the study introduced a breathing assessment survey, unveiling significant associations between self-perceived breathing and spirometric and tested parameters. Outcomes emphasized the relevance of subjective experiences in COPD research. In conclusion, this research underscored the potential of salivary biomarkers as diagnostic tools for COPD, offering a non-invasive and accessible alternative to traditional methods. The findings paved the way for improved modern diagnostic approaches.

Urban-rural and socio-economic differences in inhaled corticosteroid treatment for chronic obstructive pulmonary disease: A nationwide register-based cross-sectional study

BACKGROUND

Urban-rural disparities within chronic obstructive pulmonary disease (COPD) have been documented in USA, but not in Europe. Inhaled corticosteroids (ICS) are widely used in COPD despite strict recommendations. We aimed to investigate urban-rural and socioeconomic differences in ICS treatment for COPD.

METHODS

A Danish nationwide register-based cross-sectional study. All patients alive on the December 31, 2018 with a J44 ICD-10 diagnosis code (COPD) were included (99,057 patients). Daily average ICS dose was calculated from the accumulated ICS use during 2018 based on redeemed prescriptions. Patients were divided into groups: No ICS, low dose ICS, medium dose ICS, high dose ICS. A multinomial logistic regression model including educational level, co-habitation status, age, and sex was performed with "No ICS" as reference group.

RESULTS

Compared to capital municipalities, living in other municipality types was associated with an increased probability of receiving medium and high dose ICS treatment, and increasing odds ratios (ORs) were seen with increasing ICS dose (medium dose ICS: ORs between 1.31 (95 % confidence interval (CI) 1.24-1.38) and 1.35 (95%CI 1.28-1.41), high dose ICS: ORs between 1.73 (95%CI 1.59-1.88) and 1.80 (95%CI 1.68-1.92)). Patients had increased probability of receiving ICS treatment if they were female, were co-habiting, or had completed only primary education.

CONCLUSION

Patients with a hospital-registered COPD diagnosis in non-capital municipalities receive more ICS, and in higher doses, compared to patients in capital municipalities. This is the first study to confirm that such urban-rural differences exist in Europe, and further research on this area is warranted.

Cigarette smoke-induced dysbiosis: comparative analysis of lung and intestinal microbiomes in COPD mice and patients

BACKGROUND

The impact of cigarette smoke (CS) on lung diseases and the role of microbiome dysbiosis in chronic obstructive pulmonary disease (COPD) have been previously reported; however, the relationships remain unclear.

METHODS

Our research examined the effects of 20-week cigarette smoke (CS) exposure on the lung and intestinal microbiomes in C57BL/6JNarl mice, alongside a comparison with COPD patients' intestinal microbiome data from a public dataset.

RESULTS

The study found that CS exposure significantly decreased forced vital capacity (FVC), thickened airway walls, and induced emphysema. Increased lung damage was observed along with higher lung keratinocyte chemoattractant (KC) levels by CS exposure. Lung microbiome analysis revealed a rise in Actinobacteriota, while intestinal microbiome showed significant diversity changes, indicating dysbiosis. Principal coordinate analysis highlighted distinct intestinal microbiome compositions between control and CS-exposed groups. In the intestinal microbiome, notable decreases in Patescibacteria, Campilobacterota, Defferibacterota, Actinobacteriota, and Desulfobacterota were observed. We also identified correlations between lung function and dysbiosis in both lung and intestinal microbiomes. Lung interleukins, interferon-ɣ, KC, and 8-isoprostane levels were linked to lung microbiome dysbiosis. Notably, dysbiosis patterns in CS-exposed mice were similar to those in COPD patients, particularly of Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage 4 patients. This suggests a systemic impact of CS exposure.

CONCLUSION

In summary, CS exposure induces significant dysbiosis in lung and intestinal microbiomes, correlating with lung function decline and injury. These results align with changes in COPD patients, underscoring the important role of microbiome in smoke-related lung diseases.

Chronic obstructive pulmonary disease burden, grades and erythrocytosis at a tertiary hospital in western Uganda

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide among people over 40 years of age, and erythrocytosis is one of the major complications associated with increased mortality among COPD patients. The study aimed to determine the proportion of COPD, associated factors, and the burden of erythrocytosis among COPD participants.

METHODS AND MATERIALS

A descriptive cross-sectional study design was used. A consecutive sampling technique was used to obtain study participants at the Fort Portal Regional Referral Hospital outpatient clinic. Focused history and physical examination were carried out to select eligible participants. Participants were screened using the COPD population screener for spirometry after consenting to participate. The study enrolled all adults at risk of having COPD based on the COPD population screener and able to undergo spirometry. Spirometry was carried out according to the Global Chronic Obstructive Lung Disease and European Respiratory Society guidelines, and haemoglobin concentration was measured.

RESULTS

One hundred eighty participants were enrolled in the study, most of whom were females. The modal and mean age of participants was 60 years with 139 (77.2%) females and primary as the highest education level 149(82.8%). The proportion of COPD was 25% (45) [95% CI 18.9 - 32] and highest among females (68.9%) and those aged 60 years and above (70%). The combined COPD assessment tool groups had a proportion of 55.6%, 37.8%, 4.4%, and 2.2% for groups A, B, C, and D, respectively. Age < 50 years was protective against COPD, while for every additional year of smoking, there was an associated 6.5% increased risk compared to the general population. Additionally, the proportion of erythrocytosis among COPD participants was 6.7%.

CONCLUSIONS AND RECOMMENDATIONS

There was a high proportion of COPD among study participants (25%), with a 6.7% proportion of erythrocytosis. We recommend a complete blood count for every patient in groups C and D of the ABCD COPD GOLD groups.

The Fagerström Test for Nicotine Dependence, as a prognostic factor, in current smokers with and without COPD: A cross-sectional study in northern Greece

BACKGROUND

Smoking poses the most common risk factor for chronic obstructive pulmonary disease (COPD) and aggravates disease progression. Tobacco dependence inhibits smoking cessation and may affect smoking patterns that increase tobacco exposure and predispose to lung function decline.

AIMS AND OBJECTIVES

We aimed to assess tobacco dependence in current smokers with and without COPD and evaluate its role in disease development.

METHOD

This cross-sectional study was conducted in Greek rural areas. Current smokers completed the Fagerström Test for Nicotine Dependence and were classified into COPD and non-COPD groups based on spirometry parameters.

RESULTS

Among current smokers, 288 participants comprised the non-COPD and 71 the COPD group. Both presented moderate tobacco dependence, but smokers with COPD started to smoke earlier in the morning. Multiple logistic regression analysis revealed higher COPD prevalence in smokers with higher scores in the Fagerström test (odds ratio OR = 1.12, 95% confidence interval [1.01 - 1.24]) and older age (OR = 1.06 [1.03 - 1.09]), independently of pack-years smoking index. Multiple linear regression analysis in smokers with COPD showed that the forced expiratory volume in the 1st second decreased by 2.3% of the predicted value for each point increase in the Fagerström Test and 0.59% for each year of age, independently of participants' sex and pack-years smoking index.

CONCLUSION

The Fagerström score appears to indicate a higher probability for COPD and lung function deterioration when assessed along with age in current smokers. Smoking cessation support programs are fundamental to COPD prevention and management.

Lung transplantation for emphysema: only emphysema or something else?

Background

Some studies have reviewed lung explants histology to determine the frequency of pretransplant non-identified neoplasms or explore its diagnostic correlation with a previous diagnosis of interstitial lung disease (ILD). This study aims to review the histopathology of explants from patients who underwent lung transplantation (LT).

Methods

A retrospective, single-center study that included patients who underwent LT for emphysema between 01 January 2011 and 31 October 2021. The control group was composed of patients with lung cancer who underwent a lung resection between 01 November 2011 and 31 December 2019 and had a previous diagnosis of chronic obstructive pulmonary disease (COPD) prior to lung resection surgery. A systematic review was performed of histological findings to compare the frequency of additional histological diagnoses.

Results

The study sample included 160 patients (43.8%) who received a lung transplant for emphysema and 205 patients with COPD and lung cancer treated surgically. Although the patients in the cancer group were significantly older and had more comorbidities and higher cumulative tobacco consumption, transplant recipients received an additional significative histologic diagnosis more frequently (58.1% vs. 12.7%; P<0.001) including ILD, pneumoconiosis and others.

Conclusions

Significant additional histological findings were more frequent in the group of lung transplant recipients with emphysema. Notably, these findings were not explained by tobacco use, and they were significantly more frequent in transplant recipients than in patients with a previous diagnosis of COPD and higher cumulative tobacco consumption but with a better respiratory functional status.

Early detection of chronic obstructive pulmonary disease in primary care: a randomised controlled trial

BACKGROUND

Worldwide, chronic obstructive pulmonary disease (COPD) remains largely underdiagnosed.

AIM

To assess whether the use of Global Initiative for Chronic Obstructive Lung Disease (GOLD) questions and COPD coordination, either alone or combined, would detect new COPD cases in primary care.

DESIGN AND SETTING

GPs in Brittany, France, systematically enrolled patients aged 40-80 years over a 4-month period in this French multicentre cluster randomised controlled study.

METHOD

GPs were randomly allocated to one of four groups: control (standard of care), GOLD questions (adapted from symptoms and risk factors identified by GOLD), COPD coordination, and GOLD questions with COPD coordination. New cases of COPD were those confirmed by spirometry: post-bronchodilator forced expiratory volume in 1 second over forced vital capacity of <0.7.

RESULTS

In total, 11 430 consultations were conducted by 47 GPs, who enrolled 3162 patients who did not have prior diagnosed asthma or COPD. Among these, 802 (25%) were enrolled in the control, 820 (26%) in the GOLD questions, 802 (25%) in the COPD coordination, and 738 (23%) in the GOLD questions with COPD coordination groups. In the control group, COPD was not evoked, and no spirometry was prescribed. All new cases of COPD diagnosed (n = 24, 0.8%) were in the intervention groups, representing 6.8% of patients who performed spirometry. Statistically significantly more new cases of COPD were detected with COPD coordination (P = 0.01).

CONCLUSION

Interventions that can be easily implemented, such as the GOLD questions and COPD coordination, can identify new cases of COPD. Studies are needed to identify the most appropriate case-finding strategies for GPs to detect COPD in primary care for each country.

Incidence and Risk Factors for Pneumonitis Associated With Checkpoint Inhibitors in Advanced Non-Small Cell Lung Cancer: A Single Center Experience

INTRODUCTION

Immune checkpoint inhibitor (ICI) pneumonitis causes substantial morbidity and mortality. Estimates of real-world incidence and reported risk factors vary substantially.

METHODS

We conducted a retrospective review of 419 patients with advanced non-small cell lung cancer (NSCLC) who were treated with anti-PD-(L)1 with or without anti-CTLA-4 therapy. Clinical, imaging, and microbiological data were evaluated by multidisciplinary adjudication teams. The primary outcome of interest was grade ≥2 (CTCAEv5) pneumonitis. Clinicopathologic variables, tobacco use, cancer therapies, and preexisting lung disease were assessed for univariate effects using Cox proportional hazards models. We created multivariate Cox proportional hazards models to assess risk factors for pneumonitis and mortality. Pneumonitis, pneumonia, and progression were modeled as time-dependent variables in mortality models.

RESULTS

We evaluated 419 patients between 2013 and 2021. The cumulative incidence of pneumonitis was 9.5% (40/419). In a multivariate model, pneumonitis increased the risk for mortality (HR 1.6, 95% CI, 1.0-2.5), after adjustment for disease progression (HR 1.6, 95% CI, 1.4-1.8) and baseline shortness of breath (HR 1.5, 95% CI, 1.2-2.0). Incomplete resolution was more common with more severe pneumonitis. Interstitial lung disease was associated with higher risk for pneumonitis (HR 5.4, 95% CI, 1.1-26.6), particularly in never smokers (HR 26.9, 95% CI, 2.8-259.0).

CONCLUSION

Pneumonitis occurred at a high rate and significantly increased mortality. Interstitial lung disease, particularly in never smokers, increased the risk for pneumonitis.

Tobacco Patterns and Risk of Chronic Obstructive Pulmonary Disease: Results From a Cross-Sectional Study

INTRODUCTION

There is still uncertainty about which aspects of cigarette smoking influence the risk of Chronic Obstructive Pulmonary Disease (COPD). The aim of this study was to estimate the COPD risk as related to duration of use, intensity of use, lifetime tobacco consumption, age of smoking initiation and years of abstinence.

METHODS

We conducted an analytical cross-sectional study based on data from the EPISCAN-II study (n=9092). All participants underwent a face-to-face interview and post-bronchodilator spirometry was performed. COPD was defined as post-bronchodilator FEV1/FVC<70%. Parametric and nonparametric logistic regression models with generalized additive models were used.

RESULTS

8819 persons were included; 858 with COPD and 7961 without COPD. The COPD risk increased with smoking duration up to ≥50 years [OR 3.5 (95% CI: 2.3-5.4)], with smoking intensity up to ≥39cig/day [OR 10.1 (95% CI: 5.3-18.4)] and with lifetime tobacco consumption up to >29 pack-years [OR 3.8 (95% CI: 3.1-4.8)]. The COPD risk for those who started smoking at 22 or later was 0.9 (95% CI: 0.6-1.4). The risk of COPD decreased with increasing years of cessation. In comparison with both never smokers and current smokers, the lowest risk of COPD was found after 15-25 years of abstinence.

CONCLUSION

COPD risk increases with duration, intensity, and lifetime tobacco consumption and decreases importantly with years of abstinence. Age at smoking initiation shows no effect. After 15-25 years of cessation, COPD risk could be equal to that of a never smoker. This work suggests that the time it takes to develop COPD in a smoker is about 30 years.

Up in smoke? Limited evidence of a smoking harm paradox in 17-year cohort study

BACKGROUND

Socioeconomic differences in the impact of alcohol consumption on health have been consistently reported in the so-called "alcohol harm paradox" (i.e., individuals from higher socioeconomic backgrounds (SES) drink more alcohol than individuals from lower SES, but the latter accrue more alcohol-related harm). Despite the severe health risks of smoking however, there is a scarcity of studies examining a possible "smoking harm paradox" (SHP). We aim to fill this gap.

METHODS

We conducted a prospective cohort study with adolescents from the Norwegian Longitudinal Health Behaviour Study (NLHB). Our study used data from ages 13 to 30 years. To analyse our data, we used the random-intercept cross-lagged panel model (RI-CLPM) with smoking and self-reported health as mutual lagged predictors and outcomes as well as parental income and education as grouping variables. Parental income and education were used as proxies for adolescent socioeconomic status (SES). Smoking was examined through frequency of smoking (every day, every week, less than once a week, not at all). General health compared to others was measured by self-report.

RESULTS

Overall, we found inconclusive evidence of the smoking harm paradox, as not all effects from smoking to self-reported health were moderated by SES. Nevertheless, the findings do suggest that smoking predicted worse subjective health over time among individuals in the lower parental education group compared with those in the higher parental education group. This pattern was not found for parental income.

CONCLUSIONS

While our results suggest limited evidence for a smoking harm paradox (SHP), they also suggest that the impact of adolescent smoking on later subjective health is significant for individuals with low parental education but not individuals with high parental education. This effect was not found for parental income, highlighting the potential influence of parental education over income as a determinant of subjective health outcomes in relation to smoking.

Identification of predictive factors for early relapse in patients with unresectable stage III non-small cell lung cancer receiving consolidation durvalumab after concurrent chemoradiation therapy

BACKGROUND

Patients with locally advanced, unresectable, non-small cell lung cancer (NSCLC) receiving definitive concurrent chemoradiation therapy (CCRT) benefit from durvalumab consolidation therapy. However, predictive factors for early relapse during durvalumab maintenance have not yet been identified.

METHODS

The present study included the lung cancer cohort of the Catholic Medical Centers at the Catholic University of Korea from January 2018 to December 2021. A total of 51 NSCLC patients treated with durvalumab consolidation therapy after definitive CCRT were included in the analysis. Early relapse was defined as patients experiencing relapse within 6 months of starting initial durvalumab therapy.

RESULTS

Among the 51 patients, 15 (29.4%) relapsed during the study period. Median time from initial therapy of durvalumab to progression was 451.00 ± 220.87 days (95% confidence interval [CI]: 18.10-883.90) in overall patients. In multivariate analysis, younger age (adjusted odds ratio [aOR], 0.792; 95% CI: 0.642-0.977; p = 0.030), higher pack-years (aOR, 1.315; 95% CI: 1.058-1.635; p = 0.014), non-COPD (aOR, 0.004; 95% CI: 0.000-0.828; p = 0.004) and anemia (aOR, 234.30; 95% CI: 1.212-45280.24; p = 0.042), were independent predictive factors for early relapse during durvalumab consolidation therapy.

CONCLUSION

Younger age, higher number of pack-years, non-COPD, and anemia were independent predictive factors for early relapse during durvalumab consolidation therapy in patients with unresectable stage III NSCLC after definitive CCRT. Careful patient selection and clinical attention are needed for high-risk individuals.

Associations between birth weight and lung function in a Japanese adult population: The tohoku medical megabank community-based cohort study

BACKGROUND

Birth weight, as a measure of intrauterine growth, is commonly used in epidemiological studies and is reported to be associated with adult lung function. However, findings regarding this association in previous studies have been inconsistent. Furthermore, no studies have reported associations stratified by age or smoking status, or adjusted for eosinophil count or other parameters related to type 2 airway inflammation.

METHODS

This cross-sectional study included 2632 men and 7237 women aged ≥20 years living in Miyagi Prefecture, Japan. Lung function was assessed based on spirometry. Birth weight data were obtained through a questionnaire survey. Analysis of covariance was used to evaluate the associations between birth weight and lung function, adjusting for potential confounders. Stratified analyses by age and smoking status were also conducted, together with a sub-analysis for low birth-weight participants.

RESULTS

Birth weight was positively associated with forced expiratory volume in 1 s (FEV1) for both sexes and with vital capacity in women, after adjusting for height, age, smoking status, and parameters related to type 2 airway inflammation. The stratified analysis for smoking status revealed associations in never-smokers and ex-smokers. When stratified by age, the associations were confirmed in middle-aged participants. The effect of smoking status on the FEV1 of low birth-weight participants was not significant.

CONCLUSIONS

Our analysis of a large, Japanese adult population showed that birth weight was independently and positively associated with adult lung function, even after adjustment for age, height, smoking status, and parameters related to type 2 airway inflammation.

Health-Related Quality of Life and Stress-Related Disorders in Patients with Bronchiectasis after Pulmonary Resection

This multicenter, cross-sectional study investigates the potential correlation between the development of bronchiectasis after lung resection surgery and the health-related quality of life (HRQoL) of the patients. The study aims to provide new insights into the long-term outcomes of patients post-lung resection surgery. The study includes adult patients who underwent lung resection surgery for suspicious lung nodules and developed bronchiectasis within a follow-up period of six months. Bronchiectasis was confirmed by high-resolution computed tomography scans. The patient's health-related quality of life (HRQoL), anxiety, depression, and stress-related disorders were assessed using WHOQOL-BREF, SF-36, HADS, and PSS-10 questionnaires. Out of the 135 patients included in the study, 44 developed bronchiectasis after lung resection surgery. No statistically significant differences were observed between the groups in terms of demographics and medical history. Patients with bronchiectasis demonstrated a lower overall health status, increased deterioration of respiratory symptoms, lower physical activity levels, lower quality of life scores, and experienced more severe anxiety symptoms. Additionally, patients in this group also perceived higher levels of stress; although, the correlation with physical functioning was contradictory. The development of bronchiectasis post-lung resection surgery was associated with poorer quality of life, increased respiratory symptoms, higher anxiety levels, and increased perception of stress. While the correlation between bronchiectasis and HRQoL was statistically significant, the contradictory correlations with stress and physical functioning call for further research. This study underscores the importance of ongoing patient monitoring and the detailed evaluation of respiratory function following lung resection surgery for lung nodules, especially among those who develop bronchiectasis.

Cigarettes, ENDS Use, and Chronic Obstructive Pulmonary Disease Incidence: A Prospective Longitudinal Study

INTRODUCTION

Understanding the relationship between ENDS use and chronic obstructive pulmonary disease (COPD) and other respiratory conditions is critical. However, most previous studies have not fully adjusted for cigarette smoking history.

METHODS

Using Waves 1-5 of the U.S. Population Assessment of Tobacco and Health study, the association between ENDS use and self-reported incident COPD was examined among adults aged 40+ years using discrete-time survival models. Current ENDS use was measured as a time-varying covariate, lagged by 1 wave, defined as established daily or some days of use. Multivariable models were adjusted for baseline demographics (age, sex, race/ethnicity, education), health characteristics (asthma, obesity, exposure to second-hand smoke), and smoking history (smoking status and cigarette pack years). Data were collected between 2013 and 2019, and the analysis was conducted in 2021-2022.

RESULTS

Incident COPD was self-reported by 925 respondents during the 5-year follow-up. Before adjusting for other covariates, time-varying ENDS use appeared to double COPD incidence risk (hazard ratio=1.98, 95% CI=1.44, 2.74). However, ENDS use was no longer associated with COPD (adjusted hazard ratio=1.10, 95% CI=0.78, 1.57) after adjusting for current cigarette smoking and cigarette pack years.

CONCLUSIONS

ENDS use did not significantly increase the risk of self-reported incident COPD over a 5-year period once current smoking status and cigarette pack years were included. Cigarette pack years, by contrast, remained associated with a net increase in COPD incidence risk. These findings highlight the importance of using prospective longitudinal data and adequately controlling for cigarette smoking history to assess the independent health effects of ENDS.

Longitudinal Follow-Up of Participants With Tobacco Exposure and Preserved Spirometry

Importance

People who smoked cigarettes may experience respiratory symptoms without spirometric airflow obstruction. These individuals are typically excluded from chronic obstructive pulmonary disease (COPD) trials and lack evidence-based therapies.

Objective

To define the natural history of persons with tobacco exposure and preserved spirometry (TEPS) and symptoms (symptomatic TEPS).

Design, Setting, and Participants

SPIROMICS II was an extension of SPIROMICS I, a multicenter study of persons aged 40 to 80 years who smoked cigarettes (>20 pack-years) with or without COPD and controls without tobacco exposure or airflow obstruction. Participants were enrolled in SPIROMICS I and II from November 10, 2010, through July 31, 2015, and followed up through July 31, 2021.

Exposures

Participants in SPIROMICS I underwent spirometry, 6-minute walk distance testing, assessment of respiratory symptoms, and computed tomography of the chest at yearly visits for 3 to 4 years. Participants in SPIROMICS II had 1 additional in-person visit 5 to 7 years after enrollment in SPIROMICS I. Respiratory symptoms were assessed with the COPD Assessment Test (range, 0 to 40; higher scores indicate more severe symptoms). Participants with symptomatic TEPS had normal spirometry (postbronchodilator ratio of forced expiratory volume in the first second [FEV1] to forced vital capacity >0.70) and COPD Assessment Test scores of 10 or greater. Participants with asymptomatic TEPS had normal spirometry and COPD Assessment Test scores of less than 10. Patient-reported respiratory symptoms and exacerbations were assessed every 4 months via phone calls.

Main Outcomes and Measures

The primary outcome was assessment for accelerated decline in lung function (FEV1) in participants with symptomatic TEPS vs asymptomatic TEPS. Secondary outcomes included development of COPD defined by spirometry, respiratory symptoms, rates of respiratory exacerbations, and progression of computed tomographic-defined airway wall thickening or emphysema.

Results

Of 1397 study participants, 226 had symptomatic TEPS (mean age, 60.1 [SD, 9.8] years; 134 were women [59%]) and 269 had asymptomatic TEPS (mean age, 63.1 [SD, 9.1] years; 134 were women [50%]). At a median follow-up of 5.76 years, the decline in FEV1 was -31.3 mL/y for participants with symptomatic TEPS vs -38.8 mL/y for those with asymptomatic TEPS (between-group difference, -7.5 mL/y [95% CI, -16.6 to 1.6 mL/y]). The cumulative incidence of COPD was 33.0% among participants with symptomatic TEPS vs 31.6% among those with asymptomatic TEPS (hazard ratio, 1.05 [95% CI, 0.76 to 1.46]). Participants with symptomatic TEPS had significantly more respiratory exacerbations than those with asymptomatic TEPS (0.23 vs 0.08 exacerbations per person-year, respectively; rate ratio, 2.38 [95% CI, 1.71 to 3.31], P < .001).

Conclusions and Relevance

Participants with symptomatic TEPS did not have accelerated rates of decline in FEV1 or increased incidence of COPD vs those with asymptomatic TEPS, but participants with symptomatic TEPS did experience significantly more respiratory exacerbations over a median follow-up of 5.8 years.

Impact of Bronchiectasis on COPD Severity and Alpha-1 Antitrypsin Deficiency as a Risk Factor in Individuals with a Heavy Smoking History

Rationale

Bronchiectasis is common among those with heavy smoking histories, but risk factors for bronchiectasis, including alpha-1 antitrypsin deficiency, and its implications for COPD severity are uncharacterized in such individuals.

Objectives

To characterize the impact of bronchiectasis on COPD and explore alpha-1antitrypsin as a risk factor for bronchiectasis.

Methods

SubPopulations and InteRmediate Outcome Measures In COPD Study (SPIROMICS) participants (N=914; ages 40-80 years; ≥20-pack-year smoking) had high-resolution computed tomography (CT) scans interpreted visually for bronchiectasis, based on airway dilation without fibrosis or cicatrization. We performed regression-based models of bronchiectasis with clinical outcomes and quantitative CT measures. We deeply sequenced the gene encoding -alpha-1 antitrypsin, SERPINA1, in 835 participants to test for rare variants, focusing on the PiZ genotype (Glu366Lys, rs28929474).

Measurements and Main Results

We identified bronchiectasis in 365 (40%) participants, more frequently in women (45% versus 36%, p=0.0045), older participants (mean age=66[standard deviation (SD)=8.3] versus 64[SD=9.1] years, p=0.0083), and those with lower lung function (forced expiratory volume in 1 second [FEV1 ] percentage predicted=66%[SD=27] versus 77%[SD=25], p<0.0001; FEV1 to forced vital capacity [FVC] ratio=0.54[0.17] versus 0.63[SD=0.16], p<0.0001). Participants with bronchiectasis had greater emphysema (%voxels ≤-950 Hounsfield units, 11%[SD=12] versus 6.3%[SD=9], p<0.0001) and parametric response mapping functional small airways disease (26[SD=15] versus 19[SD=15], p<0.0001). Bronchiectasis was more frequent in the combined PiZZ and PiMZ genotype groups compared to those without PiZ, PiS, or other rare pathogenic variants (N=21 of 40 [52%] versus N=283 of 707[40%], odds ratio [OR]=1.97; 95% confidence interval [CI]=1.002, 3.90, p=0.049), an association attributed to White individuals (OR=1.98; 95%CI = 0.9956, 3.9; p=0.051).

Conclusions

Bronchiectasis was common in those with heavy smoking histories and was associated with detrimental clinical and radiographic outcomes. Our findings support alpha-1antitrypsin guideline recommendations to screen for alpha-1 antitrypsin deficiency in an appropriate bronchiectasis subgroup with a significant smoking history.

Clinical Use of an Exposure, Symptom, and Spirometry Algorithm to Stratify Smokers into COPD Risk Phenotypes: A Case Finding Study Combined with Smoking Cessation Counseling

Background

Chronic obstructive pulmonary disease (COPD) case-finding aims to detect airflow obstruction in symptomatic smokers and ex-smokers. We used a clinical algorithm including smoking, symptoms, and spirometry to classify smokers into COPD risk phenotypes. In addition, we evaluated the acceptability and effectiveness of including smoking cessation advice in the case-finding intervention.

Methods

Smoking, symptoms, and spirometry abnormalities (airflow obstruction: forced expiratory volume in 1 second [FEV1] to forced vital capacity [FVC] <0.7 or preserved-ratio spirometry (FEV1<80% of predicted value and FEV1/FVC ratio ≥ 0.7)] were assessed in a group of 864 smokers aged ≥ 30 years. The combination of these parameters allowed the identification of 4 phenotypes: Phenotype A (no symptoms, normal spirometry; reference), Phenotype B (symptoms; normal spirometry; possible COPD), Phenotype C (no symptoms; abnormal spirometry; possible COPD), and Phenotype D (symptoms; abnormal spirometry; probable COPD). We assessed phenotype differences in clinical variables and modeled the trend from phenotype A to phenotype D. Smoking cessation advice based on spirometry was provided. Follow-up was done by telephone 3 months later.

Results

Using smokers without symptoms or abnormal spirometry (phenotype A; n=212 [24.5%]) as a reference, smokers were classified into possible COPD (phenotype B;n=332 [38.4%]; and C: n=81 [9.4%]) and probable COPD (phenotype D: n=239 [27.2%]). The trend from baseline phenotype A to probable COPD phenotype D was significant for the number of cigarettes/day and the number of years of smoking (p=0.0001). At follow-up, 58 (7.7%) of the respondents (n=749) reported that they had quit smoking.

Conclusions

Our clinical algorithm allowed us to classify smokers into COPD phenotypes whose manifestations were associated with smoking intensity and to significantly increase the number of smokers screened for COPD. Smoking cessation advice was well accepted, resulting in a low but clinically significant quit rate.

Analysis of the Comorbid Course of Chronic Obstructive Pulmonary Disease

(1) Background. Chronic obstructive pulmonary disease (COPD) has a heterogeneous natural history, manifested both in the variability of clinical features and in association with various comorbid pathologies. Atherosclerotic cardiovascular disease (ASCVD) is of great clinical importance and contributes significantly to the natural history and prognosis of COPD. The present study aimed to evaluate the nature of the comorbid course of COPD during a 15-year follow-up. (2) Methods: A total of 170 male COPD patients were included in this study. Spirometry values, symptom severity, presence of risk factors, and comorbidities were considered. Prognostic factors were evaluated using the Kaplan-Meier method. (3) Results: ASCVD was the most common comorbidity and the main cause of death in patients with COPD. Patients with comorbid COPD and ASCVD had more severe dyspnea, higher frequency of COPD exacerbations, and worse survival than patients without ASCVD (p < 0.01). Among patients with COPD, the risk of death from ASCVD was higher in those older than 60 years (OR 3.23, 95% CI [1.72, 6.07]), those with rapidly declining FEV1 (OR 4.35, 95% CI [2.28, 8.30]), those with more than two exacerbations per year (OR 3.21, 95% CI [1.71, 6.11]), and those with a pack year index greater than 30 (OR 2.75, 95% CI [1.38, 5.51]. High Charlson comorbidity index scores in patients with COPD were associated with a more severe disease course, including severity of dyspnea, frequency of exacerbations, and multivariate index scores. A high Charlson comorbidity index score was an adverse prognostic factor. (4) Conclusions: ASCVD influences the course of the disease and is a major cause of mortality in COPD patients.

Predicting Lung Function Using Biomarkers in Alpha-1 Antitrypsin Deficiency

Lung disease progression in alpha-1 antitrypsin deficiency (AATD) is heterogenous and manifests in different ways. Blood biomarkers are an attractive method of monitoring diseases as they are easy to obtain and repeatable. In non-AATD COPD, blood biomarker panels have predicted disease severity, progression, and mortality. We measured a panel of seven serum biomarkers in 200 AATD patients and compared levels between those with COPD and those without. We assessed whether biomarkers were associated with baseline lung function parameters (FEV1 and TLco) or absolute change in these parameters. In total, 111 patients with a severely deficient genotype of AATD (PiZZ) and COPD were included in the analyses. Pearson's correlation coefficient was measured for biomarker correlations and models were compared using ANOVA. CRP and CCL18 were significantly higher in the serum of AATD COPD versus AATD with no COPD. Biomarkers were not predictive of cross-sectional lung function measurements, however, CC16 was significantly associated with an absolute change in TLco (p = 0.018). An addition of biomarkers to the predictive model for TLco added significant value over covariates alone (R2 0.13 vs. 0.02, p = 0.028). Our findings suggest that CC16 is predictive of emphysema progression in AATD COPD. Proteomics data may reveal alternative candidate biomarkers and further work should include the use of longitudinal biomarker measurements.

Impact of Lung-Related Polygenic Risk Scores on Chronic Obstructive Pulmonary Disease Risk and Their Interaction with w-3 Fatty Acid Intake in Middle-Aged and Elderly Individuals

Chronic obstructive pulmonary disease (COPD) is a complex, progressive respiratory disorder with persistent airflow limitation and tissue destruction. We aimed to explore the genetic impact of COPD and its interaction with nutrient intake in 8840 middle-aged and elderly individuals from the Ansan/Ansung cohorts. Participants were diagnosed with COPD if the ratio of forced expiratory volume in 1 s (FEV1) to forced vital capacity (FVC) was less than 0.7 using spirometry, and if they were previously diagnosed with COPD by a physician. Genome-wide association studies (GWAS) were performed to screen for genetic variants associated with COPD risk. Among them, we selected the genetic variants that exhibited interactions using the generalized multifactor dimensionality reduction (GMDR) method. The polygenic risk score (PRS) was computed by summing the number of risk alleles in the SNP-SNP interaction models that adhered to specific rules. Subsequently, participants were categorized into low-PRS, medium-PRS, and high-PRS groups. The participants with COPD exhibited significantly lower FEV1/FVC ratios (0.64) than those without COPD (0.82). It was positively associated with inflammation markers (serum C-reactive protein and white blood cell levels). A higher proportion of COPD participants were smokers and engaged in regular exercise. The 5-SNP model consisted of FAM13A_rs1585258, CAV1_rs1997571, CPD_rs719601, PEPD_rs10405598, and ITGA1_rs889294, and showed a significant association with COPD risk (p < 0.001). Participants in the high-PRS group of this model had a 2.2-fold higher risk of COPD than those in the low-PRS group after adjusting for covariates. The PRS interacted with w-3 fatty acid intake and exercise, thus influencing the risk of COPD. There was an increase in COPD incidence among individuals with a higher PRS, particularly those with low consumption of w-3 fatty acid and engaged in high levels of exercise. In conclusion, adults with a high-PRS are susceptible to COPD risk, and w-3 fatty acid intake and exercise may impact the risk of developing COPD, potentially applying to formulate precision medicines to prevent COPD.

Current Perspectives of Pharmacotherapies for COPD

Pharmacotherapies and avoidance of environmental/inhaled toxins are core to managing COPD. Compared to the drugs available 50 years ago, there has been substantial progress with COPD pharmacotherapies, but gaps in adherence and inhaler use persist. Personalizing inhaled pharmacotherapies is now possible with digital technologies by objectively documenting adherence and guiding inhaler technique. Another means to improve existing pharmacotherapies is through phenotyping and biomarkers. This is especially important considering the heterogeneity of the disease COPD. Blood eosinophils are now a recommended biomarker to guide use of inhaled corticosteroids and biologics in COPD. On the near horizon, we will see new inhaled medications as dual phosphodiesterase inhibitors, drugs to treat basic protein abnormalities as in alpha-1 antitrypsin deficiency that could have remarkable benefits, and biologic drugs targeting specific cell/mediator types in the COPD population. Characterization of COPD phenotypes, as asthma/COPD overlap and comorbid heart disease are vital to understand how to optimize pharmacotherapies. Importantly, we must determine how to optimize current medications; otherwise, we will repeat the same mistakes with new medications. But as we know so well, as we peel one layer of complexity, we encounter many more questions, all the while dedicated to limiting the burden of COPD.

Age at smoking initiation and smoking cessation influence the incidence of stroke in China: a 10-year follow-up study

Our study aimed to explore the correlation between age at smoking initiation and smoking cessation for the risk for stroke in China. We investigated 50,174 participants from one of the urban areas of China Kadoorie Biobank (CKB) Study. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) for association between smoking and incidence of stroke were estimated using Cox regression model. During a median of 10.7 years of follow-up, 4370 total stroke cases were documented. Among men, comparing current smokers to never smokers, the HR of total stroke for current smokers was 1.279 (95% CI, 1.134-1.443) for total stroke. The HRs of total stroke were 1.344 (1.151-1.570) for those started smoking at age less than 20 years, 1.254 (1.090-1.443) for those started smoking at age 20-30 years, and 1.205 (1.012-1.435) for those started smoking at age 30 year and above, with a dose-response relation (P for trend, 0.004). Comparing former smokers to current smokers, in the low pack-year group, those stopped smoking at age less than 65 years had a 18.2% decreased risk for total stroke (0.818; 0.673-0.994). The decreased risk was not found in those stopped smoking at age 65 years and above. Similar results were observed in the high pack-year group. In conclusion, we found that current smokers had a higher stroke risk than never smokers, and the risk increased with a younger age at smoking initiation. Smoking cessation can reduce the risk for stroke, especially could benefit from cessation at a younger age.

Partial pressure of carbon dioxide levels reflect disease severity in idiopathic pleuroparenchymal fibroelastosis

BACKGROUND

Hypercapnia can cause a disturbance of consciousness and adversely affect a patient's general condition. Patients with interstitial lung disease seldom experience hypercapnia. Hypercapnia is a typical phenomenon in patients with pleuroparenchymal fibroelastosis (PPFE), especially in advanced stages. However, the clinical significance of hypercapnia in patients with idiopathic PPFE (iPPFE) has not been studied in detail.

METHODS

We retrospectively selected patients with iPPFE who had undergone blood gas analysis. The first blood gas data obtained after iPPFE diagnosis were examined. The partial pressure of carbon dioxide (PCO₂) levels and their association with characteristic iPPFE parameters, including the flat chest index (the ratio of the anteroposterior diameter of the thoracic cage to the transverse diameter of the thoracic cage), were investigated.

RESULTS

A total of 47 patients with iPPFE were included in this study. The PCO₂ level was moderately and inversely correlated with the forced vital capacity. (r = -0.431, P = 0.014), flat chest index (r = -0.497, P < 0.001), and body mass index (r = -0.313, P = 0.038) and was positively correlated with residual volume/total lung capacity. (r = 0.514, P < 0.01). A higher PCO₂ level was also significantly associated with poorer prognosis in patients with iPPFE.

CONCLUSIONS

PCO₂ levels could be used as an indicator of disease severity in patients with iPPFE.

Factors influencing influenza, pneumococcal and shingles vaccine uptake and refusal in older adults: a population-based cross-sectional study in England

OBJECTIVES

Uptake of influenza, pneumococcal and shingles vaccines in older adults vary across regions and socioeconomic backgrounds. In this study, we study the coverage and factors associated with vaccination uptake, as well as refusal in the unvaccinated population and their associations with ethnicity, deprivation, household size and health conditions.

DESIGN, SETTING AND PARTICIPANTS

This is a cross-sectional study of adults aged 65 years or older in England, using a large primary care database. Associations of vaccine uptake and refusal in the unvaccinated with ethnicity, deprivation, household size and health conditions were modelled using multivariable logistic regression.

OUTCOME MEASURE

Influenza, pneumococcal and shingles vaccine uptake and refusal (in the unvaccinated).

RESULTS

This study included 2 054 463 patients from 1318 general practices. 1 711 465 (83.3%) received at least one influenza vaccine, 1 391 228 (67.7%) pneumococcal vaccine and 690 783 (53.4%) shingles vaccine. Compared with White ethnicity, influenza vaccine uptake was lower in Chinese (OR 0.49; 95% CI 0.45 to 0.53), 'Other ethnic' groups (0.63; 95% CI 0.60 to 0.65), black Caribbean (0.68; 95% CI 0.64 to 0.71) and black African (0.72; 95% CI 0.68 to 0.77). There was generally lower vaccination uptake among more deprived individuals, people living in larger household sizes (three or more persons) and those with fewer health conditions. Among those who were unvaccinated, higher odds of refusal were associated with the black Caribbean ethnic group and marginally with increased deprivation, but not associated with higher refusal in those living in large households or those with lesser health conditions.

CONCLUSION

Certain ethnic minority groups, deprived populations, large households and 'healthier' individuals were less likely to receive a vaccine, although higher refusal was only associated with ethnicity and deprivation but not larger households nor healthier individuals. Understanding these may inform tailored public health messaging to different communities for equitable implementation of vaccination programmes.

Biological and Genetic Mechanisms of COPD, Its Diagnosis, Treatment, and Relationship with Lung Cancer

Chronic obstructive pulmonary disease (COPD) is one of the most prevalent chronic adult diseases, with significant worldwide morbidity and mortality. Although long-term tobacco smoking is a critical risk factor for this global health problem, its molecular mechanisms remain unclear. Several phenomena are thought to be involved in the evolution of emphysema, including airway inflammation, proteinase/anti-proteinase imbalance, oxidative stress, and genetic/epigenetic modifications. Furthermore, COPD is one main risk for lung cancer (LC), the deadliest form of human tumor; formation and chronic inflammation accompanying COPD can be a potential driver of malignancy maturation (0.8-1.7% of COPD cases develop cancer/per year). Recently, the development of more research based on COPD and lung cancer molecular analysis has provided new light for understanding their pathogenesis, improving the diagnosis and treatments, and elucidating many connections between these diseases. Our review emphasizes the biological factors involved in COPD and lung cancer, the advances in their molecular mechanisms' research, and the state of the art of diagnosis and treatments. This work combines many biological and genetic elements into a single whole and strongly links COPD with lung tumor features.

ROS induced the Rab26 promoter hypermethylation to promote cigarette smoking-induced airway epithelial inflammation of COPD through activation of MAPK signaling

Cigarette smoking (CS) exposure-induced airway inflammatory responses drive the occurrence and development of emphysema and chronic obstructive pulmonary disease (COPD). However, its precise mechanisms have not been fully elucidated. In this study, we explore the role of Rab26 in CS exposure modulating the inflammatory response of airway epithelium and the novel mechanism of CS exposure regulation Rab26. These data showed that CS exposure and H₂O₂ (a type of ROS) suppressed the expression of Rab26 and increased the expression of DNMT3b in vivo and in vitro. GEO data analysis found the level of Rab26 was decreased in the lung tissue of COPD patients. CSE-induced ROS promoted DNA methylation of the Rab26 promoter and inhibited its promoter activity by elevating the DNMT3b level. Antioxidants N-Acetyl-l-cysteine (NAC), 5-Aza-2'-deoxycytidine (5-AZA) (DNA methylation inhibitor) and DNMT3B siRNA alleviated CSE's inhibitory effect on Rab26 expression in vitro. Importantly, NAC alleviated the improved expression of Rab26 and reduced DNMT3B expression, in the airway of smoking exposure as well as attenuated the inflammatory response in vivo. Overexpression of Rab26 attenuated CSE-induced production of inflammatory mediators through part inactivation of p38 and JNK MAPK. On the contrary, silencing Rab26 enhanced p38 and JNK activation and aggravated inflammatory response. These findings suggest that ROS-mediated Rab26 promoter hypermethylation is a critical step in cigarette smoking-induced airway epithelial inflammatory response. Restoring Rab26 in the airway epithelium might be a potential strategy for treating airway inflammation and COPD.

Therapeutic Potential of Small Molecules Targeting Oxidative Stress in the Treatment of Chronic Obstructive Pulmonary Disease (COPD): A Comprehensive Review

Chronic obstructive pulmonary disease (COPD) is an increasing and major global health problem. COPD is also the third leading cause of death worldwide. Oxidative stress (OS) takes place when various reactive species and free radicals swamp the availability of antioxidants. Reactive nitrogen species, reactive oxygen species (ROS), and their counterpart antioxidants are important for host defense and physiological signaling pathways, and the development and progression of inflammation. During the disturbance of their normal steady states, imbalances between antioxidants and oxidants might induce pathological mechanisms that can further result in many non-respiratory and respiratory diseases including COPD. ROS might be either endogenously produced in response to various infectious pathogens including fungi, viruses, or bacteria, or exogenously generated from several inhaled particulate or gaseous agents including some occupational dust, cigarette smoke (CS), and air pollutants. Therefore, targeting systemic and local OS with therapeutic agents such as small molecules that can increase endogenous antioxidants or regulate the redox/antioxidants system can be an effective approach in treating COPD. Various thiol-based antioxidants including fudosteine, erdosteine, carbocysteine, and N-acetyl-L-cysteine have the capacity to increase thiol content in the lungs. Many synthetic molecules including inhibitors/blockers of protein carbonylation and lipid peroxidation, catalytic antioxidants including superoxide dismutase mimetics, and spin trapping agents can effectively modulate CS-induced OS and its resulting cellular alterations. Several clinical and pre-clinical studies have demonstrated that these antioxidants have the capacity to decrease OS and affect the expressions of several pro-inflammatory genes and genes that are involved with redox and glutathione biosynthesis. In this article, we have summarized the role of OS in COPD pathogenesis. Furthermore, we have particularly focused on the therapeutic potential of numerous chemicals, particularly antioxidants in the treatment of COPD.

Respiratory Symptoms among US Adults: a Cross-Sectional Health Survey Study

INTRODUCTION

Data collected through ongoing, state-based, cross-sectional health surveys could be used to better understand the contribution of respiratory symptoms to impaired health among the US adult population.

METHODS

We used the 2015 Behavioral Risk Factor Surveillance System telephone health survey in four states (Kentucky, Florida, South Carolina, Texas) to describe the relationship between symptoms, associated factors such as tobacco smoking, and health impairments. Self-reported productive cough, shortness of breath (SOB), and dyspnea on exertion (DOE) were categorized as minimal, moderate, or severe. Data were analyzed using multiple logistic regression models with age as a covariate to assess relationships of symptoms with other factors.

RESULTS

Among adults ≥ 18 years, respiratory impairment [current asthma, chronic obstructive pulmonary disease (COPD), or a current moderate or severe symptom] occurred in 39.1% of the population. More than half of adults reporting moderate or severe symptoms had not been diagnosed with asthma or COPD, particularly with DOE and productive cough. Subjects were at greater risk of moderate and severe SOB or productive cough with increasing age, prolonged smoking duration (≥ 20 years), being an ever-smoker, or if reporting COPD, current asthma, or any other comorbidity except cancer. Morbid obesity [body mass index (BMI) > 35 kg/m²] was associated with severe DOE at a rate similar to current asthma or COPD (25.6%, 95% CI 20.9-30.3%; 20.8%, 95% CI 16.4-25.1%; 21.3%, 95% CI 17.5-25.1%, respectively); it was the most common cause of DOE. SOB was associated with worse general health impairment and limited ambulation compared with other symptoms. Tobacco smoking prevalence and race varied among states, affecting symptom prevalence.

CONCLUSION

In the largest US survey in decades, we provide a current perspective of respiratory symptoms among adults of all ages. While known risk factors were apparent, low-risk persons also frequently reported symptoms and impairments.

Mortality and morbidity risk prediction for older former smokers based on a score of smoking history: evidence from UK Biobank and ESTHER cohorts

BACKGROUND

Rapid population ageing has raised the proportion of older former smokers considerably, but a comprehensive assessment tool of former smoking-related health risks is absent.

OBJECTIVE

We utilised the large-scale data of UK Biobank and ESTHER study to build a former smoking score (FSS) for older former smokers using three major former smoking traits: pack-years, smoking duration and time since smoking cessation.

DESIGN

UK Biobank and ESTHER study are two cohorts of older adults with 502,528 and 9,940 participants from the UK and Germany, respectively.

METHODS

Smoking history and covariates were retrieved from the self-administrated questionnaires and mortality and morbidity data were obtained through regular linkages to hospital records.

RESULTS

We constructed the FSS based on the 94,446 former smokers of UK Biobank by retrieving the averaged effect estimates of each trait with a 100-time random sampling. This score was robustly associated with higher risks of mortality and incidence of major smoking-related diseases, outperforming each trait. In the validation panel of 2,683 former smokers from ESTHER study, the FSS was highly predictive of mortality and morbidities. Particularly, compared with the 1st quartile of the FSS group, the 4th quartile group had 114.1, 104.5 and 158.9% higher risks of all-cause, CVD and cancer mortality, respectively, and 41.9, 31.9, 52.4 and 831.3% higher risks of incident CVD, type 2 diabetes, any cancers and lung cancer, respectively.

CONCLUSIONS

Our study demonstrates the large potential of refined risk assessment of former smokers by more comprehensive consideration of the major traits of former smoking.

Burden of current and past smoking across 28 European countries in 2017: A cross-sectional analysis

INTRODUCTION

Most studies use the prevalence of current smoking as an indicator to quantify the burden of smoking. However, length and intensity of smoking, as well as time since cessation for former smokers are also known to impact smoking-related health risks. The aim of this study was to quantify and compare the burden of smoking across the European Union (EU) using a range of smoking burden indicators.

METHODS

We conducted a cross-sectional analysis using data from the March 2017 Eurobarometer 87.1 (n=27901, people aged ≥15 years) in 28 European Union Member States (EU MS) and the Tobacco Control Scale. We defined five indicators of smoking burden including the prevalence of current and ever smoking, length of smoking, pack-years, and discounted pack-years, and ranked EU MS by each indicator. Two-level linear and logistic regressions were performed to assess the association between these indicators and sociodemographic and tobacco policy factors.

RESULTS

Wide variations across the EU countries were observed in all smoking burden indicators. While some MS ranked consistently high (e.g. Greece, France) or consistently low (e.g. Ireland, United Kingdom) in all indicators, we found substantial discrepancies in ranking depending on the indicator used for MS such as Malta, Denmark, Finland and the Netherlands. All indicators of smoking burden were lower among women and respondents without financial difficulties; however, the magnitude of those inequalities varied two-fold among the different indicators.

CONCLUSIONS

Using a range of smoking burden indicators can be more informative than relying on prevalence alone. Our analysis highlights the limitations of relying solely on prevalence of current smoking to estimate the burden of smoking and the potential value of more nuanced indicators. We recommend that multiple and more nuanced indicators that consider former smokers, intensity and duration of smoking should be utilized to monitor tobacco use and evaluate tobacco control policies.

Influence of PM1 exposure on total and cause-specific respiratory diseases: a systematic review and meta-analysis

An increasing number of studies examined the potential effects of PM1 (submicronic particulate matter with an aerodynamic diameter ≤ 1 μm) on the risk of respiratory diseases; however, the results have been inconclusive. This study aimed to determine the overall association between PM1 with total and cause-specific respiratory diseases. A systematic review and meta-analysis was conducted with 68 related articles retrieved, and six articles met the full inclusion criteria for the final analysis. For a 10 μg/m3 increase in PM1, the pooled odds ratio (OR) was 1.05 (95% CI 0.98-1.12) for total respiratory diseases, 1.25 (95% CI 1.00-1.56) for asthma, and 1.07 (95% CI 1.04-1.10) for pneumonia with the I2 value of 87%, 70%, and 0%, respectively. Subgroup analyses showed that long-term exposure to PM1 was associated with increased risk of asthma (OR 1.47, 95% CI 1.33-1.63) with an I2 value of 0%, while short-term exposure to PM1 was not associated with asthma (OR 1.07, 95% CI 0.89-1.27) with the I2 value of 0%. Egger's test showed that publication bias existed (P = 0.041); however, the funnel plot was symmetrical with the inclusion of the moderator. In conclusion, elevated levels of PM1 may increase morbidity in total and cause-specific respiratory diseases in the population.

The impact of the Hazelwood coal mine fire smoke exposure on asthma

OBJECTIVE

In 2014, a fire at an open cut coal mine in South-eastern Australia burned for about 6 weeks. Residents of the adjacent town were exposed to high levels of fine particulate matter (PM2.5) during this period. Three and a half years after the event, this study aimed to investigate potential long-term impacts of short-term exposure to coal mine fire smoke on asthma.

METHODS

A cross-sectional analysis was undertaken in a group of exposed participants with asthma from Morwell (n = 165) and a group of unexposed participants with asthma from the control town of Sale (n = 64). Exposure was determined by modeled PM2.5 data for the mine fire period. Respiratory symptoms were assessed with a validated respiratory health questionnaire and symptom severity score. Asthma control was assessed with a validated questionnaire. Lung function testing included spirometry, bronchodilator response, and fraction of exhaled nitric oxide.

RESULTS

There was no evidence that exposed participants had more severe asthma symptoms, worse lung function, or more eosinophilic airway inflammation than unexposed participants. However, there was some evidence that Morwell participants had more uncontrolled than well-controlled asthma, compared to the participants from Sale (adjusted relative risk ratio 2.71 95% CI: 1.02, 7.21, p = .046).

CONCLUSION

Three and a half years after exposure, coal mine fire smoke did not appear to be associated with more severe asthma symptoms or worse lung function but might be associated with poorer asthma control.

Association of demographic variables and smoking habits with the severity of lung function in adult smokers

Background:

This study aims to evaluate the association between demographic and smoking variables with the severity of lung function loss (Stage I to IV) and spirometry data in smokers.

Materials and Methods:

Three hundred and fifty smoker men over the age of 20 who had visited in AL-Zahra hospital were involved. Spirometry tests were performed for measuring forced vital capacity (FVC), FEV1, and FEV1%FVC. COPD was categorized into four stages by the (Global Initiative for Chronic Obstructive Lung Disease) criteria of postbronchodilator FEV1/FVC <0.70. FEV1/FVC <70%, in combination with FEV1 ≥80% (Stage I), or 50%≤FEV1 <80% (Stage II), or 30%≤FEV1 <50% (Stage III), or FEV1 ≤30% (Stage IV). Independent t-test, Spearman correlation analysis was used for data analysis. To determine the predicting factors for pulmonary function multiple regressions analysis was performed.

Results:

43 (19.5%) of men were defined as Chronic Obstructive Lung Disease (COPD) which 7% of them were Stage I, 23.3% were Stage II, 39.5% were III and 30.2% were stage IV. In 60 (27.1%) of men, the index of Fev1/FVC was <80%. The criteria of PRIS in 74 (33.5%) of the patients and BDR in 59 (26.7%) of participation was positive. There were significant differences in the mean of FEV1 with respect to history of lung disease in relatives (P = 0.035), lung disease hospitalization (P < 0.001) and previous diagnosis of asthma variables (P < 0.001). The mean of FVC was significantly different in patients categorized based on lung disease hospitalization (P < 0.001) and previous diagnosis of asthma (P = 0.018). Furthermore, there was a significant difference in the mean of FEV1/FVC for variables as follows: Time to start smoking after waking up (P = 0.007), lung disease hospitalization (P < 0.001) and previous diagnosis of asthma (P < 0.001). There was a significant association between stages of lung function loss and age of onset of smoking (β-0.355 P = 0.019) and pack per year (β = 0.354 P = 0.02). A linear regression model showed that lung disease hospitalization and age were the influential variables on FEV1 with (B = −21.79 confidence interval [CI]: −28.7, −14.87, P < 0.001and B = −0.418 CI: −0.63, −0.21, P < 0.001), respectively. The only significant influential variable on FVC was lung disease hospitalization (B = −15.89 CI: −21.49, −10.296, P < 0.001). Body mass index, lung disease hospitalization, time to start smoking after waking up in the morning and age had significant relationship on FEV1/FVC with (B = 0.71CI: 0.32, 1.11, P < 0.001, B = −14.29, CI: −19.61,-8.97, P < 0.001, B = 6.54, CI: 2.26, 10.82, P = 0.003 and B = −0.44, CI: −0.59, −0.28, P < 0.001), respectively.

Conclusion:

The age of onset of smoking and pack-year appears to be associated with the severity of COPD. Hospitalization history due to lung disease, age, the time between waking up in the morning and first cigarette use, BMI, lung disease history in relatives, previous diagnosis of asthma have a negative relationship with lung function.

Genetic loci for lung function in Japanese adults with adjustment for exhaled nitric oxide levels as airway inflammation indicator

Lung function reflects the ability of the respiratory system and is utilized for the assessment of respiratory diseases. Because type 2 airway inflammation influences lung function, genome wide association studies (GWAS) for lung function would be improved by adjustment with an indicator of the inflammation. Here, we performed a GWAS for lung function with adjustment for exhaled nitric oxide (FeNO) levels in two independent Japanese populations. Our GWAS with genotype imputations revealed that the RNF5/AGER locus including AGER rs2070600 SNP, which introduces a G82S substitution of AGER, was the most significantly associated with FEV1/FVC. Three other rare missense variants of AGER were further identified. We also found genetic loci with three candidate genes (NOS2, SPSB2 and RIPOR2) associated with FeNO levels. Analyses with the BioBank-Japan GWAS resource revealed genetic links of FeNO and asthma-related traits, and existence of common genetic background for allergic diseases and their biomarkers. Our study identified the genetic locus most strongly associated with airway obstruction in the Japanese population and three genetic loci associated with FeNO, an indicator of type 2 airway inflammation in adults.

Dose-Response Reduction in Risk of Nasopharyngeal Carcinoma From Smoking Cessation: A Multicenter Case-Control Study in Hong Kong, China

BACKGROUND

Cigarette smoking is associated with nasopharyngeal cancer (NPC) risk. Whether quitting reduces the risk is unclear. We investigated the associations of NPC with duration of and age at quitting in an endemic region.

METHODS

We investigated the associations between NPC and quitting in a multicenter case-control study in Hong Kong with 676 newly diagnosed NPC cases and 1,285 hospital controls between 2014 and 2017, using a computer-assisted self-administered questionnaire. Multivariable unconditional logistic regression yielded adjusted odds ratios (AORs) of NPC by quitting status, duration and age of quitting, combinations of duration and age of quitting, and quitting to smoking duration ratio, compared with current smoking.

RESULTS

Quitting (AOR: 0.72; 95% CI: 0.53-0.98) and never smoking (0.73, 0.56-0.95) were associated with lower NPC risk. NPC risk decreased with (i) longer quitting duration (p < 0.01), reaching significance after 11-20 (0.62, 0.39-0.99) and 21+ years (0.54, 0.31-0.92) of quitting; (ii) younger quitting age (p = 0.01), reaching significance for quitting at <25 years (0.49, 0.24-0.97); and (iii) higher quitting to smoking duration ratio (p < 0.01), reaching significance when the ratio reached 1 (0.60, 0.39-0.93). Quitting younger (age <25) appeared to confer larger reductions (49% for ≤10 years of quitting, 50% for 11+ years) in NPC risk than quitting at older ages (25+) regardless of quitting duration (16% for ≤10 years, 39% for 11+ years).

CONCLUSIONS

We have shown longer duration and younger age of quitting were associated with lower NPC risk, with dose-response relations. Our findings support including smoking as a cause of NPC. Stronger tobacco control measures and quitting services are needed to prevent NPC.

Comparative effectiveness of pneumococcal vaccination with PPV23 and PCV13 in COPD patients over a 5-year follow-up cohort study

Vaccination against Streptococcus pneumoniae is among the most effective measures for preventing pneumonia and reducing the rate of chronic obstructive pulmonary disease (COPD) exacerbations. The objective of this work was to evaluate the long-term effectiveness of PCV13 and PPV23 for preventing pneumonia and COPD exacerbations. The open-label, prospective, observational cohort study involved 302 male patients aged ≥ 45 years: PCV13 group (n = 123); PPV23 group (n = 32); and vaccine-naïve group (n = 147). The primary endpoint included the frequency of pneumonia episodes and COPD exacerbations per year over a 5-year follow-up period. The secondary endpoints included the dynamics of dyspnea severity (MMRC), the BODE index, FEV1, the CAT index, the SGRQ score, and the results of 6-min walk test. Vaccination with PCV13 and PPV23 significantly reduces the total rate of pneumonia during the first year after vaccination. Starting with the second year, clinical effectiveness in PPV23 group decreases compared with both PCV13 group and vaccine-naïve patients. Pneumonia by year 5 after vaccination was registered in 47% of patients in the PPV23 group, versus 3.3% of patients in the PCV13 group (p < 0.001); COPD exacerbations—in 81.3% versus 23.6%, respectively (p < 0.001). Vaccination with PCV13 significantly reduced and maintained the BODE index over the 5-year follow-up period. Although both vaccines have comparable clinical effects during the first year after vaccination, only PCV13 is characterized by persistent clinical effectiveness during the 5-year follow-up period. Patients older than 55 years who received PPV23 have significantly higher risks of having pneumonia episodes more frequently during the long-term follow-up.

More to Explore: Further Definition of Risk Factors for COPD - Differential Gender Difference, Modest Elevation in PM2.5, and e-Cigarette Use

Chronic obstructive pulmonary disease (COPD) is a severe respiratory disease with high morbidity and mortality, representing the third leading cause of death worldwide. Traditional risk factors for COPD include aging, genetic predisposition, cigarette smoking, exposure to environmental pollutes, occupational exposure, and individual or parental respiratory disease history. In addition, latest studies have revealed novel and emerging risk factors. In this review, differential gender difference as a factor for COPD development at different territories is discussed for the first time. First, women seem to have more COPD, while more women die of COPD or have more severe COPD, in Western societies. This seems different from the impression that COPD dominants in men, which is true in Eastern societies. It might be related to higher rate of cigarette smoking in women in developed countries (i.e., 12.0% of women in United States smoke vs. 2.2% in China). Nonetheless, women in Eastern societies are exposed to more biomass usage. Second, modest elevation in PM2.5 levels at >∼21.4-32.7 μg/m3, previously considered "cleaner air," is associated with incidence of COPD, indicating that more stringent goals should be set for the reduction of PM2.5 levels to prevent COPD development. Last but not least, e-cigarette use, which has become an epidemic especially among adolescents as officially declared by the United States government, has severe adverse effects that may cause development of COPD early in life. Built upon an overview of the established risk factors for COPD primarily focusing on cigarette smoking and environmental pollutions, the present review further discusses novel concepts, mechanisms, and solutions evolved around the emerging risk factors for COPD discussed above, understanding of which would likely enable better intervention of this devastating disease.

NK Cells in the Pathogenesis of Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a prevalent chronic airway disease with varied frequencies of acute exacerbations, which are the main cause of morbidity and mortality of the disease. It is, therefore, urgent to develop novel therapies for COPD and its exacerbations, which rely heavily on understanding of the pathogenesis and investigation for potential targets. Current evidence indicates that natural killer (NK) cells play important roles in the pathological processes of COPD. Although novel data are revealing the significance of NK cells in maintaining immune system homeostasis and their involvement in pathogenesis of COPD, the specific mechanisms are largely unknown. Specific and in-depth studies elucidating the underlying mechanisms are therefore needed. In this review, we provided a brief overview of the biology of NK cells, from its development to receptors and functions, and outlined their subsets in peripheral blood and lungs. Then we reviewed published findings highlighting the important roles played by NK cells in COPD and its exacerbations, with a view of providing the current state of knowledge in this area to facilitate related in-depth research.