Association between ambient air pollution and daily hospital admissions for ischemic stroke: A nationwide time-series analysis

Short-term effect of PM2.5 on stroke in susceptible populations: A case-crossover study

BACKGROUND

Fine particulate matter (PM2.5) is a risk factor for stroke, and patients with pre-existing diseases appear to be particularly susceptible. We conducted a case-crossover study to examine the association between short-term exposure to fine particulate matter (PM2.5) and hospital admission for stroke in individuals with atrial fibrillation (AF), hypertension, diabetes, or hyperlipidemia.

METHODS

Patients diagnosed with acute ischemic stroke (AIS) were recruited from 2015 to 2017 in Chinese Stroke Center Alliances. We estimated daily PM2.5 average exposures with a spatial resolution of 0.1° using a data assimilation approach combining satellite measurements, air model simulations, and monitoring values. Conditional logistic regression was used to assess PM2.5-related stroke risk in patients with pre-existing medical co-morbidities.

RESULTS

A total of 155,616 patients diagnosed with AIS were admitted. Patients with a history of AF (n = 15,430), hypertension (n = 138,220), diabetes (n = 43,737), or hyperlipidemia (n = 16,855) were assessed separately. A 10 µg/m³ increase in daily PM2.5 was associated with a significant increase in AIS for individuals with AF at lag 4 (odds ratio (OR), 1.008; 95% confidence interval (CI), 1.002-1.014), and with hypertension (OR, 1.008; 95% CI, 1.006-1.010), diabetes (OR, 1.006; 95% CI, 1.003-1.010), and hyperlipidemia (OR, 1.007; 95% CI, 1.001-1.012) at lags 0-7. Elderly (⩾ 65 years old) and female patients with AF had significantly higher associations at lag 5 (OR, 1.009; 95% CI, 1.002-1.015) and lag 5 (OR, 1.010; 95% CI, 1.002-1.018), respectively.

CONCLUSION

Short-term exposure to PM2.5 is significantly associated with hospital admission for stroke in individuals with pre-existing medical histories, especially in older or female patients with AF. Preventive measures to reduce PM2.5 concentrations are particularly important in individuals with other medical co-morbidities.

Effects of short-term high-concentration exposure to PM2.5 on pulmonary tissue damage and repair ability as well as innate immune events

Short-term heavy air pollution still occurs frequently worldwide, especially during the winter heating period in some developing countries, which is usually accompanied by the temporary explosive growth of PM_2.5. The pulmonary damage caused by PM_2.5 exposure has been determined, but there have been few studies on the repair ability after the cessation of exposure and the important role of innate immune events. This study established a short-term (30 days) high-concentration (15 mg/kg body weight) PM_2.5 exposure and recovery (15 days of exposure cessation) model by intratracheal instillation. The results showed that short-term PM_2.5 exposure increased the content of collagen fiber in rat lung tissue, which was significantly repaired after recovery by 15 days of exposure cessation. Meanwhile, exposure to PM_2.5 also caused changes in lung epithelial function, macrophage polarization and cell autophagy function. Most of these changes could be restored or reversed to a certain extent after recovery. However, there were also some biomarkers, including CLDN18.1, SP-A, SP-D, iNOS, CD206, Beclin1, p62 and LC3B, that were still significantly different between the exposure and control groups after recovery, suggesting that some toxic effects, especially epithelial function damage, were not completely repaired. In addition, there was a significant correlation between pulmonary fibrosis and innate immunity. The present study demonstrated that short-term high-concentration exposure to PM_2.5 could cause temporary lung tissue damage and related innate immune events in rats, and the repair ability existed after the cessation of exposure, but part of the damage that required special attention still persisted.

Stock volatility and hospital admissions for cardiovascular disease: results from the National Insurance Claims for Epidemiological Research (NICER) study

BACKGROUND

The association between stock volatility and cardiovascular diseases (CVD) was described during the 2008 Global Stock Market Crash; however, whether the finding in an occasional stock market crash is spurious remains unclear.

METHODS

A time-series design was used to evaluate the association between short-term exposure to daily returns of two major indices and daily hospital admissions for CVD and its subtypes based on claims data from the National Insurance Claims for Epidemiological Research (NICER) study covering 174 major cities in China. The average percentage change in daily hospital admissions for cause-specific CVD per 1% change in daily index returns was calculated because the Chinese stock market policy limits its change by 10% of the previous day's closing price. A Poisson regression in a generalised additive model was used to assess the city-specific association; then, overall national estimations were pooled by random-effects meta-analysis.

FINDINGS

Totally 8,234,164 hospital admissions for CVD were recorded during 2014-2017. Points of the Shanghai closing indices ranged from 1991·3 to 5166·4. A U-shaped association was observed between daily index returns and CVD admissions. Changes of 1% in daily returns of the Shanghai index corresponded to 1·28%(95%CI: 1·04%-1·53%), 1·25%(0·99%-1·51%), 1·42%(1·13%-1·72%), and 1·14%(0·39%-1·89%) increases in hospital admissions for total CVD, ischaemic heart disease, stroke, or heart failure on the same day, respectively. Similar results were observed for the Shenzhen index.

INTERPRETATION

Stock market volatility is associated with an increased CVD admission.

FUNDING

Chinese Ministry of Science and Technology (2020YFC2003503) and National Natural Science Foundation of China (81973132, 81961128006).

Circulatory health risks from additive multi-pollutant models: short-term exposure to three common air pollutants in Canada

Numerous studies have reported adverse health effects of ambient air pollution on circulatory health outcomes mainly based on single-pollutant models. However, limited studies have focused on adjusted effect of multi-pollutant exposures on public health. This study aimed to examine short-term effects of three common air pollutants-ground-level ozone (ozone), nitrogen dioxide (NO2), and fine particulate matter (PM2.5)-through multi-pollutant models for mixed effect of adjustment. Daily data (circulatory hospitalization and mortality) and hourly data (air pollutants and temperature) were collected for 24 Canadian cities for 2001-2012. We applied generalized additive over-dispersion Poisson regression models with 1, 2, or 3 pollutants for city-specific risks, and Bayesian hierarchical models for national risks. This study found little mixed effect of adjustment through multi-pollutant models (ozone and/or NO2 and/or PM2.5) for circulatory hospitalization or mortality in Canada for 2001-2012, indicating that the 1-pollutant model did not result in considerable under- or over-estimates. It seemed weak-to-moderate correlations among air pollutants did not change the significant effect of one air pollutant after accounting for others. Inconsistent findings between other previous studies and this study indicate the need of comparable study design for multi-pollutant effect analysis.

The association between short-term ambient sulfur dioxide exposure and hospitalization costs of ischemic stroke: a hospital-based study in Chongqing, China

Evidence of the short-term effects of ambient sulfur dioxide (SO₂) exposure on the economic burden of ischemic stroke is limited. This study aimed to explore the association between short-term ambient SO₂ exposure and hospitalization costs for ischemic stroke in Chongqing, the most populous city in China. The hospital-based study included 7271 ischemic stroke inpatients. Multiple linear regression models were used to estimate the association between SO₂ concentration and hospitalization costs. Propensity score matching was used to compare the patients' characteristics when exposed to SO₂ concentrations above and below 20 μg/m³. It is found that short-term SO₂ exposure was positively correlated with the hospitalization costs of ischemic stroke. The association was more evident in males, people younger than 65, and people hospitalized in the cool seasons. Besides, among the components of hospitalization costs, medicine costs were most significantly associated with SO₂. More interesting, the lower concentration of SO₂, the higher costs associated with 1 μg/m³ SO₂ change. Above all, SO₂ was positively associated with hospitalization costs of ischemic stroke, even at its low levels. The measures to reduce the level of SO₂ can help reduce the burden of ischemic stroke.

Associations between short-term exposure to ambient PM2.5 and incident cases of cerebrovascular disease in Yantai, China

There are limited studies examining the association between PM_2.5 exposure and incident cerebrovascular disease (CD) cases in China. In this study, daily counts of incident CD cases and daily PM_2.5 concentrations were obtained in Yantai, Shandong Province, China from 2014 to 2019. We used a combination of the Poisson-distribution generalized linear model (GLM) and a distributed lag nonlinear model (DLNM) to examine the association of short-term exposure to ambient PM_2.5 and incident cases of CD. The results revealed that for every 10 μg/m³ increment of PM_2.5 would increase the incident CD cases by 0.216% (RR:1.00216, 95%CI:1.0016-1.0028) at lag4. The stratified analysis demonstrated that the females and residents aged 65 years or above presented higher short-term PM_2.5-associated CD risks than the males and aged below 65 years. Targeted prevention strategies should be adopted to reduce the PM_2.5-related CD burden, especially for the susceptible population in China.

Ambient temperature variability and hospital admissions for pneumonia: A nationwide study

Few investigations have assessed the impact of short-term ambient temperature change on pneumonia risk. We aimed to study the relation of temperature variability (TV) with daily hospitalizations for pneumonia in China. We conducted a time-series study in 184 major cities by extracting daily hospital data between 2014 and 2017 from a medical insurance claims database of 0.28 billion beneficiaries. TV was calculated as standard deviation of daily minimum and maximum temperatures over exposure days. We estimated associations of pneumonia admissions with TV for each city using over-dispersed generalized linear models controlling for weather conditions and ambient air pollution, and pooled city-specific estimates using random effects meta-analyses. We also investigated exposure-response relationship curve and potential effect modifiers. We identified 4.2 million pneumonia hospitalizations during the study period. TV was positively related to daily pneumonia admissions. At the national-average level, each 1-°C increase in TV at 0-6 days' exposure corresponded to a 0.65 % (95 % CI: 0.34 %-0.96 %) increase in pneumonia admissions. An approximately linear exposure-response curve for the relation of TV with pneumonia admission was noted. The relations were more evident in cities with larger average age (P = 0.038). As the first study in China to assess the impact of temperature change on pneumonia on a national scale, our results indicated that acute TV exposure was related to higher admissions for pneumonia. Our findings should provide new insight into the health impacts associated with climate change.

Ambient particulate matter pollution of different sizes associated with recurrent stroke hospitalization in China: A cohort study of 1.07 million stroke patients

BACKGROUND

To estimate the associations between ambient particulate matter (PM) pollution of different sizes (PM₁, PM_2.5, and PM₁₀) and risk of rehospitalization among stroke patients, as well as the attributable burden in China.

METHODS

We built a cohort of 1,066,752 participants with an index stroke hospitalization in Sichuan, China from 2017 to 2019. Seven-day and annual average exposures to PM pollution prior to the date of the index hospitalization were linked with residential address using a bilinear interpolation approach. Cox proportional hazard models were constructed to assess the association between ambient PM and the risk of rehospitalization. The burden of stroke rehospitalization was estimated using a counterfactual approach.

RESULTS

245,457 (23.0 %) participants experienced rehospitalization during a mean of 1.15 years (SD: 0.90 years) of follow-up. Seven-day average concentrations of PM were associated with increased risk of rehospitalization: the hazard ratios (HRs) per 10 μg/m³ were 1.034 (95 % confidence interval [CI]: 1.029-1.038) for PM₁, 1.033 (1.031-1.036) for PM_2.5, and 1.030 (1.028-1.031) for PM₁₀; the hazard ratios were larger for annual average concentrations: 1.082 (1.074-1.090) for PM₁, 1.109 (1.104-1.114) for PM_2.5, and 1.103 (1.099-1.106) for PM₁₀. The associations were stronger in participants who were female, of minority ethnicity (non-Han Chinese), who suffered from an ischemic stroke, and those admitted under normal conditions. Population attributable fractions for stroke rehospitalization ranged from 4.66 % (95 % CI: 1.69 % to 7.63 %) for the 7-day average of PM₁ to 17.05 % (14.27 % to 19.83 %) for the annual average of PM₁₀; the reducible average cost of rehospitalization per participant attributable to PM ranged from 492.09 (178.19 to 806) RMB for the 7-day average of PM₁ to 1801.65 (1507.89 to 2095.41) RMB for the annual average of PM₁₀.

CONCLUSIONS

Ambient PM pollution may increase the risk of rehospitalization in stroke patients and is responsible for a significant burden of stroke rehospitalization.

Particulate Air Pollution Exposure and Stroke among Adults in Israel

Stroke is the second most common cause of death and disability in the world. Many studies have found fine particulate matter (PM2.5) exposure to be associated with an increased risk of atherosclerotic cardiovascular disease, mostly focusing on ischemic heart disease and acute myocardial infarction. In a national analysis conducted in Israel-an area with unique climate conditions and high air pollution levels, we estimated the association between short-term PM2.5 exposure and ischemic stroke, intracerebral hemorrhage (ICH), or transient ischemic attacks (TIA). Using the Israeli National Stroke Registry, we obtained information on all stroke cases across Israel in 2014-2018. We obtained daily PM2.5 exposures from spatiotemporally resolved exposure models. We restricted the analytical data to days in which PM2.5 levels did not exceed the Israeli 24 h standard (37.5 µg/m3). We repeated the analysis with a stratification by sociodemographic characteristics and comorbidities. For all outcomes, the exposure-response curves were nonlinear. PM2.5 exposure was associated with a higher ischemic stroke risk, with larger effect estimates at higher exposure levels. Although nonsignificant, the exposure-response curve for TIA was similar. The associations with ICH were nonsignificant throughout the PM2.5 exposure distribution. The associations with ischemic stroke/TIA were larger among women, non-Jewish individuals, older adults, and individuals with diabetes, hypertension, and ischemic heart disease. In conclusion, short-term PM2.5 exposure is associated with a higher risk for ischemic stroke and possibly TIA, even when PM2.5 concentrations do not exceed the Israeli air quality guideline threshold. Vulnerability to the air pollution effects differed by age, sex, ethnicity, and comorbidities.

Association between ambient temperature and cardiovascular diseases related hospital admissions in Lanzhou, China

Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality worldwide, ranking first in the global disease burden. Evidence on association between temperature and cardiovascular disease is insufficient and inconsistent in developing countries. In this study, a distributed lag nonlinear model (DLNM) was used to determine the association between daily mean temperature and cardiovascular diseases (CVD) related admission in Lanzhou 2015-2019. We included 41,389 patients with CVD in this study. The relative risk (RR) of CVD admission increased significantly with temperature in lag 5-10 days, and we found harvesting effect of temperature in the study, shown as decreased RR in lag 15-30 days. The maximum RR was 1.15 (95% confidence interval [CI]: 1.03-1.30), corresponding to 24 °C. Both cold and heat effects of temperature could impact the CVD admission. Compared with the 25th percentile of temperature (2 °C), the cumulative relative risk (cumRR) of extreme cold (-5 °C, the 2.5th percentile of the temperature) was 0.69 (95% CI: 0.51-0.94) in lag 0-14, whereas the cumRR of moderate cold (-2 °C, the 10th percentile) was 0.83 (95% CI:0.71-0.97). Compared with the 75th percentile of temperature (20-°C), the cumRR of extreme heat (27 °C, the 97.5th percentile) was 0.93 (95% CI: 0.78-1.10) in lag 0, whereas the cumRR of moderate heat (24 °C, the 90th percentile) was 1.01 (95% CI: 0.94-1.08). In the stratified analysis, cold decreased RR significantly in female and ≥65 years, whereas heat increased it more obviously in male and ≥65 years. Ambient temperature and CVD admissions were positively associated, with the harvesting effect. Our findings demonstrate the adaption of residents in Lanzhou to cold temperature. Public and environmental policies and measures aimed at moderate heat may minimize CVD burden effectively.

Synergism of cell adhesion regulatory genes and instant air pollutants on blood pressure elevation

Accumulating evidence suggests that an instant exposure to particulate matter (PM) may elevate blood pressure (BP), where cell-adhesion regulatory genes may be involved in the interplay. However, few studies to date critically examined their interaction, and it remained unclear whether these genes modified the association. To assess the association between instant PM exposure and BP, and to examine whether single-nucleotide polymorphisms (SNPs) mapped in four cell adhesion regulatory genes modify the relationship, a cross-sectional study was performed, based on the baseline of an ongoing family-based cohort in Beijing, China. A total of 4418 persons from 2089 families in Northern China were included in the analysis. Four tagged SNPs in cell adhesion regulatory genes were selected among ZFHX3, CXCL12, RASGRP1 and MIR146A. A generalized additive model (GAM) with a Gaussian link was adopted to estimate the change in blood pressure after instant PM_2.5 or PM₁₀ exposure. A cross-product term of PM_2.5/PM₁₀ and genotype was incorporated into the GAM model to test for interaction. The study observed that an instant exposure to either PM_2.5 or PM₁₀ was found to be associated with elevated systolic blood pressure (SBP). On average, a 10 μg/m³ increase in instant exposure to PM_2.5 and PM₁₀ concentration corresponded to 0.140% (95% CI: 0.014%-0.265%, P = 0.029) and 0.173% (95% CI: 0.080%-0.266%, P < 0.001) higher SBP. However, diastolic blood pressure (DBP) was not elevated as the PM_2.5 or PM₁₀ concentration increased (P > 0.05). A synergetic interaction on SBP was observed between SNPs in four cell adhesion regulatory genes (rs2910164 in MIR146A, rs2297630 in CXCL12, rs7403531 in RASGRP1, and rs7193343 in ZFHX3) and instant PM_2.5 exposure (P_{for interaction} <0.05). Briefly, as carriers of risk alleles in each of these four genes increased, an enhanced association was found between instant PM_2.5 exposure and SBP.

Quantifying the associations of the air pollutant SO2 on outpatient visits for conjunctivitis in Hangzhou, China

The aim of this study is to further investigate the single and cumulative associations of SO₂ on outpatient visits for conjunctivitis. Data from outpatient visits, air pollutants, and meteorology was collected by the Eye Center of the Second Affiliated Hospital of the Zhejiang University School of Medicine, the Environmental Protection Department of Zhejiang Province, and the Meteorological Administration of Zhejiang Province from July 1, 2014, to November 30, 2019. A Poisson generalized linear regression model (PGLM), combined with a distributed lag nonlinear model (DLNM), was employed to analyze the association between SO₂ and outpatient visits for conjunctivitis using PM_2.5 and NO₂ as covariates. Of the 539,649 outpatients for conjunctivitis recruited for analysis, 58.1% were female. Obvious single associations of SO₂ were observed in outpatient visits for conjunctivitis, which is consistent with our previous results using a time-stratified case crossover design. A delay in the associations of SO₂ on outpatient visits for conjunctivitis was further confirmed, with the longest lag being 12 days. The strongest lag effect was found at lag 0-11 with RR_95th vs _25th = 1.30 (1.24, 1.37), and RR_90h vs _25th = 1.23 (1.18, 1.28). Furthermore, the results showed that old people may be more sensitive to the associations of SO₂ than adults and the younger ones. Our study provides the first evidence that outpatient visits for conjunctivitis are positively associated with both single and cumulative air pollutant SO₂ exposure, suggesting that people especially elders had better to decrease outdoor activities when the SO₂ concentration is above safe level.

Influence of air pollution on influenza-like illness in China: a nationwide time-series analysis

BACKGROUND

Evidence concerning effects of air pollution on influenza-like illness (ILI) from multi-center is limited and little is known about how regional factors might modify this relationship.

METHODS

In this ecological study, ILI cases defined as outpatients with temperature ≥38 °C, accompanied by cough or sore throat, were collected from National Influenza Surveillance Network in China. We adopted generalized additive model with quasi-Poisson to estimate province-specific association between air pollution and ILI in 30 Chinese provinces during 2015-2019, after adjusting for time trend and meteorological factors. We then pooled province-specific association by using random-effect meta-analysis. Potential effect modifications of season and regional characteristics were explored.

FINDINGS

A total of 26, 004, 853 ILI cases and 777, 223, 877 hospital outpatients were collected. In general, effects of air pollutants were acute. An inter-quartile range increase of PM_2.5, SO₂, PM₁₀, NO₂ and CO at lag0, and O₃ at lag0-2 was associated with 3.08% (95% CI: 1.91%, 4.27%), 3.00% (1.86%, 4.16%), 6.46% (4.71%, 8.25%), 7.21% (5.73%, 8.71%), 4.37% (3.05%, 5.70%), and -9.26% (-11.32%, -7.14%) change of ILI at national level, respectively. Associations between air pollutants and ILI varied by season and regions, with higher effect estimates in cold season, eastern and central regions and provinces with more humid condition and larger population.

INTERPRETATION

This study indicated that most air pollutants increased the risk of ILI in China. Our findings might provide implications for the development of policies to protect public health from air pollution and influenza.

FUNDING

National Natural Science Foundation of China and Chongqing Health Commission Program.

Association and interaction of O3 and NO2 with emergency room visits for respiratory diseases in Beijing, China: a time-series study

BACKGROUND

Ozone (O₃) and nitrogen dioxide (NO₂) are the two main gaseous pollutants in the atmosphere that act as oxidants. Their short-term effects and interaction on emergency room visits (ERVs) for respiratory diseases remain unclear.

METHODS

We conducted a time-series study based on 144,326 ERVs for respiratory diseases of Peking University Third Hospital from 2014 to 2019 in Beijing, China. Generalized additive models with quasi-Poisson regression were performed to analyze the association of O₃, NO₂ and their composite indicators (O_x and O_x^wt) with ERVs for respiratory diseases. An interaction model was further performed to evaluate the interaction between O₃ and NO₂.

RESULTS

Exposure to O₃, NO₂, O_x and O_x^wt was positively associated with ERVs for total respiratory diseases and acute upper respiratory infection (AURI). For instance, a 10 μg/m³ increase in O₃ and NO₂ were associated with 0.93% (95%CI: 0.05%, 1.81%) and 5.87% (95%CI: 3.92%, 7.85%) increase in AURI at lag0-5 days, respectively. Significant linear exposure-response relationships were observed in O_x and O_x^wt over the entire concentration range. In stratification analysis, stronger associations were observed in the group aged < 18 years for both O₃ and NO₂, in the warm season for O₃, but in the cold season for NO₂. In interaction analysis, the effect of O₃ on total respiratory emergency room visits and AURI visits was the strongest at high levels (> 75% quantile) of NO₂ in the < 18 years group.

CONCLUSIONS

Short-term exposure to O₃ and NO₂ was positively associated with ERVs for respiratory diseases, particularly in younger people (< 18 years). This study for the first time demonstrated the synergistic effect of O₃ and NO₂ on respiratory ERVs, and O_x and O_x^wt may be potential proxies.

Exposure to ambient air pollutants with kidney function decline in chronic kidney disease patients

Chronic kidney disease (CKD) has been a global public health problem with many adverse outcomes, but data are lacking regarding the relationship between air pollutants and risk of renal progression in patients with CKD. This study was to investigate whether 1-year average exposure to ambient air pollutants -CO, NO, NO₂, SO₂, O₃, PM_2.5, and PM₁₀-is related to renal function deterioration among patients with CKD. A total of 5301 CKD patients were included in this study between October 2008 and February 2016. To estimate each patient's exposure to ambient air pollution, we used the 24-h ambient air pollution concentration monitoring data collected one year prior to renal progression or their last renal function assessment. Renal progression was considered when estimated glomerular filtration rate (eGFR) decreased more than 25% from the baseline eGFR. Cox proportional hazard regression was performed to calculate hazard ratios (HRs). Among 5301 patients with CKD, 1813 (34.20%) developed renal progression during the 30.48 ± 14.99-month follow-up. Patients with the highest quartile exposure to CO [HR = 1.53 (95% CI: 1.24, 1.88)], NO [HR = 1.38 (95% CI: 1.11, 1.71)], NO₂ [HR = 1.63 (95% CI: 1.36, 1.97)], SO₂ [HR = 2.27 (95% CI: 1.83, 2.82)], PM_2.5 [HR = 7.58 (95% CI: 5.97, 9.62)], and PM₁₀ [HR = 3.68 (95% CI: 2.84, 4.78)] had a significantly higher risk of renal progression than those with the lowest quartile exposure. In the multipollutant model, the analyses yielded to similar results. These results reinforce the importance of measures to mitigate air pollution and strategies to prevent worsening of kidney function in patients with CKD. One-year high exposure to ambient CO, NO, NO₂, SO₂, PM_2.5, and PM₁₀ is significantly associated with deteriorated kidney function in patients with CKD among Taiwanese adults.

An integrative analysis of miRNA and mRNA expression in the brains of Alzheimer's disease transgenic mice after real-world PM2.5 exposure

Fine particulate matter (PM_2.5) is associated with increased risks of Alzheimer's disease (AD), yet the toxicological mechanisms of PM_2.5 promoting AD remain unclear. In this study, wild-type and APP/PS1 transgenic mice (AD mice) were exposed to either filtered air (FA) or PM_2.5 for eight weeks with a real-world exposure system in Taiyuan, China (mean PM_2.5 concentration in the cage was 61 µg/m³). We found that PM_2.5 exposure could remarkably aggravate AD mice's ethological and brain ultrastructural damage, along with the elevation of the pro-inflammatory cytokines (IL-6 and TNF-α), Aβ-42 and AChE levels and the decline of ChAT levels in the brains. Based on high-throughput sequencing results, some differentially expressed (DE) mRNAs and DE miRNAs in the brains of AD mice after PM_2.5 exposure were screened. Using RT-qPCR, seven DE miRNAs (mmu-miR-193b-5p, 122b-5p, 466h-3p, 10b-5p, 1895, 384-5p, and 6412) and six genes (Pcdhgb8, Unc13b, Robo3, Prph, Pter, and Tbata) were evidenced the and verified. Two miRNA-target gene pairs (miR-125b-Pcdhgb8 pair and miR-466h-3p-IL-17Rα/TGF-βR2/Aβ-42/AChE pairs) were demonstrated that they were more related to PM_2.5-induced brain injury. Results of Gene Ontology (GO) pathways and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways predicted that synaptic and postsynaptic regulation, axon guidance, Wnt, MAPK, and mTOR pathways might be the possible regulatory mechanisms associated with pathological response. These revealed that PM_2.5-elevated pro-inflammatory cytokine levels and PM_2.5-altered neurotransmitter levels in AD mice could be the important causes of brain damage and proposed the promising miRNA and mRNA biomarkers and potential miRNA-mRNA interaction networks of PM_2.5-promoted AD.

Effect of ambient temperature and other environmental factors on stroke emergency department visits in Beijing: A distributed lag non-linear model

Background

Most studies have focused on the relationship between ambient temperature and stroke mortality, but studies on the relationship between ambient temperature and stroke occurrence are still limited and inconsistent.

Objective

This study aimed to analyze the effect of ambient temperature and other environmental factors on emergency stroke visits in Beijing.

Methods

Our study utilized stroke visit data from the Beijing Red Cross Emergency Medical Center during 2017-2018, and applied a generalized additive model (GAM) as well as a distributed lag non-linear model (DLNM), respectively, regarding the direct, lagged, and cumulative effects of ambient temperature alone and with correction for other environmental factors on stroke occurrence.

Results

With a total of 26,984 emergency stroke patients in 2017-2018, both cold and hot effects were observed and weakened after correction for other environmental factors. Compared to the reference temperature, in the multi-factor model, extreme cold (-10°C) reached a maximum relative risk (RR) of 1.20 [95% Confidence Interval (CI): 1.09, 1.32] at lag 14 days, and extreme hot (30°C) had a maximum RR of 1.07 (95% CI: 1.04, 1.11) at lag 6 days. The cumulative effect of extreme cold reached a maximum of 2.02 (95% CI: 1.11, 3.67) at lag 0-14 days, whereas the cumulative effect of extreme hot temperature is greatest at lag 0-10 days, but no statistically significant effect was found. In addition, ischemic stroke patients, the elderly, and males were more susceptible to the effects of cold temperature.

Conclusions

There is a non-linear relationship between ambient temperature and stroke occurrence, with cold temperature having a greater and longer-lasting impact than hot temperature.

Short-term associations of ambient air pollution with hospital admissions for ischemic stroke in 97 Japanese cities

The short-term association between ambient air pollution and hospital admissions for ischemic stroke is not fully understood. We examined the association between four regularly measured major ambient air pollutants, i.e., sulfur dioxide (SO₂), nitrogen dioxide (NO₂), photochemical oxidants (O_x), and particulate matter with aerodynamic diameters ≤ 2.5 μm (PM_2.5), and hospital admissions for ischemic stroke by analyzing 3 years of nationwide claims data from 97 cities in Japan. We first estimated city-specific results by using generalized additive models with a quasi-Poisson regression, and we obtained the national average by combining city-specific results with the use of random-effect models. We identified a total of 335,248 hospital admissions for ischemic stroke during the 3-year period. Our analysis results demonstrated that interquartile range increases in the following four ambient air pollutants were significantly associated with hospital admissions for ischemic stroke on the same day: SO₂ (1.05 ppb), 1.05% (95% CI: 0.59-1.50%); NO₂ (6.40 ppb), 1.10% (95% CI: 0.61-1.59%); O_x (18.32 ppb), 1.43% (95% CI: 0.81-2.06%); and PM_2.5 (7.86 μg/m³), 0.90% (95% CI: 0.35-1.45%). When the data were stratified by the hospital admittees' medication use, we observed stronger associations with SO₂, NO₂, and PM_2.5 among the patients who were taking antihypertensive drugs and weaker associations with SO₂, NO₂, and O_x among those taking antiplatelet drugs. Short-term exposure to ambient air pollution was associated with increased hospital admissions for ischemic stroke, and medication use and season may modify the association.

Acute exposure to air pollutants increase the risk of acute glaucoma

Background

Ambient air pollution is related to the onset and progression of ocular disease. However, the effect of air pollutants on the acute glaucoma remains unclear.

Objective

To investigate the effect of air pollutants on the incidence of acute glaucoma (acute angle closure glaucoma and glaucomatocyclitic crisis) among adults.

Methods

We conducted a time-stratified case-crossover study based on the data of glaucoma outpatients from January, 2015 to Dec, 2021 in Shanghai, China. A conditional logistic regression model combined with a polynomial distributed lag model was applied for the statistical analysis. Each case serves as its own referent by comparing exposures on the day of the outpatient visit to the exposures on the other 3–4 control days on the same week, month and year. To fully capture the delayed effect of air pollution, we used a maximum lag of 7 days in main model.

Results

A total of 14,385 acute glaucoma outpatients were included in this study. We found exposure to PM_2.5, PM₁₀, nitrogen dioxide (NO₂) and carbon monoxide (CO) significantly increased the odds of outpatient visit for acute glaucoma. Wherein the odds of acute glaucoma related to PM_2.5 and NO₂ were higher and more sustained, with OR of 1.07 (95%CI: 1.03–1.11) and 1.12 (95% CI: 1.08–1.17) for an IQR increase over lag 0–3 days, than PM₁₀ and CO over lag 0–1 days (OR:1.03; 95% CI: 1.01–1.05; OR: 1.04; 95% CI: 1.01–1.07).

Conclusions

This case-crossover study provided first-hand evidence that air pollutants, especially PM_2.5 and NO₂, significantly increased risk of acute glaucoma.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-14078-9.

Airborne fine particulate matter (PM2.5) damages the inner blood-retinal barrier by inducing inflammation and ferroptosis in retinal vascular endothelial cells

This study was the first to explore the effect of airborne fine particulate matter (PM_2.5) exposure on the inner blood-retinal barrier (iBRB). In this study, retinal vascular permeability and diameter were enhanced in the PM_2.5-exposed animal model (1 mg/mL PM_2.5, 10 μL per eye, 4 times per day, 3 days), together with observable retinal edema and increased inflammation level in retina. PM_2.5-induced cell damage in human retinal microvascular endothelial cells (HRMECs) occurred in a time- and dose-dependent manner. Decreased cell viability, proliferation, migration, and angiogenesis, as well as increased apoptosis and inflammation, were observed. Iron overload and excessive lipid oxidation were also discovered after PM_2.5 exposure (25, 50, and 100 μg/mL PM_2.5 for 24 h), along with significantly altered expression of ferroptosis-related genes, such as prostaglandin-endoperoxide synthase 2, glutathione peroxidase 4, and ferritin heavy chain 1. Moreover, Ferrostatin-1, an inhibitor of ferroptosis, evidently alleviated the PM_2.5-induced cytotoxicity of HRMECs. The present study investigated the in vivo effects of PM_2.5 on retinas, revealing that PM_2.5 exposure induced retinal inflammation, vascular dilatation, and caused damage to the iBRB. The crucial role of ferroptosis was discovered during PM_2.5-induced HRMEC cytotoxicity and dysfunction, indicating a potential precautionary target in air pollution-associated retinal vascular diseases.

Length of Stay, Hospital Costs and Mortality Associated With Comorbidity According to the Charlson Comorbidity Index in Immobile Patients After Ischemic Stroke in China: A National Study

BACKGROUND

In this study, we examined the length of stay (LoS)-predictive comorbidities, hospital costs-predictive comorbidities, and mortality-predictive comorbidities in immobile ischemic stroke (IS) patients; second, we used the Charlson Comorbidity Index (CCI) to assess the association between comorbidity and the LoS and hospitalization costs of stroke; third, we assessed the magnitude of excess IS mortality related to comorbidities.

METHODS

Between November 2015 and July 2017, 5114 patients hospitalized for IS in 25 general hospitals from six provinces in eastern, western, and central China were evaluated. LoS was the period from the date of admission to the date of discharge or date of death. Costs were collected from the hospital information system (HIS) after the enrolled patients were discharged or died in hospital. The HIS belongs to the hospital's financial system, which records all the expenses of the patient during the hospital stay. Cause of death was recorded in the HIS for 90 days after admission regardless of whether death occurred before or after discharge. Using the CCI, a comorbidity index was categorized as zero, one, two, and three or more CCI diseases. A generalized linear model with a gamma distribution and a log link was used to assess the association of LoS and hospital costs with the comorbidity index. Kaplan-Meier survival curves was used to examine overall survival rates.

RESULTS

We found that 55.2% of IS patients had a comorbidity. Prevalence of peripheral vascular disease (21.7%) and diabetes without end-organ damage (18.8%) were the major comorbidities. A high CCI=3+ score was an effective predictor of a high risk of longer LoS and death compared with a low CCI score; and CCI=2 score and CCI=3+ score were efficient predictors of a high risk of elevated hospital costs. Specifically, the most notable LoS-specific comorbidities, and cost-specific comorbidities was dementia, while the most notable mortality-specific comorbidities was moderate or severe renal disease.

CONCLUSION

CCI has significant predictive value for clinical outcomes in IS. Due to population aging, the CCI should be used to identify, monitor and manage chronic comorbidities among immobile IS populations.

Modification effects of seasonal and temperature variation on the association between exposure to nitrogen dioxide and ischemic stroke onset in Shenzhen, China

The independent associations of extreme temperature and ambient air pollutant with the admission to hospital and mortality of ischemic stroke have been widely investigated. However, knowledge about the modification effects of variation in season and temperature on the association between exposure to nitrogen dioxide (NO₂) and ischemic stroke onset is still limited. This study purposed to explore the effect of NO₂ on daily ischemic stroke onset modified by season and ambient temperature, and identify the potential population that susceptible to ischemic stroke onset connected with NO₂ and ambient temperature. Data on daily ischemic stroke counts, weather conditions, and ambient air pollutant concentrations in Shenzhen were collected between January 1, 2008, and December 31, 2014. The seasonal effect on the NO₂-associated onset was measured by a distributed-lag linear model. Furthermore, a generalized additive model that incorporated with stratification analyses was used to calculate the interactive effects between NO₂ and ambient temperature. During the winter, the average percentage increase in daily ischemic stroke onset for each 10 μg/m³ increment in NO₂ concentration on lagged 2 days was 3.05% (95% CI: 1.31-4.82%), while there was no statistically significant effect of NO₂ during summer. And the low-temperature days ([Formula: see text] mean temperature), with a 2.23% increase in incidence (95% CI: 1.18-3.29%) for the same concentration increase in NO₂, were significant higher than high temperature days ([Formula: see text] mean temperature). The modification effects of temperature on the study association were more pronounced in individuals aged 65 years or more and in males. The adverse health effects of NO₂ on ischemic stroke are more pronounced during winter or low temperature periods. Elderly adults or males presented higher risks with these exposures.

Association between ambient air pollution and hospital admissions, length of hospital stay and hospital cost for patients with cardiovascular diseases and comorbid diabetes mellitus: Base on 1,969,755 cases in Beijing, China, 2014-2019

BACKGROUND

Evidence on the effects of the air pollutants on the hospital admissions, hospital cost and length of stay (LOS) among patients with comorbidities remains limited in China, particularly for patients with cardiovascular diseases and comorbid diabetes mellitus (CVD-DM).

METHODS

We collected daily data on CVD-DM patients from 242 hospitals in Beijing between 2014 and 2019. Generalized additive model was employed to quantify the associations between admissions, LOS, and hospital cost for CVD-DM patients and air pollutants. We further evaluated the attributable risk posed by air pollutants to CVD-DM patients, using both Chinese and WHO air quality guidelines as reference.

RESULTS

Per 10 ug/m³ increase of particles with an aerodynamic diameter < 2.5 μm (PM_2.5), particles with an aerodynamic diameter < 10 μm (PM₁₀), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), carbonic oxide (CO) and ozone (O₃) corresponded to a 0.64% (95% CI: 0.57 to 0.71), 0.52% (95% CI: 0.46 to 0.57), 0.93% (95% CI: 0.67 to 1.20), 0.98% (95% CI: 0.81 to 1.16), 1.66% (95% CI: 1.18 to 2.14) and 0.53% (95% CI: 0.45 to 0.61) increment for CVD-DM patients' admissions. Among the six pollutants, particulate pollutants (PM_2.5 and PM₁₀) in most lag days exhibited adverse effects on LOS and hospital cost. For every 10 ug/m³ increase in PM_2.5 and PM₁₀, the absolute increase with LOS will increase 62.08 days (95% CI: 28.93 to 95.23) and 51.77 days (95% CI:22.88 to 80.66), respectively. The absolute increase with hospital cost will increase 105.04 Chinese Yuan (CNY) (95% CI: 49.27 to 160.81) and 81.76 CNY (95% CI: 42.01 to 121.51) in PM_2.5 and PM₁₀, respectively. Given WHO 2021 air quality guideline as the reference, PM_2.5 had the maximum attributable fraction of 3.34% (95% CI: 2.94% to 3.75%), corresponding to an avoidable of 65,845 (95% CI: 57,953 to 73,812) patients with CVD-DM.

CONCLUSION

PM_2.5 and PM₁₀ are positively associated with hospital admissions, hospital cost and LOS for patients with CVD-DM. Policy changes to reduce air pollutants exposure may reduce CVD-DM admissions and substantial savings in health care spending and LOS.

Associations between ambient air pollution, meteorology, and daily hospital admissions for ischemic stroke: a time-stratified case-crossover study in Beijing

Air pollution and ischemic stroke (IS) are both vital factors affecting the health of Beijing citizens. This study aims at exploring the associations between air pollution, meteorology, and the hospital admission of IS (IS HA). Information on 476,659 IS inpatients in secondary and higher hospitals in Beijing from 2013 to 2018 were collected. A time-stratified case-crossover design with the generalized additive model and the distributed lag nonlinear model were used. In the single-pollutant models, an inter-quartile range increase in O_3, SO₂, CO, and NO₂ resulted in a significant highest increase in IS HA by 2.23% (95% CI: 1.56%, 2.90%), 1.53% (95% CI: 1.12%, 1.95%), 1.05% (95% CI: 0.70%, 1.40%), and 0.51% (95% CI: 0.24%, 0.79%) on the day of pollution, so did PM_2.5 and PM₁₀ by 1.13% (95% CI: 0.68%, 1.59%) and 1.19% (95% CI: 0.74%, 1.64%) at a lag of 0-5 days. There was a nonlinear relationship between meteorology and IS HA. In the multivariate model, the cumulative relative risks with a maximum lag time of 21 days of PM_2.5 and NO₂ were 1.11 (95% CI: 1.04, 1.19) and 0.88 (95% CI: 0.82, 0.94), while the effects of SO₂, O₃, and meteorology were insignificant. The findings suggested that particulate pollutants could increase the risk of IS, and the elderly were more sensitive to it, while the results of gaseous pollutants are still discordant. The control of air pollution and the protection of susceptible populations should receive higher attention from policymakers.

Fine particulate matter exposure aggravates ischemic injury via NLRP3 inflammasome activation and pyroptosis

Aims

Accumulating evidence has suggested that airborne fine particulate matter (PM2.5) exposure is associated with an increased risk of ischemic stroke. However, the underlying mechanisms have not been fully elucidated. In this study, we aim to investigate the role and mechanisms of NLRP3 inflammasome and pyroptosis in ischemic stroke after PM2.5 exposure.

Methods

The BV‐2 and HMC‐3 microglial cell lines were established and subjected to oxygen–glucose deprivation and reoxygenation (OGD/R) with or without PM2.5 exposure. We used the CCK‐8 assay to explore the effects of PM2.5 on cell viability of BV‐2 and HMC‐3 cells. Then, the effects of PM2.5 exposure on NLRP3 inflammasome and pyroptosis following OGD/R were detected by western blotting, ELISA, and the confocal immunofluorescence staining. Afterwards, NLRP3 was knocked down to further validate the effects of PM2.5 on cell viability, NLRP3 inflammasome activation, and pyroptosis after OGD/R in HMC‐3 cells. Finally, the intracellular reactive oxygen species (ROS) was measured and the ROS inhibitor N‐acetyl‐L‐cysteine (NAC) was used to investigate whether ROS was required for PM2.5‐induced NLRP3 inflammasome activation and pyroptosis under ischemic conditions.

Results

We found that PM2.5 exposure decreased the viability of BV‐2 and HMC‐3 cells in a dose‐ and time‐dependent manner under ischemic conditions. Furthermore, PM2.5 exposure aggravated NLRP3 inflammasome activation and pyroptosis after OGD/R, as indicated by an increased expression of NLRP3, ASC, pro‐caspase‐1, Caspase‐1, GSDMD, and GSDMD‐N; increased production of IL‐1β and IL‐18; and enhanced Caspase‐1 activity and SYTOX green uptake. However, shRNA NLRP3 treatment attenuated the effects of PM2.5 on cell viability, NLRP3 inflammasome activation, and pyroptosis. Moreover, we observed that PM2.5 exposure increased the production of intracellular ROS following OGD/R, while inhibiting ROS production with NAC partially attenuated PM2.5‐induced NLRP3 inflammasome activation and pyroptosis under ischemic conditions.

Conclusion

These results suggested that PM2.5 exposure triggered the activation of NLRP3 inflammasome and pyroptosis under ischemic conditions, which may be mediated by increased ROS production after ischemic stroke. These findings may provide a more enhanced understanding of the interplay between PM2.5 and neuroinflammation and cell death, and reveal a novel mechanism of PM2.5‐mediated toxic effects after ischemic stroke.

Ambient particulate air pollution, blood cell parameters, and effect modification by psychosocial stress: Findings from two studies in three major Chinese cities

The associations between particulate matter (PM) exposure, psychosocial stress and blood cell parameters are bringing novel insights to characterize the early damage of multiple diseases. Based on two studies conducted in three Chinses cities using cross-sectional (Beijing, 425 participants) and panel study (Tianjin and Shanghai, 92 participants with 361 repeated measurements) designs, this study explored the associations between short-term exposure to ambient PM and blood cell parameters, and the effect modification by psychosocial stress. Increasing PM_2.5 exposure was significantly associated with decreases in red blood cell (RBC) count and mean corpuscular hemoglobin concentration (MCHC), and increases in mean corpuscular volume (MCV), platelets count (PLT) and platelet hematocrit (PCT) in both studies. For instance, a 10 μg/m³ increment in PM_2.5 concentration was associated with a 1.04% (95%CI: 0.16%, 1.92%) increase in PLT (4-d) and a 1.09% (95%CI: 0.31%, 1.87%) increase in PCT (4-d) in the cross-sectional study, and a 0.64% (95%CI: 0.06%, 1.22%) increase in PLT (1-d) and a 0.72% (95%CI: 0.33%, 1.11%) increase in PCT (1-d) in the panel study, respectively. In addition, stronger increases in MCV, PLT, and PCT associated with PM_2.5 exposure were found in higher psychosocial stress group compared to lower psychosocial stress group (p for interaction <0.10), indicating that blood cell parameters of individuals with higher psychosocial stress might be more susceptible to the early damages of PM_2.5 exposure.

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.

Air Pollution and Its Devastating Effects on the Central Nervous System

Air pollution is a real public health problem, it being one of the five most common causes of mortality in developing countries. However, pollution studies have focused on the cardiovascular and pulmonary systems in recent decades. Recently, researchers have moved towards a new direction, tracing a direct link between pollution and stroke. Stroke has many known risk factors such as smoking, a sedentary lifestyle, and hypertension. Pollution is universally widespread, already a matter of public interest, so that, although intuitive, it is difficult to connect the two. The particles found in the air that we breathe, regardless of their origin, can attack the body in different ways, causing inflammation, and triggering a true cascade of phenomena that end up attacking the central nervous system and other organs. This article tries to explain the series of phenomena that determine the harmful effect of particles present in the air, with an increased focus on the central nervous system and especially on strokes. A deeper understanding of these phenomena helps in guiding future studies and finding viable solutions to protect people at risk.

Association of Ambient Particulate Matter Pollution of Different Sizes With In-Hospital Case Fatality Among Stroke Patients in China

BACKGROUND AND OBJECTIVES

To characterize the association of ambient particulate matter (PM) pollution of different sizes (PM ≤1 µm in aerodynamic diameter [PM1], PM2.5, and PM10) with in-hospital case fatality among patients with stroke in China.

METHODS

We collected hospitalizations due to stroke in 4 provinces in China from 2013 to 2019. Seven-day and annual averages of PM prior to hospitalization were estimated using bilinear interpolation and residential addresses. Associations with in-hospital case fatality were estimated using random-effects logistic regression models. Potential reducible fraction and the number of fatalities attributed to PM were estimated using a counterfactual approach.

RESULTS

Among 3,109,634 stroke hospitalizations (mean age 67.23 years [SD 12.22]; 1,765,644 [56.78%] male), we identified 32,140 in-hospital stroke fatalities (case fatality rate 1.03%). Each 10 µg/m3 increase in 7-day average (short-term) exposure to PM was associated with increased in-hospital case fatality: odds ratios (ORs) were 1.058 (95% CI 1.047-1.068) for PM1, 1.037 (95% CI 1.031-1.043) for PM2.5, and 1.025 (95% CI 1.021-1.029) for PM10. Similar but larger ORs were observed for annual averages (long-term): 1.240 (95% CI 1.217-1.265) for PM1, 1.105 (95% CI 1.094-1.116) for PM2.5, and 1.090 (95% CI 1.082-1.099) for PM10. In counterfactual analyses, PM10 was associated with the largest potential reducible fraction in in-hospital case fatality (10% [95% CI 8.3-11.7] for short-term exposure and 21.1% [19.1%-23%] for long-term exposure), followed by PM1 and PM2.5.

DISCUSSION

PM pollution is a risk factor for in-hospital stroke-related deaths. Strategies that target reducing PM pollution may improve the health outcomes of patients with stroke.

Acute effect of air pollutants' peak-hour concentrations on ischemic stroke hospital admissions among hypertension patients in Beijing, China, from 2014 to 2018

Air pollutants' effect on ischemic stroke (IS) has been widely reported. But the effect of high-level concentrations during people's outdoor periods among hypertension patients was unknown. Peak-hour concentrations were defined considering air pollutants' high concentrations as well as people's outdoor periods. We conducted a time-series study and used the generalized additive model to analyze peak-hour concentrations' acute effect. A total of 315,499 IS patients comorbid with hypertension were admitted to secondary and above hospitals in Beijing from 2014 to 2018. A 10 µg/m³ (CO: 1 mg/m³) increase of the peak-hour concentrations was positively associated with IS hospital admissions among hypertension patients. The maximum effect sizes were as follows: for PM_2.5, 0.17% (95% confidence interval [CI]: 0.10-0.24%) at Lag0 and 0.22% (95% CI: 0.12-0.33%) at Lag0-5; for PM₁₀, 0.09% (95% CI: 0.05-0.13%) at Lag5 and 0.17% (95% CI: 0.09-0.26%) at Lag0-5; for SO₂, 0.87% (95% CI: 0.46-1.29%) at Lag5; for NO₂, 0.83% (95% CI: 0.62-1.04%) at Lag0 and 0.86% (95% CI: 0.59-1.13%) at Lag0-1; for CO 1.23% (95% CI: 0.66-1.80%) at Lag0 and 1.33% (95% CI: 0.33-2.35%) at Lag0-5; for O₃ 0.23% (95% CI: 0.12-0.35%) at Lag0 and 0.20% (95% CI: 0.05-0.34%) at Lag0-1. The effect sizes of PM_2.5, NO₂, and O₃ remained significant after adjusting daily mean. Larger effect sizes were observed for PM_2.5 and PM₁₀ in cool season and for O₃ in warm season. As significant exposure indicators of air pollution, peak-hour concentrations exposure increased the risk of IS hospital admissions among hypertension patients and it is worthy of consideration in relative environmental standard. It is suggested for hypertension patients to avoid outdoor activity during peak hours. More relevant searches are required to further illustrate air pollutant's effect on chronic disease population.

Comparison of metropolitan cities for mortality rates attributed to ambient air pollution using the AirQ model

In the present study, the air pollution dynamics of the metropolitan cities of Balıkesir, Bursa, Istanbul, Kocaeli, Sakarya and Tekirdağ in the Marmara Region, which is the geographical region with the highest urban and industrial activity in Turkey, were examined for the time period between 2016 and 2019. Annual changes in the cities in terms of air pollution, which was examined with a focus on the PM_2.5 parameter as indicated by United Nations (UN) Sustainable Development Goals (SDGs); differences in the cities by years; and the seasonal changes in air pollution in the cities were investigated. Additionally, mortality rates attributed to air pollution were calculated with the AirQ + software based on integrated exposure-response function recommended by the World Health Organization (WHO) and the UN using city-scale statistics of fatal disease cases that can be attributed to air pollution. It was determined that all cities in the Marmara Region study area exceeded the limit PM_2.5 values specified by the European Union (EU) in the years 2016, 2017 and 2018 while only Kocaeli and Tekirdağ were below the limit values in 2019. The limit values specified by the WHO were exceeded in all cities in each year. A total of 46,920 premature deaths attributed to the exceedance of WHO limit values were calculated for the years 2016, 2017, 2018 and 2019 with 11,895, 13,853, 11,748 and 9,429, respectively. Determining national limit values for the PM_2.5 parameter, which is among the most important factors of air pollution, and monitoring it in a sustainable manner using a sufficient number of well-equipped stations is of great importance. This way, national, regional and urban action plans regarding the impact of air pollution on human health, as indicated by UN SDGs, can be prepared.

Short-Term Effects of Low-Level Ambient Air NO2 on the Risk of Incident Stroke in Enshi City, China

Previous studies found that exposure to ambient nitrogen dioxide (NO₂) was associated with an increased risk of incident stroke, but few studies have been conducted for relatively low NO₂ pollution areas. In this study, the short-term effects of NO₂ on the risk of incident stroke in a relatively low-pollution area, Enshi city of Hubei Province, China, were investigated through time-series analysis. Daily air-pollution data, meteorological data, and stroke incidence data of residents in Enshi city from 1 January 2015 to 31 December 2018 were collected. A time-series analysis using a generalised additive model (GAM) based on Poisson distribution was applied to explore the short-term effects of low-level NO₂ exposure on the risk of incident stroke and stroke subtypes, as well as possible age, sex, and seasonal differences behind the effects. In the GAM model, potential confounding factors, such as public holidays, day of the week, long-term trends, and meteorological factors (temperature and relative humidity), were controlled. A total of 9122 stroke incident cases were included during the study period. We found that NO₂ had statistically significant effects on the incidence of stroke and ischemic stroke, estimated by excess risk (ER) of 0.37% (95% CI: 0.04–0.70%) and 0.58% (95% CI: 0.18–0.98%), respectively. For the cumulative lag effects, the NO₂ still had a statistically significant effect on incident ischemic stroke, estimated by ER of 0.61% (95% CI: 0.01–1.21%). The two-pollutant model showed that the effects of NO₂ on incident total stroke were still statistically significant after adjusting for other air pollutants (PM_2.5, PM₁₀, SO₂, CO, and O₃). In addition, the effects of NO₂ exposure on incident stroke were statistically significant in elderly (ER = 0.75%; 95% CI: 0.11–1.40%), males (ER = 0.47%; 95% CI: 0.05–0.89%) and cold season (ER = 0.83%; 95% CI: 0.15–1.51%) subgroups. Our study showed that, as commonly observed in high-pollution areas, short-term exposure to low-level NO₂ was associated with an increased risk of incident stroke, including ischemic stroke. Males and elderly people were more vulnerable to the effects of NO₂, and the adverse effects might be promoted in the cold season.

Association of PM2.5 and PM10 with Acute Exacerbation of Chronic Obstructive Pulmonary Disease at lag0 to lag7: A Systematic Review and Meta-Analysis

This study aimed to conduct a meta-analysis to investigate whether short-term exposure to fine (PM_2.5) and coarse (PM₁₀) particulate matter was associated with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) hospitalization, emergency room visit, and outpatient visit at different lag values. PubMed, Embase, and the Cochrane Library were searched for relevant papers published up to March 2021. For studies reporting results per 1-µg/m³ increase in PM_2.5, the results were recalculated as per 10-µg/m³ increase. We manually calculated the RRs for these two studies and transferred the RRs to estimate 10 µg/m³ increases in PM_2.5. Automation tools were initially used to remove ineligible studies. Two reviewers independently screened the remaining records and retrieved reports. Twenty-six studies (28 datasets; 7,018,419 patients) were included. There was a significant association between PM_2.5 and AECOPD events on lag0 (ES = 1.01, 95%CI: 1.01-1.02, p < 0.001; I²=88.6%, P_{heterogeneity}<0.001), lag1 (ES = 1.00, 95%CI: 1.00-1.01, p < 0.001; I²=82.5%, P_{heterogeneity}<0.001), lag2 (ES = 1.01, 95%CI: 1.01-1.01, p < 0.001; I²=90.6%, P_{heterogeneity}<0.001), lag3 (ES = 1.01, 95%CI: 1.00-1.01, p < 0.001; I²=88.9%, P_{heterogeneity}<0.001), lag4 (ES = 1.00, 95%CI: 1.00-1.01, p < 0.001; I²=83.7%, P_{heterogeneity}<0.001), and lag7 (ES = 1.00, 95%CI: 1.00-1.00, p < 0.001; I²=0.0%, P_{heterogeneity}=0.743). The subgroup analyses showed that PM_2.5 influenced the rates of hospitalization, emergency room visits, and outpatient visits. Similar trends were observed with PM₁₀. The risk of AECOPD events (hospitalization, emergency room visit, and outpatient visit) was significantly increased with a 10-µg/m³ increment in PM_2.5 and PM₁₀ from lag0 to lag7.List Of Abbreviations: particulate matter (PM_2.5 and PM₁₀); acute exacerbation of chronic obstructive pulmonary disease (AECOPD); Chronic obstructive pulmonary disease (COPD); Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA); Effect sizes [48]; confidence intervals (CIs).

Effects of the COVID-19 Lockdown on Air Pollutant Levels and Associated Reductions in Ischemic Stroke Incidence in Shandong Province, China

Background

Local governments in China took restrictive measures after the outbreak of COVID-19 to control its spread, which unintentionally resulted in reduced anthropogenic emission sources of air pollutants. In this study, we intended to examine the effects of the COVID-19 lockdown policy on the concentration levels of particulate matter with aerodynamic diameters of ≤1 μm (PM₁), ≤2.5 μm (PM_2.5), and ≤10 μm (PM₁₀), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), ozone (O₃), and carbon monoxide (CO) and the potential subsequent reductions in the incidence of ischemic and hemorrhagic stroke in Shandong Province, China.

Methods

A difference-in-difference model combining the daily incidence data for ischemic and hemorrhagic stroke and air pollutant data in 126 counties was used to estimate the effect of the COVID-19 lockdown on the air pollutant levels and ischemic and hemorrhagic stroke incident counts. The avoided ischemic stroke cases related to the changes in air pollutant exposure levels were further estimated using concentration-response functions from previous studies.

Results

The PM₁, PM_2.5, PM₁₀, NO₂, and CO levels significantly decreased by −30.2, −20.9, −13.5, −46.3, and −13.1%, respectively. The O₃ level increased by 11.5% during the lockdown compared with that in the counterfactual lockdown phase of the past 2 years. There was a significant reduction in population-weighted ischemic stroke cases (−15,315, 95% confidence interval [CI]: −27,689, −2,942), representing a reduction of 27.6% (95% CI: −49.9%, −5.3%). The change in the number of hemorrhagic stroke cases was not statistically significant. The total avoided PM₁-, PM_2.5-, PM₁₀-, NO₂-, and CO–related ischemic stroke cases were 739 (95% CI: 641, 833), 509 (95% CI: 440, 575), 355 (95% CI: 304, 405), 1,132 (95% CI: 1,024, 1,240), and 289 (95% CI: 236, 340), respectively.

Conclusion

The COVID-19 lockdown indirectly reduced the concentration levels of PM₁, PM_2.5, PM₁₀, NO₂, and CO and subsequently reduced the associated ischemic stroke incidence. The health benefits due to the lockdown are temporary, and long-term measures should be implemented to increase air quality and related health benefits in the post-COVID-19 period.

Short term exposure to ambient air pollutants and cardiovascular emergency department visits in Mexico city

Available data on the acute cardiovascular effect of ambient air pollution (AAP) in Latin America is limited considering that over 80% of its 1 billion inhabitants live in urban settlements with poor air quality. The study aim was to evaluate the association between Cardiovascular Emergency Department Visits (CEDVs) and AAP in Mexico City from 2016 to 2019 using generalized additive models with distributed lags to examine the percentage change of CEDVs and a backward approach of time-series model to calculate attributable fractions. A total of 48,891 CEDVs were recorded in a period of 1019 days. We estimated a significant percentage increase for each 10 μg/m³ of PM₁₀ at Lag0-5 (2.8%, 95%CI 0.6-5.0), PM_2.5 at Lag0-6 (3.7%, 95%CI 0.1-7.6), O₃ at Lag0-5 (1.1%, 95%CI 0.2-2.0), NO₂ at Lag0-4 (2.5%, 95%CI 0.3-4.7) and for each 1 mg/m³ of CO at Lag0 (6.6%, 95%CI 0.3-13.2). Overall, 10.3% of CEDVs in Mexico City may be related to PM¹⁰ exposure, 9.5% to PM_2.5, 10.3% to O₃, 11% to NO₂ and 5.7% to CO. AAP significantly increase cardiovascular morbidity impacting on emergency medical services.

The association between ozone and ischemic stroke morbidity among patients with type 2 diabetes in Beijing, China

BACKGROUND

The association between ozone and ischemic stroke has been widely reported; however, the association among patients with type 2 diabetes (T2D) has remained largely unknown.

METHODS

The time series data of daily morbidity and concentrations of ozone from 2014 to 2018 were collected in Beijing, China. A time-stratified case-crossover study combined with a distributed lag nonlinear model was used to estimate the ozone effect on stroke morbidity among T2D patients. Based on principal diagnosis, ischemic stroke cases were identified according to the International Classification of Diseases (I63), and a history of T2D was coded as E12.

RESULTS

A total of 149,757 hospital admissions for ischemic stroke among T2D patients were recorded in Beijing. Approximately U-shaped exposure-response curves were observed for ozone and ischemic stroke morbidity among T2D patients. With a reference at 54.91 μg/m³, extreme-low (5th: 9.59 μg/m³) ozone was significantly associated with a decreased risk for ischemic stroke [RR = 0.88, 95% confidence interval (CI): 0.80-0.98]. Subgroup analysis showed that extremely low-ozone (5th) level only had a significant protective effect in males and elderly population, with a RR value of 0.86 (95% CI: 0.76-0.97) and 0.85 (95% CI: 0.75-0.96), respectively. Extreme-high ozone (99th: 157.06 μg/m³) was significantly associated with an increased risk for ischemic stroke (RR = 1.33, 95% CI: 1.12-1.57). The effect size was 1.34 (95% CI: 1.10-1.63) for males and 1.32 (95% CI: 1.07-1.63) for females, and the difference was not significant (Z = -0.29, P = 0.77). The effect size in younger adults was significantly higher than that in participants aged ≥65 years [1.52 (95% CI: 1.21-1.91) vs. 1.22 (95% CI: 1.01-1.47), Z = -1.62, P < 0.05].

CONCLUSIONS

U-shaped associations were observed between ozone and ischemic stroke morbidity in T2D patients. Men and elderly population are vulnerable to low-ozone level, and the younger adults are more susceptible to extremely high-ozone level than the elderly.

Short-term exposure to ambient air pollution and risk of daily hospital admissions for anxiety in China: A multicity study

The potential impact of short-term exposure to ambient air pollution on risk of anxiety remains uncertain. We performed a detailed evaluation based on data from national insurance databases in China. Daily hospital admissions for anxiety disorders were identified in 2013-2017 from the national insurance databases covering up to 261 million urban residents in 56 cities in China. A two-stage time-series study was conducted to evaluate the associations between short-term exposure to major ambient air pollutants, including fine particles, inhalable particles, nitrogen dioxide (NO₂), sulfur dioxide (SO₂), ozone, and carbon monoxide, and risk of daily hospital admissions for anxiety. Significant associations between short-term exposures to ambient NO₂ and SO₂ and risk of daily hospital admissions for anxiety were found in the overall analysis. Per 10 μg/m³ increases in NO₂ at lag0 and SO₂ at lag6 were associated with significant increases of 1.37% (95% CI: 0.14%, 2.62%) and 1.53% (95% CI: 0.59%, 2.48%) in anxiety admissions, respectively. Stronger associations were found in the southern region and patients <65 years for SO₂. Short-term exposure to ambient air pollution is associated with increased risk of anxiety admissions, which may provide important implications for promotion of mental health in the public.

Impact of Long-Term Exposure to Air Pollution on Cognitive Decline in Older Adults Without Dementia

Background: Air pollution control is necessary to decrease the burden on older adults with cognitive impairment, especially in low- and middle-income countries (LMICs). Objective: This study retrospectively examined the effect of cumulative exposure to air pollution, including NO2, SO2, CO, fine particulate matter (PM)10, PM2.5, and O3, on cognitive function in older individuals. Methods: Community-dwelling older adults who underwent the Mini-Mental State Examination (MMSE) from 2007 to 2018 were included in the analyses. We excluded older individuals diagnosed with dementia at baseline, while those who had completed more than two MMSE tests were included in the longitudinal analyses. Baseline MMSE and changes in MMSE scores were analyzed according to 5-year average concentrations of the district-level air pollutants, after controlling for covariates associated with cognitive decline in older adults. Results: In total, 884,053 (74.3±7.1 years; 64.1% females) and 398,889 (72.3±6.4 years; 67.0% females) older individuals were included in the cross-sectional and longitudinal analyses, respectively. Older individuals exposed to higher levels of NO2, SO2, CO, and PM10 showed lower baseline MMSE scores. During follow-up, exposure to higher levels of NO2, SO2, CO, and PM10 was associated with greater decreases in MMSE scores in older individuals; for O3, the opposite pattern was observed. Conclusion: Our findings suggest that exposure to high levels of air pollutants can worsen the cognitive performance of older adults without dementia. Efforts to reduce air pollution in LMICs that have similar levels of pollutants to South Korea are necessary to reduce the burden on older adults with cognitive impairment.

The short-term effects and burden of particle air pollution on hospitalization for coronary heart disease: a time-stratified case-crossover study in Sichuan, China

BACKGROUND

Coronary heart disease (CHD), the leading cause of death globally, might be developed or exacerbated by air pollution, resulting high burden to patients. To date, limited studies have estimated the relations between short-term exposure to air pollution and CHD disease burden in China, with inconsistent results. Hence, we aimed to estimate the short-term impact and burden of ambient PM pollutants on hospitalizations of CHD and specific CHD.

METHODS

PM10 and PM2.5 were measured at 82 monitoring stations in 9 cities in Sichuan Province, China during 2017-2018. Based on the time-stratified case-crossover design, the effects of short-term exposure to particle matter (PM) pollution on coronary heart disease (CHD) hospital admissions were estimated. Meanwhile, the linked burden of CHD owing to ambient PM pollution were estimated.

RESULTS

A total of 104,779 CHD records were derived from 153 hospitals from these 9 cities. There were significant effects of PM pollution on hospital admissions (HAs) for CHD and specific CHD in Sichuan Province. A 10 μg/m3 increase of PM10 and PM2.5 was linked with a 0.46% (95% CI: 0.08, 0.84%), and 0.57% (95% CI: 0.05, 1.09%) increments in HAs for CHD at lag7, respectively. The health effects of air pollutants were comparable modified by age, season and gender, showing old (≥ 65 years) and in cold season being more vulnerable to the effects of ambient air pollution, while gender-specific effects is positive but not conclusive. Involving the WHO's air quality guidelines as the reference, 1784 and 2847 total cases of HAs for CHD could be attributable to PM10 and PM2.5, separately. The total medical cost that could be attributable to exceeding PM10 and PM2.5 were 42.04 and 67.25 million CNY from 2017 to 2018, respectively.

CONCLUSIONS

This study suggested that the short-term exposure to air pollutants were associated with increased HAs for CHD in Sichuan Province, which could be implications for local environment improvement and policy reference.

Ambient Air Pollution and Hospitalizations for Ischemic Stroke: A Time Series Analysis Using a Distributed Lag Nonlinear Model in Chongqing, China

Short-term exposure to air pollution has been associated with ischemic stroke (IS) hospitalizations, but the evidence of its effects on IS in low- and middle-income countries is limited and inconsistent. We aimed to quantitatively estimate the association between air pollution and hospitalizations for IS in Chongqing, China. This time series study included 2,299 inpatients with IS from three hospitals in Chongqing from January 2015 to December 2016. Generalized linear regression models combined with a distributed lag nonlinear model (DLNM) were used to investigate the impact of air pollution on IS hospitalizations. Stratification analysis was further implemented by sex, age, and season. The maximum lag-specific and cumulative percentage changes of IS were 1.2% (95% CI: 0.4–2.1%, lag 3 day) and 3.6% (95% CI: 0.5–6.7%, lag 05 day) for each 10 μg/m³ increase in PM_2.5; 1.0% (95% CI: 0.3–1.7%, lag 3 day) and 2.9% (95% CI: 0.6–5.2%, lag 05 day) for each 10 μg/m³ increase in PM₁₀; 4.8% (95% CI: 0.1–9.7%, lag 4 day) for each 10 μg/m³ increase in SO₂; 2.5% (95% CI: 0.3–4.7%, lag 3 day) and 8.2% (95% CI: 0.9–16.0%, lag 05 day) for each 10 μg/m3 increase in NO₂; 0.7% (95% CI: 0.0–1.5%, lag 6 day) for each 10 μg/m³ increase in O₃. No effect modifications were detected for sex, age, and season. Our findings suggest that short-term exposure to PM_2.5, PM₁₀, SO₂, NO₂, and O₃ contributes to more IS hospitalizations, which warrant the government to take effective actions in addressing air pollution issues.

Association of short-term exposure to air pollution with recurrent ischemic cerebrovascular events in older adults

The acute effects of ambient air pollution on recurrence of ischemic cerebrovascular events (ICEs) remains largely unknown. We therefore conducted a time-stratified case-crossover study of 43,896 patients who were 60 years or older and were admitted to hospital for recurrent ICEs including ischemic stroke and transient ischemic attack in Guangzhou, China during 2016-2019. Based on each patient's home address and pollutant data from its neighboring air quality monitoring stations, we used an inverse distance weighting method to assess exposures to particulate matter with an aerodynamic diameter ≤2.5 μm (PM_2.5), particulate matter with an aerodynamic diameter ≤10 μm (PM₁₀), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), carbon monoxide (CO) and ozone (O₃). Conditional logistic regression models were used to quantify exposure-response associations. During the study period, there were 43,896 case days and 149,131 control days. In single-pollutant models, each 10 μg/m³ increase in exposure to PM₁₀, NO₂ and CO (mean exposure on date of admission and 1 day prior) was significantly associated with a 0.74% (95% confidence interval [CI]: 0.13-1.36%), 2.15% (1.38-2.93%) and 0.14% (0.07-0.21%) increase in odds of hospital admissions for recurrent ICEs, respectively, and no significant departures from linearity were detected. The association for NO₂ exposure remained consistent in 2-pollutant models, while the associations for PM₁₀ and CO disappeared or changed materially with adjustment for other pollutants. Stronger association for NO₂ exposure was observed in cool season than that in warm season. We found that short-term exposure to ambient air pollutants, especially NO₂, was associated with increased risk of hospital admissions for recurrent ICEs in older adults.

Association of air pollution with acute ischemic stroke risk in Singapore: a time-stratified case-crossover study

Background:

Air quality is an important determinant of cardiovascular health such as ischemic heart disease and acute ischemic stroke (AIS) with substantial mortality and morbidity reported across the globe. However, associations between air quality and AIS in the current literature remain inconsistent, with few studies undertaken in cosmopolitan cities located in the tropics.

Objectives:

We evaluated the associations between individual ambient air pollutants and AIS.

Methods:

We performed a nationwide, population-based, time-stratified case-crossover analysis on all AIS cases reported to the Singapore Stroke Registry from 2009 to 2018. We estimated the incidence rate ratio (IRR) of AIS across different concentrations of each pollutant by quartiles (referencing the 25th percentile), in single-pollutant conditional Poisson models adjusted for time-varying meteorological effects. We stratified our analysis by predetermined subgroups deemed at higher risk.

Results:

A total of 51,675 episodes of AIS were included. Ozone (O3) (IRR4th quartile: 1.05, 95% confidence interval (CI): 1.01–1.08) and carbon monoxide (CO) (IRR2nd quartile: 1.05, 95% CI: 1.02–1.08, IRR3rd quartile: 1.07, 95% CI: 1.04–1.10, IRR4th quartile: 1.07, 95% CI: 1.04–1.11) were positively associated with AIS incidence. The increased incidence of AIS due to O3 and CO persisted for 5 days after exposure. Those under 65 years of age were more likely to experience AIS when exposed to CO. Individuals with atrial fibrillation (AF) were more susceptible to exposure from O3, CO, and PM10. Current/ex-smokers were more vulnerable to the effect of O3.

Conclusion:

Air pollution increases the incidence of AIS, especially in those with AF and in those who are current or ex-smokers.

PM2.5-associated risk for cardiovascular hospital admission and related economic burdens in Beijing, China

BACKGROUND

The study of ambient air particulate matter (PM_2.5)-associated health and economic burdens of cardiovascular disease are crucial for air pollution control and disease prevention strategies. Quantified evidence remains inadequate.

OBJECTIVES

This study aimed to estimate the PM_2.5 associated risk in cardiovascular hospital admission as well as attributable health burdens and economic costs.

METHODS

A total of 2,202,244 hospital admission records of cardiovascular disease and six common clinical subtypes in Beijing were included. A time-stratified case-crossover design was applied to estimate the associations and the concentration-response curve. Then, the annual average additional hospital admissions, days of hospital stay, and hospital expenditures were evaluated from 2013 to 2017 and compared between 2017 and 2013.

RESULTS

The results showed that each 10 μg/m³ increase in previous-day PM_2.5 concentration was associated with a risk increase of 0.44% (95%CI: 0.40%, 0.47%) for cardiovascular disease, 0.66% (95%CI: 0.58%, 0.73%) for angina pectoris, 0.53% (95%CI: 0.39%, 0.66%) for chronic ischemic heart disease, 0.48% (95%CI: 0.34%, 0.63%) for myocardial infarction, 0.44% (95%CI: 0.29%, 0.60%) for hypertensive heart disease and 0.40% (95%CI: 0.27%, 0.52%) for ischemic stroke. There were 1938 PM_2.5 attributed additional hospital admissions, resulting in 21,668 additional days in hospital, along with 5527.12 and 1947.04 ten-thousand of additional total hospital cost and self-afforded cost, respectively. Compared with 2013, the above-mentioned four burdens decreased by 18.17%, 28.80%, 18.90% and 13.72% in 2017, respectively.

CONCLUSION

PM_2.5 exposure was significantly associated with substantial burdens of cardiovascular hospital admission and economic expenditures. The results highlight the necessity of continuous PM_2.5 control from the perspective of healthy and sustainable city development in urban China.

Association Between the Ambient Fine Particulate Pollution and the Daily Internal Medicine Outpatient Visits in Zhoushan, China: A Time-Series Study

Background: There has been a recent worsening of air pollution in China, which poses a huge threat to public health by inducing and promoting circulatory and respiratory diseases. This study aimed to explore the association between the concentration of air pollution and daily internal medicine outpatient visits registered for the treatment of circulatory and respiratory symptoms in Zhoushan, China using a time-series method.

Methods: We validated and acquired the daily internal medicine outpatient visits records between January 1, 2014, and December 31, 2019, from the Zhoushan Center for Disease Control and Prevention in Zhejiang, China. Further, we collected the daily average records of the ambient air pollutants from the Zhoushan Environmental Monitoring Centre within the same duration. A generalized additive model with the natural splines was constructed to explore the association between the ambient air pollutants and daily internal medicine outpatient visits. Further, we conducted a lag analysis by using the distributed lag non-linear model to estimate the time-delayed effects of the air pollutants on the daily internal medicine outpatient visits.

Results: A total of 2,190,258 daily internal medicine outpatient visits with a mean of 202.4 visits per day were recorded. The non-linear relationships were found among particulate matter_2.5 (PM_2.5), sulfur dioxide (SO₂), and the daily internal medicine outpatient visits. Overall, PM_2.5 was positively correlated with the daily internal medicine outpatient visits. Both ozone (O₃) and SO₂ had significant delayed effects on the daily internal medical outpatient numbers; however, PM_2.5 only showed a short-term risk.

Conclusion: Short-term exposure to PM_2.5 was associated with an increase in the daily internal medicine outpatient visits for circulatory and respiratory diseases/symptoms in Zhoushan, China. SO₂ and O₃ were shown to induce significant effects after a concentration-dependent time lag.

Changes in Air Pollution-Related Behaviour Measured by Google Trends Search Volume Index in Response to Reported Air Quality in Poland

Decreased air quality is connected to an increase in daily mortality rates. Thus, people’s behavioural response to sometimes elevated air pollution levels is vital. We aimed to analyse spatial and seasonal changes in air pollution-related information-seeking behaviour in response to nationwide reported air quality in Poland. Google Trends Search Volume Index data was used to investigate Poles’ interest in air pollution-related keywords. PM₁₀ and PM_2.5 concentrations measured across Poland between 2016 and 2019 as well as locations of monitoring stations were collected from the Chief Inspectorate of Environmental Protection databases. Pearson Product-Moment Correlation Coefficients were used to measure the strength of spatial and seasonal relationships between reported air pollution levels and the popularity of search queries. The highest PM₁₀ and PM_2.5 concentrations were observed in southern voivodeships and during the winter season. Similar trends were observed for Poles’ interest in air pollution-related keywords. Greater interest in air quality data in Poland strongly correlates with both higher regional and higher seasonal air pollution levels. It appears that Poles are socially aware of this issue and that their intensification of the information-seeking behaviour seems to indicate a relevant ad hoc response to variable threat severity levels.

Short-Term Association of Air Pollutant Levels and Hospital Admissions for Stroke and Effect Modification by Apparent Temperature: Evidence From Shanghai, China

The epidemiological evidence on relationships between air pollution, temperature, and stroke remains inconclusive. Limited evidence is available for the effect modification by apparent temperature, an indicator reflecting reactions to the thermal environment, on short-term associations between air pollution and hospital admissions for stroke. We used a generalized additive model with Poisson regression to estimate the relative risk (RR) of stroke admissions in Shanghai, China, between 2014 and 2016 associated with air pollutants, with subgroup analyses by age, sex, apparent temperature, and season. During the study period, changes in the daily number of stroke admissions per 10 μg/m³ increase in nitrogen dioxide (at lags 0, 1, 0–1, and 0–2) ranged from 1.05 (95% CI: 0.82%, 2.88%) to 2.24% (95% CI: 0.84%, 3.65%). For each 10 μg/m³ increase in sulfur dioxide concentrations at lags 1, 2, 0–1, and 0–2, the RR of daily stroke admissions increased by 3.34 (95% CI: 0.955%, 5.79%), 0.32 (95% CI: −1.97%, 2.67%), 3.33 (95% CI: 0.38%, 6.37%), and 2.86% (95% CI: −0.45%, 6.28%), respectively. The associations of same-day exposure to nitrogen dioxide with stroke admissions remained significant after adjustment for ozone levels. These associations were not modified by sex, age, apparent temperature, or season. More research is warranted to determine whether apparent temperature modifies the associations between air pollution and stroke admissions.

The association between air pollution parameters and emergency department visits and hospitalizations due to cardiovascular and respiratory diseases: a time-series analysis

OBJECTIVE

In this study, the association between cardiovascular and respiratory Emergency Department (ED) visits and hospitalizations and Sulfur Dioxide (SO₂) and particulate matter with an aerodynamic diameter ≤ 10 µm (PM₁₀) was determined.

METHODS

The records of a total of 632,223 people diagnosed with cardiovascular diseases (ICD-10 code I00-I99) and respiratory diseases (ICD-10 code J00-J99) at and over the age of 18 between 2012 and 2018 in three hospitals in Karaman in Turkey were examined in the present study. The daily 24-h averages for SO₂ and PM₁₀ concentrations were acquired in National Air Quality Monitoring. A time-series analysis with Poisson Generalized Linear Model was used.

RESULTS

Among the air pollution parameters, the mean ± standard deviation of SO₂ and PM₁₀ were 16.2 ± 22.1 and 75.8 ± 48.2 μg/m³, respectively. An increase of 10 μg/m³ in SO₂ was associated with a 3% [Relative Risk (RR), 95% Confidence Interval (CI): 2-4)] increase in cardiovascular ED visit and 2% (RR, 95% CI 2-3) increase in respiratory ED visit, and 1% (RR, 95% CI 1-3) increase in respiratory hospitalizations. An increase of 10 μg/m³ in PM₁₀ was associated with a 1% (RR, 95% CI 1-2) increase in cardiovascular hospitalizations.

CONCLUSIONS

Increases in SO₂ are a risk factor for cardiovascular and respiratory ED visits, and respiratory hospitalizations. Increases in PM₁₀ are a risk factor for cardiovascular hospitalizations.

Association between long-term exposure to ambient air pollution and clinical outcomes among patients with heart failure: Findings from the China PEACE Prospective Heart Failure Study

BACKGROUND

The health effects of air pollution on heart failure (HF) patients have not been adequately studied.

OBJECTIVES

We assessed the associations between long-term air pollution exposure and prognosis in HF patients.

METHODS

HF patients were prospectively recruited from 52 hospitals throughout China between August 2016 and May 2018. The participants were followed up for 12 months after discharge from index hospitalization. Long-term air pollution was calculated as annual average level of air pollution before the date of the index hospitalization. Outcomes were defined as HF readmission, cardiovascular death, and composite events. Cox proportional hazards model was applied to quantify the associations between air pollution exposure and clinical outcomes.

RESULTS

Of 4866 patients included in the analysis, mean age was 65.2 ± 13.5 years, and 62.5% were male. During 1-year follow-up, 1577 (32.4%) participants were readmitted for HF and 550 (11.3%) died from cardiovascular disease. Though no associations between long-term air pollution and HF readmission in the overall participants, geographic and age heterogeneity in the long-term effects of air pollutants on HF readmission was observed. Air pollutants included PM_2.5 [HR (hazard ratio) = 1.146, 95% CI (confidence interval): 1.044, 1.259], PM₁₀ (HR = 1.120, 95% CI: 1.043, 1.203), SO₂ (HR = 1.808, 95% CI: 1.190, 2.747), and CO (HR = 3.596, 95% CI: 1.792, 7.218) were associated with higher risk of HF readmission in South China, but not in North China, where people spend less time outdoors and have limited indoor-outdoor ventilation. PM_2.5, PM_10, O₃, and CO among patients ≥ 65 years were found to be associated with higher risk of HF readmission. The effects on composite outcomes were broadly consistent with that of HF readmission. Cardiovascular death was not significantly associated with air pollution in the overall or subgroups.

DISCUSSION

Among HF patients who were older, living in South China, more HF readmissions occurred with higher long-term air pollution exposure. The findings suggest that the elderly patients and those living in South China should particularly enhance their personal protection against air pollution.