Association between ambient air pollution and out-of-hospital cardiac arrest: are there potentially susceptible groups?

Epigenetic transgenerational effects of PM2.5 collected from southern Taiwan on sperm functions and DNA methylation in mouse offspring

During respiration, particulate matter with a diameter of 2.5 µm or less (PM2.5) suspended in the atmosphere enters the terminal alveoli and blood. PM2.5 particles can attach to toxic substances, resulting in health problems. Limited information is available regarding the effects of prenatal exposure to water-soluble PM2.5 (WS-PM2.5) and water-insoluble PM2.5 (WI-PM2.5) on male reproduction. In addition, whether exposure to these particles has transgenerational effects remains unknown. We investigated whether prenatal exposure to WS-PM2.5 and WI-PM2.5 disrupts sperm function in generations F1, F2, and F3 of male mice. Pregnant BALB/c mice were treated using intratracheal instillation on gestation days 7, 11, and 15 with 10 mg of a water extract or insoluble PM2.5. On postnatal day 105, epididymal sperm count, motility, morphology, mitochondrial membrane potential (MMP), reactive oxygen species (ROS) production, the sperm chromatin DNA fragmentation index (DFI), and testicular DNA methyltransferase (Dnmt) levels were evaluated in all generations. Whole-genome bisulfite sequencing was used to analyze the DNA methylation status of generation F3. According to the results, exposure to WS-PM2.5 affected sperm morphology, ROS production, and mean DFI in generation F1; ROS production and mean DFI in generation F2; and sperm morphology and MMP in generation F3. Similarly, exposure to WI-PM2.5 affected sperm morphology, ROS production, mean DFI, %DFI, and Dnmt1 expression in generation F1; sperm morphology, MMP, and ROS production in generation F2; and sperm morphology, ROS, and %DFI in generation F3. Two hypermethylated genes, PRR16 and TJP2, were observed in the WS-PM2.5 and WI-PM2.5 groups, two hypomethylated genes, NFATC1 and APOA5, were observed in the WS-PM2.5 group, and two hypomethylated genes, ZFP945 and GSE1, were observed in the WI-PM2.5 group. Hence, prenatal exposure to PM2.5 resulted in transgenerational epigenetic effects, which may explain certain phenotypic changes in male reproduction.

Short-Term Ambient Air Pollution Exposure and Risk of Out-of-Hospital Cardiac Arrest in Sweden: A Nationwide Case-Crossover Study

Background Air pollution is one of the main risk factors for cardiovascular disease globally, but its association with out-of-hospital cardiac arrest at low air pollution levels is unclear. This nationwide study in Sweden aims to investigate if air pollution is associated with a higher risk of out-of-hospital cardiac arrest in an area with relatively low air pollution levels. Methods and Results This study was a nationwide time-stratified case-crossover study investigating the association between short-term air pollution exposures and out-of-hospital cardiac arrest using data from the SRCR (Swedish Registry for Cardiopulmonary Resuscitation) between 2009 and 2019. Daily air pollution levels were estimated in 1×1-km grids for all of Sweden using a satellite-based machine learning model. The association between daily air pollutant levels and out-of-hospital cardiac arrest was quantified using conditional logistic regression adjusted for daily air temperature. Particulate matter <2.5 μm exposure was associated with a higher risk of out-of-hospital cardiac arrest among a total of 29 604 cases. In a multipollutant model, the association was most pronounced for intermediate daily lags, with an increased relative risk of 6.2% (95% CI, 1.0-11.8) per 10 μg/m3 increase of particulate matter <2.5 μm 4 days before the event. A similar pattern of association was observed for particulate matter <10 μm. No clear association was observed for O3 and NO2. Conclusions Short-term exposure to air pollution was associated with higher risk of out-of-hospital cardiac arrest. The findings add to the evidence of an adverse effect of particulate matter on out-of-hospital cardiac arrest, even at very low levels below current regulatory standards.

Fine and coarse particulate air pollution and out-of-hospital cardiac arrest onset: a nationwide case-crossover study in China

Out-of-hospital cardiac arrest (OHCA) is a global public health concern. Nationwide studies on the effects of short-term exposure to particulate matter (PM) on OHCA risk are rare in regions with high PM levels, and evidence for coarse PM (PM_2.5-10) is limited and inconsistent. To evaluate the associations between fine PM (PM_2.5) and PM_2.5-10 and OHCA onset, a time-stratified case-crossover study was conducted on 77,261 patients with cardiac OHCA in 26 cities across China in 2020. Daily PM_2.5 and PM_2.5-10 concentrations were assessed with high-resolution and full-coverage PM estimations. Conditional logistic regression models were applied in analyses. Each interquartile range of PM increase in 3-day moving average was associated with an increased risk of cardiac OHCA onset of 2.37% (95% CI, 1.20-3.56%) for PM_2.5 and 2.12% (95% CI, 0.70-3.56%) for PM_2.5-10. Stratified analyses showed higher susceptibility in patients over 75 years for PM_2.5 exposure and with diabetes for PM_2.5-10. This first nationwide study in region with high PM levels and great PM variability found not only PM_2.5 but also PM_2.5-10 were associated with a higher risk of OHCA onset, which could add powerful epidemiological evidence to this field and provide new evidence for the formulation of air quality guidelines.

Epigenetic age stratifies the risk of blood pressure elevation related to short-term PM2.5 exposure in older adults

BACKGROUND

Exposure to fine particulate matter (PM_2.5) is a prominent risk factor for cardiovascular aging in older adults and causes mild syndromes or other comorbidities in otherwise healthy older adults. Accordingly, a precise tool for PM_2.5 exposure risk stratification is urgently needed. We aimed to address this need by comparing the performances of seven types of epigenetic age and chronological age to classify the effects of short-term PM_2.5 exposure on blood pressure (BP), a typical clinical surrogate marker of cardiovascular aging.

METHODS

We conducted a panel study of the Chinese healthy adults aged 60-69 years through five monthly visits. Personal PM_2.5 exposures were measured using wearable monitoring devices for three consecutive days, and DNA methylation was determined by the Illumina MethylationEPIC BeadChip using blood samples collected at each visit. Systolic BP, diastolic BP, mean arterial pressure and pulse pressure were measured by the electronic BP monitor. Linear mixed models with interaction terms between PM_2.5 and different ages were used to assess their potential usefulness for stratification.

RESULTS

DNAmPhenoAge, Skin & blood clock, DNAmGrimAge acceleration, and DunedinPoAm had significant modifying effects on the relationship between PM_2.5 and BP. For instance, a 10-μg/m³ increase in the 72-h moving mean PM_2.5 was significantly associated with 0.30% (95% CI: 0.10%, 0.51%) and -0.07% (95% CI: -0.32%, 0.18%) increases in systolic BP at higher and lower DNAmPhenoAge acceleration, respectively. Joint models further revealed that using a combination of epigenetic ages could more precisely stratify the effect of PM_2.5 on BP.

CONCLUSIONS

Our research indicates that epigenetic age may be a useful tool for evaluating the effect of short-term PM_2.5 exposure on cardiovascular aging status.

Ambient Air Pollution and Risk for Stroke Hospitalization: Impact on Susceptible Groups

Stroke is a leading cause of death, and air pollution is associated with stroke hospitalization. However, the susceptibility factors are unclear. Retrospective studies from 2014 to 2018 in Kaohsiung, Taiwan, were analyzed. Adult patients (>17 years) admitted to a medical center with stroke diagnosis were enrolled and patient characteristics and comorbidities were recorded. Air pollutant measurements, including those of particulate matter (PM) with aerodynamic diameters < 10 μm (PM10) and < 2.5 μm (PM2.5), nitrogen dioxide (NO2), and ozone (O3), were collected from air quality monitoring stations. During the study period, interquartile range (IQR) increments in PM2.5 on lag3 and lag4 were 12.3% (95% CI, 1.1−24.7%) and 11.5% (95% CI, 0.3−23.9%) concerning the risk of stroke hospitalization, respectively. Subgroup analysis revealed that the risk of stroke hospitalization after exposure to PM2.5 was greater for those with advanced age (≥80 years, interaction p = 0.045) and hypertension (interaction p = 0.034), after adjusting for temperature and humidity. A dose-dependent effect of PM2.5 on stroke hospitalization was evident. This is one of few studies focusing on the health effects of PM2.5 for patients with risk factors of stroke. We found that patients with risk factors, such as advanced age and hypertension, are more susceptible to PM2.5 impacts on stroke hospitalization.

Association between Ambient Air Pollution and Emergency Room Visits for Pediatric Respiratory Diseases: The Impact of COVID-19 Pandemic

The level and composition of air pollution have changed during the coronavirus disease 2019 (COVID-19) pandemic. However, the association between air pollution and pediatric respiratory disease emergency department (ED) visits during the COVID-19 pandemic remains unclear. The study was retrospectively conducted between 2017 and 2020 in Kaohsiung, Taiwan, from 1 January 2020 to 1 May 2020, defined as the period of the COVID-19 pandemic, and 1 January 2017 to 31 May 2019, defined as the pre-COVID-19 pandemic period. We enrolled patients under 17 years old who visited the ED in a medical center and were diagnosed with respiratory diseases such as pneumonia, asthma, bronchitis, and acute pharyngitis. Measurements of particulate matter (PM) with aerodynamic diameters of <10 μm (PM10) and < 2.5 μm (PM2.5), nitrogen dioxide (NO2), and Ozone (O3) were collected. During the COVID-19 pandemic, an increase in the interquartile range of PM2.5, PM10, and NO2 levels was associated with increases of 72.5% (95% confidence interval [CI], 50.5−97.7%), 98.0% (95% CI, 70.7−129.6%), and 54.7% (95% CI, 38.7−72.6%), respectively, in the risk of pediatric respiratory disease ED visits on lag 1, which were greater than those in the pre-COVID-19 pandemic period. After adjusting for temperature and humidity, the risk of pediatric respiratory diseases after exposure to PM2.5 (inter p = 0.001) and PM10 (inter p < 0.001) was higher during the COVID-19 pandemic. PM2.5, PM10, and NO2 may play important roles in pediatric respiratory events in Kaohsiung, Taiwan. Compared with the pre-COVID-19 pandemic period, the levels of PM2.5 and PM10 were lower; however, the levels were related to a greater increase in ED during the COVID-19 pandemic.

Air pollution and hospital admissions for critical illness in emergency department: a tertiary-center research in Changsha, China, 2016-2020

We aimed to comprehensively investigate the associations of air pollutants with hospital admissions for critical illness in ED. Patients with critical illness including level 1 and level 2 of the Emergency Severity Index admitted in ED of Changsha Central Hospital from January 2016 to December 2020 were enrolled. Meteorological and air pollutants data source were collected from the National Meteorological Science Data Center. A Poisson generalized linear regression combined with a polynomial distributed lag model (PDLM) was utilized to explore the effect of air pollution on hospital admissions for critical illness in ED. Benchmarks as references (25th) were conducted for comparisons with high levels of pollutant concentrations (75th). At first, lagged effects of all different air pollutants were analyzed. Then, based on the most significant factor, analyses in subgroups were performed by gender (male and female), age (< 45, 45-65, and > 65), disorders (cardiovascular, neurological, respiratory), and seasons (spring, summer, autumn, and winter). A total of 47,290 patients with critical illness admitted in ED were included. The effects of air pollutants (PM_2.5, PM₁₀, SO₂, NO₂, O₃ and CO) on critical illness ED visits were statistically significant. Strong collinearity between PM_2.5 and PM₁₀ (r = 0.862) was found. Both single-day lag and cumulative-day lag day models showed that PM_2.5 had the strongest effects (lag 0, RR = 1.025, 95% CI 1.008-1.043, and lag 0-14, RR = 1.067, 95% CI 1.017-1.120, respectively). In both PM_2.5 and PM₁₀, the risks of critical illness in male, > 65 ages, respiratory diseases, and winter increased the most significant. Air pollutants, especially PM_2.5 and PM₁₀ exposure, could increase the risk of critical illness admission.

Effects of Fine Particulate Matter and Its Components on Emergency Room Visits for Pediatric Pneumonia: A Time-Stratified Case-Crossover Study

Pneumonia, one of the important causes of death in children, may be induced or aggravated by particulate matter (PM). Limited research has examined the association between PM and its constituents and pediatric pneumonia-related emergency department (ED) visits. Measurements of PM_2.5, PM₁₀, and four PM_2.5 constituents, including elemental carbon (EC), organic carbon (OC), nitrate, and sulfate, were extracted from 2007 to 2010 from one core station and two satellite stations in Kaohsiung City, Taiwan. Furthermore, the medical records of patients under 17 years old who had visited the ED in a medical center and had a diagnosis of pneumonia were collected. We used a time-stratified, case-crossover study design to estimate the effect of PM. The single-pollutant model demonstrated interquartile range increase in PM_2.5, PM₁₀, nitrate, OC, and EC on lag 3, which increased the risk of pediatric pneumonia by 18.2% (95% confidence interval (Cl), 8.8-28.4%), 13.1% (95% CI, 5.1-21.7%), 29.7% (95% CI, 16.4-44.5%), 16.8% (95% CI, 4.6-30.4%), and 14.4% (95% Cl, 6.5-22.9%), respectively. After PM_2.5, PM₁₀, and OC were adjusted for, nitrate and EC remained significant in two-pollutant models. Subgroup analyses revealed that nitrate had a greater effect on children during the warm season (April to September, interaction p = 0.035). In conclusion, pediatric pneumonia ED visit was related to PM_2.5 and its constituents. Moreover, PM_2.5 constituents, nitrate and EC, were more closely associated with ED visits for pediatric pneumonia, and children seemed to be more susceptible to nitrate during the warm season.

Repeated exposure to fine particulate matter constituents lead to liver inflammation and proliferative response in mice

BACKGROUND

Fine particulate matter (particulate matter with aerodynamic diameter of ≦2.5 µm, PM2.5) exposure cause adverse health effects, including lung inflammation. Through intra-tracheal instillation of PM2.5 components, the study aimed to evaluate the inflammatory and proliferative effects on mice liver. PM2.5 samples were collected near an industrial complex at southern Taiwan. Mice were exposed to water extracts or insoluble particles by intra-tracheal instillation. Male C57BL/6 mice were divided into five groups: control, low dose insoluble particle exposure (LP), high dose insoluble particle exposure (HP), low dose water extract exposure (LW), and high dose water extract exposure (HW). Biochemical analysis, western blotting, histological examination, and immunohistochemistry were employed to evaluate the results.

RESULT

Enrichment factor (EF) of metallic elements showed that the EFs of trace elements (Ti, V, Ni, Zn, Pb, Cr, and Cu) in PM2.5 were above 10. Hematoxylin and Eosin (H&E) staining of the liver tissue showed inflammatory infiltration in particle exposure group; hepatocyte ballooning degeneration and karyomegaly were seen in the water extract exposure group. Upregulation of inflammatory signaling, p65 and p50, and caspase-3 (an important effector involved in apoptosis) positive hepatocytes was significantly increased in the HP group, followed by an elevation in protein levels of growth arrest and DNA damage-inducible protein 153 (GADD153). Increased protein expression of proliferating cell nuclear antigen (PCNA) was noted in the LW and HW groups. An increase in phosphorylation of regulators of cell proliferation, Akt and extracellular signal-regulated kinase (ERK) 1/2, were detected in the LW and HW groups.

CONCLUSION

The present study shows that the insoluble particle composition of PM2.5 induced inflammatory signaling and cytokines upregulation in the liver, accompanied with inflammatory cell and macrophage infiltration and an abnormal liver function. Exposure of water extract to PM2.5 induced signals of upregulated cellular proliferation, elevated markers of cell proliferation in liver, hepatocyte ballooning degeneration and karyomegaly.

Short-Term Effects of Particulate Matter and Its Constituents on Emergency Room Visits for Chronic Obstructive Pulmonary Disease: A Time-Stratified Case-Crossover Study in an Urban Area

Background: PM_2.5 exposure is associated with pulmonary and airway inflammation, and the health impact might vary by PM_2.5 constitutes. This study evaluated the effects of increased short-term exposure to PM_2.5 constituents on chronic obstructive pulmonary disease (COPD)-related emergency department (ED) visits and determined the susceptible groups. Methods: This retrospective observational study performed in a medical center from 2007 to 2010, and enrolled non-trauma patients aged >20 years who visited the emergency department (ED) and were diagnosed as COPD. Concentrations of PM_2.5, PM₁₀, and the four PM_2.5 components, including organic carbon (OC), elemental carbon (EC), nitrate (NO₃⁻), and sulfate (SO₄²⁻), were collected by three PM supersites in Kaohsiung City. We used an alternative design of the Poisson time series regression models called a time-stratified and case-crossover design to analyze the data. Results: Per interquartile range (IQR) increment in PM_2.5 level on lag 2 were associated with increments of 6.6% (95% confidence interval (CI), 0.5–13.0%) in risk of COPD exacerbation. An IQR increase in elemental carbon (EC) was significantly associated with an increment of 3.0% (95% CI, 0.1–5.9%) in risk of COPD exacerbation on lag 0. Meanwhile, an IQR increase in sulfate, nitrate, and OC levels was not significantly associated with COPD. Patients were more sensitive to the harmful effects of EC on COPD during the warm season (interaction p = 0.019). The risk of COPD exacerbation after exposure to PM_2.5 was higher in individuals who are currently smoking, with malignancy, or during cold season, but the differences did not achieve statistical significance. Conclusion: PM_2.5 and EC may play an important role in COPD events in Kaohsiung, Taiwan. Patients were more susceptible to the adverse effects of EC on COPD on warm days.

Association between prehospital prognostic factors on out-of-hospital cardiac arrest in different age groups

Background

The prognosis of out-of-hospital cardiac arrest (OHCA) is very poor. While several prehospital factors are known to be associated with improved survival, the impact of prehospital factors on different age groups is unclear. The objective of the study was to access the impact of prehospital factors and pre-existing comorbidities on OHCA outcomes in different age groups.

Methods

A retrospective observational analysis was conducted using the emergency medical service (EMS) database from January 2015 to December 2019. We collected information on prehospital factors, underlying diseases, and outcome of OHCAs in different age groups. Kaplan-Meier type survival curves and multivariable logistic regression were used to analyze the association between modifiable pre-hospital factors and outcomes.

Results

A total of 4188 witnessed adult OHCAs were analyzed. For the age group 1 (age ≦75 years old), after adjustment for confounding factors, EMS response time (odds ratio [OR] = 0.860, 95% confidence interval [CI]: 0.811–0.909, p < 0.001), public location (OR = 1.843, 95% CI: 1.179–1.761, p < 0.001), bystander CPR (OR = 1.329, 95% CI: 1.007–1.750, p = 0.045), attendance by an EMT-Paramedic (OR = 1.666, 95% CI: 1.277–2.168, p < 0.001), and prehospital defibrillation by automated external defibrillator (AED)(OR = 1.666, 95% CI: 1.277–2.168, p < 0.001) were prognostic factors for survival to hospital discharge in OHCA patients. For the age group 2 (age > 75 years old), age (OR = 0.924, CI:0.880–0.966, p = 0.001), EMS response time (OR = 0.833, 95% CI: 0.742–0.928, p = 0.001), public location (OR = 4.290, 95% CI: 2.450–7.343, p < 0.001), and attendance by an EMT-Paramedic (OR = 2.702, 95% CI: 1.704–4.279, p < 0.001) were independent prognostic factors for survival to hospital discharge in OHCA patients.

Conclusions

There were variations between younger and older OHCA patients. We found that bystander CPR and prehospital defibrillation by AED were independent prognostic factors for younger OHCA patients but not for the older group.

Pre-hospital Prognostic Factors of Out-of-Hospital Cardiac Arrest: The Difference Between Pediatric and Adult

The prognosis of out-of-hospital cardiac arrest (OHCA) is very poor. Although several pre-hospital factors are associated with survival, the different association of pre-hospital factors with OHCA outcomes in pediatric and adult groups remain unclear. To assess the association of pre-hospital factors with OHCA outcomes among pediatric and adult groups, a retrospective observational study was conducted using the emergency medical service (EMS) database in Kaohsiung from January 2015 to December 2019. Pre-hospital factors, underlying diseases, and OHCA outcomes were collected for the pediatric (Age ≤ 20) and adult groups. Kaplan-Meier type plots and multivariable logistic regression were used to analyze the association between pre-hospital factors and outcomes. In total, 7,461 OHCAs were analyzed. After adjusting for EMS response time, bystander CPR, attended by EMT-P, witness, and pre-hospital defibrillation, we found that age [odds ratio (OR) = 0.877, 95% confidence interval (CI): 0.764-0.990, p = 0.033], public location (OR = 7.681, 95% CI: 1.975-33.428, p = 0.003), and advanced airway management (AAM) (OR = 8.952; 95% CI, 1.414-66.081; p = 0.02) were significantly associated with survival till hospital discharge in pediatric OHCAs. The results of Kaplan-Meier type plots with log-rank test showed a significant difference between the pediatric and adult groups in survival for 2 h (p < 0.001), 24 h (p < 0.001), hospital discharge (p < 0.001), and favorable neurologic outcome (p < 0.001). AAM was associated with improved survival for 2 h (p = 0.015), 24 h (p = 0.023), and neurologic outcome (p = 0.018) only in the pediatric group. There were variations in prognostic factors between pediatric and adult patients with OHCA. The prognosis of the pediatric group was better than that of the adult group. Furthermore, AAM was independently associated with outcomes in pediatric patients, but not in adult patients. Age and public location of OHCA were independently associated with survival till hospital discharge in both pediatric and adult patients.