Ambient Air Pollution and Dysanapsis: Associations with Lung Function and Chronic Obstructive Pulmonary Disease in the Canadian Cohort Obstructive Lung Disease Study

Clinical characteristics and outcomes of chronic obstructive pulmonary disease patients with family history of chronic airway disease

BACKGROUND

Chronic Obstructive Pulmonary Disease (COPD) is a heterogeneous condition with different risk factors, including family history. This study aimed to explore association between a family history of chronic airway disease and features and outcomes of COPD.

METHODS

Participants were obtained from the RealDTC study between December 2016 and December 2022. Data on demographics, pulmonary function, history of exacerbation at baseline, acute exacerbation during 1-year follow-up and survival status during 3-years follow-up were collected.

RESULTS

5020 patients were enrolled, with 1307 patients (26.0%) having a family history of chronic airway diseases. Compared with patients without a family history of chronic airway diseases, patients with a family history had a lower forced expiratory Volume in one second (FEV1), higher Modified Medical Research Council (mMRC) score and COPD Assessment Test (CAT) score, higher rate of acute exacerbation and hospitalization in the past year (p < 0.05) and rate of acute exacerbation and hospitalization during 1 year follow-up period (p < 0.05). It was an independent risk factor for acute exacerbation (OR = 2.196; 95% CI =1.873-2.576) and hospitalization (OR = 2.199; 95% CI =1.812-2.670). Over 3 years of follow-up, there were no significant differences in mortality rates and annual changes in FEV1 between two groups.

CONCLUSION

COPD patients with a family history of chronic airway disease are not rare, and they tend to have more severe symptoms and a higher risk of future deterioration. In the management of COPD, special attention should be paid to patients with a family history of chronic airway disease.

129Xe-MRI ventilation and acinar abnormalities highlight the significance of spirometric dysanapsis: findings from the NOVELTY ADPro UK substudy

RATIONALE

Airways dysanapsis is defined by CT or spirometry as a mismatch between the size of the airways and lung volume and is associated with increased risk of developing chronic obstructive pulmonary disease (COPD). Lung disease in participants with dysanapsis and a label of asthma and/or COPD remains poorly understood.

METHODS

In participants with asthma and/or COPD, we used 129Xe-MRI to assess ventilation, acinar dimensions and gas exchange, and pulmonary function tests, and compared people with spirometric dysanapsis (forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC)<-1.64 z and FEV1>-1.64 z) to those with normal spirometry (FEV1, FVC and FEV1/FVC>-1.64 z).

RESULTS

From 165 participants assessed in the NOVELTY (NOVEL observational longiTudinal studY) ADPro (advanced diagnostic profiling) study with a physician-assigned diagnosis of asthma and/or COPD, 43 had spirometric dysanapsis and were age-matched to 43 participants with normal spirometry. Participants with dysanapsis had significantly increased ventilation defects (median difference (md) (95% CI) = 4.0% (1.42% to 5.38%), p<0.001), ventilation heterogeneity (md (95% CI) = 2.56% (1.31% to 3.56%), p<0.001) and measures of acinar dimensions (md (95% CI) = 0.004 cm2.s-1 (0.0009 to 0.007), p=0.009) from 129Xe-MRI, than those with normal spirometry. At the 1-year follow-up, only participants with dysanapsis had a significant increase in ventilation defects (md (95% CI)=0.45% (0.09% to 2.1%),p=0.016). Lower FEV1/FVC in the dysanapsis cohort was associated with increased ventilation defects (r=-0.64, R2=0.41, p<0.001) and increased acinar dimensions (r=-0.52, R2=0.38, p<0.001), with the highest values seen in those with an FVC above the upper limit of normal.

CONCLUSIONS

Participants with asthma and/or COPD, presenting to primary care with spirometric dysanapsis, exhibited increased lung abnormalities on 129Xe-MRI, when compared with those with normal spirometry. Spirometric dysanapsis in asthma and/or COPD is therefore associated with significant lung disease, and the FEV1/FVC is related to the degree of airways abnormality on 129Xe-MRI.

Biomass Smoke Exposure Reduces DNA Methylation Levels in PRSS23 (cg23771366) in Women with Chronic Obstructive Pulmonary Disease

COPD induced by biomass-burning smoke is a public health problem in developing countries. Biomass-based fuels are ineffective and deliver elevated levels of carbon monoxide, polycyclic aromatic hydrocarbons, and fine particulate matter. PRSS23 participates in extracellular matrix remodeling processes in COPD patients. Our objective was to estimate the DNA methylation levels of cg23771366 (PRSS23) and their clinical relevance in COPD caused by chronic exposure to biomass-burning smoke (BBS). We included 80 women with COPD (COPD-BBS) (≥200 h per year), 180 women with exposure to BBS (≥200 h per year) but without COPD (BBES), and 79 lung-healthy women (HW) without exposure to biomass-burning smoke. The DNA methylation analysis shows significant differences between the three groups included in this study (p < 0.001). HW had high methylation levels (100%) in cg23771366 (PRSS23). In comparison, COPD-BBS and BBES had low levels [0.91% vs. 9.17%, respectively], showing statistically significant differences (p = 0.011) between both groups, with the COPD-BBS presenting the lowest levels in the methylation of cg23771366. In conclusion, chronic biomass-burning smoke exposure is associated with decreased levels of DNA methylation at the CpG cg23771366 site in PRSS23, reinforcing the relationship between PRSS23 and particulate matter.

COPD Exacerbations, Air Pollutant Fluctuations, and Individual-Level Factors in the Pandemic Era

Purpose

Pandemic-era associations between air pollutant exposures and exacerbations of chronic obstructive pulmonary disease (COPD) are under-explored. Given the considerable observed pandemic-era pollutant fluctuations, these associations were investigated along with possible individual-level risk factors.

Patients and Methods

Participants with spirometry-confirmed COPD from Canadian Cohort Obstructive Lung Disease (CanCOLD) were included, with data collected before ("pre-pandemic") and during ("pandemic") the COVID-19 pandemic. Nitrogen dioxide (NO2), fine particulate matter (PM2.5), ground-level ozone (O3), total oxidant (Ox) and weather data were obtained from national databases. Associations between each air pollutant and "symptom-based" exacerbations (increased dyspnea or sputum volume/purulence ≥48hrs) and "event-based" exacerbations ("symptom-based" plus requiring antibiotics, corticosteroids, or unscheduled healthcare use) were estimated in separate models. Generalized estimating equations (GEE) models were reported as rate ratios (RRs) per interquartile range (IQR) increment in pollutant concentration with 95% confidence intervals (95% CIs).

Results

NO2, PM2.5, and Ox (NO2+O3) concentrations (but not O3) fell significantly during the pandemic. In the 673 participants with COPD included, both symptom-based and event-based exacerbation rates were likewise significantly higher during the pre-pandemic period. During the pre-pandemic period, Ox was positively associated with symptom-based exacerbations (RR: 1.21 [1.08,1.36]). During the pandemic period, Ox was positively associated with symptom-based (1.46 [1.13,1.89]) and event-based (1.43 [1.00,2.05]) exacerbations. Fewer self-reported pandemic protective behaviors, and higher viral infectious symptoms, were also associated with exacerbations. In stepwise multivariable risk-factor analyses, female gender (1.23 [1.04,1.45] and 1.41 [1.13,1.76]) and co-morbid asthma (1.65 [1.34,2.03] and 1.54 [1.19,2.00]) were associated with symptom-based and event-based exacerbations, respectively, blood eosinophils (1.42 [1.10,1.84]) were associated with event-based exacerbations, and each IQR increment in Ox was associated with symptom-based exacerbations (1.31 [1.06,1.61]).

Conclusion

Ox exposure was consistently associated with symptom-based COPD exacerbations, and female gender, co-morbid asthma, and blood eosinophilia were found to be relevant risk factors.

Molecular Approaches to Treating Chronic Obstructive Pulmonary Disease: Current Perspectives and Future Directions

Chronic obstructive pulmonary disease (COPD) is a clinical syndrome that presents as airflow limitation with poor reversibility accompanied by dynamic hyperinflation of the lung. It is a complex disease with chronic inflammatory airway changes caused by exposure to noxious particles or gases, such as cigarette smoke. The disease involves persistent inflammation and oxidative stress, perpetuated by frequent exacerbations. The prevalence of COPD is on the rise, with the prediction that it will be the leading cause of morbidity and mortality over the next decade. Despite the global burden of COPD and its associated morbidity and mortality, treatment remains limited. Although the understanding of the pathogenesis of COPD has increased over the last two decades, molecular approaches to develop new therapies for the treatment of COPD have lagged. Here, we review the molecular approaches that have the potential for developing novel therapies for COPD.

Frequency of Exacerbations of Chronic Obstructive Pulmonary Disease Associated with the Long-Term Exposure to Air Pollution in the AIREPOC Cohort

Background

Exacerbations of chronic obstructive pulmonary disease (COPD-E) have been associated with levels of air pollution. The occurrence of COPD-E is associated with increased mortality in this population.

Purpose

To determine the association between long-term exposure to PM2.5 and NO2, and the frequency of COPD-E in patients belonging to AIREPOC, an institutional integrated care program for COPD in Bogota, Colombia.

Patients and Methods

Retrospective cohort study included patients with COPD living in Bogotá, between 2018 and 2021, who received health care in the AIREPOC program. Each patient´s home address was geolocated. Information from local air quality network stations was used to estimate daily and annual mean PM2.5 and NO2 exposure level for each patient using the inverse distance squared weighted regression (IDWR) method. The effect of PM2.5 and NO2 concentrations categorized at 15 µg/m3 and 25 µg/m3 respectively on the frequency of COPD-E was estimated using a zero-truncated negative binomial model adjusted for potential confounders. Goodness-of-fit was assessed by residuals.

Results

During the observation period, 580 COPD-E occurred in 722 patients. Significant associations were found between COPD-E and NO2 concentrations ≥25 µg/m3 (incidence density ratio, RDI: 1.29, 95% CI: 1.02-1.67) after adjustment for sun exposure, COPD severity, depression, and ambient humidity. No association was found between the frequency of COPD-E and PM2.5 concentrations ≥15µg/m3.

Conclusion

Prolonged exposure to high levels of NO2 increases the frequency of COPD exacerbations in patients residing in Bogotá. These results highlight the importance of strengthening air quality control measures and educating people with COPD to know and interpret the local air quality indices and to follow the recommendations derived from its alterations.

Clinicopathological relationship between PM2.5 exposure and acute exacerbations of chronic obstructive pulmonary disease

OBJECTIVE

This study investigates the association between fine particulate matter (PM2.5) exposure and acute exacerbations of chronic obstructive pulmonary disease (AECOPD).

METHODS

A retrospective analysis was conducted on 1284 AECOPD hospitalizations at Shanxi Medical University's Second Hospital from 2018 to 2022. This data was paired with Shanxi's average monthly PM2.5 data from the Tracking Air Pollution in China (TAP) dataset. Correlations between PM2.5 levels and AECOPD clinicopathological features were assessed using ANOVA and Spearman's correlation.

RESULTS

Higher PM2.5 concentrations were observed during February-April and November-January, correlating with increased AECOPD admissions (r = 0.754), outpatient visits (r = 0.799), emergency visits (r = 0.447), and ICU transfers (r = 0.860). Among the patients, 76.5 % were smokers and 68.4 % were over 60 years old. Inflammatory markers (leukocyte and neutrophil counts, eosinophil percentages, C-reactive protein), D-dimer levels, PaCO2, and pulmonary fibrosis indicators showed positive correlations with PM2.5 levels, whereas Pulmonary Function measures (FEV1/ FVC, FEV1 %) and PaO2 showed inverse correlations.

CONCLUSION

Elevated PM2.5 exposure significantly increases the risk of AECOPD, linked to heightened inflammation, pulmonary fibrosis, and diminished pulmonary function, and the majority of these patients are over 60 years old or are smokers. This study provides valuable theoretical and practical insights for the proactive prevention and management of AECOPD in clinical settings.

Spirometry estimation of central airway dysanapsis on computed tomography in healthy subjects without active lung diseases

The original concept of the airway-to-lung size mismatch, termed dysanapsis, was introduced on spirometry and was extended by computed tomography (CT) evaluation of the central airways. CT-assessed dysanapsis allows a risk estimation of lung disease development in healthy subjects, although radiation exposure limits its use, particularly for younger subjects. This study investigated which spirometry indices can be used to estimate CT-assessed central airway dysanapsis in healthy subjects. In consecutive lung cancer screening subjects without active lung diseases, the dysanapsis ratio (DR), forced mid-expiratory flow/forced vital capacity (FEF25-75/FVC), forced expiratory volume in 1 s/FVC (FEV1/FVC), and peak expiratory flow/FVC (PEF/FVC) were obtained via spirometry. The airway-to-lung size ratio for four locations, including the trachea, both main bronchi, and bronchus intermedius (ALR4), and for 14 locations, including the same four airways and 10 segmental and subsegmental airways (ALR14), were obtained via CT. According to the quartiles of the ALR14 or ALR4, 163 male and 190 female subjects were divided into four groups. CT-assessed dysanapsis was defined as the lowest quartile of the ALR14 (or ALR4). Among the spirometry indices, the area under the curve (AUC) for detecting the lowest ALR14 group was the highest for DR (0.80 and 0.78 for males and females, respectively). In contrast, the AUC for detecting the lowest ALR4 group was the highest for PEF/FVC (0.67 and 0.77 for males and females, respectively). DR and PEF/FVC on spirometry could be associated with CT-assessed dysanapsis, but the associations varied depending on the airway locations used for the ALR calculation.NEW & NOTEWORTHY The airway-to-lung size discrepancy on computed tomography (CT-assessed dysanapsis) highlights a lifelong risk for developing lung diseases. This study demonstrated that the spirometric index of the dysanapsis ratio can be used for estimating CT-assessed dysanapsis of the entire central airway tree from the trachea to subsegmental airways, whereas a novel index, peak expiratory flow/forced vital capacity (PEF/FVC), can be used for estimating CT-assessed dysanapsis of the extrapulmonary airways (the trachea, main bronchus, and bronchus intermedius).

The impact of airborne particulate matter-based pollution on the cellular and molecular mechanisms in chronic obstructive pulmonary disease (COPD)

Inhalation of particulate matter (PM), one of the many components of air pollution, is associated with the development and exacerbation of chronic respiratory diseases, such as chronic obstructive pulmonary disease (COPD). COPD is one of the leading causes of global mortality and morbidity, with a paucity of therapeutic options and a significant contributor to global health expenditure. This review aims to provide a mechanistic understanding of the cellular and molecular pathways that lead to the development of COPD following chronic PM exposure. Our review describes how the inhalation of PM can lead to lung parenchymal destruction and cellular senescence due to chronic pulmonary inflammation and oxidative stress. Following inhalation of PM, significant increases in a range of pro-inflammatory cytokines, mediated by the nuclear factor kappa B pathway are reported. This review also highlights how the inhalation of PM can lead to deleterious chronic oxidative stress persisting in the lung post-exposure. Furthermore, our work summarises how PM inhalation can lead to airway remodelling, with increases in pro-fibrotic cytokines and collagen deposition, typical of COPD. This paper also accentuates the interconnection and possible synergism between the pathophysiological mechanisms leading to COPD. Our work emphasises the serious health consequences of PM exposure on respiratory health. Elucidation of the cellular and molecular mechanisms can provide insight into possible therapeutic options. Finally, this review should serve as a stark reminder of the need for genuine action on air pollution to decrease the associated health burden on our growing global population.

Sensitive outcome measures to detect the association between PM2.5 and lung function impairment

See related article

Chest CT Airway and Vascular Measurements in Females with COPD or Long-COVID

Chest CT provides a way to quantify pulmonary airway and vascular tree measurements. In patients with COPD, CT airway measurement differences in females are concomitant with worse quality-of-life and other outcomes. CT total airway count (TAC), airway lumen area (LA), and wall thickness (WT) also differ in females with long-COVID. Our objective was to evaluate CT airway and pulmonary vascular and quality-of-life measurements in females with COPD as compared to ex-smokers and patients with long-COVID. Chest CT was acquired 3-months post-COVID-19 infection in females with long-COVID for comparison with the same inspiratory CT in female ex-smokers and COPD patients. TAC, LA, WT, and pulmonary vascular measurements were quantified. Linear regression models were adjusted for confounders including age, height, body-mass-index, lung volume, pack-years and asthma diagnosis. Twenty-one females (53 ± 14 years) with long-COVID, 17 female ex-smokers (69 ± 9 years) and 13 female COPD (67 ± 6 years) patients were evaluated. In the absence of differences in quality-of-life scores, females with long-COVID reported significantly different LA (p = 0.006) compared to ex-smokers but not COPD (p = 0.7); WT% was also different compared to COPD (p = 0.009) but not ex-smokers (p = 0.5). In addition, there was significantly greater pulmonary small vessel volume (BV5) in long-COVID as compared to female ex-smokers (p = 0.045) and COPD (p = 0.003) patients and different large (BV10) vessel volume as compared to COPD (p = 0.03). In females with long-COVID and highly abnormal quality-of-life scores, there was CT evidence of airway remodelling, similar to ex-smokers and patients with COPD, but there was no evidence of pulmonary vascular remodelling.Clinical Trial Registration: www.clinicaltrials.gov NCT05014516 and NCT02279329.

Discordant definitions of small airway dysfunction between spirometry and parametric response mapping: the HRCT-based study

OBJECTIVES

To analyze the lung structure of small airway dysfunction (SAD) defined by spirometry and parametric response mapping (PRM) using high-resolution computed tomography (HRCT), and to analyze the predictive factors for SAD.

METHODS

A prospective study was conducted with 388 participants undergoing pulmonary function test (PFT) and inspiratory-expiratory chest CT scans. The clinical data and HRCT assessments of SAD patients defined by both methods were compared. A prediction model for SAD was constructed based on logistic regression.

RESULTS

SAD was defined in 122 individuals by spirometry and 158 by PRM. In HRCT visual assessment, emphysema, tree-in-bud sign, and bronchial wall thickening have higher incidence in SAD defined by each method. (p < 0.001). Quantitative CT showed that spirometry-SAD had thicker airway walls (p < 0.001), smaller lumens (p = 0.011), fewer bronchi (p < 0.001), while PRM-SAD had slender blood vessels. Predictive factors for spirometry-SAD were age, male gender, the volume percentage of emphysema in PRM (PRMEmph), tree-in-bud sign, bronchial wall thickening, bronchial count; for PRM-SAD were age, male gender, BMI, tree-in-bud sign, emphysema, the percentage of blood vessel volume with a cross-sectional area less than 1 mm2 (BV1/TBV). The area under curve (AUC) values for the fitted predictive models were 0.855 and 0.808 respectively.

CONCLUSIONS

Compared with PRM, SAD defined by spirometry is more closely related to airway morphology, while PRM is sensitive to early pulmonary dysfunction but may be interfered by pulmonary vessels. Models combining patient information and HRCT assessment have good predictive value for SAD.

CRITICAL RELEVANCE STATEMENT

HRCT reveals lung structural differences in small airway dysfunction defined by spirometry and parametric response mapping. This insight aids in understanding methodological differences and developing radiological tools for small airways that align with pathophysiology.

KEY POINTS

Spirometry-SAD shows thickened airway walls, narrowed lumen, and reduced branch count, which are closely related to airway morphology. PRM shows good sensitivity to early pulmonary dysfunction, although its assessment of SAD based on gas trapping may be affected by the density of pulmonary vessels and other lung structures. Combining patient information and HRCT features, the fitted model has good predictive performance for SAD defined by both spirometry and PRM (AUC values are 0.855 and 0.808, respectively).

Causal relationships between genetically predicted particulate air pollutants and neurodegenerative diseases: A two-sample Mendelian randomization study

Accumulating observational studies have linked particulate air pollutants to neurodegenerative diseases (NDDs). However, the causal links and the direction of their associations remain unclear. Therefore, we adopted a two-sample Mendelian randomization (TSMR) design using the GWAS-based genetic instruments of particulate air pollutants (PM2.5 and PM10) from the UK Biobank to explore their causal influence on four common neurodegenerative diseases. Estimates of causative relationships were generated by the Inverse variance weighted (IVW) method with multiple sensitive analyses. The heterogeneity and pleiotropy tests were additionally performed to verify whether our findings were robust. Genetically predicted PM2.5 and PM10 could elevate the occurrence of AD (odds ratio [OR] = 2.22, 95 % confidence interval [CI] 1.53-3.22, PIVW = 2.85×10-5, PFalsediscovery rate[FDR]= 2.85×10-4 and OR = 2.41, 95 % CI: 1.26-4.60, PIVW = 0.008, PFDR=0.039, respectively). The results were robust in sensitive analysis. However, no evidence of causality was found for other NDDs. Our present study suggests that PM2.5 and PM10 have a detrimental effect on AD, which indicates that improving air quality to prevent AD may have pivotal public health implications.

The effect of air pollutants on COPD-hospitalized patients in Lanzhou, China (2015-2019)

BACKGROUND

Lanzhou is the largest heavy industrial city in northwest China and it is a typical geographical valley-like city. However, there are few studies on the relationship between air pollutants and COPD, and their respective sample sizes are small, resulting in inconsistent results. The aim of this study is to analyze the effects of air pollutants on COPD hospitalizations in Lanzhou, China.

METHODS

An ecological time series study with distributed lag non-linear model (DLNM) was used for analysis. Daily COPD hospitalization data in Lanzhou from 1 January 2015 to 31 December 2019 were collected from 25 hospitals, as well as air pollutant data and meteorological data.

RESULTS

A total of 18,275 COPD hospitalizations were enrolled. For 10 μg/m3 increase in PM2.5, PM10, SO2, NO2, and 1 mg/m3 increase in CO at lag 07 day, the RR95%CI of COPD hospitalizations were 1.048 (1.030, 1.067), 1.008 (1.004, 1.013), 1.091 (1.048, 1.135), 1.043 (1.018, 1.068), and 1.160 (1.084, 1.242), respectively. The exposure-response curves between air pollutants (except O3-8h) and COPD hospitalizations were approximately linear with no thresholds. Female, and the harmful effect of PM on aged <65 years, the effect of gaseous pollutant on those aged ≥65 years, were stronger, particularly in the cold season. Exposure to air pollutants (except O3-8h) might increase the risk of COPD hospitalizations. O3-8h has a weak and unstable effect on COPD.

CONCLUSION

Exposure to air pollutants (except O3-8h) increases the risk of COPD hospitalizations. O3-8h has a weak and unstable effect on COPD hospital admissions. The harmful effect of gaseous pollutants (except O3-8h) on COPD-hospitalized patients was stronger than that of PM.

Associations of fractional exhaled nitric oxide with airway dimension and mucus plugs on ultra-high-resolution computed tomography in former smokers and nonsmokers with asthma

BACKGROUND

Associations of fractional exhaled nitric oxide (FeNO) with airway wall remodeling and mucus plugs remain to be explored in smokers and nonsmokers with asthma. Ultra-high-resolution computed tomography (U-HRCT), which allows accurate structural quantification of airways >1 mm in diameter, was used in this study to examine whether higher FeNO was associated with thicker walls of the 3rd to 6th generation airways and mucus plugging in patients with asthma.

METHODS

The retrospective analyses included consecutive former smokers and nonsmokers with asthma who underwent U-HRCT in a hospital. The ratio of wall area to summed lumen and wall area was calculated as the wall area percent (WA%). Mucus plugging was visually scored.

RESULTS

Ninety-seven patients with asthma (including 59 former smokers) were classified into low (<20 ppb), middle (20-35 ppb), and high (>35 ppb) FeNO groups (n = 24, 26, and 47). In analysis including all patients and subanalysis including nonsmokers or former smokers, WA% in the 6th generation airways was consistently higher in the high FeNO group than in the low FeNO group, whereas WA% in the 3rd to 5th generation airways was not. In multivariable models, WA% in the 6th generation airways and the rate of mucus plugging were higher in the high FeNO group than in the low FeNO group after adjusting for age, sex, body mass index, smoking status, lung volume, and allergic rhinitis presence.

CONCLUSIONS

Higher FeNO may reflect the inflammation and remodeling of relatively peripheral airways in asthma in both former smokers and nonsmokers.

Airway Tree Caliber and Susceptibility to Pollution-associated Emphysema: MESA Air and Lung Studies

Rationale: Airway tree morphology varies in the general population and may modify the distribution and uptake of inhaled pollutants. Objectives: We hypothesized that smaller airway caliber would be associated with emphysema progression and would increase susceptibility to air pollutant-associated emphysema progression. Methods: MESA (Multi-Ethnic Study of Atherosclerosis) is a general population cohort of adults 45-84 years old from six U.S. communities. Airway tree caliber was quantified as the mean of airway lumen diameters measured from baseline cardiac computed tomography (CT) (2000-2002). Percentage emphysema, defined as percentage of lung pixels below -950 Hounsfield units, was assessed up to five times per participant via cardiac CT scan (2000-2007) and equivalent regions on lung CT scan (2010-2018). Long-term outdoor air pollutant concentrations (particulate matter with an aerodynamic diameter ⩽2.5 μm, oxides of nitrogen, and ozone) were estimated at the residential address with validated spatiotemporal models. Linear mixed models estimated the association between airway tree caliber and emphysema progression; modification of pollutant-associated emphysema progression was assessed using multiplicative interaction terms. Measurements and Main Results: Among 6,793 participants (mean ± SD age, 62 ± 10 yr), baseline airway tree caliber was 3.95 ± 1.1 mm and median (interquartile range) of percentage emphysema was 2.88 (1.21-5.68). In adjusted analyses, 10-year emphysema progression rate was 0.75 percentage points (95% confidence interval, 0.54-0.96%) higher in the smallest compared with largest airway tree caliber quartile. Airway tree caliber also modified air pollutant-associated emphysema progression. Conclusions: Smaller airway tree caliber was associated with accelerated emphysema progression and modified air pollutant-associated emphysema progression. A better understanding of the mechanisms of airway-alveolar homeostasis and air pollutant deposition is needed.

Long-term exposure to PM10 and respiratory health among Parisian subway workers

Exposure to ambient PM10 may increase the risk of chronic obstructive pulmonary disease (COPD) and lung function decline. We evaluated the long-term exposure to PM10 and its relationship with COPD prevalence and lung function in Parisian subway workers. Participants were randomly selected from a 15,000-subway worker cohort. Individual annual external exposure to PM10 (ePM10) was estimated using a company-specific job-exposure-matrix based on PM10 measurements conducted between 2004 and 2019 in the Parisian subway network. Mean annual inhaled PM10 exposure (iPM10) was modeled as function of ePM10 exposure, inhalation rate, and filtration efficiency of the respiratory protection used. COPD diagnosis was performed in March-May 2021 based on post-bronchodilator spirometry. The relationship between iPM10 and outcomes was assessed using logistic and linear regression models, adjusted for exposure duration and potential confounders. Amongst 254 participants with complete data, 17 were diagnosed as COPD. The mean employment duration was 23.2 ± 7.3years, with annual mean ePM10 of 71.8 ± 33.7 μg/m3 and iPM10 of 0.59 ± 0.27 μg/shift, respectively. A positive but statistically non-significant association was found for COPD prevalence with iPM10 (OR = 1.034, 95%-CI = 0.781; 1.369, per 100 ng/shift) and ePM10 (OR = 1.029, 95%-CI = 0.879; 1.207, per 10 μg/m3). No decline in lung function was associated with PM10 exposure. However, forced expiratory volume during the first second and forced vital capacity lower than normal were positively associated with exposure duration (OR = 1.125, 95%-CI = 1.004; 1.260 and OR = 1.171, 95%-CI = 0.989; 1.386 per year, respectively). Current smoking was strongly associated with COPD prevalence (OR = 6.85, 95%-CI = 1.87; 25.10) and most lung function parameters. This is the first study assessing the relationship between long-term exposure to subway PM10 and respiratory health in subway workers. The risk estimates related with subway PM10 exposure are compatible with those related to outdoor PM10 exposure in the large recent studies. Large cohorts of subway workers are necessary to confirm these findings.

Effective-components combination alleviates PM2.5-induced inflammation by evoking macrophage autophagy in COPD

ETHNOPHARMACOLOGICAL RELEVANCE

Bufei Yishen formula (BYF) is clinically used to treat chronic obstructive pulmonary disease (COPD). Effective-component compatibility (ECC) is a combination of five active components derived from BYF, which has an equal effect on COPD to BYF. Our previous study has also demonstrated that ECC can protect COPD rats against PM2.5 exposure. However, the precise mechanisms remain to be elucidated.

AIM OF THE STUDY

To explore the mechanism underlying the anti-inflammatory effects of ECC-BYF against PM2.5-accelerated COPD.

MATERIALS AND METHODS

MH-S macrophages were stimulated by PM2.5 suspension to establish an in vitro model. Western blotting and immunofluorescent staining were used to measure the protein levels of autophagy markers. ELISA and quantitative PCR were used to detect the levels of inflammatory cytokines. In vivo, an established PM2.5-accelerated COPD rat model was used to determine the protective effect of ECC-BYF. Lung function, pathology, autophagy, and inflammatory mediators were detected.

RESULTS

Firstly, we observed a significantly increased number of macrophages in the lungs upon PM2.5 exposure. Then, decreased autophagy flux while elevated inflammation was detected in PM2.5-exposed rats and MH-S cells. In MH-S cells, ECC-BYF significantly suppressed the PM2.5-increased inflammatory cytokines production, which was accompanied by the enhancement of autophagy flux. An autophagy inhibitor counteracted the anti-inflammatory effect elicited by ECC-BYF. In addition, ECC-BYF stimulated Foxo3 nuclear translocation and upregulated Foxo3 expression, whereas Foxo3 knockdown abrogated the inhibitory effect of ECC-BYF on inflammation. In PM2.5-accelerated COPD rats, ECC-BYF also attenuated the autophagy disruption and increased Foxo3 in the lungs, finally resulting in a suppression of pulmonary inflammation and an enhancement of lung function.

CONCLUSION

ECC-BYF can ameliorate PM2.5-aggravated inflammation in COPD, which might be associated with the enhancement of autophagy flux in alveolar macrophages through the activation of Foxo3 signals.

Estimating the global prevalence of chronic obstructive pulmonary disease (COPD): a systematic review and meta-analysis

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a major public health problem. The present study aims to provide a global and regional estimate of the prevalence of COPD based on spirometry according to the two most widely used diagnostic criteria of COPD: fixed ratio (FR) and lower limit of normal (LLN).

METHODS

We conducted a systematic review of the literature according to PRISMA guidelines. MEDLINE, Web of Sciences, and Scopus databases were searched to identify studies on the spirometry-based prevalence of COPD in individuals aged 40 years and older. The meta-analysis was performed using MedCalc 19 software.

RESULTS

In total, 42 of the 3393 studies reviewed were eligible for inclusion. The overall prevalence of COPD in people aged 40 years and older was 12.64% (95% CI 10.75%-14.65%) and 7.38% (95% CI 5.47% - 9.55%) based on FR and LLN criteria, respectively. By gender, men had a higher prevalence of COPD compared to women (15.47%; 95% CI 12.22%-19.02% for men versus 8.79%; 95% CI 6.94%-10.82% for women). Using the LLN criteria, the prevalence of COPD in both sexes was almost identical (8.67%; 95% CI 8.44%- 8.90% for men and 8.00%; 95% CI 6.42% - 9.73% for women). We reported a high prevalence of COPD among smokers and the elderly by both definitions of airway obstruction. Regional prevalence estimates using the FR definition indicate that the highest COPD prevalence was recorded in the Americas and the lowest was recorded in the Eastern Mediterranean region. Using the LLN definition, the highest prevalence was recorded in the Southeast Asian region and the lowest prevalence was recorded in the American region. The most common COPD stage was stage II, with a prevalence of 50.46%. The results indicate a huge lack of prevalence data in the African and Eastern Mediterranean region. The results were given using a random-effect model due to the high heterogeneity between studies.

CONCLUSION

Results show that the prevalence of COPD differs according to the diagnostic criteria used. In addition, management and prevention strategies targeting risk factors for COPD are certainly needed to reduce the global burden of this chronic respiratory disease.

Deep learning parametric response mapping from inspiratory chest CT scans: a new approach for small airway disease screening

OBJECTIVES

Parametric response mapping (PRM) enables the evaluation of small airway disease (SAD) at the voxel level, but requires both inspiratory and expiratory chest CT scans. We hypothesize that deep learning PRM from inspiratory chest CT scans can effectively evaluate SAD in individuals with normal spirometry.

METHODS

We included 537 participants with normal spirometry, a history of smoking or secondhand smoke exposure, and divided them into training, tuning, and test sets. A cascaded generative adversarial network generated expiratory CT from inspiratory CT, followed by a UNet-like network predicting PRM using real inspiratory CT and generated expiratory CT. The performance of the prediction is evaluated using SSIM, RMSE and dice coefficients. Pearson correlation evaluated the correlation between predicted and ground truth PRM. ROC curves evaluated predicted PRMfSAD (the volume percentage of functional small airway disease, fSAD) performance in stratifying SAD.

RESULTS

Our method can generate expiratory CT of good quality (SSIM 0.86, RMSE 80.13 HU). The predicted PRM dice coefficients for normal lung, emphysema, and fSAD regions are 0.85, 0.63, and 0.51, respectively. The volume percentages of emphysema and fSAD showed good correlation between predicted and ground truth PRM (|r| were 0.97 and 0.64, respectively, p < 0.05). Predicted PRMfSAD showed good SAD stratification performance with ground truth PRMfSAD at thresholds of 15%, 20% and 25% (AUCs were 0.84, 0.78, and 0.84, respectively, p < 0.001).

CONCLUSION

Our deep learning method generates high-quality PRM using inspiratory chest CT and effectively stratifies SAD in individuals with normal spirometry.

Effects of climate and environment on migratory old people with allergic diseases in China: Protocol for a Sanya cohort study

Background

Several studies have reported that the mountain climate can alleviate asthma, however, the effect of tropical climate on migratory elderly, especially in people with respiratory or allergic diseases is unknown.

Objectives

This cohort study aims to explore impact of climate and environmental changes on allergic diseases in migratory old people.

Methods

In this prospective cohort study, we recruited 750 older migratory people, the majority of whom were homeowners to minimize the risk of loss to follow up. The study's inclusion criteria were elderly individuals had moved from northern China to Sanya and suffered from either asthma or allergic diseases. Prior to participation, these individuals provided informed consent and underwent baseline assessment. Subsequently, they will be followed for three years. A face-to-face interview was conducted to gather information regarding their living environment and habits. Trained investigators administered the questionnaires and performed physical examinations including height, weight, and blood pressure, while a professional respiratory doctor conducted pulmonary function tests. Blood samples were promptly tested routine blood test, liver function, kidney function, glucose, triglyceride, allergens, and inflammatory factors. Climate and environmental data were obtained from Sanya Meteorological Bureau and Ecological Environment Bureau, respectively. We primarily compared the differences of participants with asthma or allergic diseases between northern China and Sanya in southern China by Chi-square test, t-test or Wilcoxon rank-sum test.

Findings

A total of 750 participants were recruited in this cohort from fourteen communities. All participants were surveyed questionnaires about health and family environment, underwent physical examinations, and collected biological samples for laboratory examinations.

Novelty

This is the first study to evaluate the effects of tropical climate and environment on elderly migrants from cold regions. This study has important implication for the health tourism and aging health, especially for the elderly migrants who suffered the respiratory and allergic diseases. Furthermore, this cohort study establishes a solid foundation for investigating the influence of environmental changes on elderly migrants with allergic diseases.

Randomised controlled trial of a behavioural intervention to reduce exposure to PM2.5 in patients with COPD

BACKGROUND

Fine particulate matter (PM2.5) is a well-known risk factor for worse outcomes of chronic obstructive pulmonary disease (COPD). However, evidence-based guidance on effective personal behavioural strategies to minimise the effects of PM2.5 is limited. This study aimed to assess the effectiveness of a behavioural intervention in reducing PM2.5 exposure and improving clinical outcomes in patients with COPD.

MATERIALS AND METHODS

Participants were 1:1 randomised, and the intervention group received a behavioural intervention consisting of five activities, while the control group received usual care. The participants were followed up for 9 months. The primary outcomes were differences in the score of St. George's Respiratory Questionnaire for patients with COPD (SGRQ-C) and COPD assessment test (CAT) from baseline.

RESULTS

A total of 106 participants were enrolled and 102 completed the study. At the end of the study, the intervention group showed significant improvements in the primary outcomes compared to the control group, with a group difference of -5.9 in the reduction of total SGRQ-C (-3.4 vs. 2.5; p = 0.049) and -3.8 in the CAT score (-1.2 vs. 2.7; p = 0.001). Participants with good adherence to the intervention demonstrated a greater extent of improvement in CAT score and lower PM2.5 levels compared to those who had poor adherence or were in the control group. Regular checking of air quality forecasts was significantly associated with a reduction in CAT scores among all the intervention activities.

CONCLUSION

Individual-level behavioural interventions can be an effective strategy for mitigating the health hazards associated with PM2.5.

CLINICALTRIALS

gov Identifier: NCT04878367.

Polish Adaptation and Psychometric Validation of the PREM-C9 Questionnaire for Patients with Chronic Obstructive Pulmonary Disease

Introduction: Chronic obstructive pulmonary disease (COPD) is a common, preventable, and treatable disease. The first PREM (patient-reported outcome measure)-type questionnaire that has been dedicated to assess the experience of care in COPD is the PREM-C9. Aim: The aim of this study was to create a Polish version of the PREM-C9 and determine its psychometric characteristics. Methods: The validation procedure involved forward and back translation. We included 42 patients with COPD. The psychometric properties were assessed using Cronbach's alpha, Bartlett's test, the Kaiser-Meyer-Olkin test, and Spearman's correlation coefficient. The validity of the questionnaire was assessed using a principal component analysis for the extracted principal components. The validity of the factor analysis was demonstrated using Bartlett's sphericity test and the Kaiser-Meyer-Olkin (KMO) test. A factor analysis was performed using the Oblimin and Varimax rotation. The reliability of the questionnaire was assessed using Cronbach's alpha. Results: The Polish version of the analyzed questionnaire met all the validation criteria: face, translation, psychometric, functional, and reconstruction equivalence. Spearman's correlation results between the Polish PREM-C9 and CAT were as follows: rho = 0.44, p = 0.003539; HADS-Anxiety: rho = 0.370864, p = 0.015612; and HADS-Depression: rho = 0.387405, p = 0.011253. Conclusions: The developed Polish PREM-C9 questionnaire is a reliable and valid tool that assesses Polish COPD patients' experiences of their disease and the care they receive.

Editorial: Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2023 Guidelines for COPD, Including COVID-19, Climate Change, and Air Pollution

The 2023 Global Initiative for Chronic Obstructive Lung Disease (GOLD) report includes relevant topics from the clinician's perspective and evidence published on chronic obstructive pulmonary disease (COPD) since GOLD 2017. The World Health Organization (WHO) and GOLD 2023 have developed an updated definition of COPD as, "a heterogeneous lung condition characterized by chronic respiratory symptoms (dyspnea, cough, expectoration, exacerbations) due to abnormalities of the airway (bronchitis, bronchiolitis) and/or alveoli (emphysema) that cause persistent, often progressive, airflow obstruction." GOLD 2023 includes recommendations for COPD patients diagnosed with COVID-19 and acknowledges the role of reduced air quality in the etiology and progression of COPD. In May 2023, the GOLD Scientific Committee on Air Pollution and COPD reported that air pollution increasingly contributes to the pathogenesis of COPD. This Editorial aims to introduce the updated GOLD 2023 report in the context of climate change and the aftermath of the COVID-19 pandemic.

Evaluation of Potential Effects of Increased Outdoor Temperatures Due to Global Warming on Cerebral Blood Flow Rate and Respiratory Function in Chronic Obstructive Disease and Anemia

Global warming due to increased outdoor carbon dioxide (CO2) levels may cause several health problems such as headaches, cognitive impairment, or kidney dysfunction. It is predicted that further increases in CO2 levels will increase the morbidity and mortality of patients affected by a variety of diseases. For instance, patients with Chronic Obstructive Pulmonary Disease (COPD) may suffer cognitive impairments or intracranial bleeding due to an increased cerebral blood flow rate. Predicting the harmful effects of global warming on human health will help to take measures for potential problems. Therefore, the quantification of physiological parameters is an essential step to investigate the effects of global warming on human health. In this study, the effects of increased outdoor temperatures due to climate change on cerebral blood flow rate and respiratory function in healthy subjects and COPD patients with anemia and respiratory acidosis are evaluated utilizing numerical simulations. The numerical model simulates cardiac function and blood circulation in systemic, pulmonary and cerebral circulations, cerebral autoregulatory functions, respiratory function, alveolar gas exchange, oxygen (O2) and CO2 contents, and hemoglobin levels in the blood. The simulation results show that although the cardiovascular function is not significantly altered, the respiratory function and cerebral blood flow rates are altered remarkably.

Elucidating the Link: Chronic Obstructive Pulmonary Disease and the Complex Interplay of Gastroesophageal Reflux Disease and Reflux-Related Complications

Background and Objective: Presenting chronic obstructive pulmonary disease (COPD) patients frequently report concurrent symptoms of gastroesophageal reflux disease (GERD). Few studies have shown a correlation between GERD and COPD. We aimed to examine the correlation between GERD and COPD as well as secondary related reflux complications, such as esophageal stricture, esophageal cancer, and Barrett's esophagus. Methods: This population-based analysis included 7,159,694 patients. Patients diagnosed with GERD with and without COPD were compared to those without GERD. The enrollment of COPD included centrilobular and panlobular emphysema and chronic bronchitis. Risk factors of COPD or GERD were used for adjustment. Bivariate analyses were performed using the chi-squared test or Fisher exact test (2-tailed) for categorical variables as appropriate to assess the differences in the groups. Results: Our results showed that COPD patients had a significantly higher incidence of GERD compared to those without COPD (27.8% vs. 14.1%, p < 0.01). After adjustment of demographics and risk factors, COPD patients had a 1.407 times higher risk of developing non-erosive esophagitis (p < 0.01), 1.165 higher risk of erosive esophagitis (p < 0.01), 1.399 times higher risk of esophageal stricture (p < 0.01), 1.354 times higher risk of Barrett's esophagus without dysplasia (p < 0.01), 1.327 times higher risk of Barrett's esophagus with dysplasia, as well as 1.235 times higher risk of esophageal cancer than those without COPD. Conclusions: Based on the evidence from this study, there are sufficient data to provide convincing evidence of an association between COPD and GERD and its secondary reflux-related complications.

Air pollution and COPD: GOLD 2023 committee report

Exposure to air pollution is a major contributor to the pathogenesis of COPD worldwide. Indeed, most recent estimates suggest that 50% of the total attributable risk of COPD may be related to air pollution. In response, the Global Initiative for Chronic Obstructive Lung Disease (GOLD) Scientific Committee performed a comprehensive review on this topic, qualitatively synthesised the evidence to date and proffered recommendations to mitigate the risk. The review found that both gaseous and particulate components of air pollution are likely contributors to COPD. There are no absolutely safe levels of ambient air pollution and the relationship between air pollution levels and respiratory events is supra-linear. Wildfires and extreme weather events such as heat waves, which are becoming more common owing to climate change, are major threats to COPD patients and acutely increase their risk of morbidity and mortality. Exposure to air pollution also impairs lung growth in children and as such may lead to developmental COPD. GOLD recommends strong public health policies around the world to reduce ambient air pollution and for implementation of public warning systems and advisories, including where possible the use of personalised apps, to alert patients when ambient air pollution levels exceed acceptable minimal thresholds. When household particulate content exceeds acceptable thresholds, patients should consider using air cleaners and filters where feasible. Air pollution is a major health threat to patients living with COPD and actions are urgently required to reduce the morbidity and mortality related to poor air quality around the world.

Longitudinal lung function in urban firefighters: A group-based multi-trajectory modelling approach

BACKGROUND AND OBJECTIVE

Urban firefighters are routinely exposed to both physical and chemical hazards that can negatively impact lung health, but it is unclear if firefighters experience accelerated decline in spirometry parameters due to chronic exposure and acute insults. This study aimed to describe sub-groups of firefighters with differing spirometry trajectories and examine the relationship between the identified trajectories and demographic, lifestyle and occupational characteristics.

METHODS

Data from six waves of the Respiratory Function Measurement and Surveillance for South Australian Metropolitan Fire Service Study (2007-2019) were used to identify spirometry parameter z-score trajectories, using group-based multi-trajectory modelling (GBMTM). Analysis of variance and chi-square statistics were used to assess trajectory group differences in baseline self-reported demographic, lifestyle and occupational characteristics.

RESULTS

In the 669 included firefighters, we identified five trajectories for the combination of Forced Expiratory Volume in the first second z-score (FEV₁ z), Forced Vital Capacity z-score (FVCz) and the ratio of FEV₁ and FVC z-score (FEV₁ /FVCz). There were three stable trajectories of low, average and very high lung function and two declining trajectories of average and high lung function. Analysis of subgroup characteristics revealed no significant differences between expected and actual group proportions for the occupational characteristics of years of service and respiratory protection use. Significant differences were seen in respiratory health and body mass index.

CONCLUSION

GBMTM defined distinct, plausible spirometry trajectory sub-groups. Firefighter longitudinal spirometry trajectory group membership was associated with BMI and respiratory disease or symptoms but not with self-reported smoking history or occupational factors.

The Effects and Pathogenesis of PM2.5 and Its Components on Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD), a heterogeneous disease, is the leading cause of death worldwide. In recent years, air pollution, especially particulate matter (PM), has been widely studied as a contributing factor to COPD. As an essential component of PM, PM2.5 is associated with COPD prevalence, morbidity, and acute exacerbations. However, the specific pathogenic mechanisms were still unclear and deserve further research. The diversity and complexity of PM2.5 components make it challenging to get its accurate effects and mechanisms for COPD. It has been determined that the most toxic PM2.5 components are metals, polycyclic aromatic hydrocarbons (PAHs), carbonaceous particles (CPs), and other organic compounds. PM2.5-induced cytokine release and oxidative stress are the main mechanisms reported leading to COPD. Nonnegligibly, the microorganism in PM 2.5 may directly cause mononuclear inflammation or break the microorganism balance contributing to the development and exacerbation of COPD. This review focuses on the pathophysiology and consequences of PM2.5 and its components on COPD.

Mortality benefits of reduction fine particulate matter in Vietnam, 2019

Introduction and objectives

Studies assessing the health benefits of air pollution reduction in Vietnam are scarce. This study quantified the annual mortality burden due to PM_2.5 pollution in Vietnam above the World Health Organization recommendation for community health (AQG: 5 μg/m³) and the proposed National Technical Regulation on Ambient Air Quality (proposed QCVN: 15 μg/m³).

Methodology

This study applied a health impact assessment methodology with the hazard risk function for non-communicable diseases (NCDs) and lower respiratory infections (LRIs) in the Global Exposure Mortality Model (GEMM) to calculate attributable deaths, Years of Life lost, and Loss of Life expectancy at birth due to air pollution in the Vietnamese population above 25 years of age in 11 provinces. We obtained annual average PM_2.5 concentrations for Vietnam in 2019 at a 3x3 km grid modeled using Mixed Linear regression and multi-data sources. Population and baseline mortality data were obtained from administrative data system in Vietnam. We reported the findings at both the provincial and smaller district levels.

Results

Annual PM_2.5 concentrations in all studied provinces exceeded both the AQG and the proposed QCVN. The maximum annual number of attributable deaths in the studied provinces if they had complied with WHO air quality guidelines was in Ha Noi City, with 5,090 (95%CI: 4,253-5,888) attributable deaths. At the district level, the highest annual rate of attributable deaths if the WHO recommendation for community health had been met was 104.6 (95%CI: 87.0-121.5) attributable deaths per 100,000 population in Ly Nhan (Ha Nam province).

Conclusion

A much larger number of premature deaths in Vietnam could potentially be avoided by lowering the recommended air quality standard. These results highlight the need for effective clean air action plans by local authorities to reduce air pollution and improve community health.

A computed tomography imaging-based subject-specific whole-lung deposition model

The respiratory tract is an important route for beneficial drug aerosol or harmful particulate matter to enter the body. To assess the therapeutic response or disease risk, whole-lung deposition models have been developed, but were limited by compartment, symmetry or stochastic approaches. In this work, we proposed an imaging-based subject-specific whole-lung deposition model. The geometries of airways and lobes were segmented from computed tomography (CT) lung images at total lung capacity (TLC), and the regional air-volume changes were calculated by registering CT images at TLC and functional residual capacity (FRC). The geometries were used to create the structure of entire subject-specific conducting airways and acinar units. The air-volume changes were used to estimate the function of subject-specific ventilation distributions among acinar units and regulate flow rates in respiratory airway models. With the airway dimensions rescaled to a desired lung volume and the airflow field simulated by a computational fluid dynamics model, particle deposition fractions were calculated using deposition probability formulae adjusted with an enhancement factor to account for the effects of secondary flow and airway geometry in proximal airways. The proposed model was validated in silico against existing whole-lung deposition models, three-dimensional (3D) computational fluid and particle dynamics (CFPD) for an acinar unit, and 3D CFPD deep lung model comprising conducting and respiratory regions. The model was further validated in vivo against the lobar particle distribution and the coefficient of variation of particle distribution obtained from CT and single-photon emission computed tomography (SPECT) images, showing good agreement. Subject-specific airway structure increased the deposition fraction of 10.0-μm particles and 0.01-μm particles by approximately 10%. An enhancement factor increased the overall deposition fractions, especially for particle sizes between 0.1 and 1.0 μm.

Mortality benefits of reduction fine particulate matter in Vietnam, 2019

INTRODUCTION AND OBJECTIVES

Studies assessing the health benefits of air pollution reduction in Vietnam are scarce. This study quantified the annual mortality burden due to PM_2.5 pollution in Vietnam above the World Health Organization recommendation for community health (AQG: 5 μg/m³) and the proposed National Technical Regulation on Ambient Air Quality (proposed QCVN: 15 μg/m³).

METHODOLOGY

This study applied a health impact assessment methodology with the hazard risk function for non-communicable diseases (NCDs) and lower respiratory infections (LRIs) in the Global Exposure Mortality Model (GEMM) to calculate attributable deaths, Years of Life lost, and Loss of Life expectancy at birth due to air pollution in the Vietnamese population above 25 years of age in 11 provinces. We obtained annual average PM_2.5 concentrations for Vietnam in 2019 at a 3x3 km grid modeled using Mixed Linear regression and multi-data sources. Population and baseline mortality data were obtained from administrative data system in Vietnam. We reported the findings at both the provincial and smaller district levels.

RESULTS

Annual PM_2.5 concentrations in all studied provinces exceeded both the AQG and the proposed QCVN. The maximum annual number of attributable deaths in the studied provinces if they had complied with WHO air quality guidelines was in Ha Noi City, with 5,090 (95%CI: 4,253-5,888) attributable deaths. At the district level, the highest annual rate of attributable deaths if the WHO recommendation for community health had been met was 104.6 (95%CI: 87.0-121.5) attributable deaths per 100,000 population in Ly Nhan (Ha Nam province).

CONCLUSION

A much larger number of premature deaths in Vietnam could potentially be avoided by lowering the recommended air quality standard. These results highlight the need for effective clean air action plans by local authorities to reduce air pollution and improve community health.