Outdoor Air Pollution and COPD-Related Emergency Department Visits, Hospital Admissions, and Mortality: A Meta-Analysis

Imbalanced and Unchecked: The Role of Metal Dyshomeostasis in Driving COPD Progression

Chronic obstructive pulmonary disease (COPD) is a chronic respiratory condition characterized by persistent inflammation and oxidative stress, which ultimately leads to progressive restriction of airflow. Extensive research findings have cogently suggested that the dysregulation of essential transition metal ions, notably iron, copper, and zinc, stands as a critical nexus in the perpetuation of inflammatory processes and oxidative damage within the lungs of COPD patients. Unraveling the intricate interplay between metal homeostasis, oxidative stress, and inflammatory signaling is of paramount importance in unraveling the intricacies of COPD pathogenesis. This comprehensive review aims to examine the current literature on the sources, regulation, and mechanisms by which metal dyshomeostasis contributes to COPD progression. We specifically focus on iron, copper, and zinc, given their well-characterized roles in orchestrating cytokine production, immune cell function, antioxidant depletion, and matrix remodeling. Despite the limited number of clinical trials investigating metal modulation in COPD, the advent of emerging methodologies tailored to monitor metal fluxes and gauge responses to chelation and supplementation hold great promise in unlocking the potential of metal-based interventions. We conclude that targeted restoration of metal homeostasis represents a promising frontier for ameliorating pathological processes driving COPD progression.

Sex Differences in Impacts of Early Gestational and Peri-Adolescent Ozone Exposure on Lung Development in Rats: Implications for Later Life Disease in Humans

Air pollution exposure during pregnancy may affect fetal growth. Fetal growth restriction (FGR) is associated with reduced lung function in children that can persist into adulthood. Using an established model of asymmetrical FGR in Long-Evans rats, this study investigated sex differences in effects of early life ozone exposure on lung development and maturation. Adverse health effects for i) gestational exposure (with impacts on primary alveolarization), ii) peri-adolescent exposure (with impacts on secondary alveolarization), and iii) cumulative exposure across both periods were evaluated. Notably, female offspring were most affected by gestational ozone exposure, likely because of impaired angiogenesis and corresponding decreases in primary alveolarization. Females had diminished lung capacity, fewer mature alveoli, and medial hypertrophy of small and large pulmonary arteries. Males, especially FGR-prone offspring, were more affected by peri-adolescent ozone exposure. Males had increased ductal areas, likely due to disrupted secondary alveolarization. Altered lung development may increase risk of developing diseases, such as pulmonary arterial hypertension or chronic obstructive pulmonary disease. Pulmonary arterial hypertension disproportionately affects women. In the United States, chronic obstructive pulmonary disease prevalence is increasing, especially in women; and prevalence for both men and women is highest in urbanized areas. This investigation underlines the importance of evaluating results separately by sex, and provides biologic plausibility for later consequences of early-life exposure to ozone, a ubiquitous urban air pollutant.

The Impact of Acute Peri-operative Particulate Matter Exposure on Endoscopic Sinus Surgery Outcomes: A Preliminary Multi-site Investigation

BACKGROUND

Environmental exposures have been postulated to play an important role in the pathophysiology of chronic rhinosinusitis (CRS). Particulate matter (PM) is one of the most widely studied ambient air pollutants, but its peri-operative impact on CRS is unknown.

OBJECTIVE

To determine the effect of acute, peri-operative PM exposure on outcomes after endoscopic sinus surgery (ESS).

METHODS

Participants with CRS who self-selected ESS were prospectively enrolled. The 22-item SinoNasal Outcome Test (SNOT-22) and Medical Outcomes Study Questionnaire Short-Form 6-D (SF-6D) health utility values scores were recorded. Using residence zip codes, a secondary analysis of patient exposure to PM <2.5 μm and <10 μm (PM2.5 and PM10, respectively) was performed for the month of surgery utilizing data from Environmental Protection Agency air quality monitors. Spearman's correlation coefficients (ρ), 95% confidence intervals (CIs), and effect estimates (β) were used to determine the magnitudes of association. Simple, multivariate regression analysis was also completed.

RESULTS

One hundred and seven patients from four geographically unique institutions across the US were enrolled with a follow-up of 6 months. Patients with higher peri-operative PM2.5 exposure had less improvement in their SNOT-22 scores after ESS compared to those with less exposure using both univariate analysis (ρ = 0.26, 95% CI: 0.08, 0.43; P  =  .01) and after covariate adjustment with multivariate analysis (B  =  1.06, 95% CI: 0.001, 2.14, P  =  .05). Similar associations were not found with SF-6D outcomes or with PM10 as an exposure of interest. No significant correlations were found between peri-operative PM levels and Lund-Kennedy endoscopy scores post-operatively.

CONCLUSION

Preliminary data from this pilot study reveal that PM exposure at the time of ESS may negatively associate with post-operative improvement in sinonasal quality-of-life. Larger, population-based studies with more standardized PM exposure windows are needed to confirm the clinical significance of the present findings.

Environmental Exposure and Respiratory Health: Unraveling the Impact of Toxic Release Inventory Facilities on COPD Prevalence

This cross-sectional geospatial analysis explores the prevalence of Chronic Obstructive Pulmonary Disease (COPD) concerning the proximity to toxic release inventory (TRI) facilities in Jefferson County, Alabama. Employing the fuzzy analytical hierarchy process (FAHP), the study evaluates COPD prevalence, comorbidities, healthcare access, and individual health assessments. Given the mounting evidence linking environmental pollutants to COPD exacerbations, the research probes the influence of TRI sites on respiratory health, integrating Geographic Information Systems (GIS) to scrutinize the geospatial vulnerability of communities neighboring TRI sites. Socio-demographic disparities, economic conditions, and air pollution are emphasized in the analysis. The EPA's Toxic Release Inventory serves as the cornerstone for assessing the association between TRI proximity and COPD prevalence. The analysis uncovers a notable inverse correlation between distance from TRI sites and COPD prevalence, signaling potential health risks for populations residing closer to these facilities. Moreover, factors such as minority status, low income, and air pollution are associated with higher COPD prevalence, underscoring the imperative of comprehending the interplay between environmental exposure and respiratory health. This study bridges gaps in the literature by addressing the geographical nexus between COPD prevalence and pollution exposure. By leveraging FAHP, the research furnishes a holistic understanding of the multifaceted factors influencing vulnerability to COPD. The findings underscore the necessity for targeted public health interventions and policy measures to redress environmental disparities and alleviate the repercussions of TRI facilities on respiratory health.

Does air pollutant exposure impact disease severity or outcomes in chronic rhinosinusitis?

BACKGROUND

Poor air quality increases the risk of developing chronic rhinosinusitis (CRS) and other airway diseases. However, there are limited data on air pollutants and CRS-specific disease severity. We assessed the impact of air pollutants on sinonasal-specific and general quality-of-life (QOL) measures in a multi-institutional cohort of patients with CRS.

METHODS

Participants with CRS were prospectively enrolled in a cross-sectional study and self-selected continued appropriate medical therapy or endoscopic sinus surgery (ESS). The 22-item SinoNasal Outcome Test (SNOT-22) and Medical Outcomes Study Questionnaire Short-Form 6-D (SF-6D) health utility value scores were recorded. Patient exposure to air pollutants was determined using residence zip codes. Unadjusted group differences were compared, and correlation coefficients were evaluated to identify the magnitude of bivariate association.

RESULTS

A total of 486 patients were enrolled and followed for a mean of 6.9 (standard deviation [SD] ± 2.3) months. Pollutant exposure did not significantly correlate with baseline SNOT-22 or SF-6D scores. Revision ESS was associated with higher median fine particulate matter (PM2.5; Δ = 0.12, [95% confidence interval {CI}: 0.003, 0.234]; p = 0.006) compared with primary surgery. PM2.5, PM10, and nitrogen dioxide concentrations (μg/m3) did not correlate with change in total SNOT-22 or SF-6D scores after treatment. Nevertheless, sulfur dioxide (SNOT-22: ρ = -0.121 [95% CI: -0.210, -0.030]; p = 0.007; SF-6D: ρ = 0.095 [95% CI: 0.002, 0.186]; p = 0.04) and carbon monoxide (SNOT-22: ρ = -0.141 [95% CI: -0.230, 0.050]; p = 0.002) exposure did correlate with these outcome measures.

CONCLUSION

Air pollutants may contribute, at least in part, to disease severity in CRS; future investigation is needed to further elucidate the nature of this relationship.

Individual Risk Factors of PM2.5 Associated With Wintertime Mortality in Urban Patients With COPD

BACKGROUND

Air pollution contributes to premature mortality, but potential impacts differ in populations with existing disease, particularly for individuals with multiple risk factors. Although COPD increases vulnerability to air pollution, individuals with COPD and other individual risk factors are at the intersection of multiple risks and may be especially susceptible to the effect of acute outdoor air pollution.

RESEARCH QUESTION

What is the association between wintertime air pollution and mortality in patients with COPD and the modifying role of individual risk factors?

STUDY DESIGN AND METHODS

This study evaluated 19,243 deceased veterans with prior COPD diagnosis who had resided in 25 US metropolitan regions (2016-2019). Electronic health records included patient demographic characteristics; smoking status; and comorbidities such as asthma, coronary artery disease (CAD), obesity, and diabetes. Using geocoded addresses, individuals were assigned wintertime fine particulate matter (particulate matter smaller than 2.5 μg in diameter [PM2.5]) and nitrogen dioxide air pollution exposures. Associations between acute air pollution and mortality were estimated by using a time-stratified case-crossover design with a conditional logistic model, and individual risk differences were assessed according to stratified analysis.

RESULTS

A 1.05 (95% CI, 1.02-1.09) mortality risk was estimated for each 10 μg/m3 increase in daily wintertime PM2.5). Older patients and Black individuals displayed elevated risk. Obesity was a substantial air pollution-related mortality risk factor (OR, 1.11; 95% CI, 1.01-1.23), and the estimated risk for individuals with obesity plus CAD or obesity plus diabetes was 16% higher.

INTERPRETATION

Wintertime PM2.5 exposure was associated with elevated mortality risk in people with COPD, but individuals with multiple comorbidities, notably obesity, had high vulnerability. Our study suggests that obesity, CAD, and diabetes are understudied modifiers of air pollution-related risks for people with existing COPD.

Increase in sick leave episodes from short-term fine particulate matter exposure: A case-crossover study in Stockholm, Sweden

Air pollution's short-term effects on a wide range of health outcomes have been studied extensively, primarily focused on vulnerable groups (e.g., children and the elderly). However, the air pollution effects on the adult working population through sick leave have received little attention. This study aims to 1) estimate the associations between particulate matter ≤2.5 μm3 (PM2.5) and sick leave episodes and 2) calculate the attributable number of sick leave days and the consequential productivity loss in the City of Stockholm, Sweden. Individual level daily sick leave data was obtained from Statistics Sweden for the years 2011-2019. Daily average concentrations of PM2.5 were obtained from the main urban background monitoring station in Stockholm. A case-crossover study design was applied to estimate the association between short-term PM2.5 and onset of sick leave episodes. Conditional logistic regression was used to estimate the relative increase in odds of onset per 10 μg/m3 of PM2.5, adjusting for temperature, season, and pollen. A human capital method was applied to estimate the PM2.5 attributable productivity loss. In total, 1.5 million (M) individual sick leave occurrences were studied. The measured daily mean PM2.5 concentration was 4.2 μg/m3 (IQR 3.7 μg/m3). The odds of a sick leave episode was estimated to increase by 8.5% (95% CI: 7.8-9.3) per 10 μg/m3 average exposure 2-4 days before. Sub-group analysis showed that private sector and individuals 15-24 years old had a lower increase in odds of sick leave episodes in relation to PM2.5 exposure. In Stockholm, 4% of the sick leave episodes were attributable to PM2.5 exposure, corresponding to €17 M per year in productivity loss. Our study suggests a positive association between PM2.5 and sick leave episodes in a low exposure area.

PM10 increases mortality risk in rheumatoid arthritis-associated interstitial lung disease

OBJECTIVES

The effect of air pollution on the prognosis of rheumatoid arthritis-associated interstitial lung disease (RA-ILD) remains poorly understood. We aimed to evaluate the effect of long-term exposure to particulate matter with an aerodynamic diameter of ≤10 µm (PM10) and nitrogen dioxide (NO2) on mortality in patients with RA-ILD.

METHODS

We included 309 patients (mean age, 61.7 years; male, 44.3%) with RA-ILD. Individual-level long-term exposures to PM10 and NO2 at their residential addresses were estimated using a national-scale exposure prediction model. The effect of the two air pollutants on mortality was estimated using a Cox-proportional hazards model adjusted for individual-level and area-level characteristics.

RESULTS

The median follow-up period was 4.8 years, and 40.8% of patients died or underwent lung transplantation. The annual average concentrations of PM10 and NO2 were 56.3 μg/m3 and 22.4 ppb, respectively. When air pollutant levels were stratified by quartiles, no association was observed between air pollutant concentration and mortality in patients with RA-ILD. However, when stratified by two groups (high exposure (top 25th percentile) vs low exposure (bottom 75th percentile)), we observed a significant association between high PM10 exposure and mortality (HR 1.68; 95% CI 1.11 to 2.52; p=0.013) but no association between NO2 exposure and mortality. In the subgroup analyses, the effect of high PM10 exposure on mortality was significant in patients aged <65 years (HR 1.98; 95% CI 1.02 to 3.85; p=0.045).

CONCLUSIONS

Our results indicated that high PM10 exposure may be associated with mortality in patients with RA-ILD.

Integrating Clinical and Air Quality Data to Improve Prediction of COPD Exacerbations

Several studies have found associations between air pollution and respiratory disease outcomes. However, there is minimal prognostic research exploring whether integrating air quality into clinical prediction models can improve accuracy and utility. In this study, we built models using both logistic regression and random forests to determine the benefits of including air quality data with meteorological and clinical data in prediction of COPD exacerbations requiring medical care. Logistic models were not improved by inclusion of air quality. However, the net benefit curves of random forest models showed greater clinical utility with the addition of air quality data. These models demonstrate a practical and relatively low-cost way to include environmental information into clinical prediction tools to improve the clinical utility of COPD prediction. Findings could be used to provide population level health warnings as well as individual-patient risk assessments.

Biomarkers of the relationship of particulate matter exposure with the progression of chronic respiratory diseases

A high level of particulate matter (PM) in air is correlated with the onset and development of chronic respiratory diseases. We conducted a systematic literature review, searching the MEDLINE, EMBASE, and Cochrane databases for studies of biomarkers of the effect of PM exposure on chronic respiratory diseases and the progression thereof. Thirty-eight articles on biomarkers of the progression of chronic respiratory diseases after exposure to PM were identified, four of which were eligible for review. Serum, sputum, urine, and exhaled breath condensate biomarkers of the effect of PM exposure on chronic obstructive pulmonary disease (COPD) and asthma had a variety of underlying mechanisms. We summarized the functions of biomarkers linked to COPD and asthma and their biological plausibility. We identified few biomarkers of PM exposure-related progression of chronic respiratory diseases. The included studies were restricted to those on biomarkers of the relationship of PM exposure with the progression of chronic respiratory diseases. The predictive power of biomarkers of the effect of PM exposure on chronic respiratory diseases varies according to the functions of the biomarkers.

Analyses of Factors Associated with Acute Exacerbations of Chronic Obstructive Pulmonary Disease: A Review

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) is the exacerbation of a range of respiratory symptoms during the stable phase of chronic obstructive pulmonary disease (COPD). AECOPD is thus a dangerous stage and key event in the course of COPD, as its deterioration and frequency seriously affects the quality of life of patients and shortens their survival. Acute exacerbations occur and develop due to many factors such as infection, tobacco smoke inhalation, air pollution, comorbidities, airflow limitation, various biomarkers, history of previous deterioration, natural killer cell abnormalities, immunoglobulin G deficiency, genetics, abnormal muscle and nutritional status, negative psychology, and seasonal temperature changes. There is relatively limited research on the impact of the role of standardized management on the alleviation of AECOPD. However, with the establishment of relevant prevention and management systems and the promotion of artificial intelligence technology and Internet medical approaches, long-term effective and standardized management of COPD patients may help to achieve the quality of life and disease prognosis in COPD patients and reduce the risk of AE.

Redox and inflammatory mechanisms linking air pollution particulate matter with cardiometabolic derangements

Air pollution is the largest environmental risk factor for disease and premature death. Among the different components that are present in polluted air, fine particulate matter below 2.5 μm in diameter (PM2.5) has been identified as the main hazardous constituent. PM2.5 mainly arises from fossil fuel combustion during power generation, industrial processes, and transportation. Exposure to PM2.5 correlates with enhanced mortality risk from cardiovascular diseases (CVD), such as myocardial infarction and stroke. Over the last decade, it has been increasingly suggested that PM2.5 affects CVD already at the stage of risk factor development. Among the multiple biological mechanisms that have been described, the interplay between oxidative stress and inflammation has been consistently highlighted as one of the main drivers of pulmonary, systemic, and cardiovascular effects of PM2.5 exposure. In this context, PM2.5 uptake by tissue-resident immune cells in the lung promotes oxidative and inflammatory mediators release that alter tissue homeostasis at remote locations. This pathway is central for PM2.5 pathogenesis and might account for the accelerated development of risk factors for CVD, including obesity and diabetes. However, transmission and end-organ mechanisms that explain PM2.5-induced impaired function in metabolic active organs are not completely understood. In this review, the main features of PM2.5 physicochemical characteristics related to PM2.5 ability to induce oxidative stress and inflammation will be presented. Hallmark and recent epidemiological and interventional studies will be summarized and discussed in the context of current air quality guidelines and legislation, knowledge gaps, and inequities. Lastly, mechanistic studies at the intersection between redox metabolism, inflammation, and function will be discussed, with focus on heart and adipose tissue alterations. By offering an integrated analysis of PM2.5-induced effects on cardiometabolic derangements, this review aims to contribute to a better understanding of the pathogenesis and potential interventions of air pollution-related CVD.

Relationship between fine particulate matter (PM2.5) concentration and risk of hospitalization due to chronic obstructive pulmonary disease: a systematic review and meta-analysis

BACKGROUND

Short-term exposure to PM2.5 has been associated with human health risks. However, evidence on the association between short-term exposure to PM2.5 and the risk of chronic obstructive pulmonary disease (COPD) remains limited and controversial. This study aimed to specifically assess the relationship between exposure to PM2.5 and the risk of hospitalization due to COPD.

METHODS

A systematic search was conducted in PubMed, Web of Science, and Google Scholar databases from January 1, 2010 to May 1, 2022. The odds ratio (OR) statistic was calculated as a common measure of effect size. Publication bias was also examined in all eligible studies on COPD hospitalization using funnel plots and Egger's test, as well as trim-and-fill method for missing studies on COPD hospitalization.

RESULTS

A total of 19 studies were included in this meta-analysis. Random-effects models were plotted to calculate the pooled effect size by measuring OR (χ2 = 349.95; df = 18; I2 = 94.86%; P = 0.007; Z = 2.68; P < 0.001). A 10-mg/m3 daily increase in PM2.5 concentration was associated with a 1.6% (95% CI: 0.4-2.9%) increase in COPD hospitalization. There was no publication bias regarding the association between COPD hospitalization and PM2.5 (bias = 1.508; 95% CI: -1.475, 4.491; t = 1.066; P = 0.301). The subgroups of age ≥ 65 years and Asian countries were associated with an increased risk of COPD hospitalization. Besides, higher risks were estimated in the subgroups of studies performed in the warm season, case-crossover studies, studies with three lag days, and studies without adjustments for humidity and temperature confounders, with very small heterogeneity.

CONCLUSION

Evidence suggests that short-term exposure to PM2.5 increases COPD hospitalization. Further studies are needed to understand the mechanism of the association between PM2.5 and COPD for reducing air pollution, which can be beneficial for COPD patients.

Global Chronic obstructive pulmonary disease burden attributable to air pollution from 1990 to 2019

BACKGROUND

The disease burden attributable to chronic obstructive pulmonary disease (COPD) is significant worldwide. Some studies have linked exposure to air pollution to COPD, but there has been little research on this.

METHODS

We aimed to assess the COPD-related disease burden attributable to air pollution from multiple epidemiological perspectives. This study conducted a three-stage analysis. Firstly, we reported on the burden of disease worldwide in 2019 by different subgroups including sex, age, region, and country. Secondly, we studied the trends in disease burden from 1990 to 2019. Finally, we explored the association of some national indicators with disease burden to look for risk factors.

RESULTS

In 2019, the death number of COPD associated with air pollution accounted for 2.32% of the total global death, and the number of DALY accounted for 1.12% of the global DALY. From 1990 to 2019, the death number of COPD associated with air pollution increased peaked at 1.41 million in 1993, fluctuated, and then declined. We found the same temporal pattern of DALY. The corresponding age-standardized rates had been falling. At the same time, the burden of COPD associated with air pollution was also affected by some national indicators.

CONCLUSIONS

This study indicated that air pollution-related COPD contributed to a significant global disease burden. We called for health policymakers to take action and interventions targeting vulnerable countries and susceptible populations.

Medium term moderate to low-level air pollution exposure is associated with higher C-reactive protein among healthy Danish blood donors

Air pollution is a significant contributor to the global burden of disease with a plethora of associated health effects such as pulmonary and systemic inflammation. C-reactive protein (CRP) is associated with a wide range of diseases and is associated with several exposures. Studies on the effect of air pollution exposure on CRP levels in low to moderate pollution settings have shown inconsistent results. In this cross-sectional study high sensitivity CRP measurements on 18,463 Danish blood donors were linked to modelled air pollution data for NOx, NO2, O3, CO, SO2, NH3, mineral dust, black carbon, organic carbon, sea salt, secondary inorganic aerosols and its components, primary PM2.5, secondary organic aerosols, total PM2.5, and total PM10 at their residential address over the previous month. Associations were analysed using ordered logistic regression with CRP quartile as individuals outcome and air pollution exposure as scaled deciles. Analyses were adjusted for health related and socioeconomic covariates using health questionnaires and Danish register data. Exposure to different air pollution components was generally associated with higher CRP (odds ratio estimates ranging from 1.11 to 1.67), while exposure to a few air pollution components was associated with lower CRP. For example, exposure to NO2 increased the odds of high CRP 1.32-fold (95%CI 1.16-1.49), while exposure to NH3 decreased the odds of high CRP 0.81-fold (95%CI 0.73-0.89). This large study among healthy individuals found air pollution exposure to be associated with increased levels of CRP even in a setting with low to moderate air pollution levels.

Long-term effects of air pollution on hospital admissions and mortality for chronic obstructive pulmonary disease in Beijing, China

OBJECTIVE

We aimed to clarify the association between air pollution and hospital admissions for chronic obstructive pulmonary disease (COPD) and mortality in Beijing, China.

METHODS

In this retrospective study, we recruited 510 COPD patients from 1 January 2006 to 31 December 2009. The patient data were obtained from the electronic medical records of Peking University Third Hospital in Beijing. Air pollution and meteorological data were obtained from the Institute of Atmospheric Physics of the Chinese Academy of Sciences. Monthly COPD hospital admissions, mortality and air pollution data were analysed using Poisson regression in generalised additive models adjusted for mean temperature, pressure and relative humidity.

RESULTS

There were positive correlations between sulfur dioxide (SO2 ), particulate matter with an aerodynamic diameter ≤ 10 μm (PM10 ) and COPD hospital admissions in the single-pollutant model. An increase of 10 μg/m3 in SO2 and PM10 were associated with an increase of 4.053% (95% CI: 1.470-5.179%) and 1.401% (95%CI: 0.6656-1.850%) in COPD hospital admissions. In the multiple-pollutant model [SO2 and nitrogen dioxide (NO2 ) combinations], there was only a positive correlation between SO2 and COPD hospital admissions. An increase of 10 μg/m3 in SO2 were associated with an increase of 1.916% (95% CI: 1.118-4.286%) in COPD hospital admissions. There was no correlation between three pollutant combinations and COPD hospital admissions. We did not find correlations between air pollution and COPD mortality in either single- or multiple-pollutant models.

CONCLUSIONS

SO2 and PM10 may be important factors for the increase in COPD hospital admissions in Beijing, China.

Urban-rural difference in the lagged effects of PM2.5 and PM10 on COPD mortality in Chongqing, China

BACKGROUND

It is true that Chronic obstructive pulmonary disease (COPD) will increase social burden, especially in developing countries. Urban-rural differences in the lagged effects of PM2.5 and PM10 on COPD mortality remain unclear, in Chongqing, China.

METHODS

In this study, a distributed lag non-linear model (DLNMs) was established to describe the urban-rural differences in the lagged effects of PM2.5, PM10 and COPD mortality in Chongqing, using 312,917 deaths between 2015 and 2020.

RESULTS

According to the DLNMs results, COPD mortality in Chongqing increases with increasing PM2.5 and PM10 concentrations, and the relative risk (RR) of the overall 7-day cumulative effect is higher in rural areas than in urban areas. High values of RR in urban areas occurred at the beginning of exposure (Lag 0 ~ Lag 1). High values of RR in rural areas occur mainly during Lag 1 to Lag 2 and Lag 6 to Lag 7.

CONCLUSION

Exposure to PM2.5 and PM10 is associated with an increased risk of COPD mortality in Chongqing, China. COPD mortality in urban areas has a high risk of increase in the initial phase of PM2.5 and PM10 exposure. There is a stronger lagging effect at high concentrations of PM2.5 and PM10 exposure in rural areas, which may further exacerbate inequalities in levels of health and urbanization.

Air pollution and mortality in patients with chronic obstructive pulmonary disease: a cohort study in South Korea

Background

Evidence on whether long-term exposure to air pollution increases the mortality risk in patients with chronic obstructive pulmonary disease (COPD) is limited.

Objectives

We aimed to investigate the associations of long-term exposure to particulate matter with diameter <10 µm (PM10) and nitrogen dioxide (NO2) with overall and disease-specific mortality in COPD patients.

Design

We conducted a nationwide retrospective cohort study of 121,423 adults ⩾40 years diagnosed with COPD during 1 January to 31 December 2009.

Methods

Exposure to PM10 and NO2 was estimated for residential location using the ordinary kriging method. We estimated the risk of overall mortality associated with 1-, 3-, and 5-years average concentrations of PM10 and NO2 using Cox proportional hazards models and disease-specific mortality using the Fine and Gray method adjusted for age, sex, income, body mass index, smoking, comorbidities, and exacerbation history.

Results

The adjusted hazard ratios (HRs) for overall mortality associated with a 10 µg/m3 increase in 1-year PM10 and NO2 exposures were 1.004 [95% confidence interval (CI) = 0.985, 1.023] and 0.993 (95% CI = 0.984, 1.002), respectively. The results were similar for 3- and 5-year exposures. For a 10-µg/m3 increase in 1-year PM10 and NO2 exposures, the adjusted HRs for chronic lower airway disease mortality were 1.068 (95% CI = 1.024, 1.113) and 1.029 (95% CI = 1.009, 1.050), respectively. In stratified analyses, exposures to PM10 and NO2 were associated with overall mortality in patients who were underweight and had a history of severe exacerbation.

Conclusion

In this large population-based study of patients with COPD, long-term PM10 and NO2 exposures were not associated with overall mortality but were associated with chronic lower airway disease mortality. PM10 and NO2 exposures were both associated with an increased risk of overall mortality, and with overall mortality in underweight individuals and those with a history of severe exacerbation.

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.

Association between short-term ambient air pollution and outpatient visits for acute exacerbation of chronic obstructive pulmonary disease in Lanzhou, 2013-19

Evidence between air pollution and hospital visits for acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is inconsistent and limited in China. In this study, we constructed a time-series study to evaluate the association between air pollution and AECOPD outpatient visits. Daily hospital outpatient visits for AECOPD in three top level hospitals in Lanzhou from January 2013 to December 2019, as well as the air pollutants and meteorological data in the same period, were collected. Then, generalized additive models with quasi-Poisson regression were utilized to estimate the associations with single-day lags from lag0 to lag7 and cumulative-day lag from lag01 to lag07. For example, lag0 referred to the concentration of air pollutants at the current day and lag1 referred to the previous-day air pollutant concentration and so on. Lag01 meant the average concentration of air pollutants at the current and previous day, and lag07 corresponded to the eight-day moving average value of the current and previous 7 days. In addition, stratified analyses were performed by gender, age, and season. The risk estimates were expressed in terms of the percentage changes (PC) in AECOPD outpatient visits per 10 µg/m³ increment of air pollutants (except that CO was per 1 mg/m³) and their respective 95% confidence intervals (CIs). The strongest effect on AECOPD morbidity was found lag07 for PM_2.5 (PC = 1.96, 95% CI 1.07, 2.86 per 10 μg/m³), lag03 for PM₁₀ (PC = 0.25, 95% CI 0.01, 0.49 per 10 μg/m³), lag05 for SO₂ (PC = 1.67, 95% CI 0.54, 3.93 per 10 μg/m³), and lag03 for NO₂ (PC = 1.37, 95% CI 0.25, 2.51 per 10 μg/m³). No significant association of O₃ and CO with AECOPD onset was found. In the subgroup analyses, the associations of PM_2.5 and SO₂ were more pronounced on males than female, the patients aged < 65 years were more vulnerable to PM_2.5 and NO₂, but 65-74 years old were more vulnerable to PM_2.5, SO₂, and NO₂. Patients aged ≥ 75 years suffered more from PM_2.5, PM₁₀, and SO₂. The associations between PM_2.5, PM₁₀, SO₂, NO₂, and AECOPD outpatients were stronger in the cold season than those in the hot season. From exposure-response curves, we observe linear relationships of PM_2.5, SO₂, NO₂, O₃8h, and CO with hospital outpatient visits for AECOPD. The increase in PM_2.5, PM₁₀, SO₂, and NO₂ concentration will lead to an increase in the number of outpatient visits for AECOPD and have different influence patterns in different genders, ages, and seasons.

Associations between air pollutants and hospital admissions for chronic obstructive pulmonary disease in Jinan: potential benefits from air quality improvements

Evidence between air pollution and chronic obstructive pulmonary disease (COPD) is inconsistent and limited in China. In this study, we aim to examine the associations between air pollutants and hospital admissions for COPD, hoping to provide practical advice for prevention and control of COPD. Hospital admissions for COPD were collected from a Grade-A tertiary hospital in Jinan from 2014 to 2020. A generalized additive model (GAM) was used to examine the associations between air pollutants and hospital admissions for COPD. Stratified analysis was also conducted for gender, age (20-74 and ≥75 years), and season (warm and cold). The avoidable number of COPD hospital admissions was calculated when air pollutants were controlled under national and WHO standards. Over the study period, a total of 4,012 hospital admissions for COPD were recorded. The daily hospital admissions of COPD increased by 2.36% (95%CI: 0.13-4.65%) and 2.39% (95%CI: 0.19-4.65%) for per 10 μg/m³ increase of NO₂ and SO₂ concentrations at lag2, respectively. There was no statistically significant difference in health effects caused by increased concentrations of PM_2.5, PM₁₀, CO, and O₃. The health effects of increased SO₂ concentration were stronger in women, the ≥75 years old people and the cold season. About 2 (95%CI: 0-3), 64 (95%CI: 4-132) and 86 (95%CI: 6-177) COPD admissions would be avoided when the SO₂ concentration was controlled below the NAAQS-II (150 μg/m³), NAAQS-I (50 μg/m³), and WHO's AQG2021 standard (40 μg/m³), respectively. These findings suggest that short-term exposure to NO₂ and SO₂ was associated with increased risks of daily COPD admissions, especially for females and the elderly. The control of SO₂ and NO₂ under the national and WHO standards could avoid more COPD admissions and obtain greater health benefits.

Spatial association between green space and COPD mortality: a township-level ecological study in Chongqing, China

BACKGROUND

There are regional differences in the effect of green space on mortality of Chronic obstructive pulmonary disease (COPD). We conduct an ecological study, using the administrative divisions of Chongqing townships in China as the basic unit, to investigate the association between COPD mortality and green space based on data of 313,013 COPD deaths in Chongqing from 2012 to 2020. Green space is defined by Fractional vegetation cover (FVC), which is further calculated based on the normalised vegetation index (NDVI) from satellite remote sensing imagery maps.

METHODS

After processing the data, the non-linear relationship between green space and COPD mortality is revealed by generalised additive models; the spatial differences between green space and COPD mortality is described by geographically weighted regression models; and finally, the interpretive power and interaction of each factor on the spatial distribution of COPD mortality is examined by a geographic probe.

RESULTS

The results show that the FVC local regression coefficients ranged from - 0.0397 to 0.0478, 63.0% of the regions in Chongqing have a positive correlation between green space and COPD mortality while 37.0% of the regions mainly in the northeast and west have a negative correlation. The interpretive power of the FVC factor on the spatial distribution of COPD mortality is 0.08.

CONCLUSIONS

Green space may be a potential risk factor for increased COPD mortality in some regions of Chongqing. This study is the first to reveal the relationship between COPD mortality and green space in Chongqing at the township scale, providing a basis for public health policy formulation in Chongqing.

The relationship between exposure to Hurricane Harvey and mortality among nursing home residents

BACKGROUND

Nursing home (NH) residents are vulnerable to mortality after natural disasters. We examined NH residents' excess all-cause mortality associated with Hurricane Harvey, a unique disaster with long-lasting flooding effects. We also explored how mortality differed between short-stay and long-stay residents and by chronic conditions.

METHODS

We conducted a retrospective observational study of Texas NH residents, comparing 30- and 90-day mortality among residents exposed to Hurricane Harvey in August 2017 to residents not exposed in the same location and time period during the previous 2 years. Data came from the Minimum Data Set Assessments and the Medicare Beneficiary Summary File. We used linear probability models to examine the association between hurricane exposure and mortality, adjusting for resident demographics, clinical acuity, and NH fixed effects. Models were stratified by short-stay and long-stay status. We also described differences in mortality by residents' chronic conditions.

RESULTS

In 2017, 18,479 Texas NH residents were exposed to Hurricane Harvey. Exposure to Hurricane Harvey was not significantly associated with 30-day mortality. However, 7.6% (95% CI: 7.2, 7.9) of long-stay residents died 90 days after exposure to Harvey, compared to 6.3% (95% CI: 6.0, 6.7) during 2015. Apparently, this effect was driven by chronic obstructive pulmonary disease (COPD) as approximately 9.2% of these residents died within 90 days after Harvey landing compared to 7.2% in 2015 (p < 0.01).

CONCLUSIONS

Hurricane exposure appears to have significant consequences for mortality among long-stay NH residents, which appear to materialize over the long-term (90 days post-hurricane in our study) and may not be apparent immediately (30 days post-hurricane in our study). NH residents with COPD may be particularly vulnerable to increased mortality risk following hurricane exposure. The results highlight the need to pay special attention to mortality risk in NH residents, particularly those with COPD, following hurricane exposure.

Environmental pollution in North-Eastern Italy and its influence on chronic obstructive pulmonary disease: time series modelling and analysis using visibility graphs

The impact on human health from environmental pollution is receiving increasing attention. In the case of respiratory diseases such as chronic obstructive pulmonary disease (COPD), the relationship is now well documented. However, few studies have been carried out in areas with low population density and low industrial production, such as the province of Belluno (North-Eastern Italy). The aim of the study was to analyze the effect of exposure to certain pollutants on the temporal dynamics of hospital admissions for COPD in the province of Belluno. Daily air pollution concentration, humidity, precipitations, and temperature were collected from the air monitoring stations in Belluno. Generalized additive mixed models (GAMM) and visibility graphs were used to determine the effects of the short-term exposure to environmental agents on hospital admissions associated to COPD. In the case of the city of Belluno, the GAMM showed that hospital admissions were associated with NO₂, PM₁₀, date, and temperature, while for the city of Feltre, GAMM produced no associated variables. Several visibility graph indices (average edge overlap and interlayer mutual information) showed a significant overlap between environmental agents and hospital admission for both cities. Our study has shown that visibility graphs can be useful in establishing associations between environmental agents and COPD hospitalization in sparsely populated areas.

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.

Study Protocol. Evaluating the life-course health impact of a city-wide system approach to improve air quality in Bradford, UK: A quasi-experimental study with implementation and process evaluation

BACKGROUND

Air quality is a major public health threat linked to poor birth outcomes, respiratory and cardiovascular disease, and premature mortality. Deprived groups and children are disproportionately affected. Bradford will implement a Clean Air Zone (CAZ) as part of the Bradford Clean Air Plan (B-CAP) in 2022 to reduce pollution, providing a natural experiment. The aim of the current study is to evaluate the impact of the B-CAP on health outcomes and air quality, inequalities and explore value for money. An embedded process and implementation evaluation will also explore barriers and facilitators to implementation, impact on attitudes and behaviours, and any adverse consequences.

METHODS

The study is split into 4 work packages (WP). WP1A: 20 interviews with decision makers, 20 interviews with key stakeholders; 10 public focus groups and documentary analysis of key reports will assess implementation barriers, acceptability and adverse or unanticipated consequences at 1 year post-implementation (defined as point at which charging CAZ goes 'live'). WP1B: A population survey (n = 2000) will assess travel behaviour and attitudes at baseline and change at 1 year post-implementation). WP2: Routine air quality measurements will be supplemented with data from mobile pollution sensors in 12 schools collected by N = 240 pupil citizen scientists (4 within, 4 bordering and 4 distal to CAZ boundary). Pupils will carry sensors over four monitoring periods over a 12 month period (two pre, and two post-implementation). We will explore whether reductions in pollution vary by CAZ proximity. WP3A: We will conduct a quasi-experimental interrupted time series analysis using a longitudinal routine health dataset of > 530,000 Bradford residents comparing trends (3 years prior vs 3 years post) in respiratory health (assessed via emergency/GP attendances. WP3B: We will use the richly-characterised Born in Bradford cohort (13,500 children) to explore health inequalities in respiratory health using detailed socio-economic data. WP4: will entail a multi-sectoral health economic evaluation to determine value for money of the B-CAP.

DISCUSSION

This will be first comprehensive quasi-experimental evaluation of a city-wide policy intervention to improve air quality. The findings will be of value for other areas implementing this type of approach.

TRIAL REGISTRATION

ISRCTN67530835 https://doi.org/10.1186/ISRCTN67530835.

Prediction of COPD acute exacerbation in response to air pollution using exosomal circRNA profile and Machine learning

Ambient fine particulate matter (PM2.5) is linked to an increased risk of chronic obstructive pulmonary disease (COPD) exacerbations, which significantly increase the risk of mortality in COPD patients. Identifying the subtype of COPD patients who are sensitive to environmental aggressions is necessary. Using in vitro and in vivo PM2.5 exposure models, we demonstrate that exosomal hsa_circ_0005045 is upregulated by PM2.5 and binds to the protein cargo peroxiredoxin2, which functionally aggravates hallmarks of COPD by recruiting neutrophil elastase and triggering in situ release of tumor necrosis factor (TNF)-α by inflammatory cells. The biological function of hsa_circ_0005045 associated with aggravation of COPD is validated using exosome-transplantation and conditional circRNA-knockdown murine models. By sorting the major components of PM2.5, we find that PM2.5-bound heavy metals, which are distinguishable from the components of cigarette smoke, trigger the elevation of exosomal hsa_circ_0005045. Finally, using machine learning models in a cohort with 327 COPD patients, the PM2.5 exposure-sensitive COPD patients are characterized by relatively high hsa_circ_0005045 expression, non-smoking, and group C (mMRC 0-1 (or CAT < 10) and ≥ 2 exacerbations (or ≥ 1 exacerbation leading to hospital admission) in the past year). Thus, our results suggest that environmental reduction in PM2.5 emission provides a targeted approach to protecting non-smoking COPD patients against air pollution-related disease exacerbation.

Health and Clinical Impacts of Air Pollution and Linkages with Climate Change

Air Pollution Impacts and Climate Change LinksAs part of the NEJM Group series on climate change, Keswani and colleagues review the linkages between climate change and air pollution and suggest strategies that clinicians may use to mitigate the adverse health impacts of air pollution.

Particulate matter in COPD pathogenesis: an overview

Chronic obstructive pulmonary disease (COPD) is a progressive lung disorder with substantial patient burden and leading cause of death globally. Cigarette smoke remains to be the most recognised causative factor behind COPD pathogenesis. Given the alarming increase in prevalence of COPD amongst non-smokers in recent past, a potential role of air pollution particularly particulate matter (PM) in COPD development has gained much attention of the scientists. Indeed, several epidemiological studies indicate strong correlation between airborne PM and COPD incidence/exacerbations. PM-induced oxidative stress seems to be the major player in orchestrating COPD inflammatory cycle but the exact molecular mechanism(s) behind such a process are still poorly understood. This may be due to the complexity of multiple molecular pathways involved. Oxidative stress-linked mitochondrial dysfunction and autophagy have also gained importance and have been the focus of recent studies regarding COPD pathogenesis. Accordingly, the present review is aimed at understanding the key molecular players behind PM-mediated COPD pathogenesis through analysis of various experimental studies supported by epidemiological data to identify relevant preventive/therapeutic targets in the area.

Association Between Air Pollutants and Pediatric Respiratory Outpatient Visits in Zhoushan, China

Objective

This study aimed to explore the time-series relationship between air pollutants and the number of children's respiratory outpatient visits in coastal cities.

Methods

We used time series analysis to investigate the association between air pollution levels and pediatric respiratory outpatient visits in Zhoushan city, China. The population was selected from children aged 0–18 who had been in pediatric respiratory clinics for eight consecutive years from 2014 to 2020. After describing the population and weather characteristics, a lag model was used to explore the relationship between outpatient visits and air pollution.

Results

We recorded annual outpatient visits for different respiratory diseases in children. The best synergy lag model found a 10 μg/m³ increase in PM_2.5 for every 4–10% increase in the number of pediatric respiratory outpatient visits (P < 0.05). The cumulative effect of an increase in the number of daily pediatric respiratory clinics with a lag of 1–7 days was the best model.

Conclusions

PM_2.5 is significantly related to the number of respiratory outpatient visits of children, which can aid in formulating policies for health resource allocation and health risk assessment strategies.

Ambient heat exposure and COPD hospitalisations in England: a nationwide case-crossover study during 2007-2018

Background

There is emerging evidence suggesting a link between ambient heat exposure and chronic obstructive pulmonary disease (COPD) hospitalisations. Individual and contextual characteristics can affect population vulnerabilities to COPD hospitalisation due to heat exposure. This study quantifies the effect of ambient heat on COPD hospitalisations and examines population vulnerabilities by age, sex and contextual characteristics.

Methods

Individual data on COPD hospitalisation at high geographical resolution (postcodes) during 2007–2018 in England was retrieved from the small area health statistics unit. Maximum temperature at 1 km ×1 km resolution was available from the UK Met Office. We employed a case-crossover study design and fitted Bayesian conditional Poisson regression models. We adjusted for relative humidity and national holidays, and examined effect modification by age, sex, green space, average temperature, deprivation and urbanicity.

Results

After accounting for confounding, we found 1.47% (95% Credible Interval (CrI) 1.19% to 1.73%) increase in the hospitalisation risk for every 1°C increase in temperatures above 23.2°C (lags 0–2 days). We reported weak evidence of an effect modification by sex and age. We found a strong spatial determinant of the COPD hospitalisation risk due to heat exposure, which was alleviated when we accounted for contextual characteristics. 1851 (95% CrI 1 576 to 2 079) COPD hospitalisations were associated with temperatures above 23.2°C annually.

Conclusion

Our study suggests that resources should be allocated to support the public health systems, for instance, through developing or expanding heat-health alerts, to challenge the increasing future heat-related COPD hospitalisation burden.

Asthma and COPD exacerbation in relation to outdoor air pollution in the metropolitan area of Berlin, Germany

Background

Ambient air pollution poses a major risk for the development and aggravation of respiratory diseases. Evidence suggests that even in low-level air pollution environments there is a risk for an increase in adverse respiratory symptoms. We examined whether variations in daily air pollution levels of nitrogen dioxide, ozone, or particulate matter in Berlin, Germany were associated with hospital admissions of chronic obstructive pulmonary disease (COPD) and asthma patients in a time series analysis.

Methods

We calculated single and multi-pollutant models, investigated possible lags in effect, and analysed the influence of meteorological variables on the results. Data from January 2005 through December 2015 were used to quantify the concentration–response.

Results

The risk ratio for asthma patients to be hospitalised on the same day of NO₂ exposure was 1.101 per 10 µg/m³ NO₂ increase (95% CI: 1.013 to 1.195), for COPD patients 1.123 (95% CI: 1.081 to 1.168). Neither the exposure to ozone (95% CI: 0.904 to 1.020), PM₁₀ (95% CI: 0.990 to 1.127), nor PM_2.5 (95% CI: 0.981 to 1.148) was associated with an increased risk ratio for asthma patients to be hospitalised. Risk ratios for the hospital admission of COPD patients were also not increased due to ozone (95% CI: 0.981 to 1.033), PM₁₀ (95% CI: 0.988 to 1.032), or PM_2.5 (95% CI: 0.966 to 1.019) exposure. The presented risk ratios and confidence intervals relate to the day of exposure. We found no increased hospitalisation risks with a delayed occurrence on subsequent days.

Conclusions

A quantifiable, statistically significant increase in risk for asthma and COPD exacerbations owing to NO₂ exposure at levels well below European regulatory limit values was observed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-01983-1.

Long-term PM2.5 exposure and various health outcomes: An umbrella review of systematic reviews and meta-analyses of observational studies

Adverse effects from exposure to particulate matter <2.5 μm in diameter (PM_2.5) on health-related outcomes have been found in a range of experimental and epidemiological studies. This study aimed to assess the significance, validity, and reliability of the relationship between long-term PM_2.5 exposure and various health outcomes. The Embase, PubMed, Web of Science, CNKI, WANFANG, VIP, and SinoMed databases and reference lists of the retrieved review articles were searched to obtain meta-analysis and systematic reviews focusing on PM_2.5-related outcomes as of August 31, 2021. Random-/fixed-effects models were applied to estimate summary effect size and 95% confidence intervals (CIs). The quality of included meta-analyses was evaluated based on the AMSTAR 2 tool. Small-study effect and excess significance bias studies were conducted to further assess the associations. Registered PROSPERO number: CRD42020200606. This included 24 articles involving 71 associations between PM_2.5 exposure and the health outcomes. The evidence for the positive association of 10 μg/m³ increments of long-term exposure to PM_2.5 and stroke incidence in Europe was convincing (effect size = 1.07, 95% CI: 1.05-1.10). There was evidence that was highly suggestive of a positive association between 10 μg/m³ increments of long-term exposure to PM_2.5 and the following health-related outcomes: mortality of lung cancer (effect size = 1.11, 95% CI: 1.08-1.13) and Alzheimer's disease (effect size = 4.79, 95% CI: 2.79-8.21). There was highly suggestive evidence that chronic obstructive pulmonary disease risk is positively associated with higher long-term PM_2.5 exposure versus lower long-term PM_2.5 exposure (effect size = 2.32, 95% CI: 1.88-2.86). In conclusion, the positive association of long-term exposure to PM_2.5 and stroke incidence in Europe was convincing. Given the validity of numerous associations of long-term exposure to PM_2.5 and health-related outcomes is subject to biases, more robust evidence is urgently needed.

A Bayesian Multi-Outcome Analysis of Fine Particulate Matter and Cardiorespiratory Hospitalizations

BACKGROUND

Short-term fine particulate matter (PM2.5) exposure is positively associated with acute cardiovascular and respiratory events. Understanding whether this association varies across specific cardiovascular and respiratory conditions has important biologic, clinical, and public health implications.

METHODS

We conducted a time-stratified case-crossover study of hospitalizations from 2000 through 2014 among United States Medicare beneficiaries aged 65+. The outcomes were hospitalizations with any of 57 cardiovascular and 32 respiratory discharge diagnoses. We estimated associations with two-day moving average PM2.5 as a piecewise linear term with a knot at PM2.5 = 25 g/m3. We used Multi-Outcome Regression with Tree-structured Shrinkage (MOReTreeS) to identify de novo groups of related diseases such that PM2.5 associations are: (1) similar within outcome groups; but (2) different between outcome groups. We adjusted for temperature, humidity, and individual-level characteristics. We introduce an R package, moretrees.

RESULTS

Our dataset included 16,007,293 cardiovascular and 8,690,837 respiratory hospitalizations. Of 57 cardiovascular diseases, 51 were grouped and positively associated with PM2.5. We observed a stronger positive association for heart failure, which formed a separate group. We observed negative associations for groups containing the outcomes other aneurysm and intracranial hemorrhage. Of 32 respiratory outcomes, 31 were grouped and were positively associated with PM2.5. Influenza formed a separate group with a negative association.

CONCLUSIONS

We used a new statistical approach, MOReTreeS, to uncover variation in the association between short-term PM2.5 exposure and hospitalizations for cardiovascular and respiratory causes controlling for patient characteristics, time trends, and environmental confounders.

Impact of Exposure to Diesel Exhaust on Inflammation Markers and Proteases in Former Smokers with COPD: A Randomized, Double-Blinded, Crossover Study

Rationale: There is growing evidence that chronic obstructive pulmonary disease (COPD) can be caused and exacerbated by air pollution exposure. Objectives: Document the impact of short-term air pollution exposure on inflammation markers, proteases, and antiproteases in lower airways of older adults with and without COPD. Methods: Thirty participants (10 ex-smokers with mild-moderate COPD, 20 healthy (9 ex-smokers, 11 never-smokers), average age 60, completed this double-blinded controlled human crossover exposure study. Each participant was exposed to filtered air (control) and diesel exhaust (DE), in washout-separated two hour periods, in a randomly assigned order. Bronchoscopy was performed 24 hours post-exposure to collect lavage. Cell counts were performed on blood and airway samples. Enzyme-linked immunosorbent assays were performed to measure acute inflammatory proteins, matrix proteinases, and anti-proteases in the airway and blood samples. Measurements and Main Results: In former smokers with COPD, but not in the other participants, exposure to DE increased serum amyloid A (1.67 [1.21 to 2.30], p=0.04) and matrix metalloproteinase 10 (2.61 [1.38 to 4.91], p=0.04) in bronchoalveolar lavage. Circulating lymphocytes were increased following DE (0.14 [0.05 to 0.24] cells x 10⁹/L, p=0.03), irrespective of COPD status. Conclusions: A controlled human crossover study of diesel exhaust reveals that former smokers with COPD may be susceptible to an inflammatory response compared to ex-smokers without COPD or never-smoking healthy controls. Clinical trial registration available at www.clinicaltrials.gov, ID: NCT02236039.

Ambient Particulate Air Pollution and Daily Hospital Admissions in 31 Cities in Poland

A strong and consistent association has been observed between morbidity or mortality rates and PM concentration, and is well documented in many countries. In Poland, despite poor air quality, studies concerning the evaluation of acute health effects of ambient air pollution on morbidity from respiratory or cardiovascular diseases are rare. We examined the short-term impact of PMx concentration on hospital admission in 31 Polish cities based on the daily PM10, PM2.5 concentration, meteorological variables, and hospital data. The generalized additive model (GAM) and a random-effects meta-analysis were used to assess the impact of air pollution on morbidity within the exposed population. Almost 1.6 million cardiovascular admissions and 600 thousand respiratory disorders were analyzed. The RR values for PM10-related cardiovascular and respiratory hospital admissions in Poland are equal to 1.0077 (95% confidence interval, 1.0062 to 1.0092) and 1.0218 (95% confidence interval, 1.0182 to 1.0253), respectively, while for PM2.5 1.0088 (95% confidence interval, 1.0072 to 1.0103) and 1.0289 (95% confidence interval, 1.0244 to 1.0335), respectively. Moreover, a moderate heterogeneity of RR estimates was observed between the analyzed cities (I2 values from 27% to 45%). The presented analysis confirms the significant association between hospital admission and PMx concentration, especially during heating seasons.

A nationwide study of air pollution from particulate matter and daily hospitalizations for respiratory diseases in Italy

BACKGROUND/AIM

The relationship between air pollution and respiratory morbidity has been widely addressed in urban and metropolitan areas but little is known about the effects in non-urban settings. Our aim was to assess the short-term effects of PM10 and PM2.5 on respiratory admissions in the whole country of Italy during 2006-2015.

METHODS

We estimated daily PM concentrations at the municipality level using satellite data and spatiotemporal predictors. We collected daily counts of respiratory hospital admissions for each Italian municipality. We considered five different outcomes: all respiratory diseases, asthma, chronic obstructive pulmonary disease (COPD), lower and upper respiratory tract infections (LRTI and URTI). Meta-analysis of province-specific estimates obtained by time-series models, adjusting for temperature, humidity and other confounders, was applied to extrapolate national estimates for each outcome. At last, we tested for effect modification by sex, age, period, and urbanization score. Analyses for PM_2.5 were restricted to 2013-2015 cause the goodness of fit of exposure estimation.

RESULTS

A total of 4,154,887 respiratory admission were registered during 2006-2015, of which 29% for LRTI, 12% for COPD, 6% for URTI, and 3% for asthma. Daily mean PM₁₀ and PM_2.5 concentrations over the study period were 23.3 and 17 μg/m³, respectively. For each 10 μg/m³ increases in PM₁₀ and PM_2.5 at lag 0-5 days, we found excess risks of total respiratory diseases equal to 1.20% (95% confidence intervals, 0.92, 1.49) and 1.22% (0.76, 1.68), respectively. The effects for the specific diseases were similar, with the strongest ones for asthma and COPD. Higher effects were found in the elderly and in less urbanized areas.

CONCLUSIONS

Short-term exposure to PM is harmful for the respiratory system throughout an entire country, especially in elderly patients. Strong effects can be found also in less urbanized areas.

Early Diagnosis and Real-Time Monitoring of Regional Lung Function Changes to Prevent Chronic Obstructive Pulmonary Disease Progression to Severe Emphysema

First- and second-hand exposure to smoke or air pollutants is the primary cause of chronic obstructive pulmonary disease (COPD) pathogenesis, where genetic and age-related factors predispose the subject to the initiation and progression of obstructive lung disease. Briefly, airway inflammation, specifically bronchitis, initiates the lung disease, leading to difficulty in breathing (dyspnea) and coughing as initial symptoms, followed by air trapping and inhibition of the flow of air into the lungs due to damage to the alveoli (emphysema). In addition, mucus obstruction and impaired lung clearance mechanisms lead to recurring acute exacerbations causing progressive decline in lung function, eventually requiring lung transplant and other lifesaving interventions to prevent mortality. It is noteworthy that COPD is much more common in the population than currently diagnosed, as only 16 million adult Americans were reported to be diagnosed with COPD as of 2018, although an additional 14 million American adults were estimated to be suffering from COPD but undiagnosed by the current standard of care (SOC) diagnostic, namely the spirometry-based pulmonary function test (PFT). Thus, the main issue driving the adverse disease outcome and significant mortality for COPD is lack of timely diagnosis in the early stages of the disease. The current treatment regime for COPD emphysema is most effective when implemented early, on COPD onset, where alleviating symptoms and exacerbations with timely intervention(s) can prevent steep lung function decline(s) and disease progression to severe emphysema. Therefore, the key to efficiently combatting COPD relies on early detection. Thus, it is important to detect early regional pulmonary function and structural changes to monitor modest disease progression for implementing timely interventions and effectively eliminating emphysema progression. Currently, COPD diagnosis involves using techniques such as COPD screening questionnaires, PFT, arterial blood gas analysis, and/or lung imaging, but these modalities are limited in their capability for early diagnosis and real-time disease monitoring of regional lung function changes. Hence, promising emerging techniques, such as X-ray phase contrast, photoacoustic tomography, ultrasound computed tomography, electrical impedance tomography, the forced oscillation technique, and the impulse oscillometry system powered by robust artificial intelligence and machine learning analysis capability are emerging as novel solutions for early detection and real time monitoring of COPD progression for timely intervention. We discuss here the scope, risks, and limitations of current SOC and emerging COPD diagnostics, with perspective on novel diagnostics providing real time regional lung function monitoring, and predicting exacerbation and/or disease onset for prognosis-based timely intervention(s) to limit COPD–emphysema progression.

From Biomarkers to Novel Therapeutic Approaches in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a heterogeneous and complex disorder. In this review, we provided a comprehensive overview of biomarkers involved in COPD, and potential novel biological therapies that may provide additional therapeutic options for COPD. The complex characteristics of COPD have made the recommendation of a generalized therapy challenging, suggesting that a tailored, personalized strategy may lead to better outcomes. Existing and unmet needs for COPD treatment support the continued development of biological therapies, including additional investigations into the potential clinical applications of this approach.

Association between air pollution and chronic rhinosinusitis: a nested case-control study using meteorological data and national health screening cohort data

BACKGROUND

Inconsistent results about the effect of air pollution on chronic rhinosinusitis (CRS) have been reported. This study aimed to evaluate the impact of meteorological conditions/air pollution on the prevalence of CRS in adult Koreans.

METHODOLOGY

The data from the Korean National Health Insurance Service-Health Screening Cohort from 2002 through 2015 were used. A CRS group (defined as ICD-10 codes J32, n=6159) was matched with a control group (n=24,636) in 1:4 ratios by age, sex, income, and region of residence. The meteorological conditions and air pollution data included the daily mean, highest, and lowest temperature (°C), daily temperature range (°C), relative humidity (%), ambient atmospheric pressure (hPa), sunshine duration (hr), and the rainfall (mm), SO2 (ppm), NO2 (ppm), O3 (ppm), CO (ppm), and PM10 (μg/m3) levels before the CRS diagnosis. Crude and adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for CRS were analyzed using logistic regression analyses.

RESULTS

When the NO2 level increased by 0.1 ppm, the odds for CRS increased 5.40 times, and when the CO level increased by 1 ppm and PM10 increased by 10 μg/m3, the odds for CRS decreased 0.75 times and 0.93 times, respectively. Other meteorological conditions, such as the mean/highest/lowest temperature, temperature range, rainfall and other air pollution, such as SO2 and O3, were not statistically significant. NO2 for 90 days before the index date increased the risk of CRS in all subgroups, except for the nasal polyp and older age subgroups.

CONCLUSION

CRS is related to high concentrations of NO2.

Intra-city variability of fine particulate matter during COVID-19 lockdown: A case study from Park City, Utah

Urban air quality is a growing concern due a range of social, economic, and health impacts. Since the SARS-CoV-19 pandemic began in 2020, governments have produced a range of non-medical interventions (NMIs) (e.g. lockdowns, stay-at-home orders, mask mandates) to prevent the spread of COVID-19. A co-benefit of NMI implementation has been the measurable improvement in air quality in cities around the world. Using the lockdown policy of the COVID-19 pandemic as a natural experiment, we traced the changing emissions patterns produced under the pandemic in a mid-sized, high-altitude city to isolate the effects of human behavior on air pollution. We tracked air pollution over time periods reflecting the Pre-Lockdown, Lockdown, and Reopening stages, using high quality, research grade sensors in both commercial and residential areas to better understand how each setting may be uniquely impacted by pollution downturn events. Based on this approach, we found the commercial area of the city showed a greater decrease in air pollution than residential areas during the lockdown period, while both areas experienced a similar rebound post lockdown. The easing period following the lockdown did not lead to an immediate rebound in human activity and the air pollution increase associated with reopening, took place nearly two months after the lockdown period ended. We hypothesize that differences in heating needs, travel demands, and commercial activity, are responsible for the corresponding observed changes in the spatial distribution of pollutants over the study period. This research has implications for climate policy, low-carbon energy transitions, and may even impact local policy due to changing patterns in human exposure that could lead to important public health outcomes, if left unaddressed.

Is PM2.5 associated with emergency department visits for mechanical ventilation in acute exacerbation of chronic obstructive pulmonary disease?

BACKGROUND

Patients with chronic obstructive pulmonary disease (COPD) can have recurrent exacerbations and acute respiratory failure (ARF) triggered by particulate matter with a diameter of ≤2.5 μm (PM_2.5). To prevent ventilator shortages, this study investigated the short-term association between PM_2.5 concentration and emergency department visits (EDVs) among patients with acute exacerbation of COPD (AECOPD) requiring mechanical ventilation (MV).

METHODS

We conducted a time-series study to predict the PM_2.5 concentration and number of ventilators needed. Daily counts of EDVs among AECOPD patients requiring ventilation from 2015 to 2019 were obtained from a hospital. Generalized linear models extending Poisson regression were used to explore the association of AECOPD with PM_2.5 after controlling for the time trend, seasonal variations, and meteorological variables.

RESULTS

Eight hundred seventy-five AECOPD patients receiving MV were recorded, of whom 734 received noninvasive ventilation and 141 received invasive ventilatory support. EDVs for AECOPD patients with ARF significantly increased by 3.5% (95% confidence interval [CI]: 2.51%-4.42%) per 10 μg m^-3 increase in PM_2.5 concentration. Among seasons, PM_2.5 concentration had the strongest effect on AECOPD patients with ARF in spring (<24.5 °C), with a 1.64% (95% CI: -0.56% to 3.83%) increase in admissions per 10 μg m^-3 increase in same-day PM_2.5 concentration. The interquartile range increase of 20 μg m^-3 between winter and spring was associated with an average EDV increase of 48.66%.

CONCLUSION

This is the first study to predict the number of ventilators required by calculating quantitative estimates of the short-term effects of PM_2.5 on EDVs for AECOPD patients with ARF. Adverse effects of PM_2.5 on AECOPD patients requiring MV are evident, especially in the spring. Establishing protective standards and reducing the PM_2.5 concentration to below various thresholds are urgently needed.

Quantifying the Health Benefits of Face Masks and Respirators to Mitigate Exposure to Severe Air Pollution

Familiarity with the use of face coverings to reduce the risk of respiratory disease has increased during the coronavirus pandemic; however, recommendations for their use outside of the pandemic remains limited. Here, we develop a modeling framework to quantify the potential health benefits of wearing a face covering or respirator to mitigate exposure to particulate air pollution. This framework accounts for the wide range of available face coverings and respirators, fit factors and efficacy, air pollution characteristics, and exposure-response data. Our modeling shows that N95 respirators offer robust protection against different sources of particulate matter, reducing exposure by more than a factor of 14 when worn with a leak rate of 5%. Synthetic-fiber masks offer less protection with a strong dependence on aerosol size distribution (protection factors ranging from 4.4 to 2.2), while natural-fiber and surgical masks offer reductions in the exposure of 1.9 and 1.7, respectively. To assess the ability of face coverings to provide population-level health benefits to wildfire smoke, we perform a case study for the 2012 Washington state fire season. Our models suggest that although natural-fiber masks offer minor reductions in respiratory hospitalizations attributable to smoke (2%-11%) due to limited filtration efficiency, N95 respirators and to a lesser extent surgical and synthetic-fiber masks may lead to notable reductions in smoke-attributable hospitalizations (22%-39%, 9%-24%, and 7%-18%, respectively). The filtration efficiency, bypass rate, and compliance rate (fraction of time and population wearing the device) are the key factors governing exposure reduction potential and health benefits during severe wildfire smoke events.

Long-term analysis of the relationships between indoor and outdoor fine particulate pollution: A case study using research grade sensors

The growing concern of air quality and its associated health-related impacts has led to increased awareness of pollutant exposure. Most human populations spend the majority of their time indoors and the COVID-19 pandemic has likely exacerbated this behavior. While significant amounts of research have focused on outdoor air quality, to date there have been no studies that examined simultaneous long-term trends on indoor and outdoor air quality on a site using research-grade sensors. We measured fine particulate matter (PM_2.5) for a year using sensors located on the rooftop, air handling room, and indoor office space in a building and captured the impacts of three types of regularly occurring elevated pollution events: wintertime atmospheric inversions, wildfires, and fireworks. The events had different magnitudes and durations, and infiltration rates varied for each event leading to dissimilar indoor air pollution levels. The building's air handling unit and different environmental conditions (lower indoor humidity and temperature during the winter) combined to reduce indoor pollution from inversion events however, particulate matter from wildfires and fireworks infiltrated at higher rates. Together, this suggests possible intervention strategies, such as ventilation rates and filter upgrades, that could be used to mitigate contaminant intrusion during elevated pollution events. This year-long study illustrates an array of ways that elevated pollution events interact with the protective effects that buildings have against air pollution for its occupants. Furthermore, we show that outdoor air pollution is an important variable to consider when studying indoor air quality as contaminant infiltration is strongly dependent on the specific pollution source.

Ventilation-Associated Particulate Matter Is a Potential Reservoir of Multidrug-Resistant Organisms in Health Facilities

Most healthcare-associated infections (HCAIs) develop due to the colonisation of patients and healthcare workers by multidrug-resistant organisms (MDRO). Here, we investigated whether the particulate matter from the ventilation systems (Vent-PM) of health facilities can harbour MDRO and other microbes, thereby acting as a potential reservoir of HCAIs. Dust samples collected in the ventilation grilles and adjacent air ducts underwent a detailed analysis of physicochemical properties and biodiversity. All Vent-PM samples included ultrafine PM capable of reaching the alveoli. Strikingly, >70% of Vent-PM samples were contaminated, mostly by viruses (>15%) or multidrug-resistant and biofilm-producing bacterial strains (60% and 48% of all bacteria-contaminated specimens, respectively). Total viable count at 1 m from the ventilation grilles was significantly increased after opening doors and windows, indicating an association between air flow and bacterial contamination. Both chemical and microbial compositions of Vent-PM considerably differed across surgical vs. non-surgical and intensive vs. elective care units and between health facilities located in coal and chemical districts. Reduced diversity among MDRO and increased prevalence ratio in multidrug-resistant to the total Enterococcus spp. in Vent-PM testified to the evolving antibiotic resistance. In conclusion, we suggest Vent-PM as a previously underestimated reservoir of HCAI-causing pathogens in the hospital environment.

Evaluation of a Meta-Analysis of Ambient Air Quality as a Risk Factor for Asthma Exacerbation

Background: An irreproducibility crisis currently afflicts a wide range of scientific disciplines, including public health and biomedical science. A study was undertaken to assess the reliability of a meta-analysis examining whether air quality components (carbon monoxide, particulate matter 10 µm and 2.5 µm (PM10 and PM2.5), sulfur dioxide, nitrogen dioxide and ozone) are risk factors for asthma exacerbation. Methods: The number of statistical tests and models were counted in 17 randomly selected base papers from 87 used in the meta-analysis. Confidence intervals from all 87 base papers were converted to p-values. p-value plots for each air component were constructed to evaluate the effect heterogeneity of the p-values. Results: The number of statistical tests possible in the 17 selected base papers was large, median = 15,360 (interquartile range = 1536–40,960), in comparison to results presented. Each p-value plot showed a two-component mixture with small p-values < 0.001 while other p-values appeared random (p-values > 0.05). Given potentially large numbers of statistical tests conducted in the 17 selected base papers, p-hacking cannot be ruled out as explanations for small p-values. Conclusions: Our interpretation of the meta-analysis is that random p-values indicating null associations are more plausible and the meta-analysis is unlikely to replicate in the absence of bias.

Assessing PM2.5-associated risk of hospitalization for COPD: an application of daily excessive concentration hours

Existing PM2.5-morbidity studies using daily mean concentration as exposure metric may fail to capture intra-day variations of PM2.5 concentrations, resulting in underestimated health impacts to some extent. This study introduced a novel indicator, daily excessive concentration hours (DECH), defined as sums of per-hourly excessive concentrations of PM2.5 against a specific threshold within a day. PM2.5 DECHs were separately calculated as daily concentration-hours >8, 10, 15, 20, and 25 μg/m3 (abbreviations: DECH-8, DECH-10, DECH-15, DECH-20, and DECH-25). We adopted a time-stratified case-crossover design with conditional logistic regression models to compare risks of hospitalizations for chronic obstructive pulmonary disease (COPD) associated with PM2.5 mean and DECHs in Shenzhen, China. We observed highly comparable PM2.5-COPD associations using exposure metrics of daily mean and DECHs with above-defined thresholds. For instance, PM2.5 mean and DECHs showed similar increases in risks of COPD hospitalization for an interquartile range rise in exposure, with odds ratio estimates of 1.26 (95% confidence interval: 1.06-1.50) for PM2.5 mean, 1.24 (1.05-1.46) for DECH-10 and 1.21 (1.06-1.39) for DECH-25, respectively. Findings remained robust after further adjusting for gaseous pollutants (e.g., SO2, NO2, CO, and O3) and meteorologic factors (e.g., wind speed and air pressure). Our study strengthened the evidence that DECHs could come be as a novel exposure metric in health risk assessments associated with short-term exposure to ambient PM2.5.