Association of smoking cessation with airflow obstruction in workers with silicosis: A cohort study.

BACKGROUND: Studies in general population reported a positive association between tobacco smoking and airflow obstruction (AFO), a hallmark of chronic obstructive pulmonary disease (COPD). However, this attempt was less addressed in silica dust-exposed workers. METHODS: This retrospective cohort study consisted of 4481 silicotic workers attending the Pneumoconiosis Clinic during 1981-2019. The lifelong work history and smoking habits of these workers were extracted from medical records. Spirometry was carried out at the diagnosis of silicosis (n = 4177) and reperformed after an average of 9.4 years of follow-up (n = 2648). AFO was defined as forced expiratory volume in one second (FEV1)/force vital capacity (FVC) less than lower limit of normal (LLN). The association of AFO with smoking status was determined using multivariate logistics regression, and the effect of smoking cessation on the development of AFO was evaluated Cox regression. RESULTS: Smoking was significantly associated with AFO (current smokers: OR = 1.92, 95% CI 1.51-2.44; former smokers: OR = 2.09, 95% CI 1.65-2.66). The risk of AFO significantly increased in the first 3 years of quitting smoking (OR = 1.23, 95% CI 1.02-1.47) but decreased afterwards with increasing years of cessation. Smoking cessation reduced the risk of developing AFO no matter before or after the confirmation of silicosis (pre-silicosis cessation: HR = 0.58, 95% CI 0.46-0.74; post-silicosis cessation: HR = 0.62, 95% CI 0.48-0.79). CONCLUSIONS: Smoking cessation significantly reduced the risk of AFO in the workers with silicosis, although the health benefit was not observed until 3 years of abstinence. These findings highlight the importance of early and long-term smoking cessation among silicotic or silica dust-exposed workers.

NADH Intraperitoneal Injection Prevents Lung Inflammation in a BALB/C Mice Model of Cigarette Smoke-Induced Chronic Obstructive Pulmonary Disease.

Cigarette smoke is one of the main factors in Chronic Obstructive Pulmonary Disease (COPD), a respiratory syndrome marked by persistent respiratory symptoms and increasing airway obstruction. Perturbed NAD+/NADH levels may play a role in various diseases, including lung disorders like COPD. In our study, we investigated the preventive effect of NADH supplementation in an experimental model of COPD induced by cigarette smoke extract (CSE). N = 64 mice randomly distributed in eight groups were injected with NADH (two doses of 100 mg/kg or 200 mg/kg) or dexamethasone (2 mg/kg) before being exposed to CSE for up to 9 weeks. Additionally, NADH supplementation preserved lung antioxidant defenses by preventing the functional loss of key enzymes such as superoxide dismutase (SOD), glutathione peroxidase (GPX), catalase, and the expression levels of glutathione (GSH) (n = 4, p < 0.001). It also reduced oxidative damage markers, such as malondialdehyde (MDA) and nitrites (n = 4, p < 0.001). A marked increase in tissue myeloperoxidase activity was assessed (MPO), confirming neutrophils implication in the inflammatory process. The latter was significantly ameliorated in the NADH-treated groups (p < 0.001). Finally, NADH prevented the CSE-induced secretion of cytokines such as Tumor Necrosis Factor alpha (TNF-α), IL-17, and IFN-y (n = 4, p < 0.001). Our study shows, for the first time, the clinical potential of NADH supplementation in preventing key features of COPD via its unique anti-inflammatory and antioxidant properties.

Risk of chronic obstructive pulmonary disease in a large cohort of Ontario, Canada workers.

Although several occupational exposures have been linked to the risk of COPD; limited data exists on sex-specific differences. This study aimed to identify at-risk occupations and sex differences for COPD risk. Cases were identified in a large surveillance system established through the linkage of former compensation claimants' data (non-COPD claims) to physician visits, ambulatory care data, and hospital inpatient data (1983-2020). Cox proportional hazard models were used to estimate hazard ratios (HRs) and corresponding 95% confidence intervals (CI) for occupation groups (occupation at time of claim), stratified by sex. HRs were indirectly adjusted for cigarette smoking using another population dataset. A total of 29,445 male and 14,693 female incident cases of COPD were identified. Increased risks were observed in both sexes for construction (HRmale 1.15, 95% CI 1.12-1.19; HRfemale 1.54, 95% CI 1.29-1.83) transport/equipment operating (HRmale 1.32, 95% CI 1.28-1.37; HRfemale 1.53, 95% CI 1.40-1.68) farming (HRmale 1.23, 95% CI 1.15-1.32; HRfemale 1.19, 95% CI 1.04-1.37) and janitors/cleaners (HRmale 1.31, 95% CI 1.24-1.37; HRfemale 1.40, 95% CI 1.31-1.49). Increased risks were observed for females employed as chefs and cooks (HR 1.44, 95% CI 1.31-1.58), bartenders (HR 1.38, 95% CI 1.05-1.81), and those working in food/beverage preparation (HR 1.34, 95% CI 1.24-1.45) among other occupations. This study demonstrates elevated risk of COPD among both male and female workers potentially exposed to vapours, gases, dusts, and fumes, highlighting the need for occupational surveillance of COPD.

[Pesticide exposure and chronic respiratory diseases]. / Exposition aux pesticides et maladies respiratoires chroniques.

INTRODUCTION: Pesticides are used worldwide, mainly in agriculture as a means of controlling pests and protecting crops. That said, the entire world population is ultimately subject to pesticide exposure (consumption of fruits and vegetables, living near treated fields…), with varying degrees of toxicity involved. STATE OF THE ART: In recent decades, epidemiological studies have contributed to the identification of chemical pesticide families with detrimental effects on human health: cognitive disorders, Parkinson's disease, prostate cancer… and impairment in respiratory functioning. Current scientific evidence points to the implication of the active substances in insecticides, herbicides and fungicides in chronic respiratory diseases, two examples being chronic obstructive pulmonary disease (COPD) in exposed workers, and asthmatic wheezing in children during prenatal or postnatal exposure. PERSPECTIVES: The safety of individuals exposed to pesticides is of key importance in public health. Further epidemiological investigations are needed to identify the chemical families affecting certain populations. CONCLUSIONS: The scientific literature suggests strong links between pesticide exposure and respiratory health. Whether it be environmental or occupational, pesticide exposure can lead to respiratory disorders and symptoms of varying severity.

High-Flow Nasal Cannula Oxygen Therapy versus Non-Invasive Ventilation in patients at very high risk for extubating failure: A systematic review of randomized controlled trials.

BACKGROUND: Mechanical ventilation is commonly used for managing respiratory failure in chronic obstructive pulmonary disease (COPD) patients, but weaning patients off ventilator support can be challenging and associated with complications. While many patients respond well to Non-invasive ventilation (NIV), a significant proportion may not respond as favourably. We aimed to assess whether high-flow nasal cannula (HFNC) is equally effective as NIV in reducing extubation failure among previously intubated COPD patients. METHODS: This systematic review was carried out in line with PRISMA guidelines We searched PubMed, Scopus, Web of Science, and Cochrane library from inception until February 15, 2023. Randomized Clinical Trials (RCTs) of adults at high risk for extubating failure were included. We examined the use of HFNC as the intervention and NIV as the comparator. Our outcome of interest included, reintubation rate, length of hospital or intensive care unit (ICU) stay, adverse events, and time to reintubation. The Cochrane risk-of-bias tool was used for randomized trials to assess risk of bias. RESULTS: We identified 348 citations, 11 of which were included, representing 2,666 patients. The trials indicate that HFNC is comparable to NIV in preventing reintubation after extubating in COPD patients. In comparison to NIV, HFNC also produced improved tolerance, comfort, and less complications such as airway care interventions. NIV with active humification may be more effective that HFNC in avoiding reintubation in patients who are at extremely high risk for extubating failure. CONCLUSION: The inconclusive nature of emerging evidence highlights the need for additional studies to establish the efficacy and suitability of HFNC as an alternative to NIV for previously intubated COPD patients. Clinicians should consider the available options and individualize their approach based on patient characteristics. Future research should focus on addressing these gaps in knowledge to guide clinical decision-making and optimize outcomes for this patient population.

Efficacy of Acupuncture in Acute Exacerbation of Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis.

Purpose: The effect of acupuncture as adjunctive therapy for acute exacerbation of chronic obstructive pulmonary disease (AECOPD) was controversial. Thus, we aimed to evaluate the effects of acupuncture for treating AECOPD. Methods: Eight databases were searched from database inception to July 30, 2023. All RCTs compared acupuncture plus conventional western medicine with conventional western medicine alone were included. Outcomes were quality of life, lung function, blood oxygen condition, exercise capacity, daily symptoms, duration of hospitalization, and adverse events. The statistical analyses were conducted using Stata 17.0, and methodological quality was measured by the Cochrane bias risk assessment tool. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to assess the quality of evidence. Results: Twelve studies including 915 patients were included. Compared with conventional western medicine alone, acupuncture combined with conventional western therapy significantly improved quality of life (CAT: MD: -3.25; 95% CI: -3.73 to -2.78, P<0.001) and arterial blood gas (PaCO2: MD: -1.85; 95% CI: -2.74 to -0.95, P<0.001; PaO2: MD: 5.15; 95% CI: 1.22 to 9.07, P = 0.01). And for lung function, statistical benefits were found in FEV1/FVC (MD: 4.66; 95% CI: 2.21 to 7.12, P<0.001), but no difference was seen for FEV1% (MD: 1.83; 95% CI: -0.17 to 3.83, P = 0.073). There was no significant improvement in exercise capacity (6MWD: MD: 96.69; 95% CI: -0.60 to 193.98, P = 0.051), hospitalization duration (MD: -5.70; 95% CI: -11.97 to 0.58, P = 0.075), and dyspnea (mMRC: MD: -0.19; 95% CI: -0.61 to 0.63, P = 0.376) between two groups. Overall bias for CAT and mMRC was in "high" risk, FEV1%, FEV1/FVC, PaCO2, and PaO2 was in "some concern" and 1 RCT assessing hospitalization duration was in "low" risk. And the overall assessments were either moderate, low or very low certainty. Seven trials performed safety assessment of acupuncture, and no serious adverse events were reported. Conclusion: Acupuncture might have auxiliary effects on AECOPD. However, the quality of the evidence is limited, and more high-quality RCTs are needed to be performed in the future.

Impact of smoking reduction on lung cancer risk in patients with COPD who smoked fewer than 30 pack-years: a nationwide population-based cohort study.

BACKGROUND: The effects of smoking reduction on the incidence of lung cancer in patients with chronic obstructive pulmonary disease (COPD) are not well known. This study aimed to investigate the effects of changes in smoking habits after COPD diagnosis on lung cancer development in patients who smoked less than 30 pack-years. METHODS: This nationwide retrospective cohort study included 16,832 patients with COPD who smoked less than 30 pack-years at the time of COPD diagnosis. Based on changes in smoking habits in the health screening examination data, smokers were categorized into three groups: quitters, reducers, and sustainers. The primary outcome was the risk of lung cancer development, which was estimated using the Cox proportional hazards model. We also modelled the amount of smoking reduction as a continuous variable. RESULTS: During a median follow-up of 4 years, the cumulative incidence of lung cancer was the highest among sustainers, followed by reducers and quitters. Compared with sustainers, reducers (adjusted HR 0.74, 95% CI:0.56-0.98) and quitters (adjusted HR 0.78, 95% CI:0.64-0.96) had a significantly lower risk of lung cancer. Incidence of lung cancer showed a decreasing trend with a decreasing amount of smoking (P for linearity < 0.01). CONCLUSIONS: In patients with COPD who smoked less than 30 pack-years, smoking reduction and cessation lowered the risk of lung cancer.

Impact of electronic cigarette usage on the onset of respiratory symptoms and COPD among Chinese adults.

The prevalence of dual usage and the relatively low cessation rate among e-cigarette (EC) users suggest that ECs have not demonstrated significant effectiveness as a smoking cessation tool. Furthermore, there has been a substantial increase in the prevalence of EC usage in recent years. Therefore, the objective of this study is to investigate the association between EC use and the incidence of respiratory symptoms and chronic obstructive pulmonary disease (COPD). A total of 10,326 participants aged between 20 and 55 years, without any respiratory diseases or COPD, were recruited for the study. These individuals attended employee physical examinations conducted at 16 public hospitals in Hebei province, China from 2015 to 2020. Logistic regression models were utilized to assess the association between EC use and the risk of respiratory symptoms and COPD using risk ratios along with their corresponding 95% confidence intervals. Restricted cubic spline functions were employed to investigate the dose-response non-linear relationship. The robustness of the logistic regression models was evaluated through subgroup analyses, and sensitivity analyses. During the 5-year follow-up period, a total of 1071 incident cases of respiratory symptoms and 146 incident cases of COPD were identified in this cohort study. After adjusting for relevant confounding factors, EC users demonstrated a respective increase in the risk of reporting respiratory symptoms and COPD by 28% and 8%. Furthermore, dual users who used both ECs and combustible cigarettes exhibited an elevated risk of incident respiratory symptoms and COPD by 41% and 18%, respectively, compared to those who had never used non-users of any cigarette products. The association between daily EC consumption and the development of respiratory symptoms, as well as COPD, demonstrated a significant J-shaped pattern. The potential adverse association between the consumption of ECs, particularly when used in combination with combustible cigarettes, and the development of respiratory symptoms and COPD necessitates careful consideration. Policymakers should approach ECs cautiously as a prospective smoking cessation tool.

Effects of apparent temperature on daily outpatient and inpatient visits for cause-specific respiratory diseases in Ganzhou, China: a time series study.

BACKGROUND: Non-optimum temperatures are associated with increased risk of respiratory diseases, but the effects of apparent temperature (AT) on respiratory diseases remain to be investigated. METHODS: Using daily data from 2016 to 2020 in Ganzhou, a large city in southern China, we analyzed the impact of AT on outpatient and inpatient visits for respiratory diseases. We considered total respiratory diseases and five subtypes (influenza and pneumonia, upper respiratory tract infection (URTI), lower respiratory tract infection (LRTI), asthma and chronic obstructive pulmonary disease [COPD]). Our analysis employed a distributed lag nonlinear model (DLNM) combined with a generalized additive model (GAM). RESULTS: We recorded 94,952 outpatients and 72,410 inpatients for respiratory diseases. We found AT significantly non-linearly associated with daily outpatient and inpatient visits for total respiratory diseases, influenza and pneumonia, and URTI, primarily during comfortable AT levels, while it was exclusively related with daily inpatient visits for LRTI and COPD. Moderate heat (32.1 °C, the 75.0th centile) was observed with a significant effect on both daily outpatient and inpatient visits for total respiratory diseases at a relative risk of 1.561 (1.161, 2.098) and 1.276 (1.027, 1.585), respectively (both P < 0.05), while the results of inpatients became insignificant with the adjustment for CO and O3. The attributable fractions in outpatients and inpatients were as follows: total respiratory diseases (24.43% and 18.69%), influenza and pneumonia (31.54% and 17.33%), URTI (23.03% and 32.91%), LRTI (37.49% and 30.00%), asthma (9.83% and 3.39%), and COPD (30.67% and 10.65%). Stratified analyses showed that children ≤5 years old were more susceptible to moderate heat than older participants. CONCLUSIONS: In conclusion, our results indicated moderate heat increase the risk of daily outpatient and inpatient visits for respiratory diseases, especially among children under the age of 5.

Cardiovascular disease in Alpha 1 antitrypsin deficiency: an observational study assessing the role of neutrophil proteinase activity and the suitability of validated screening tools.

BACKGROUND: Alpha 1 Antitrypsin Deficiency (AATD) is a rare, inherited lung disease which shares features with Chronic Obstructive Pulmonary Disease (COPD) but has a greater burden of proteinase related tissue damage. These proteinases are associated with cardiovascular disease (CVD) in the general population. It is unclear whether patients with AATD have a greater risk of CVD compared to usual COPD, how best to screen for this, and whether neutrophil proteinases are implicated in AATD-associated CVD. This study had three aims. To compare CVD risk in never-augmented AATD patients to non-AATD COPD and healthy controls (HC). To assess relationships between CVD risk and lung physiology. To determine if neutrophil proteinase activity was associated with CVD risk in AATD. Cardiovascular risk was assessed by QRISK2® score and aortic stiffness measurements using carotid-femoral (aortic) pulse wave velocity (aPWV). Medical history, computed tomography scans and post-bronchodilator lung function parameters were reviewed. Systemic proteinase 3 activity was measured. Patients were followed for 4 years, to assess CVD development. RESULTS: 228 patients with AATD, 50 with non-AATD COPD and 51 healthy controls were recruited. In all COPD and HC participants, QRISK2® and aPWV gave concordant results (with both measures either high or in the normal range). This was not the case in AATD. Once aPWV was adjusted for age and smoking history, aPWV was highest and QRISK2® lowest in AATD patients compared to the COPD or HC participants. Higher aPWV was associated with impairments in lung physiology, the presence of emphysema on CT scan and proteinase 3 activity following adjustment for age, smoking status and traditional CVD risk factors (using QRISK2® scores) in AATD. There were no such relationships with QRISK2® in AATD. AATD patients with confirmed CVD at four-year follow up had a higher aPWV but not QRISK2® at baseline assessment. CONCLUSION: aPWV measured CVD risk is elevated in AATD. This risk is not captured by QRISK2®. There is a relationship between aPWV, lung disease and proteinase-3 activity. Proteinase-driven breakdown of elastin fibres in large arteries and lungs is a putative mechanism and forms a potential therapeutic target for CVD in AATD.

Impact of particulate air pollution on airway injury and epithelial plasticity; underlying mechanisms.

Air pollution plays an important role in the mortality and morbidity of chronic airway diseases, such as asthma and chronic obstructive pulmonary disease (COPD). Particulate matter (PM) is a significant fraction of air pollutants, and studies have demonstrated that it can cause airway inflammation and injury. The airway epithelium forms the first barrier of defense against inhaled toxicants, such as PM. Airway epithelial cells clear airways from inhaled irritants and orchestrate the inflammatory response of airways to these irritants by secreting various lipid mediators, growth factors, chemokines, and cytokines. Studies suggest that PM plays an important role in the pathogenesis of chronic airway diseases by impairing mucociliary function, deteriorating epithelial barrier integrity, and inducing the production of inflammatory mediators while modulating the proliferation and death of airway epithelial cells. Furthermore, PM can modulate epithelial plasticity and airway remodeling, which play central roles in asthma and COPD. This review focuses on the effects of PM on airway injury and epithelial plasticity, and the underlying mechanisms involving mucociliary activity, epithelial barrier function, airway inflammation, epithelial-mesenchymal transition, mesenchymal-epithelial transition, and airway remodeling.

Secondhand smoke increases the risk of developing chronic obstructive pulmonary disease.

Smoking is the most important risk factor for chronic obstructive pulmonary disease (COPD), however evidence from large-scale studies on whether secondhand smoke (SHS) increases the risk of COPD is still lacking. We conducted this large longitudinal study to investigate the association between SHS and the development of COPD. This is a longitudinal study. Data on 6519 subjects who were never-smokers, had no history of COPD, and had complete lung function records were extracted from the Taiwan Biobank. They were divided into two groups according to SHS exposure: no exposure and exposure groups. Data were collected when participants enrolled in the study and during regular follow-up. Cox proportional hazards regression models were used to estimate the relative risk (RR) and 95% confidence interval (CI) for the association between SHS and the risk of developing COPD. At 48 months of follow-up, 260 (4%) participants in the no exposure group and 34 (7%) participants in the exposure group developed COPD. The RR of incident COPD development was significantly higher in the exposure group than that in the no exposure group after adjusting for confounders (RR = 1.49; 95% CI 1.04 to 2.14; P value = 0.031). There is a dose-response relationship between the duration of exposure to SHS and the risk of incident COPD, which demonstrates that an additional hour of exposure to SHS per week was associated with a 1.03-fold increased likelihood of developing COPD after adjusting for confounders (RR = 1.03; 95% CI 1.00 to 1.05; P value = 0.027). SHS exposure contributes to the development of COPD. This finding can help raise awareness of the harms of SHS and provide a reference for formulating anti-smoking policies.

Mediating Effect of Tobacco Dependence on the Association Between Maternal Smoking During Pregnancy and Chronic Obstructive Pulmonary Disease: Case-Control Study.

BACKGROUND: Maternal smoking during pregnancy (MSDP) is a known risk factor for offspring developing chronic obstructive pulmonary disease (COPD), but the underlying mechanism remains unclear. OBJECTIVE: This study aimed to explore whether the increased COPD risk associated with MSDP could be attributed to tobacco dependence (TD). METHODS: This case-control study used data from the nationwide cross-sectional China Pulmonary Health study, with controls matched for age, sex, and smoking status. TD was defined as smoking within 30 minutes of waking, and the severity of TD was assessed using the Fagerstrom Test for Nicotine Dependence. COPD was diagnosed when the ratio of forced expiratory volume in 1 second to forced vital capacity was <0.7 in a postbronchodilator pulmonary function test according to the 2017 Global Initiative for Chronic Obstructive Lung Disease criteria. Logistic regression was used to examine the correlation between MSDP and COPD, adjusting for age, sex, BMI, educational attainment, place of residence, ethnic background, occupation, childhood passive smoking, residential fine particulate matter, history of childhood pneumonia or bronchitis, average annual household income, and medical history (coronary heart disease, hypertension, and diabetes). Mediation analysis examined TD as a potential mediator in the link between MSDP and COPD risk. The significance of the indirect effect was assessed through 1000 iterations of the "bootstrap" method. RESULTS: The study included 5943 participants (2991 with COPD and 2952 controls). Mothers of the COPD group had higher pregnancy smoking rates (COPD: n=305, 10.20%; controls: n=211, 7.10%; P<.001). TD was more prevalent in the COPD group (COPD: n=582, 40.40%; controls: n=478, 33.90%; P<.001). After adjusting for covariates, MSDP had a significant effect on COPD (ß=.097; P<.001). There was an association between MSDP and TD (ß=.074; P<.001) as well as between TD and COPD (ß=.048; P=.007). Mediation analysis of TD in the MSDP-COPD association showed significant direct and indirect effects (direct: ß=.094; P<.001 and indirect: ß=.004; P=.03). The indirect effect remains present in the smoking population (direct: ß=.120; P<.001 and indirect: ß=.002; P=.03). CONCLUSIONS: This study highlighted the potential association between MSDP and the risk of COPD in offspring, revealing the mediating role of TD in this association. These findings contribute to a deeper understanding of the impact of prenatal tobacco exposure on lung health, laying the groundwork for the development of relevant prevention and treatment strategies.

Persistence of emphysema following cessation of cigarette smoke exposure requires a susceptibility factor.

Chronic obstructive pulmonary disease (COPD) is caused by cigarette smoke (CS) exposure but can often be progressive even in former smokers. Exposure of mice to CS for 22 wk causes emphysema, but whether emphysema persists after cessation of CS exposure is not clear. The purpose of this study was to determine whether emphysema persists in mice following a recovery period of 22 wk and whether a susceptibility factor, such as deficiency in the Bcl-2-interacting killer (Bik), is required for this persistence. Therefore, bik+/+ and bik-/- mice at 6-10 wk of age were exposed to 250 mg/m3 total particulate matter of CS or filtered air (FA) for 3 or 22 wk and were kept in FA for an additional 22 wk. Lungs were lavaged to quantify inflammatory cells, and sections were stained with hematoxylin and eosin to assess severity of emphysema. Exposure to CS for 3 wk increased the number of inflammatory cells in bik-/- mice compared with bik+/+ mice but not at 22 wk of exposure. At 22 wk of CS exposure, extent of emphysema was similar in bik+/+ and bik-/- mice. However, when mice were exposed to CS over the first 22 wk and were kept in FA for an additional 22 wk, emphysema remained similar in bik+/+ mice but was enhanced in bik-/- mice. These findings link increased inflammation with persistent emphysematous changes even after smoking cessation and demonstrate that a preexisting susceptibility condition is required to sustain enhanced emphysema that was initiated by long-term CS exposure.NEW & NOTEWORTHY Exposure of mice to cigarette smoke (CS) for 22 wk causes emphysema, but whether emphysema persists after an additional period of 6 mo after cessation of CS exposure has not been reported. In addition, the role of preexisting susceptibility in enhancing the persistence of CS-induced emphysema after exposure to CS has stopped has not been shown. The present study shows that a preexisting susceptibility must be present to enhance CS-induced emphysema after cessation of CS exposure.

[Natural history of COPD: evolution of concepts]. / Histoire naturelle de la BPCO : évolution des concepts.

NATURAL HISTORY OF COPD: EVOLUTION OF CONCEPTS. Chronic obstructive pulmonary disease (COPD) is a common chronic respiratory disease responsible for significant morbidity and mortality. The natural history of this disease is complex. The first cause is tobacco smoke exposure, followed by exposure to biomass smoke and occupational exposure to inhaled toxic substances. Genetic predisposing factors are known as the alpha-1-antitrypsin deficiency. The involvement of respiratory events in childhood in the genesis of the disease is also increasingly described. The decline of the different respiratory trajectories can be accelerated in COPD. The phenotypes of this disease also have a role in the evolution of respiratory function over time and their descriptions can modulate the therapeutic management in this disease.

HISTOIRE NATURELLE DE LA BPCO: ÉVOLUTION DES CONCEPTS. La bronchopneumopathie chronique obstructive (BPCO) est une maladie respiratoire chronique fréquente et responsable d'une morbi-mortalité importante. La compréhension de l'histoire naturelle de cette pathologie a évolué ces dernières années. La première cause de BPCO est le tabagisme, suivi de l'exposition à la fumée de biomasse et de l'exposition professionnelle à des toxiques inhalés. Des facteurs de prédisposition génétique sont connus, comme le déficit en alpha-1-antitrypsine. L'implication d'événements respiratoires au cours de l'enfance dans la genèse de la maladie est également de plus en plus décrite. Le déclin des différentes trajectoires de la fonction respiratoire peut être accéléré en cas de BPCO. Les phénotypes de cette maladie jouent aussi un rôle dans l'évolution de la fonction respiratoire au cours du temps et leur description peut moduler la prise en charge thérapeutique de cette maladie.

Association of dietary niacin intake with the prevalence and incidence of chronic obstructive pulmonary disease.

Evidence regarding the association between dietary niacin intake and chronic obstructive pulmonary disease (COPD) is limited. Our study investigates the relationship between dietary niacin intake and the prevalance and incidence of COPD in the adult population of the United States, using data from the National Health and Nutrition Examination Survey (NHANES) from 2003 to 2018. Data on niacin intake were extracted through dietary intake interviews. COPD diagnoses were based on lung function, medical history, and medication usage. We analyzed the association between niacin consumption and COPD using multiple logistic regression and restricted cubic spline models. The study included 7055 adult participants, divided into COPD (n = 243; 3.44%) and non-COPD (n = 6812; 96.56%) groups. Those with COPD had lower average niacin intake (21.39 ± 0.62 mg/day) compared to the non-COPD group (25.29 ± 0.23 mg/day, p < 0.001). In the adjusted multivariable model, the odds ratios (OR) and 95% confidence intervals (CI) for COPD in the highest versus lowest quartile of dietary niacin intake were 0.55 (0.33 to 0.89, P for trend = 0.009). Subgroup analysis, after adjustment for various variables, revealed no significant interaction effects. Dietary niacin intake was inversely associated with COPD prevalence in US adults. Participants with the highest dietary niacin intake demonstrated the lowest odds of COPD. The potential of dietary niacin supplementation as a strategy to mitigate COPD warrants further investigation.

Faecal microbial transfer and complex carbohydrates mediate protection against COPD.

OBJECTIVE: Chronic obstructive pulmonary disease (COPD) is a major cause of global illness and death, most commonly caused by cigarette smoke. The mechanisms of pathogenesis remain poorly understood, limiting the development of effective therapies. The gastrointestinal microbiome has been implicated in chronic lung diseases via the gut-lung axis, but its role is unclear. DESIGN: Using an in vivo mouse model of cigarette smoke (CS)-induced COPD and faecal microbial transfer (FMT), we characterised the faecal microbiota using metagenomics, proteomics and metabolomics. Findings were correlated with airway and systemic inflammation, lung and gut histopathology and lung function. Complex carbohydrates were assessed in mice using a high resistant starch diet, and in 16 patients with COPD using a randomised, double-blind, placebo-controlled pilot study of inulin supplementation. RESULTS: FMT alleviated hallmark features of COPD (inflammation, alveolar destruction, impaired lung function), gastrointestinal pathology and systemic immune changes. Protective effects were additive to smoking cessation, and transfer of CS-associated microbiota after antibiotic-induced microbiome depletion was sufficient to increase lung inflammation while suppressing colonic immunity in the absence of CS exposure. Disease features correlated with the relative abundance of Muribaculaceae, Desulfovibrionaceae and Lachnospiraceae family members. Proteomics and metabolomics identified downregulation of glucose and starch metabolism in CS-associated microbiota, and supplementation of mice or human patients with complex carbohydrates improved disease outcomes. CONCLUSION: The gut microbiome contributes to COPD pathogenesis and can be targeted therapeutically.

Quantitative Assessment Characteristics of Small Pulmonary Vessel Remodelling in Populations at High Risk for COPD and Smokers Using Low-Dose CT.

Purpose: To explore the morphological alterations in small pulmonary vessels in populations at high risk for chronic obstructive pulmonary disease (COPD) and smokers based on multiple computed tomography (CT) quantitative parameters. Patients and Methods: A total of 1969 Three Major Chest Diseases Screening Study participants with available demographic data and smoking history who underwent low-dose chest CT from 2018 to 2020 were included. All subjects were divided into normal, high risk for COPD, and COPD groups according to their pulmonary function test (PFT) results. Furthermore, the three groups were further subdivided into never-smokers, current smokers, and former smokers subgroups according to their smoking history. Quantitative parameters, such as the number, area at 6 mm~24 mm subpleura and volume of small pulmonary vessels, were extracted by computer software. Differences in small pulmonary vessel parameters among the groups were compared using two-way ANOVA. Results: The number, area at 6 mm~24 mm subpleura and volume of small pulmonary vessels in the group at high risk for COPD were lower than those in the normal group (P<0.05). The number, area at 6 mm~24 mm subpleura and volume of small pulmonary vessels in the COPD group were higher than those in the normal group (P<0.05). The number, area of small pulmonary vessels at 6 mm~12 mm subpleura in current smokers with high risk for COPD were higher than those in former smokers with high risk for COPD (P<0.05). Conclusion: The number, area, and volume of small pulmonary vessels in populations at high risk for COPD were decreased. Smoking cessation may impede structural changes in small pulmonary vessels in populations at high risk for COPD.

Association Between Instant Coffee Consumption and the Development of Chronic Obstructive Pulmonary Disease: Results From a Community-Based Prospective Cohort.

BACKGROUND: A poor diet is a risk factor for chronic obstructive pulmonary disease (COPD). The interaction between dietary factors and cigarette smoking in the development of COPD is unclear. We investigated the interactions between dietary patterns and smoking status on COPD-related outcomes. METHODS: We used data from the Anseong-Ansan cohort that has been followed for 20 years. A total of 6,221 individuals without COPD in the baseline survey were analyzed. Five dietary patterns were identified using a semi-quantitative food frequency questionnaire. Associations of dietary patterns with COPD and forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) ratio in different strata of smoking status were evaluated using Cox regression and linear mixed models, respectively. RESULTS: The highest quartile of the "coffee" pattern (high coffee consumption) was associated with COPD (hazard ratio, 1.46; 95% confidence interval [CI], 1.03-2.08) and lower FEV1/FVC ratio (ß = -1.2%; 95% CI, -1.9% to -0.6%) using the lowest quartile as a reference for heavy smokers, but not light or never smokers (P value for interaction = 0.035 for COPD). Regarding the associations between various consumption levels of black coffee, combined coffee, and instant coffee and COPD, an association with COPD was only observed for instant coffee in heavy smokers. CONCLUSION: High instant coffee consumption is associated with COPD development in heavy smokers, but not in light or never smokers. This may be attributed to sugar and cream in instant coffee mixes.

Association between occupational exposure and chronic obstructive pulmonary disease and respiratory symptoms in the Spanish population.

INTRODUCTION: The aim of this study was to analyze the impact of occupational exposure on chronic obstructive pulmonary disease (COPD) and respiratory symptoms in the general Spanish population. METHODS: This was a study nested in the Spanish EPISCAN II cross-sectional epidemiological study that included participants who had completed a structured questionnaire on their occupational history, a questionnaire on respiratory symptoms, and forced spirometry. The data were analyzed using Chi-square and Student's t tests and adjusted models of multiple linear regression and logistic regression. RESULTS: We studied 7502 subjects, 51.1% women, with a mean age of 60±11 years. Overall, 53.2% reported some respiratory symptoms, 7.9% had respiratory symptoms during their work activity, 54.2% were or had been smokers, and 11.3% (851 subjects) met COPD criteria on spirometry. A total of 3056 subjects (40.7%) reported exposure to vapors, gases, dust or fumes (VGDF); occupational exposure to VGDF was independently associated with the presence of COPD (OR 1.22, 95% CI: 1.03-1.44), respiratory symptoms (OR 1.45, 95%: CI 1.30-1.61), and respiratory symptoms at work (OR 4.69, 95% CI: 3.82-5.77), with a population attributable fraction for COPD of 8.2%. CONCLUSIONS: Occupational exposure is associated with a higher risk of COPD and respiratory symptoms in the Spanish population. These results highlight the need to follow strict prevention measures to protect the respiratory health of workers.