Ambient fine particulate pollution and daily morbidity of stroke in Chengdu, China

Short-Term Exposure to Air Pollution and the Incidence and Mortality of Stroke: A Meta-Analysis

BACKGROUND

The relationship between short-term exposure to various air pollutants [particulate matter <10 μm (PM 10 ), particulate matter <2.5 μm (PM 2.5 ), nitrogen dioxide (NO 2 ), sulfur dioxide (SO 2 ), carbon monoxide, and ozone (O 3 )] and the incidence and mortality of stroke remain unclear.

REVIEW SUMMARY

We conducted a comprehensive search across databases, including PubMed, Web of Science, and others. A random-effects model was employed to estimate the odds ratios (OR) and their 95% CIs. Short-term exposure to PM 10 , PM 2.5 , NO 2 , SO 2 , and O 3 was associated with increased stroke incidence [per 10 μg/m 3 increase in PM 2.5 : OR = 1.005 (95% CI: 1.004-1.007), per 10 μg/m 3 increase in PM 10 : OR = 1.006 (95% CI: 1.004-1.009), per 10 μg/m 3 increase in SO 2 : OR = 1.034 (95% CI: 1.020-1.048), per 10 μg/m 3 increase in NO 2 : OR = 1.029 (95% CI: 1.015-1.043), and O 3 for per 10 μg/m 3 increase: OR: 1.006 (95% CI: 1.004-1.007)]. In addition, short-term exposure to PM 2.5 , PM 10 , SO 2, and NO 2 was correlated with increased mortality from stroke [per 10 μg/m 3 increase in PM 2.5 : OR = 1.010 (95% CI: 1.006-1.013), per 10 μg/m 3 increase in PM 10 : OR = 1.004 (95% CI: 1.003-1.006), per 10 μg/m 3 increase in SO 2 : OR = 1.013 (95% CI: 1.007-1.019) and per 10 μg/m 3 increase in NO 2 : OR = 1.012 (95% CI: 1.008-1.015)].

CONCLUSION

Reducing outdoor air pollutant levels may yield a favorable outcome in reducing the incidence and mortality associated with strokes.

Hourly Air Pollution Exposure and Emergency Hospital Admissions for Stroke: A Multicenter Case-Crossover Study

BACKGROUND

Daily exposure to ambient air pollution is associated with stroke morbidity and mortality; however, the association between hourly exposure to air pollutants and risk of emergency hospital admissions for stroke and its subtypes remains relatively unexplored.

METHODS

We obtained hourly concentrations of fine particulate matter (PM2.5), respirable particulate matter (PM10), nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3), and carbon monoxide (CO) from the China National Environmental Monitoring Center. We conducted a time-stratified case-crossover study among 86 635 emergency hospital admissions for stroke across 10 hospitals in 3 cities (Jinhua, Hangzhou, and Zhoushan) in Zhejiang province, China, between January 1, 2016 and December 31, 2021. Using a conditional logistic regression combined with a distributed lag linear model, we estimated the association between hourly exposure to multiple air pollutants and risk of emergency hospital admissions for total stroke, ischemic stroke, hemorrhagic stroke, and undetermined type.

RESULTS

Hourly exposure to PM2.5, PM10, NO2, and SO2 was associated with an increased risk of hospital admissions for total stroke and ischemic stroke. The associations were most pronounced during the concurrent hour of exposure and lasted for ≈2 hours. We found that the risk was more pronounced among male patients or those aged <65 years old.

CONCLUSIONS

Our findings suggest that exposure to PM2.5, PM10, NO2, and SO2, but not CO and O3, is associated with emergency hospital admissions for total stroke or ischemic stroke shortly after exposure. Implementing targeted pollution emission reduction measures may have significant public health implications in controlling and reducing the burden of stroke.

Short-term effects of individual exposure to PM2.5 on hospital admissions for myocardial infarction and stroke: a population-based case-crossover study in Guangzhou, China

Some studies have investigated the effects of PM_2.5 on cardiovascular diseases based on the population-average exposure data from several monitoring stations. No one has explored the short-term effect of PM_2.5 on cardiovascular hospitalizations using individual-level exposure data. We assessed the short-term effects of individual exposure to PM_2.5 on hospitalizations for myocardial infarction (MI) and stroke in Guangzhou, China, during 2014-2019. The population-based data on cardio-cerebrovascular events were provided by Guangzhou Center for Disease Control and Prevention. Average annual percent changes (AAPCs) were used to describe trends in the hospitalization rates of MI and stroke. The conditional logistic regression model with a time-stratified case-crossover design was applied to estimate the effects of satellite-retrieved PM_2.5 with 1-km resolution as individual-level exposure. Furthermore, we performed stratified analyses by demographic characteristics and season. There were 28,346 cases of MI, 188,611, and 36,850 cases of ischemic stroke (IS) and hemorrhagic stroke (HS), respectively, with an annual average hospitalization rate of 37.2, 247, and 48.4 per 100,000 people. Over the six-year study period, significant increasing trends in the hospitalization rates were observed with AAPCs of 12.3% (95% confidence interval [CI]: 7.24%, 17.6%), 13.1% (95% CI: 9.54%, 16.7%), and 9.57% (95% CI: 6.27%, 13.0%) for MI, IS, and HS, respectively. A 10 μg/m³ increase in PM_2.5 was associated with an increase of 1.15% (95% CI: 0.308%, 1.99%) in MI hospitalization and 1.29% (95% CI: 0.882%, 1.70%) in IS hospitalization. A PM_2.5-associated reduction of 1.17% (95% CI: 0.298%, 2.03%) was found for HS hospitalization. The impact of PM_2.5 was greater in males than in females for MI hospitalization, and greater effects were observed in the elderly (≥ 65 years) and in cold seasons for IS hospitalization. Our study added important evidence on the adverse effect of PM_2.5 based on satellite-retrieved individual-level exposure data.

Air Pollution and Its Adverse Effects on the Central Nervous System

Air pollution is recognized as a significant public health problem and is associated with illnesses of the central nervous system (CNS) as well as neuroinflammation and neuropathology. Air pollution may cause chronic brain inflammation, white matter abnormalities, and microglia activation, which increases the risk of autism spectrum disorders, neurodegenerative disorders, stroke, and multiple sclerosis (MS). Methods: A literature review was done on "PubMed, EMBASE and Web of Science" on the relationship of air pollution with MS and stroke, using the keywords "air pollution" OR "pollution"; "ambient air pollution," "particulate matter, ozone, black carbon" AND "stroke" OR "cerebrovascular diseases," "multiple sclerosis," "neuroinflammation," or "neurodegeneration." Results: We first identified 128 articles and their related websites, of which 44 articles were further selected for analysis mainly based on study relevance, study quality and reliability, and date of publication. Further studies on air pollution and its adverse effects on the CNS are needed. The findings of such studies will support the development of appropriate preventive measures in the future.

Short-term exposure to ambient fine particulate pollution aggravates ventilator-associated pneumonia in pediatric intensive care patients undergoing cardiovascular surgeries

BACKGROUND

Ambient air pollutants can be hazardous to human health, especially for vulnerable children. The impact of ambient air pollutant exposure before and during intensive care unit (ICU) stays on the development of ventilator-associated pneumonia (VAP) in critically ill children has not been established. We aimed to determine the correlations between short-term exposures to ambient fine particulate matter (PM_2.5) and VAP in pediatric cardiac surgery patients in the ICU, and explore the effect of delayed exposure.

METHODS

The medical record of 1755 child patients requiring artificial ventilation in the ICU between December 2013 to December 2020, were analyzed. The daily average concentrations of particulate matters (PM_2.5 and PM₁₀), sulfur dioxide (SO₂), and ozone (O₃) were calculated from public data. Interactions between these pollutants and VAP were simulated with the distributed lag non-linear model.

RESULTS

Three hundred forty-eight cases (19.829%) of VAP were identified in this study, while the average concentrations of PM_2.5, PM₁₀, O₃ and SO₂ were 58, 118, 98 and 26 μg/m³, respectively. Exposure to increased levels of PM_2.5 two days prior (lag 2-day) to VAP diagnosis is significantly correlated with an enhanced risk for VAP development. Even a slight increase of 10 μg/m³ in PM_2.5 can translate to a 5.4% increase in VAP incidence (95% CI: 1.4%-9.5%) while the VAP incidence increased to 11.1% (95%CI: 4.5-19.5%) when PM_2.5 concentration is well below the National Ambient Air Quality standard (NAAQS) of 50 μg/m³. The association was more pronounced in those aged below 3-months, with low body mass index or suffered from pulmonary arterial hypertension.

CONCLUSION

Short-term PM_2.5 exposure is a significant risk for development of VAP in pediatric patients. This risk is present even with PM_2.5 levels below the NAAQS. Ambient PM_2.5 may represent a previously unrecognized risk factor for pneumonia and the current environmental pollution standards need to be reevaluated to consider susceptible populations.

TRIAL REGISTRATION

The trial was registered with the National Clinical Trial Center: The correlation between ambient air pollution and the complications in ICU underwent cardiac surgery.

TRIAL REGISTRATION NUMBER

ChiCTR2000030507. Date of registration: March 5, 2020. URL of trial registry record: http://www.chictr.org.cn/index.aspx .

Association between ambient carbon monoxide levels and hospitalization costs of patients with myocardial infarction: Potential effect modification by ABO blood group

Previous researches have reported the association between air pollution and various diseases. However, few researches have investigated whether air pollutants are associated with the economic loss resulting from patients' hospitalization, especially the economic loss of hospitalization due to acute cardiovascular events. The purpose of our research was to explore the association between the levels of carbon monoxide (CO), taken as an index of pollution, and the hospitalization costs of myocardial infarction (MI), and the potential effect modification by the ABO blood group. A total of 3237 MI inpatients were included in this study. A multiple linear regression model was used to evaluate the association between ambient CO levels and hospitalization costs of MI patients. Moreover, we performed stratified analyses by age, gender, body mass index (BMI), season, hypertension, and ABO blood types. There was a positive association between the levels of CO in the air and the costs of hospitalization caused by MI. Furthermore, such association was stronger in males, BMI ≥25, <65 years, with hypertension, and non-O blood group. Interestingly, we found the association was particularly significant in patients with blood group B. Overall, our study first found that ambient CO levels could have an impact on the hospitalization costs for MI patients, and those with blood group B can be more sensitive.

Acute effect of fine particulate matter and respiratory mortality in Changsha, China: a time-series analysis

Background

Previous studies have confirmed that exposure to fine particulate matter (PM_2.5) is associated with respiratory disease mortality. However, due to the differences in PM_2.5 concentration, composition and population susceptibility within different regions, the estimates of the association between PM_2.5 concentration and mortality are different. Moreover, few studies have examined the potential hazard of excessive PM_2.5 exposure in terms of respiratory disease mortality.

Methods

Daily recorded data on meteorological indices, environmental pollutants, and causes of death data in Changsha from January 2015 to December 2018 were obtained. The potential relationship between PM_2.5 concentrations and respiratory disease mortality was determined using distributed lag nonlinear model (DLNM), which includes the relative risk (RR) and cumulative relative risk (CRR) of the lagged effect. The synergistic effects of other air pollutants were also considered.

Results

A total of 8,825 cases of respiratory disease mortality occurred in Changsha between 2015 and 2018. The acute effect of PM_2.5 concentration was associated with an increased risk of respiratory disease mortality. Regarding the lag specific effect, a 10 μg/m³ increase in PM_2.5 concentration on respiratory disease mortality was statistically significant at lag day 0 and lag day 7 with a relative risk of 1.019 (95% CI 1.007- 1.031) and 1.013(95%CI: 1.002-1.024). As for the cumulative lag effect, a 4-day moving average of PM_2.5 concentrations was significantly associated with a cumulative relative risk of 1.027 (95%CI: 1.011-1.031). The single-day lag effect and cumulative 4-day lag effect for male individuals were more significant than those observed in females. The effect of PM_2.5 concentrations and respiratory disease mortality remained statistically significant in the multi-pollutant models (SO₂, NO₂, and O₃). A higher risk was observed in the cold season than in the warm season.

Conclusions

Our findings show a potential association between exposure to PM_2.5 concentration and respiratory disease mortality in Changsha, with male individuals observed to have particularly higher risk.

Dose-response relationships between polycyclic aromatic hydrocarbon exposure and blood cell counts among coke oven workers: a sex-stratified analysis

OBJECTIVES

To explore sex differences and dose-response relationships between nine urinary polycyclic aromatic hydrocarbon (PAH) metabolites and neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR) and complete blood counts among coke oven workers.

DESIGN AND SETTING

A cross-sectional study with stratified sex was conducted in Shanxi, China.

PARTICIPANTS

A total of 458 male workers and 226 female workers were selected.

PRIMARY AND SECONDARY OUTCOME MEASURES

General linear models, p values for trend tests and natural cubic spline models were used to explore the dose-response relationships between nine urinary PAH metabolites and NLR, PLR and complete blood counts.

RESULT

Compared with male workers, female workers had lower exposure level of PAH (0.95 ng/mL vs 1.38 ng/mL). Only among female workers did we observe that a 1-unit increase in lg(1-OHPyr) was related to a 0.149 (95% CI: 0.055 to 0.242; p for trend=0.041) and 0.103 (95% CI: 0.025 to 0.181; p for trend=0.007) increase in lg(NLR) and lg(PLR), and a 0.116 (95% CI: -0.179 to -0.054; p for trend=0.007) decrease in lg(lymphocyte counts (LYMs)). A 1-unit increase in lg(2-OHNap) was related to a 0.045 (95% CI: 0.003 to 0.086; p for trend=0.037) increase in lg(PLR) and a 0.029 (95% CI: -0.056 to -0.002; p for trend=0.030) and 0.016 (95% CI: -0.029 to -0.003; p for trend=0.010) decrease in lg(white blood cell counts (WBCs)) and lg(haemoglobin (HGB)).

CONCLUSION

Female workers' NLR, PLR, WBCs, HGB and LYMs may be more susceptible than those of male workers when affected by PAH.

Impact of ambient fine particulate matter on emergency department admissions for circulatory system disease in a city in Northeast China

The cardiovascular impact of fine particles has caused great concern worldwide. However, evidences on the impact of fine particulate matter (PM_2.5) on emergency department (ED) admissions for circulatory system disease in Northeast China is limited. We assessed the acute, lag, cumulative, and harvesting effects of PM_2.5 on ED admissions for circulatory system diseases and their exposure-response relationship. A total of 26,168 ED admissions, including those for hypertension, ischemic heart disease (IHD), arrhythmia, heart failure (HF), and cerebrovascular events (CVE), were collected from the Shenyang Emergency Center from 1 January 2017 to 31 December 2018. The relationship between PM_2.5 and ED admissions for circulatory system disease was estimated using a distributed lag non-linear model and a generalized additive quasi-Poisson model. We stratified the analyses by temperature. Air pollution was positively correlated with daily ED admissions for circulatory system disease or other cause-specific diseases under different lag structures. For every 10-μg/m³ increase in the PM_2.5 concentration, the relative risk of daily ED admissions for circulatory system disease was 1.007 [95% confidence interval (CI), 1.001-1.013] in lag0, 1.007 (95%CI, 1.000-1.013) in lag1, and 1.011 (95%CI, 1.002-1.021) in lag03. A lag effect was found in IHD, a cumulative effect was found in CVE, and both lag and cumulative effects were found in hypertension and arrhythmia. A harvesting effect was observed in daily ED admissions for circulatory system disease and HF. We found no interaction between pollutants and temperature. We observed a monotonic and almost linear exposure-response relationship between PM_2.5 and circulatory system disease with no threshold effect.PM_2.5 contributes to obvious acute, lag, cumulative, and harvesting effects on circulatory system disease. PM_2.5 was associated with the risk of daily ED admissions for circulatory system disease, hypertension, IHD, arrhythmia, HF, and CVE. Therefore, air quality management must be strengthened.

Characteristics of Particulate Matter at Different Pollution Levels in Chengdu, Southwest of China

Air pollution is becoming increasingly serious along with social and economic development in the southwest of China. The distribution characteristics of particle matter (PM) were studied in Chengdu from 2016 to 2017, and the changes of PM bearing water-soluble ions and heavy metals and the distribution of secondary ions were analyzed during the haze episode. The results showed that at different pollution levels, heavy metals were more likely to be enriched in fine particles and may be used as a tracer of primary pollution sources. The water-soluble ions in PM2.5 were mainly Sulfate-Nitrate-Ammonium (SNA) accounting for 43.02%, 24.23%, 23.50%, respectively. SO42−, NO3−, NH4+ in PM10 accounted for 34.56%, 27.43%, 19.18%, respectively. It was mainly SO42− in PM at Clean levels (PM2.5 = 0~75 μg/m3, PM10 = 0~150 μg/m3), and mainly NH4+ and NO3− at Light-Medium levels (PM2.5 = 75~150 μg/m3, PM10 = 150~350 μg/m3). At Heavy levels (PM2.5 = 150~250 μg/m3, PM10 = 350~420 μg/m3), it is mainly SO42− in PM2.5, and mainly NH4+ and NO3− in PM10. The contribution of mobile sources to the formation of haze in the study area was significant. SNA had significant contributions to the PM during the haze episode, and more attention should be paid to them in order to improve air quality.

Acute effect of particulate matter pollution on hospital admissions for stroke among patients with type 2 diabetes in Beijing, China, from 2014 to 2018

BACKGROUND

The health effect of particulate matter pollution on stroke has been widely examined; however, the effect among patients with comorbid type 2 diabetes (T2D) in developing countries has remained largely unknown.

METHODS

A time-series study was conducted to investigate the short-term effect of fine particulate matter (PM_2.5) and inhalable particulate matter (PM₁₀) on hospital admissions for stroke among patients with T2D in Beijing, China, from 2014 to 2018. An over-dispersed Poisson generalized additive model was employed to adjust for important covariates, such as weather conditions and long-term and seasonal trends.

RESULTS

A total of 159,298 hospital admissions for stroke comorbid with T2D were reported. Approximately linear exposure-response curves were observed for PM_2.5 and PM₁₀ in relation to stroke admissions among T2D patients. A 10 μg/m³ increase in the four-day moving average of PM_2.5 and PM₁₀ was associated with 0.14% (95% confidence interval [CI]: 0.05-0.23%) and 0.14% (95% CI: 0.06-0.22%) incremental increases in stroke admissions among T2D patients, respectively. A 10 μg/m³ increase in PM_2.5 in the two-day moving average corresponded to a 0.72% (95% CI: 0.02-1.42%) incremental increase in hemorrhagic stroke, and a 10 μg/m³ increase in PM₁₀ in the four-day moving average corresponded to a 0.14% (95% CI: 0.06-0.22%) incremental increase in ischemic stroke.

CONCLUSIONS

High particulate matter might be a risk factor for stroke among patients with T2D. PM_2.5 and PM₁₀ have a linear exposure-response relationship with stroke among T2D patients. The study provided evidence of the risk of stroke due to particulate matter pollution among patients with comorbid T2D.

Exposure interval to ambient fine particulate matter (PM2.5) collected in Southwest China induced pulmonary damage through the Janus tyrosine protein kinase-2/signal transducer and activator of transcription-3 signaling pathway both in vivo and in vitro

PM2.5 is a well-known air pollutant threatening public health. Studies confirmed that exposure to the particles could impair pulmonary function, cause chronic obstructive pulmonary disease, and increase the incidence of lung cancer. The characteristic of PM2.5 varies across regions. The toxic function of PM2.5 in southwest China remains to be elucidated. This study aimed to investigate lung injury and its mechanisms induced by PM2.5 collected in Chengdu. Rats were administered with PM2.5 by intratracheal instillation for 4 weeks. Biochemical, cell count, and inflammation-related parameters were measured. Lung tissues were obtained for hematoxylin and eosin and Masson's trichrome staining. The expression levels of vascular endothelial growth factor (VEGF), Janus tyrosine protein kinase-2 (JAK-2), and signal transducer and activator of transcription-3 (STAT-3) were detected by immunohistochemistry assays. Meanwhile, A549 cells were treated with the PM2.5. The cell cycle, and apoptosis were measured by flow cytometry. mRNA and protein expressions of JAK-2, STAT-3, p-STAT-3, and VEGFA were detected using qPCR and Western blot analysis respectively. Results of in vivo study showed that PM2.5 induced lung pathological injury, aggravated the accumulation of inflammatory cells, and increased the serum levels of inflammatory factors. In vitro experiments showed that PM2.5 disrupted the cell growth cycle and increased cell apoptosis through the activation of the JAK-2/STAT-3 signaling pathway. Taken together, this study provided convincing experimental evidence that PM2.5 collected in southwest China could induce pulmonary injury as manifested by inflammatory response and lung fibrosis, possibly through the modulation of the JAK-2/STAT-3 signaling pathway.

Short-term effect of fine particular matter on daily hospitalizations for ischemic stroke: A time-series study in Yancheng, China

OBJECTIVE

To investigate the associations between short-term exposure to fine particular matter (PM_2.5) and ischemic stroke (IS) in Yancheng, China, from 2017 to 2019.

METHODS

We designed a time-series study based on generalized additive models to explore the association of PM_2.5 and IS admitted in two major hospitals in Yancheng. We built different lag patterns and conducted stratification analyses by age, gender, and season. Moreover, we examined the robustness of the associations adopting two-pollutant models and fitted the concentration-response curves.

RESULT

We observed positive and significant associations at lag 0 day. Every 10 μg/m³ increase in PM_2.5 (lag0) was associated with 1.06% (95% CI: 0.21%-1.91%) increases in hospitalizations for IS. The association remained stable and statistically significant to the adjustment of carbon monoxide and ozone. We observed that the associations were stronger in females and during cold seasons. The overall concentration-response relationship curve was linear positive and increased slowly but rose sharply at higher concentrations in the cold season.

CONCLUSION

Our study added to the evidence that short-term exposure to PM_2.5 may induce IS, and the government should take action to address the air pollution issues and protect susceptible populations.

The 10-Year Study of the Impact of Particulate Matters on Mortality in Two Transit Cities in North-Eastern Poland (PL-PARTICLES)

The detrimental influence of air pollution on mortality has been established in a series of studies. The majority of them were conducted in large, highly polluted cities-there is a lack of studies from small, relatively clean regions. The aim was to analyze the short-term impact of particulate matters (PMs) on mortality in north-eastern Poland. Time-stratified case-crossover design was performed for mortality in years 2008-2017. Daily concentrations of PM_2.5 (28.4 µg/m³, interquartile range (IQR) = 25.2) vs. (12.6 µg/m³, IQR = 9.0) and PM₁₀ (29.0 µg/m³, IQR = 18.0) vs. (21.7 µg/m³, IQR = 14.5) were higher in Łomża than Suwałki (p < 0.001). Impact of PM_2.5 on mortality was recorded in Łomża (odds ratio (OR) for IQR increase 1.061, 1.017-1.105, p = 0.06, lag 0) and Suwałki (OR for IQR increase 1.044, 1.001-1.089, p = 0.004, lag 0). PM₁₀ had an impact on mortality in Łomża (OR for IQR increase 1.028, 1.000-1.058, p = 0.049, lag 1). Cardiovascular mortality was affected by increase of PM_2.5 in Łomża (1.086, 1.020-1.156, p = 0.01) and Suwałki (1.085, 1.005-1.171, p = 0.04). PM_2.5 had an influence on respiratory mortality in Łomża (1.163, 1.021-1.380, p = 0.03, lag 1). In the whole studied region, despite differences in the air quality, the influence of PMs on mortality was observed.

Short-term exposure to air pollution and occurrence of emergency stroke in Chongqing, China

OBJECTIVE

This study aimed to study the relationship between air pollution and stroke (especially emergency stroke) in different regions and determine which air pollutant is the most significantly associated with stroke.

METHODS

The number of patients with emergency stroke, air pollutant data and related meteorological indicators were collected from December 2013 to May 2018 for large comprehensive hospitals in Chongqing. The generalized additive model was used to analyse the relationship between air pollution and emergency stroke.

RESULTS

After analysis and adjusting for meteorological indicators and day-of-the-week effects, in the one-pollutant model, every 10 μg/m³ increase in ozone(O₃) was associated with a 2.482% (95% CI 1.044%, 3.919%) change in emergency strokes within lag0. For males, every 10 μg/m³ increase of O₃ contributed to a 0.77% percent greater change compared with females. For the group younger than 60 years, we observed a 1.14% increase in risk with every 10 μg/m³ increase in O₃. The group with pre-existing hypertension had a 0.26% higher risk than the group with no pre-existing hypertension with every 10 μg/m³ increase in O₃. In two-pollutant model, when O₃ was combined with a 10 μg/m³ increase of NO₂, it increased the most significant risk of emergency stroke by 0.22%.

CONCLUSION

These findings suggest that short-term exposure to O₃ within 0 days is associated with emergency outpatient strokes, and younger people (age < 60 years) males and people with hypertension are more sensitive than older people, females and people without pre-existing hypertension.

Particulate matter pollution and hospital outpatient visits for endocrine, digestive, urological, and dermatological diseases in Nanjing, China

Clinical or pathological evidence demonstrated that air pollution could undermine other organ systems of human body besides respiratory and circulation systems. Investigations that directly relate hospital outpatient visits for endocrine (ENDO), digestive (DIGE), urological (UROL), and dermatological (DERM) diseases categories with ambient particulate matter (PM) are still lacking, particularly in heavily polluted cities. Here, we conducted a time-series analysis using 812,624, 1,111,342, 539,803, and 741,662 hospital visits for ENDO, DIGE, UROL, and DERM, respectively, in Nanjing, China from 2013 to 2019. A generalized additive model was applied to estimate the exposure-response associations. Results showed that a 10 μg/m³ increase in PM_2.5 concentration on lag 0 day was significantly associated with 0.59% (95% CI: 0.30%, 0.88%), 0.43% (0.15%, 0.70%), 0.36% (0.06%, 0.66%), and 0.65% (0.42%, 0.87%) increase for ENDO, DIGE, UROL, and DERM hospital visits, respectively. The estimated effects of PM₁₀ were slightly smaller but still statistically significant. The magnitude and significance of the associations between PM and four health outcomes were sensitive to additional adjustment for co-pollutants. Exposure-response relationships were linear for PM concentrations lower than 100 μg/m³ but the curves became nonlinear across the full range of exposures due to a flatten slope at higher concentrations. We also explored the effect modifications by season (cold or warm), age (5-18, 18-64, 65-74, or 75+ years), and sex (male or female). Results showed that the DERM-related population aged 65 years or older was more vulnerable to PM exposure, compared with the 5 to 17-year age group; the DERM-related population aged 75 years or older and 65 years or older was more vulnerable to PM_2.5 and PM₁₀ exposure, respectively, compared with the 18 to 64-year age group. Our study provided suggestive evidence that ambient PM pollution was associated with ENDO, DIGE, UROL, and DERM outpatient hospital visits in Nanjing, China.

Ambient fine particulate matter and hospital admissions for ischemic and hemorrhagic strokes and transient ischemic attack in 248 Chinese cities

Few studies have investigated the acute effects of fine particulate matter (PM_2.5) on the risk of stroke subtypes and transient ischemic attack (TIA) in low- and middle-income countries. The primary aim of this study was to assess the associations between short-term exposure to PM_2.5 and daily hospital admissions for total cerebrovascular disease, ischemic and hemorrhagic strokes, and TIA in China. A total of 8,359,162 hospital admissions in 248 Chinese cities from 2013 to 2017 were identified from the Hospital Quality Monitoring System of China. Generalized additive models with quasi-Poisson regression were used to estimate the associations in each city, and random-effect meta-analyses were conducted to combine the city-specific estimates. We found that a 10 μg/m³ increase in PM_2.5 concentration was significantly associated with a 0.19% (95% CI, 0.13% to 0.25%), 0.26% (95% CI, 0.17% to 0.35%), and 0.26% (95% CI, 0.13% to 0.38%) increase in same-day hospital admissions for total cerebrovascular disease, ischemic stroke, and TIA, respectively. In contrast, a non-significant negative association with PM_2.5 was observed for hemorrhagic stroke in the main analyses (lag 0 day), which became statistically significant when using other single-day exposures (lag 1 or 2 days) or moving average exposures (lag 0-1, 0-2, or 0-3 days) as exposure metric. These associations were robust to adjustment for other criteria air pollutants in two-pollutant models. For ischemic stroke, the effect estimates were significantly larger in people aged 65-74 years, in cool season, and in cities with lower annual average PM_2.5 concentrations. The exposure-response curves were nonlinear with a leveling off at high concentrations. These results contribute to the relatively limited literature on the PM_2.5-related risks of cerebrovascular events in low- and middle-income countries.

Short-term associations between ambient air pollution and stroke hospitalisations: time-series study in Shenzhen, China

OBJECTIVE

To investigate the association between ambient air pollution and stroke morbidity in different subgroups and seasons.

METHODS

We performed a time-series analysis based on generalised linear models to study the short-term exposure-response relationships between air pollution and stroke hospitalisations, and conducted subgroup analyses to identify possible sensitive populations.

RESULTS

For every 10 µg/m³ increase in the concentration of air pollutants, across lag 0-3 days, the relative risk of stroke hospitalisation was 1.029 (95% CI 1.013 to 1.045) for PM_2.5, 1.054 (95% CI 1.031 to 1.077) for NO₂ and 1.012 (95% CI 1.002 to 1.022) for O₃. Subgroup analyses showed that statistically significant associations were found in both men and women, middle-aged and older populations, and both cerebral infarction and intracerebral haemorrhage. The seasonal analyses showed that statistically significant associations were found only in the winter.

CONCLUSIONS

Our study indicates that short-term exposure to PM_2.5, NO₂ and O₃ may induce stroke morbidity, and the government should take actions to mitigate air pollution and protect sensitive populations.

Association of short-term exposure to sulfur dioxide and hospitalization for ischemic and hemorrhagic stroke in Guangzhou, China

BACKGROUND

In developing countries, ambient sulfur dioxide (SO₂) is a serious air pollutant concern, but there is no enough and consistent epidemiological evidence about its health effects on stroke hospitalization.

METHODS

We collected the daily air pollution data, meteorological data and number of daily hospital admissions for ischemic and hemorrhagic stroke, in Guangzhou from January 1st 2009 to December 31st 2014. Then we applied generalized additive model with a quasi-Poisson link to assess the relationship between short-term SO₂ exposure and the total number of hospital admissions for ischemic and hemorrhagic stroke. In addition, we evaluated the effect of ambient SO₂ by age (< 65 years and ≥ 65 years).

RESULTS

During the study period, a 24-h mean concentration of ambient SO₂ of 27.82 μg/m³, a total of 58,473 ischemic stroke and 9167 hemorrhagic stroke hospital admissions hospital were recorded. Ambient SO₂ was found to increase the risk for both ischemic and hemorrhagic stroke hospital admission in single pollutant model. The maximum value of percentage changes for ischemic and hemorrhagic stroke occurred in lag 0 day and lag 1 day, per 10 μg/m³ increase in SO₂ concentrations was corresponded to a 1.27% (95% confidence interval (CI), 0.42-2.12%) and 1.55% (95%CI, 0.02-3.11%) increased risk, respectively. The association between SO₂ and ischemic stroke hospitalization was robust to two pollutant model, but for hemorrhagic stroke it's partially weakened after adjusting for co-pollutants. The effect of ambient SO₂ on ischemic stroke appeared to be greater for people < 65 years old, but null effect on hemorrhagic stroke was identified for both age groups.

CONCLUSIONS

We found short-term exposure to ambient SO₂ may significantly increase the risks of hospitalization for ischemic stroke. The findings may contribute to a better understanding of the health effects of low-levels of SO₂.

The Relationship between Daily Concentration of Fine Particulate Matter in Ambient Air and Exacerbation of Respiratory Diseases in Silesian Agglomeration, Poland

The relationship between the worsening of air quality during the colder season of the year and respiratory health problems among the exposed population in many countries located in cold climates has been well documented in numerous studies. Silesian Voivodeship, a region located in southern Poland, is one of the most polluted regions in Europe. The aim of this study was to assess the relationship between daily concentration of particulate matter (PM: PM_2.5 and PM₁₀) in ambient air and exacerbations of respiratory diseases during the period from 1 January 2016 to 31 August 2017 in the central agglomeration area of Silesian Voivodeship. The study results confirmed a significant increase of daily fine particulate matter concentration in ambient air during the cold season in Silesian Voivodeship with a simultaneous increase of the number of outpatient visits and hospitalizations due to respiratory diseases. The moving average concentration was better suited for the modelling of biological response as a result of PM_2.5 or PM₁₀ exposure than the temporal lag of health effects. Each increase of dose expressed in the form of moving average concentration over a longer time leads to an increase in the daily number of respiratory effects. The highest risk of hospitalization due to respiratory diseases was related to longer exposure of PM expressed by two to four weeks of exposure; outpatient visits was related to a shorter exposure duration of 3 days.