COPD in Never-Smokers: BOLD Australia Study

Impact of occupational exposures in patients with chronic obstructive pulmonary disease: current understanding and knowledge gaps

PURPOSE OF REVIEW

Chronic obstructive pulmonary disease (COPD) is thought of as a disease caused by tobacco exposure, but numerous occupational exposures have been identified as risk factors for development of disease and exacerbations, although these remain underappreciated and underdiagnosed. We highlight evidence of occupational exposures and how they relate to COPD, while also looking at gaps in how the changing workplace might affect the occupational COPD landscape.

RECENT FINDINGS

Historical exposures linked to COPD included inorganic dusts like coal and silica and organic dusts like cotton and wood. Other data associated agricultural exposures, cleaning agents, air pollution, and construction work with COPD. As the workplace has evolved to include more work from home and growing industries like ridesharing and delivery, items like radon and indoor and outdoor air quality must be factored into the equation as occupational exposures with the potential to cause COPD and increase its morbidity. Despite this, causal conclusions with many risk factors are challenging due to the complex interaction between patient susceptibilities and environmental factors, both occupation-related and nonoccupation related.

SUMMARY

Additional studies are needed, not only to better evaluate occupational exposures and COPD pathogenesis, but also to look at more solution-oriented areas like precision medicine and interventions targeting a healthier workplace.

Therapeutic potential of 18-β-glycyrrhetinic acid-loaded poly (lactic-co-glycolic acid) nanoparticles on cigarette smoke-induced in-vitro model of COPD

Chronic obstructive pulmonary disease (COPD) is strongly linked to cigarette smoke, which contains toxins that induce oxidative stress and airway inflammation, ultimately leading to premature airway epithelial cell senescence and exacerbating COPD progression. Current treatments for COPD are symptomatic and hampered by limited efficacy and severe side effects. This highlights the need to search for an optimal therapeutic candidate to address the root causes of these conditions. This study investigates the possible potential of poly (lactic-co-glycolic acid) (PLGA)-based nanoparticles encapsulating the plant-based bioactive compound 18-β-glycyrrhetinic acid (18βGA) as a strategy to intervene in cigarette smoke extract (CSE)-induced oxidative stress, inflammation, and senescence, in vitro. We prepared 18βGA-PLGA nanoparticles, and assessed their effects on cell viability, reactive oxygen species (ROS) production, anti-senescence properties (expression of senescence-associated β galactosidase and p21 mRNA), and expression of pro-inflammatory genes (CXCL-1, IL-6, TNF-α) and inflammation-related proteins (IL-8, IL-15, RANTES, MIF). The highest non-toxic concentration of 18βGA-PLGA nanoparticles to healthy human broncho epithelial cell line BCiNS1.1 was identified as 5 µM. These nanoparticles effectively mitigated cigarette smoke-induced inflammation, reduced ROS production, protected against cellular aging, and counteracted the effects of CSE on the expression of the inflammation-related genes and proteins. This study underscores the potential of 18βGA encapsulated in PLGA nanoparticles as a promising therapeutic approach to alleviate cigarette smoke-induced oxidative stress, inflammation, and senescence. Further research is needed to explore the translational potential of these findings in clinical and in vivo settings.

Prevalence, mortality and risk factors for self-reported COPD among smokers and never smokers, NHANES 1999-2018

INTRODUCTION

Cigarette smoke is the main risk factor for chronic obstructive pulmonary disease (COPD), but 25% to 50% of cases occur in non-smokers. In the US, limited recent national data compare COPD prevalence between smokers and never smokers. Furthermore, our study seeks to explore the prevalence and mortality of self-reported COPD among smokers (including current smokers and ex-smokers) and never smokers in the US from 1999 to 2018, and to identify the risk factors and differences.

METHODS

This cross-sectional analysis used data from the National Health and Nutrition Examination Survey (NHANES) 1999-2018. Age-standardized prevalence of self-reported COPD among current smokers, ex-smokers, and never smokers was calculated using sample weights and 2010 US Census estimates. Risk factors were evaluated through weighted logistic regression models. Subsequently, participants who enrolled in the study cohort were followed until 31 December 2019, to determine all-cause mortality rates.

RESULTS

Between 1999 and 2018, the weighted prevalence of COPD among current smokers, ex-smokers, and never smokers in the U.S. was 12.6%, 9.6%, and 4.1%, respectively. The mortality rates observed were 21.1% among current smokers with COPD, 29% among ex-smokers with COPD, and 12% among never smokers with COPD. Over this period, among the general population in the U.S., the proportion of current smokers has declined, the proportion of never smokers has increased, and the proportion of ex-smokers has remained relatively stable. From 1999 to 2018, COPD prevalence rose from 13.7% to 21.9% among current smokers, stayed at 10.1% among ex-smokers, and dropped from 4.9% to 3.3% among never smokers. Independent risk factors for COPD across all groups included being female, older, and lower income. In particular, US citizens and non-Hispanic Whites (among ex-smokers and never smokers) were at higher risk compared to their counterparts.

CONCLUSIONS

The prevalence and all-cause mortality of COPD among current smokers and ex-smokers remain elevated. Although the prevalence of COPD among never smokers is gradually declining, it continues to be significant, thereby maintaining a substantial burden of disease. Furthermore, common independent risk factors for COPD across current smokers, ex-smokers, and never smokers include female gender, advanced age, lower income, and deviations from normal body weight whether overweight or underweight.

Neutrophil-to-Lymphocyte Ratio and Blood Eosinophil Levels As Inflammatory Indicators in Smoker and Non-smoker Young Adult Patients With Chronic Obstructive Pulmonary Disease at a Tertiary Care Hospital

Background Inflammatory markers are elevated in chronic obstructive pulmonary disease (COPD) and can be quantified to detect severity, prognosis, mortality risk, and response to treatment. However, the estimation costs are high. The blood neutrophil-to-lymphocyte ratio (NLR) and eosinophil levels are emerging as biomarkers in COPD, yet there is a paucity of data. Aim and objectives This study was designed to elucidate the roles of the NLR and eosinophil levels in smokers and non-smokers with stable COPD male subjects, correlating them with lung functions. Materials and methods A prospective observational clinical study was conducted from January to June 2023, after receiving approval from the Institutional Ethics Committee, on 73 COPD patients aged 30-60 years who gave voluntary informed consent. Complete blood counts and spirometry were performed. Patients with a forced expiratory volume in one second (FEV1) % predicted <70% and an FEV1/forced vital capacity (FVC) % <70% based on the pulmonary function test (MIR Spirolab) were included. They were further divided into mild (n=10), moderate (n=27), severe (n=26), and very severe (n=10) categories as per the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines. Subjects were also categorized into smoker (n=45) and non-smoker (n=28) groups. The complete blood count was analyzed using an automated analyzer (Beckman Coulter). Analysis was also carried out with an NLR of more or less than three. A P-value of less than 0.05 was considered significant. Results Smokers constituted 61.65% (n=45) of the subjects, and non-smokers 38.35% (n=28). Among smokers, 17.78% had very severe airflow obstruction. In all COPD subjects (n=73), lymphocytes, eosinophils, and lung functions were lower in the group where the NLR was greater than three. NLR in smokers (3.52±1.43) was higher than in non-smokers (3.39±0.94). In non-smokers (n=28), blood eosinophils and lymphocytes were elevated. In smokers (n=45), blood neutrophils, monocytes, and basophils were increased. Smokers showed a non-significant increase in RBC, mean corpuscular volume (MCV), and mean corpuscular hemoglobin (MCH). Neutrophils, monocytes, eosinophils, and NLR increased with disease severity. NLR negatively correlated with FEV1 (r=-0.350, p=0.034) and positively with pack-years (r=0.546, p<0.001) in smokers. NLR negatively correlated with eosinophils, FVC, FEV1/FVC, and FEV1 % predicted. In all COPD subjects (n=73), NLR negatively correlated with blood eosinophils (r=-0.184, p=0.12), BMI, and lung functions. Conclusion NLR is elevated in COPD subjects and can serve as a marker of inflammation and a predictor of the risk and severity of airflow limitation. NLR correlates both positively and negatively with pack-years and lung functions, respectively.