Meta-analysis approach to study the prevalence of chronic obstructive pulmonary disease among current, former and non-smokers

Cigarette Smoking Patterns Among Racial and Ethnic Groups With Chronic Lung Diseases During the COVID-19 Pandemic

Introduction

Chronic obstructive pulmonary disease and asthma are significant respiratory conditions that contribute to substantial morbidity and mortality globally. Chronic obstructive pulmonary disease remains the third most prevalent cause of death worldwide, with 90% of chronic obstructive pulmonary disease deaths attributed to combustible cigarette smoking. Asthma, although often less fatal, leads to considerable health burdens, particularly among marginalized populations who are at higher risk for both more severe chronic obstructive pulmonary disease and asthma outcomes. This study investigates the association between race/ethnicity and current cigarette smoking among adults diagnosed with chronic obstructive pulmonary disease and/or asthma in the U.S. before, during, and after the COVID-19 pandemic.

Methods

The authors analyzed data from 10,763 adults (aged ≥40 years) with a history of chronic obstructive pulmonary disease and/or asthma surveyed in the 2019, 2021, and 2023 National Health Interview Survey. The authors estimated predicted probabilities derived from multiple logistic regression and negative binomial regression models to examine changes in (1) the prevalence of current cigarette smoking in the target population, (2) the mean number of days of cigarette smoking in the past 30 days, and (3) the mean number of cigarettes smoked in the past 30 days across racial/ethnic subgroups and prepandemic, pandemic, and postpandemic periods.

Results

Current cigarette smoking was reported by about one fifth (20%) of U.S. adults diagnosed with chronic obstructive pulmonary disease and asthma. Among them, the mean number of days of cigarette smoking in the past 30 days was 27 days, and the mean number of cigarettes smoked in the past 30 days was 14. Hispanic individuals had the lowest prepandemic rates of current cigarette smoking (10.5%); however, it was the only racial/ethnic group showing a significant change during the pandemic, with rates increasing to 14.9% during the pandemic. Non-Hispanic White individuals, who showed the highest rates of current cigarette smoking (21.1%) during the pandemic, were the only racial/ethnic group showing a significant decline in the postpandemic period (19.8%). No significant changes were observed in the mean number of days or cigarettes smoked in the past 30 days, except for a marginally significant increase in cigarette consumption among non-Hispanic Black individuals.

Conclusions

These analyses suggest that the pandemic had a differential impact on the rates of current smoking across racial/ethnic subgroups in adults with chronic obstructive pulmonary disease and/or asthma, with a detrimental effect in Hispanic individuals and an improvement among non-Hispanic White individuals. Given the dangers of smoking in chronic lung conditions, future research should investigate the factors behind these to develop targeted interventions.

Occupational status and chronic respiratory diseases: a cross-sectional study based on the data of the Rafsanjan Cohort Study

BACKGROUND

The aim of the present study was to investigate the possible connection between occupational status and chronic respiratory diseases (CRDs) among the Iranian population.

METHODS

The present cross-sectional study was conducted on 9934 individuals aged 35-70 years enrolled in the Rafsanjan Cohort Study (RCS), a component of the Prospective Epidemiological Research Studies in Iran (PERSIAN). Detailed questionnaires were used to collect information on various factors, such as occupation, sociodemographic characteristics, medical history, anthropometric measurements, physical activity, cigarette and hookah smoking, opium use, and alcohol consumption. The association between occupational class and CRD was evaluated using logistic regression models for rare events.

RESULTS

In the present study, 4624 (46.55%) participants were male, and 5310 (53.45%) were female. The prevalence of CRD among all participants was 2.61%. Occupational activities were classified into two categories: In class I, the largest group was the homemaker and unemployment category (41.73%), followed by self-employment (34.39%), employment (13.03%), and retired individuals (10.84%). In class II, there were pistachio farmers (12.61%), copper miners (3.62%), and others in various occupations (83.76%). Subjects with CRD were significantly more likely to be homemakers, unemployed, elderly, female, less educated, and obese. There was no significant relationship between CRD and job type/occupational status after adjusting for some potential confounding variables.

CONCLUSIONS

There was no significant relationship between CRD and job type/occupational status. However, longitudinal studies are needed to assess the impact of job type/occupational status on the risk of CRD.

Association between cigar use, with and without cigarettes, and incident diagnosed COPD: a longitudinal cohort study

BACKGROUND

While regular cigar smoking is believed to carry similar health risks as regular cigarette smoking, the impact of cigar use, alone or in combination with cigarettes, on obstructive pulmonary disease (COPD) has not been well characterized. The purpose of this study was to examine the prospective association between exclusive and dual cigar and cigarette use and incident self-reported diagnosed COPD.

METHODS

This study used data from Waves 1-5 (2013-2019) of the Population Assessment of Tobacco and Health (PATH) Study, a nationally representative survey of U.S. adults. Longitudinal data from adults aged 40 to 79 at Wave 1, without a pre-existing COPD diagnosis who participated at follow-up interview were analyzed. A time-varying current tobacco exposure, lagged by one wave and categorized as: (a) never/non-current use; (b) exclusive cigar use; (c) exclusive cigarette use; and (d) dual cigar/cigarette use. Multivariable models adjusted for demographics (age, sex, race or ethnicity, education), clinical risk factors (asthma, obesity), and smoking-related confounders (second-hand smoke exposure, other combustible tobacco product use, e-cigarette use, time since quitting, cigarette pack-years). The incidence of self-reported diagnosed COPD was estimated using discrete-time survival models, using a general linear modeling (GLM) approach with a binomial distribution and a complementary log-log link function.

RESULTS

The analytic sample consisted of 9,556 adults with a mean (SD) age of 56 (10.4), who were predominately female (52.8%) and Non-Hispanic White (70.8%). A total of 906 respondents reported a diagnosis of COPD at follow-up. In the fully adjusted model, exclusive cigar use (adjusted hazard ratio (aHR) = 1.57, 95% CI: 0.77, 3.21) was not associated with increased COPD risk compared to non-use, while exclusive cigarette use (aHR = 1.48, 95% CI: 1.13, 1.93) and dual cigar/cigarette use (aHR = 1.88, 95% CI: 1.24, 2.85) were.

CONCLUSIONS

Exclusive cigarette use and dual cigar/cigarette use were associated with diagnosed incident COPD. These results suggest that cigars, when used in combination with cigarettes, may be associated with poorer COPD health outcomes. Dual use may promote a higher likelihood of inhaling cigar smoke, and future research would benefit from examining whether inhalation of cigar smoke increases COPD risk.

Meta-analysis of single-cell RNA-sequencing data for depicting the transcriptomic landscape of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a respiratory disease characterized by airflow limitation and chronic inflammation of the lungs that is a leading cause of death worldwide. Since the complete pathological mechanisms at the single-cell level are not fully understood yet, an integrative approach to characterizing the single-cell-resolution landscape of COPD is required. To identify the cell types and mechanisms associated with the development of COPD, we conducted a meta-analysis using three single-cell RNA-sequencing datasets of COPD. Among the 154,011 cells from 16 COPD patients and 18 healthy subjects, 17 distinct cell types were observed. Of the 17 cell types, monocytes, mast cells, and alveolar type 2 cells (AT2 cells) were found to be etiologically implicated in COPD based on genetic and transcriptomic features. The most transcriptomically diversified states of the three etiological cell types showed significant enrichment in immune/inflammatory responses (monocytes and mast cells) and/or mitochondrial dysfunction (monocytes and AT2 cells). We then identified three chemical candidates that may potentially induce COPD by modulating gene expression patterns in the three etiological cell types. Overall, our study suggests the single-cell level mechanisms underlying the pathogenesis of COPD and may provide information on toxic compounds that could be potential risk factors for COPD.

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.

Identifying risk factors for COPD and adult-onset asthma: an umbrella review

BACKGROUND

COPD and adult-onset asthma (AOA) are the most common noncommunicable respiratory diseases. To improve early identification and prevention, an overview of risk factors is needed. We therefore aimed to systematically summarise the nongenetic (exposome) risk factors for AOA and COPD. Additionally, we aimed to compare the risk factors for COPD and AOA.

METHODS

In this umbrella review, we searched PubMed for articles from inception until 1 February 2023 and screened the references of relevant articles. We included systematic reviews and meta-analyses of observational epidemiological studies in humans that assessed a minimum of one lifestyle or environmental risk factor for AOA or COPD.

RESULTS

In total, 75 reviews were included, of which 45 focused on risk factors for COPD, 28 on AOA and two examined both. For asthma, 43 different risk factors were identified while 45 were identified for COPD. For AOA, smoking, a high body mass index (BMI), wood dust exposure and residential chemical exposures, such as formaldehyde exposure or exposure to volatile organic compounds, were amongst the risk factors found. For COPD, smoking, ambient air pollution including nitrogen dioxide, a low BMI, indoor biomass burning, childhood asthma, occupational dust exposure and diet were amongst the risk factors found.

CONCLUSIONS

Many different factors for COPD and asthma have been found, highlighting the differences and similarities. The results of this systematic review can be used to target and identify people at high risk for COPD or AOA.

Heated Tobacco Products and Chronic Obstructive Pulmonary Disease: A Narrative Review of Peer-Reviewed Publications

An estimated 65 million people worldwide have moderate or severe chronic obstructive pulmonary disease (COPD), an umbrella term used to describe a group of progressive lung diseases that obstruct airflow such as emphysema and chronic bronchitis. Smoking contributes to an estimated 90% of COPD cases, as the harmful chemicals produced during tobacco combustion damage the lungs and airways. Although smoking cessation is the only intervention shown to improve COPD prognosis in smokers, many patients who try to quit continue to smoke. The continued use of conventional cigarettes exacerbates COPD symptoms, and globally more than 3 million people die from the disease every year. The last two decades have seen the introduction of combustion-free nicotine delivery alternatives that produce significantly lower levels of the harmful components in cigarette smoke, and researchers have begun to assess the impact of switching from cigarettes to these products. Several studies have examined how patients with COPD use e-cigarettes as assistance for quitting, but few have examined how heated tobacco products (HTP) may reduce risk. This narrative review summarises results from pre-clinical, clinical, and real-world evidence studies showing possible harm reduction benefits for patients with COPD who switch to HTPs rather than continuing to smoke cigarettes. Epidemiological studies, real-world data analyses, and randomised clinical trials must be conducted to determine whether switching from cigarettes to HTPs can improve health outcomes in patients with COPD who would otherwise continue to smoke combustible cigarettes.

Extracellular Hsp70 modulates 16HBE cells' inflammatory responses to cigarette smoke and bacterial components lipopolysaccharide and lipoteichoic acid

Cigarette smoke is a major risk factor for chronic obstructive pulmonary disease (COPD), leading to chronic inflammation, while bacterial components lipopolysaccharide (LPS) and lipoteichoic acid (LTA) are often present in airways of COPD patients, especially during exacerbations.We hypothesised that extracellular heat shock protein 70 (eHsp70), a damage-associated molecular pattern elevated in serum of COPD patients, induces inflammation and alters cigarette smoke and LPS/LTA-induced inflammatory effects in the airway epithelium.We used 16HBE cells exposed to recombinant human (rh)Hsp70 and its combinations with cigarette smoke extract (CSE), LPS or LTA to investigate those assumptions, and we determined pro-inflammatory cytokines' secretion as well as TLR2 and TLR4 gene expression.rhHsp70 and CSE alone stimulated IL-6, IL-8 and TNF-α secretion. CSE and rhHsp70 had antagonistic effect on IL-6 secretion, while combinations of LPS or LTA with rhHsp70 showed antagonistic effect on TNF-α release. By using specific inhibitors, we demonstrated that effects of rhHsp70 on cytokines' secretion were mediated via NF-κB and/or MAPK signalling pathways. rhHsp70 increased, and CSE decreased TLR2 gene expression compared to untreated cells, but their combinations increased it compared to CSE alone. LPS and rhHsp70 combinations decreased TLR2 gene expression compared to untreated cells. TLR4 expression was not induced by any of the treatments.In conclusion, we demonstrated that extracellular Hsp70 modulates pro-inflammatory responses of human airway epithelial cells to cigarette smoke and bacterial components LPS and LTA. Simultaneous presence of those compounds and their interactions might lead to inappropriate immune responses and adverse consequences in COPD.

Therapeutic Potential of Human Umbilical Cord-Derived Mesenchymal Stem Cells in Recovering From Murine Pulmonary Emphysema Under Cigarette Smoke Exposure

Human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) were shown to have potential for immunoregulation and tissue repair. The objective of this study was to investigate the effects of hUC-MSCs on emphysema in chronic obstructive pulmonary disease (COPD). The C57BL/6JNarl mice were exposed to cigarette smoke (CS) for 4 months followed by administration of hUC-MSCs at 3 × 10⁶ (low dose), 1 × 10⁷ (medium dose), and 3 × 10⁷ cells/kg body weight (high dose). The hUC-MSCs caused significant decreases in emphysema severity by measuring the mean linear intercept (MLI) and destructive index (DI). A decrease in neutrophils (%) and an increase in lymphocytes (%) in bronchoalveolar lavage fluid (BALF) were observed in emphysematous mice after hUC-MSC treatment. Lung levels of interleukin (IL)-1β, C-X-C motif chemokine ligand 1 (CXCL1)/keratinocyte chemoattractant (KC), and matrix metalloproteinase (MMP)-12 significantly decreased after hUC-MSC administration. Significant reductions in tumor necrosis factor (TNF)-α, IL-1β, and IL-17A in serum occurred after hUC-MSC administration. Notably, the cell viability of lung fibroblasts improved with hUC-MSCs after being treated with CS extract (CSE). Furthermore, the hUC-MSCs-conditioned medium (hUC-MSCs-CM) restored the contractile force, and increased messenger RNA expressions of elastin and fibronectin by lung fibroblasts. In conclusion, hUC-MSCs reduced inflammatory responses and emphysema severity in CS-induced emphysematous mice.

Prediction of COPD risk accounting for time-varying smoking exposures

RATIONALE

Chronic Obstructive Pulmonary Disease (COPD) is the fourth leading cause of death in the United States. Studies have primarily assessed the relationship between smoking on COPD risk focusing on summary measures, like smoking status.

OBJECTIVE

Develop a COPD risk prediction model incorporating individual time-varying smoking exposures.

METHODS

The Nurses' Health Study (N = 86,711) and the Health Professionals Follow-up Study (N = 39,817) data was used to develop a COPD risk prediction model. Data was randomly split in 50-50 samples for model building and validation. Cox regression with time-varying covariates was used to assess the association between smoking duration, intensity and year-since-quit and self-reported COPD diagnosis incidence. We evaluated the model calibration as well as discriminatory accuracy via the Area Under the receiver operating characteristic Curve (AUC). We computed 6-year risk of COPD incidence given various individual smoking scenarios.

RESULTS

Smoking duration, year-since-quit (if former smokers), sex, and interaction of sex and smoking duration are significantly associated with the incidence of diagnosed COPD. The model that incorporated time-varying smoking variables yielded higher AUCs compared to models using only pack-years. The AUCs for the model were 0.80 (95% CI: 0.74-0.86) and 0.73 (95% CI: 0.70-0.77) for males and females, respectively.

CONCLUSIONS

Utilizing detailed smoking pattern information, the model predicts COPD risk with better accuracy than models based on only smoking summary measures. It might serve as a tool for early detection programs by identifying individuals at high-risk for COPD.

Alkylating and oxidative stresses in smoking and non-smoking patients with COPD: Implications for lung carcinogenesis

Chronic obstructive pulmonary disease (COPD) is a disease characterized by chronic inflammation and irreversible airway obstruction. Cigarette smoking is the predominant risk factor for developing COPD. It is well-known that the COPD is also strongly associated with an increased risk of developing lung cancer. Cigarette smoke contains elevated concentrations of oxidants and various carcinogens (e.g., tobacco-derived nitrosamines) that can cause oxidative and alkylating stresses, which can also arise from inflammation. However, it is surprising that, except for oxidative stress, little information is available on the burden of alkylating stress and the detoxification efficiency of tobacco-derived carcinogens in COPD patients. In this study, we used LC-MS/MS to measure the archetypical tobacco-specific carcinogenic 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), its major metabolite, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), three biomarkers of oxidative stress (8-oxo-7,8-dihydroguanine, 8-oxoGua; 8-oxo-7,8-dihydro-2'-deoxyguanosine, 8-oxodGuo; 8-oxo-7,8-dihydroguanosine, 8-oxoGuo) and two biomarkers of alkylating stress (N7-methylguanine, N7-MeGua and N3-methyladenine, N3-MeAde), in the urine of smoking and non-smoking COPD patients and healthy controls. Our results showed that not only was oxidative stress significantly elevated in the COPD patients compared to the controls, but also alkylating stress. Significantly, levels of alkylating stress (i.e., N7-MeGua) were highly correlated with the COPD severity and not affected by age and smoking status. Furthermore, COPD smokers had significantly higher ratios of free NNAL to the total NNAL than control smokers, implying a lower detoxification efficiency of NNK in COPD smokers. This ratio was even higher in COPD smokers with stages 3-4 than in COPD smokers with stages 1-2. Taken together, our results demonstrated that the detoxification efficiency of tobacco-derived carcinogens (e.g., NNK) was associated with the pathogenesis and possibly the progression of COPD. In addition to oxidative stress, alkylating stress derived from chronic inflammation appears to be also dominant in COPD patients.

Efficacy of a short-term residential smoking cessation therapy versus standard outpatient group therapy ('START-Study'): study protocol of a randomized controlled trial

BACKGROUND

In Germany, evidence-based outpatient smoking cessation therapies are widely available. Long-term abstinence rates, however, are limited. Studies suggest that short-term residential therapy enables a higher level of environmental control, more intense contact and greater support among patients and from therapists, which could result in higher abstinence rates. The aim of the current START-study is to investigate the long-term efficacy of a short-term residential therapy exclusively for smoking cessation, conducted by a mobile team of expert therapists.

METHODS

A randomized controlled trial (RCT) is conducted to examine the efficacy of residential behavior therapeutic smoking cessation therapy compared to standard outpatient behavior therapeutic smoking cessation group therapy. Adult smokers consuming 10 or more cigarettes per day, who are willing to stop smoking, are randomized in a ratio of 1:1 between therapy groups. The primary endpoint is sustained abstinence for 6-month and 12-month periods. Secondary endpoints include smoking status after therapy, 7-day point abstinence after the 6-month and 12-month follow-ups, level of physical dependence, cost-effectiveness, use of nicotine replacement products, health-related quality of life, self-efficacy expectation for tobacco abstinence, motivational and volitional determinants of behavior change, self-reported depressive symptom severity, adverse events and possible side effects. Assessments will take place at baseline, post-therapy, and at 6-month and 12-month intervals after smoking cessation.

DISCUSSION

There is a high demand for long-term effective smoking cessation therapies. This study represents the first prospective RCT to examine the long-term efficacy of a residential smoking cessation therapy program compared to standard outpatient group therapy as an active control condition. The residential therapeutic concept may serve as a new model to substantially enhance future cessation therapies and improve the understanding of therapeutic impact factors on tobacco abstinence. Utilizing a mobile team, the model could be applied efficiently to medical centers that do not have permanent and trained personnel for smoking cessation at their disposal.

TRIAL REGISTRATION

German Register for Clinical Trials (Deutsches Register für Klinische Studien), DRKS00013466. Retrospectively registered on 1 April 2019. https://www.drks.de/drks_web/navigate.do?navigationId=start.

Essential trace elemental levels (zinc, iron and copper) in the biological samples of smoker referent and pulmonary tuberculosis patients

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Smoking is linked with tuberculosis recurrence.

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Pakistan has not only high TB number of TB cases (fifth) but also high level of multidrug-resistant TB (fourth) in the world.

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Cu/Zn ratio was also considerably greater in all biological samples of TB patients as compared to the control group.

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The analysis the levels of the elements, {Fe, Cu, Zn and Cu/Zn ratio} may help the studies on the development of TB disease.

Tuberculosis is one of the major causes of illnesses and deaths throughout world particularly in Asia. Smoking is linked with tuberculosis recurrence and its mortality and may influence bacteriological conversion, clinical symptoms and treatment outcome. The aim of current study was to estimate association among essential trace elements {zinc (Zn), iron (Fe) and copper (Cu)} in human biological samples particularly blood, serum, scalp hair, saliva, sputum, and nasal fluid of smoking and nonsmoking pulmonary tuberculosis patients (n = 165, age ranged 16–35 years) residents of Hyderabad, Pakistan. The biological samples of age matched healthy controls were chosen as referents of both genders (n = 171) for the comparison purpose. The human biological samples were wet digested in microwave oven by 65 % HNO₃ and 30 % H₂O₂ with (2:1) ratio. The concentrations of elements in acid digested samples were determined by atomic absorption spectrometry. The average zinc and iron concentration was lower, while level of copper was higher in the biological samples of pulmonary Tuberculosis patients as compared to referent subjects (p < .001). It was also concluded as a result of Zn and Fe deficiency combined with high contact of copper due to smoking of tobacco can be synergistic with the risk factors related with pulmonary tuberculosis.

Proteases and Their Inhibitors in Chronic Obstructive Pulmonary Disease

In the context of respiratory disease, chronic obstructive pulmonary disease (COPD) is the leading cause of mortality worldwide. Despite much development in the area of drug development, currently there are no effective medicines available for the treatment of this disease. An imbalance in the protease: Antiprotease ratio in the COPD lung remains an important aspect of COPD pathophysiology and several studies have shown the efficacy of antiprotease therapy in both in vitro and in vivo COPD models. However more in-depth studies will be required to validate the efficacy of lead drug molecules targeting these proteases. This review discusses the current status of protease-directed drugs used for treating COPD and explores the future prospects of utilizing the potential of antiprotease-based therapeutics as a treatment for this disease.