Air Pollution and Acute Myocardial Infarction Hospital Admission in Alberta, Canada: A Three-Step Procedure Case-Crossover Study

Short-term effects of nitrogen dioxide on inpatient acute myocardial infarction in Lanzhou, China

Nitrogen dioxide (NO2) represents a deleterious effect on acute myocardial infarction (AMI), but few relevant studies have been conducted in China. We aim to evaluate the acute effects of NO2 exposure on hospitalization for AMI in Lanzhou, China. In this study, we applied a distributional lag nonlinear model (DLNM) to assess the association between NO2 exposure and AMI hospitalization. We explored the sensitivity of various groups through stratified analysis by gender, age, and season. The daily average concentration of NO2 is 47.50 ± 17.38 µg/m3. We observed a significant exposure-response relationship between NO2 concentration and AMI hospitalization. The single pollutant model analysis shows that NO2 is positively correlated with AMI hospitalization at lag1, lag01, lag02, and lag03. The greatest lag effect estimate occurs at lag01, where a 10 µg/m3 increase in NO2 concentrations is significantly associated with a relative risk (RR) of hospitalization due to AMI of 1.027 [95% confidence interval (CI): 1.013, 1.042]. The results of the stratified analysis by gender, age, and season indicate that males, those aged ≥65 years, and the cold season are more sensitive to the deleterious effects caused by NO2 exposure. Short-term exposure to NO2 can enhance the risk of AMI hospitalization in urban Lanzhou.Implications: Exposure to particulate matter can lead to an increased incidence of AMI. Our study once again shows that NO2 exposure increases the risk of AMI hospital admission. AMI is a common and expensive fatal condition. Reducing NO2 exposure will benefit cardiovascular health and save on healthcare costs.

Exploring the Effects of Local Air Pollution on Popliteal Artery Aneurysms

Objectives: A growing body of evidence highlights the effects of air pollution on chronic and acute cardiovascular diseases, such as associations between PM10 and several cardiovascular events. However, evidence of the impact of fine air pollutants on the development and progression of peripheral arterial aneurysms is not available. Methods: Data were obtained from the multicenter PAA outcome registry POPART and the German Environment Agency. Means of the mean daily concentration of PM10, PM2.5, NO2, and O3 concentrations were calculated for 2, 10, and 3650 days prior to surgery for each patient. Additionally, weighted ten-year averages were analyzed. Correlation was assessed by calculating Pearson correlation coefficients, and regression analyses were conducted as multiple linear or multiple logistic regression, depending on the dependent variable. Results: For 1193 patients from the POPART registry, paired air pollution data were available. Most patients were male (95.6%) and received open surgical repair (89.9%). On a regional level, the arithmetic means of the daily means of PM10 between 2000 and 2022 were neither associated with average diameters nor runoff vessels. Negative correlations for mean PAA diameter and mean NO2, as well as a positive correlation with mean O3, were found; however, they were not statistically significant. On patient level, no evidence for an association of mean PM10 exposure over ten years prior to inclusion in the registry and PAA diameter or the number of runoff vessels was found. Weighted PM10, NO2, and O3 exposure over ten years also did not result in significant associations with aneurysm diameter or runoff vessels. Short-term air pollutant concentrations were not associated with symptomatic PAAs or with perioperative complications. Conclusions: We found no indication that long-term air pollutant concentrations are associated with PAA size or severity, neither on a regional nor individual level. Additionally, short-term air pollution showed no association with clinical presentation or treatment outcomes.

Impact of Short-Term Exposure to Nitrogen Dioxide (NO2) and Ozone (O3) on Hospital Admissions for Non-ST-Segment Elevation Acute Coronary Syndrome

In the context of recent climate change, global warming, industrial growth, and population expansion, air pollution has emerged as a significant environmental and human health risk. This study employed a multivariable Poisson regression analysis to examine the association between short-term exposure to atmospheric pollutants (nitrogen dioxide-NO2, sulfur dioxide -SO2, ozone-O3, and particulate matter with a diameter less than 10 μm-PM10) and hospital admissions for non-ST-segment elevation acute coronary syndrome (NSTE-ACS). Daily data on NSTE-ACS admissions, air pollutants, and meteorological variables were collected from January 2019 to December 2021. Elevated NO2 concentrations were associated with a higher risk of NSTE-ACS hospitalization, notably in spring (OR: 1.426; 95% CI: 1.196-1.701). Hypertensive individuals (OR: 1.101; 95% CI: 1.007-1.204) and those diagnosed with unstable angina (OR: 1.107; 95%CI: 1.010-1.213) exhibited heightened susceptibility to elevated NO2 concentrations. A 10 μg/m3 increase in NO2 during spring at lag 07 (OR: 1.013; 95% CI: 1.001-1.025) and O3 in winter at lag 05 (OR: 1.007; 95% CI: 1.001-1.014) was correlated with an elevated daily occurrence of NSTE-ACS admissions. Short-term exposure to various air pollutants posed an increased risk of NSTE-ACS hospitalization, with heightened sensitivity observed in hypertensive patients and those with unstable angina. Addressing emerging environmental risk factors is crucial to mitigate substantial impacts on human health and the environment.

The Impact of Meteorological Factors and Air Pollutants on Acute Coronary Syndrome

Purpose of Review

Several studies have found that air pollution and climate change can have an impact on acute coronary syndromes (ACS), the leading cause of death worldwide. We synthesized the latest information about the impact of air pollution and climate change on ACS, the latest data about the pathophysiological mechanisms of meteorological factors and atmospheric pollutants on atherosclerotic disease, and an overall image of air pollution and coronary heart disease in the context of the COVID-19 pandemic.

Recent Findings

The variation of meteorological factors in different seasons increased the risk of ACS. Both the increase and the decrease in apparent temperature were found to be risk factors for ACS admissions. It was also demonstrated that exposure to high concentrations of air pollutants, especially particulate matter, increased cardiovascular morbidity and mortality.

Summary

Climate change as well as increased emissions of air pollutants have a major impact on ACS. The industrialization era and the growing population cause a constant increase in air pollution worldwide. Thus, the number of ACS favored by air pollution and the variations in meteorological factors is expected to increase dramatically in the next few years.

Impact of Air Pollution on the Ocular Surface and Tear Cytokine Levels: A Multicenter Prospective Cohort Study

Purpose

To assess air pollution-induced changes on ocular surface and tear cytokine levels.

Methods

As a prospective multicenter cohort study, 387 dry eye disease (DED) participants were recruited from five provinces in China and underwent measurements of ocular surface disease index (OSDI), Schirmer’s I test (ST), tear meniscus height (TMH), tear film break-up time (TBUT), corneal fluorescein staining (CFS), meibomian gland (MG) function, and tear cytokines. The associations between ocular surface parameters and exposure to particulate matter (PM), ozone (O₃), nitrogen dioxide (NO₂), and sulfur dioxide (SO₂) for 1 day, 1 week, and 1 month before the examination were analyzed in single- and multi-pollutant models adjusted for confounding factors.

Results

In the multi-pollutant model, the OSDI score was positively correlated with PM with diameter ≤2.5 μm (PM_2.5), O₃, and SO₂ exposure [PM_2.5: β (1 week/month) = 0.229 (95% confidence interval (CI): 0.035–0.424)/0.211 (95% CI: 0.160–0.583); O₃: β (1 day/week/month) = 0.403 (95% CI: 0.229–0.523)/0.471 (95% CI: 0.252–0.693)/0.468 (95% CI: 0.215–0.732); SO₂: β (1 day/week) = 0.437 (95% CI: 0.193–0.680)/0.470 (95% CI: 0.040–0.901)]. Tear secretion was negatively correlated with O₃ and NO₂ exposures but positively correlated with PM_2.5 levels. Air pollutants were negatively correlated with TBUT and positively related with CFS score. Besides SO₂, all other pollutants were associated with aggravated MG dysfunction (MG expression, secretion, and loss) and tear cytokines increasement, such as PM_2.5 and interleukin-8 (IL-8) [β (1 day) = 0.016 (95% CI: 0.003–0.029)], PM with diameter ≤10 μm (PM₁₀) and IL-6 [β (1 day) = 0.019 (95% CI: 0.006–0.033)], NO₂ and IL-6 [β (1 month) = 0.045 (95% CI: 0.018–0.072)], among others. The effects of air pollutants on DED symptoms/signs, MG functions and tear cytokines peaked within 1 week, 1 month, and 1 day, respectively.

Conclusion

Increased PM_2.5, O₃, and SO₂ exposures caused ocular discomfort and damage with tear film instability. PM₁₀ exposure led to tear film instability and ocular injury. PM, O₃, and NO₂ exposures aggravated MG dysfunction and upregulated tear cytokine levels. Therefore, each air pollutant may influence DED via different mechanisms within different time windows.

2-undecanone protects against fine particles-induced heart inflammation via modulating Nrf2/HO-1 and NF-κB pathways

Exposure to air pollution has been closely associated with some cardiovascular disease. One of the mechanisms of PM_2.5 -mediated heart injury may be to promote inflammation. We aim to investigate whether the main extract of Houttuynia cordata, 2-undecanone, can prevent the inflammation caused by PM_2.5 , and to reveal the underlying mechanisms. The results showed that PM_2.5 increased the expression of certain inflammatory cytokines, and caused oxidative damage in BALB/c mice and H9C2 cells. Supplementation with 2-undecanone attenuated this PM_2.5 -induced inflammatory injury and oxidative damage. Further, we elucidated that the protective effect of 2-undecanone may be associated with NF-κB and Nrf2/HO-1 pathways. The NF-κB pathway was distinctly activated after treated by PM_2.5 , which can be blocked by 2-undecanone, accompanied by increasing Nrf2 and HO-1 levels. To figure out the relationship between NF-κB and Nrf2/HO-1 pathways, we knocked down Nrf2 gene. NF-κB pathway proteins and downstream inflammatory cytokines were significantly increased after treatment with PM_2.5 , while 2-undecanone could decrease expression of these proteins. In conclusion, it is possible that 2-undecanone can induce the expression of the antioxidant enzyme HO-1 by activating Nrf2, thereby reducing NF-κB pathway and inflammatory damage of mouse myocardium caused by PM_2.5 exposure.

The effects of short-term and long-term air pollution exposure on meibomian gland dysfunction

We aim to assess the effects of different air pollutants on meibomian gland dysfunction (MGD). As a prospective multicenter study, 864 patients were recruited from four different regions (i.e., coal, oil, steel, and living). The oil region had a significantly lower temperature and higher O₃ and SO₂ concentrations than other regions. Notably, participants in oil region presented with more frequent and serious MGD signs and higher cytokine levels (median interleukin 6 [IL-6] in oil: 2.66, steel: 0.96, coal: 0.38, living: 0.56; IL-8 in oil: 117.52, steel: 46.94, coal: 26.89, living: 33; vascular endothelial growth factor [VEGF] in oil: 25.09, steel: 14.02, coal: 14.02, living: 28.47). The short-term fluctuations of cytokine levels were associated with the changes in gas levels (PM_2.5 and IL-8: β = 0.016 [0.004–0.029]; O₃ and IL-6: β = 0.576 [0.386–0.702]; O₃ and IL-8: β = 0.479 [0.369–0.890]; SO₂ and VEGF: β = 0.021 [0.001–0.047]). After long-term exposure, lid margin neovascularization (r = 0.402), meibomian gland (MG) expression (r = 0.377), MG secretion (r = 0.303), MG loss (r = 0.404), and tear meniscus height (r = − 0.345) were moderately correlated with air quality index (AQI). Individuals in oil region had more serious MGD signs and higher cytokine levels. MGD is susceptible to long-term exposure to high AQI.

The Impact of Short-Term Outdoor Air Pollution on Clinical Status and Prognosis of Hospitalized Patients with Coronary Artery Disease Treated with Percutaneous Coronary Intervention

BACKGROUND

The aim of this study was to determine the influence of acute exposure to air pollutants on patients' profile, short- and mid-term outcomes of hospitalized patients with coronary artery disease (CAD) treated with coronary angioplasty.

METHODS

Out of 19,582 patients of the TERCET Registry, 7521 patients living in the Upper Silesia and Zaglebie Metropolis were included. The study population was divided into two groups according to the diagnosis of chronic (CCS) or acute coronary syndromes (ACS). Data on 24-h average concentrations of particulate matter with aerodynamic diameter <10 μm (PM10), sulfur dioxide (SO2), nitrogen monoxide (NO), nitrogen dioxide (NO2), and ozone (O3) were obtained from eight environmental monitoring stations.

RESULTS

No significant association between pollutants' concentration with baseline characteristic and in-hospital outcomes was observed. In the ACS group at 30 days, exceeding the 3rd quartile of PM10 was associated with almost 2-fold increased risk of adverse events and more than 3-fold increased risk of death. Exceeding the 3rd quartile of SO2 was connected with more than 8-fold increased risk of death at 30 days. In the CCS group, exceeding the 3rd quartile of SO2 was linked to almost 2,5-fold increased risk of 12-month death.

CONCLUSIONS

The acute increase in air pollutants' concentrations affect short- and mid-term prognosis in patients with CAD.

Higher ambient nitrogen dioxide is associated with an elevated risk of hospital-acquired acute kidney injury

BACKGROUND

Previous studies have suggested that long-term exposure to air pollution increases the risk of chronic kidney disease and its progression. However, the effect of air pollution on the risk of acute kidney injury (AKI) has not been studied. We aim to evaluate the transient effect of air pollution on the risk of hospital-acquired AKI (HA-AKI).

METHODS

We selected from the Epidemiology of AKI in Chinese Hospitalized patients cohort AKI cases in which the onset date could be unambiguously determined. We obtained city-specific daily averages of the ambient level of particulate matter (2.5 μm and 10 μm), carbon monoxide, nitrogen dioxide (NO₂), sulfur dioxide (SO₂) and ozone (O₃) from the Ministry of Environmental Protection of China. We used the time-stratified case-crossover approach to examine the association between the ambient level of air pollutants and the risk of HA-AKI in the selected cases.

RESULTS

A total of 11 293 AKI cases that met the inclusion and exclusion criteria were selected. In univariable analysis, the ambient levels of NO₂ and SO₂ were significantly associated with the risk of HA-AKI. In the multivariable analysis that incorporated all six pollutants in the same model, NO₂ was the sole pollutant whose level remained associated with the risk of AKI (P < 0.001). The relationship between the level of NO₂ and the risk of HA-AKI appeared to be linear, with an estimated odds ratio of 1.063 (95% confidence interval 1.026-1.101) for each increment of 1 median absolute deviation in the exposure. The association was consistent across the subgroups stratified by age, gender, baseline estimated glomerular filtration rate, AKI severity, need for intensive care and season.

CONCLUSIONS

Higher ambient levels of NO₂ are associated with an increased risk of HA-AKI in hospitalized adults in China.

Risk and Resilience: How Is the Health of Older Adults and Immigrant People Living in Canada Impacted by Climate- and Air Pollution-Related Exposures?

BACKGROUND

In the rapidly shifting Canadian climate, an ageing population, and increased migration, a greater understanding of how local climate and air pollution hazards impact older adults and immigrant populations will be necessary for mitigating and adapting to adverse health impacts.

OBJECTIVES

To explore the reported health impacts of climate change and air pollution exposures in older adults and immigrant people living in Canada, identify known factors influencing risk and resilience in these populations and gaps in the literature.

METHODS

We searched for research focused on older adults and immigrants living in Canada, published from 2010 onward, where the primary exposures were related to climate or air pollution. We extracted data on setting, exposures, health outcomes, and other relevant contextual factors.

RESULTS AND DISCUSSION

We identified 52 eligible studies, most focused in Ontario and Quebec. Older people in Canada experience health risks due to climate and air pollution exposures. The extent of the risk depends on multiple factors. We found little information about the climate- and air pollution-related health impacts experienced by immigrant communities.

CONCLUSIONS

Further research about climate- and air pollution-related exposures, health, and which factors promote or reduce resiliency in Canada's older adults and immigrant communities is necessary.

Temporal and spatial effect of air pollution on hospital admissions for myocardial infarction: a case-crossover study

BACKGROUND

In studies showing associations between ambient air pollution and myocardial infarction (MI), data have been lacking on the inherent spatial variability of air pollution. The aim of this study was to determine whether the long-term spatial distribution of air pollution influences short-term temporal associations between air pollution and admission to hospital for MI.

METHODS

We identified adults living in Calgary who were admitted to hospital for an MI between 2004 and 2012. We evaluated associations between short-term exposure to air pollution (ozone [O₃], nitrogen dioxide [NO₂], sulfur dioxide [SO₂], carbon monoxide [CO], particulate matter < 10 μm in diameter [PM₁₀] and particulate matter < 2.5 μm in diameter [PM_2.5]), and hospital admissions for MI using a time-stratified, case-crossover study design. Air Quality Health Index (AQHI) scores were calculated from a composition of O₃, NO₂ and PM_2.5. Conditional logistic regression models were stratified by low, medium and high levels of neighbourhood NO₂ concentrations derived from land use regression models; results of these analyses are presented as odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

From 2004 to 2012, 6142 MIs were recorded in Calgary. Individuals living in neighbourhoods with higher long-term air pollution concentrations were more likely to be admitted to hospital for MI after short-term elevations in air pollution (e.g., 5-day average NO₂: OR 1.20, 95% CI 1.03-1.40, per interquartile range [IQR]) as compared with regions with lower air pollution (e.g., 5-day average NO₂: OR 0.90, 95% CI 0.78-1.04, per IQR). In high NO₂ tertiles, the AQHI score was associated with MI (e.g., 5-day average OR 1.13, 95% CI 1.02-1.24, per IQR; 3-day average OR 1.13, 95% CI 1.04-1.23, per IQR).

INTERPRETATION

Our results show that the effect of air pollution on hospital admissions for MI was stronger in areas with higher NO₂ concentrations than that in areas with lower NO₂ concentrations. Individuals living in neighbourhoods with higher traffic-related pollution should be advised of the health risks and be attentive to special air quality warnings.

Short-term exposure to carbon monoxide and myocardial infarction: A systematic review and meta-analysis

BACKGROUND

Previous studies suggest an association between short-term exposure to carbon monoxide and myocardial infarction. We performed a systematic review and meta-analysis to assess current evidence on this association to support the update of the World Health Organization (WHO) Global Air Quality Guidelines.

METHODS

We searched Medline, Embase and Cochrane Central Register of Controlled Trials to update the evidence published in a previous systematic review up to 30th September 2018 for studies investigating the association between short-term exposure to ambient carbon monoxide (up to lag of seven days) and emergency department visits or hospital admissions and mortality due to myocardial infarction. Two reviewers assessed potentially eligible studies and performed data extraction independently. Random-effects meta-analysis was used to derive the pooled risk estimate per 1 mg/m³ increase in ambient carbon monoxide concentration. Risk of bias in individual studies was assessed using a domain-based assessment tool. The overall certainty of the body of evidence was evaluated using an adapted certainty of evidence assessment framework.

RESULTS

We evaluated 1,038 articles from the previous review and our updated literature search, of which, 26 satisfied our inclusion criteria. Overall, myocardial infarction was associated with exposure to ambient carbon monoxide concentration (risk ratio of 1.052, 95% confidence interval 1.017-1.089 per 1 mg/m³ increase). A third of studies were assessed to be at high risk of bias (RoB) due to inadequate adjustment for confounding. Using an adaptation of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework, the overall evidence was assessed to be of moderate certainty.

CONCLUSIONS

This review demonstrated that the pooled risk ratio for myocardial infarction was 1.052 (95% CI 1.017-1.089) per 1 mg/m³ increase in ambient carbon monoxide concentration. However, very few studies originated from low- and middle-income countries.

Sandstorm weather is a risk factor for mortality in ischemic heart disease patients in the Hexi Corridor, northwestern China

Ischemic heart disease (IHD) is one of the leading causes of mortality worldwide. Moreover, the effects of air pollution have been associated with several cardiovascular diseases (CVDs). The relationship between sandstorm weather and IHD is unknown. The Hexi Corridor is located in northwestern China and is a typical desert region comprising a large area of desert with a high incidence of sandstorms. This study aimed to explore the association between sandstorm weather and IHD-related mortality in this area. We acquired meteorological data of sandstorm weather from 2006 to 2015 from the Gansu Meteorological Bureau, and data regarding deaths due to IHD in five cities within the Hexi Corridor were collected from the death registration system of the Center for Disease Control of Gansu during the same period. Two other cities with few sandstorm events were selected as control regions. The time series method of the generalized additive model (GAM) was used to assess the association between sandstorm weather and IHD-related mortality in the Hexi Corridor. The results showed that the frequency of sandstorms in the Hexi Corridor was higher than that in the control regions (5.48% vs 1.64%, P < 0.01), and IHD-related mortality was correspondingly higher than that in the control regions (56.42/100,000 vs 45.62/100,000, P < 0.01). After stratification by gender, age, and urban/rural residence, a significant difference in IHD-related mortality was also noted (P < 0.05). Significant associations were found between sandstorm weather and IHD-related mortality, and the relative risk (RR) increased with an increasing number of days of sandstorm weather. According to the monthly and annual analyses, the mortality rate corresponded to sandstorm frequency. Our data suggest a positive association between sandstorm weather and IHD-related mortality in the Hexi Corridor of Gansu Province. The underlying mechanism requires further study.

Association of Long-Term Exposure to Particulate Matter and Ozone With Health Status and Mortality in Patients After Myocardial Infarction

BACKGROUND

Long-term exposure to particulate matter <2.5 µm in diameter (PM_2.5) and ozone has been associated with the development and progression of cardiovascular disease and, in the case of PM_2.5, higher cardiovascular mortality. Whether exposure to PM_2.5 and ozone is associated with patients' health status and quality of life is unknown. We used data from 2 prospective myocardial infarction (MI) registries to assess the relationship between long-term PM_2.5 and ozone exposure with health status outcomes 1 year after an MI.

METHODS AND RESULTS

TRIUMPH (Translational Research Investigating Underlying Disparities in Acute Myocardial Infarction) and PREMIER (Prospective Registry Evaluating Myocardial Infarction: Events and Recovery) enrolled patients presenting with MI at 31 US hospitals between 2003 and 2008. One year later, patients were assessed with the disease-specific Seattle Angina Questionnaire, and 5-year mortality was assessed with the Centers for Disease Control's National Death Index. Individual patients' exposures to PM_2.5 and ozone over the year after their MI were estimated from the Environment Protection Agency's Fused Air Quality Surface Using Downscaling tool that integrates monitoring station data and atmospheric models to predict daily air pollution exposure at the census tract level. We assessed the association of exposure to ozone and PM_2.5 with 1-year health status and mortality over 5 years using regression models adjusting for age, sex, race, socioeconomic status, date of enrollment, and comorbidities. In completely adjusted models, higher PM_2.5 and ozone exposure were independently associated with poorer Seattle Angina Questionnaire summary scores at 1-year (β estimate per +1 SD increase =-0.8 [95% CI, -1.4 to -0.3; P=0.002] for PM_2.5 and -0.9 [95% CI, -1.3 to -0.4; P<0.001] for ozone). Moreover, higher PM_2.5 exposure, but not ozone, was independently associated with greater mortality risk (hazard ratio =1.13 per +1 SD [95% CI, 1.07-1.20; P<0.001]).

CONCLUSIONS

In our study, greater exposure to PM_2.5 and ozone was associated with poorer 1-year health status following an MI, and PM_2.5 was associated with increased risk of 5-year death.

Systematic review and meta-analysis of case-crossover and time-series studies of short term outdoor nitrogen dioxide exposure and ischemic heart disease morbidity

BACKGROUND

Nitrogen dioxide (NO₂) is a pervasive urban pollutant originating primarily from vehicle emissions. Ischemic heart disease (IHD) is associated with a considerable public health burden worldwide, but whether NO₂ exposure is causally related to IHD morbidity remains in question. Our objective was to determine whether short term exposure to outdoor NO₂ is causally associated with IHD-related morbidity based on a synthesis of findings from case-crossover and time-series studies.

METHODS

MEDLINE, Embase, CENTRAL, Global Health and Toxline databases were searched using terms developed by a librarian. Screening, data extraction and risk of bias assessment were completed independently by two reviewers. Conflicts between reviewers were resolved through consensus and/or involvement of a third reviewer. Pooling of results across studies was conducted using random effects models, heterogeneity among included studies was assessed using Cochran's Q and I² measures, and sources of heterogeneity were evaluated using meta-regression. Sensitivity of pooled estimates to individual studies was examined using Leave One Out analysis and publication bias was evaluated using Funnel plots, Begg's and Egger's tests, and trim and fill.

RESULTS

Thirty-eight case-crossover studies and 48 time-series studies were included in our analysis. NO₂ was significantly associated with IHD morbidity (pooled odds ratio from case-crossover studies: 1.074 95% CI 1.052-1.097; pooled relative risk from time-series studies: 1.022 95% CI 1.016-1.029 per 10 ppb). Pooled estimates for case-crossover studies from Europe and North America were significantly lower than for studies conducted elsewhere. The high degree of heterogeneity among studies was only partially accounted for in meta-regression. There was evidence of publication bias, particularly for case-crossover studies. For both case-crossover and time-series studies, pooled estimates based on multi-pollutant models were smaller than those from single pollutant models, and those based on older populations were larger than those based on younger populations, but these differences were not statistically significant.

CONCLUSIONS

We concluded that there is a likely causal relationship between short term NO₂ exposure and IHD-related morbidity, but important uncertainties remain, particularly related to the contribution of co-pollutants or other concomitant exposures, and the lack of supporting evidence from toxicological and controlled human studies.

Inverse probability weighted distributed lag effects of short-term exposure to PM2.5 and ozone on CVD hospitalizations in New England Medicare participants - Exploring the causal effects

BACKGROUND

Although many studies have established significant associations between short-term air pollution and the risk of getting cardiovascular diseases, there is a lack of evidence based on causal distributed lag modeling.

METHODS

Inverse probability weighting (ipw) propensity score models along with conditional logistic outcome regression models based on a case-crossover study design were applied to get the causal unconstrained distributed (lag0-lag5) as well as cumulative lag effect of short-term exposure to PM2.5/Ozone on hospital admissions of acute myocardial infarction (AMI), congestive heart failure (CHF) and ischemic stroke (IS) among New England Medicare participants during 2000-2012. Effect modification by gender, race, secondary diagnosis of Chronic Obstructive Pulmonary Diseases (COPD) and Diabetes (DM) was explored.

RESULTS

Each 10 μg/m3 increase in lag0-lag5 cumulative PM2.5 exposure was associated with an increase of 4.3% (95% confidence interval: 2.2%, 6.4%, percentage change) in AMI hospital admission rate, an increase of 3.9% (2.4%, 5.5%) in CHF rate and an increase of 2.6% (0.4%, 4.7%) in IS rate. A weakened lagging effect of PM2.5 from lag0 to lag5 could be observed. No cumulative short-term effect of ozone on CVD was found. People with secondary diagnosis of COPD, diabetes, female gender and black race are sensitive population.

CONCLUSIONS

Based on our causal distributed lag modeling, we found that short-term exposure to an increased ambient PM2.5 level had the potential to induce higher risk of CVD hospitalization in a causal way. More attention should be paid to population of COPD, diabetes, female gender and black race.

Effect of air pollution on hospitalization for acute exacerbation of chronic obstructive pulmonary disease, stroke, and myocardial infarction

This study aims to analyze the acute effects of PM_2.5, PM₁₀, SO₂, NO₂, and O₃ on hospitalizations for acute exacerbation of chronic obstructive pulmonary disease (AECOPD), stroke, and myocardial infarction (MI) from 2014 to 2017 in Shenyang, China. Hospitalization records for AECOPD (17,655), stroke (276,736) and MI (26,235) and air pollutions concentration data (PM_2.5, PM₁₀, SO₂, NO₂, and O₃) were collected. A generalized additive model (GAM) was utilized to determine the impact of air pollutants on the relative risk (RR) of hospitalization for AECOPD, stroke, and MI. Stratified analysis for AECOPD was based on gender and age. It was based on gender, age, hypertension, and diabetes for stroke, and for MI it was based on gender, age, and coronary atherosclerosis. The lag effect for AECOPD in terms of gender analysis occurred at lag3-lag5. The hospitalization risk for stroke with hypertension due to SO₂ and NO₂ was greater than that of stroke without hypertension. The risk of hospitalization for stroke with hypertension as a comorbidity due to O₃ was lower than without hypertension. The risk of hospitalization for MI combined with coronary atherosclerosis due to PM_2.5, PM₁₀, or NO₂ was higher than that of hospitalizations for MI without coronary atherosclerosis. Air pollution increased the rate of hospitalization for AECOPD. SO₂ and O₃ appeared protective for stroke patients with coronary atherosclerosis. PM_2.5, PM₁₀, and NO₂ had no influence on total hospitalization for myocardial infarction.

Acute effects of air pollutants on daily mortality and hospitalizations due to cardiovascular and respiratory diseases

Background

Chiang Dao is one of the districts in Chiang Mai, Thailand facing high level of seasonal air pollution every year, the exposure of community dwellers to outdoor air pollutants 24 hours a day during seasonal smog period because of their open-air housing style, and agricultural occupational hazard. In addition, Chiang Dao hospital is the only available hospital serving the community with open-air wards; therefore we could certainly to identify the association between air pollution and mortality of hospitalized patients. Thus, the aim of this study was to determine the association between daily average seasonal air pollutants and daily mortality of hospitalized patients and community dwellers as well as emergency and hospitalization visits for serious respiratory, cardiovascular, and cerebrovascular diseases.

Methods

This time series study was conducted between 1 March 2016 and 31 March 2017. The association of various air pollutant concentrations including particulate matter diameter less than 10 and 2.5 microns (PM₁₀ and PM_2.5), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), carbon monoxide (CO), ozone (O₃) and daily mortality of hospitalized patients and community dwellers as well as relationship with frequencies of serious respiratory, cardiovascular, and cerebrovascular diseases were analyzed using a general linear model with Poisson distribution.

Results

Only PM_2.5 was found to be associated with increased daily mortality of hospitalized patients (lag day 6, adjusted RR =1.153, 95% CI: 1.001-1.329), whereas PM₁₀, PM_2.5, NO₂, and O₃ were associated with increased daily non-accidental mortality of community dwellers (lag day 0-7, adjusted RR =1.006-1.040, 95% CI: 1.000-1.074). For acute serious respiratory events; PM₁₀ and PM_2.5 were associated with acute exacerbation of chronic obstructive pulmonary disease (AECOPD), while SO₂, CO, and O₃ were associated with emergency visits for community-acquired pneumonia (CAP). O₃ was associated with emergency visits for heart failure (HF), NO₂ with emergency visits for myocardial infarction (MI), and SO₂ with hospitalized visits for cerebrovascular accident (CVA).

Conclusions

Seasonal air pollutants were found to be associated with higher mortality among hospitalized patients and community dwellers with varying effects on severe acute respiratory, cardiovascular, and cerebrovascular diseases.

The effect of air pollution on hospitalization of individuals with respiratory and cardiovascular diseases in Jinan, China

To analyze the short-term effects of air pollution on the hospitalization rates of individuals with acute exacerbation of chronic obstructive pulmonary disease (AECOPD), stroke, and myocardial infarction (MI) after adjusting for confounding factors including weather, day of the week, holidays, and long-term trends in Jinan, China.Hospitalization information was extracted based on data from the primary class 3-A hospitals in Jinan from 2013 to 2015. The concentrations of PM2.5, PM10, SO2, NO2, and O3 were obtained from Jinan Environment Monitoring Center. The relative risk and 95% confidence intervals of AECOPD, stroke, and MI were estimated using generalized additive models with quasi-Poisson distribution in the mgcv package, using R software, version 1.0.136.The incremental increased concentrations of particulate pollutants including PM2.5 and PM10 were significantly associated with increased risk of hospitalization of AECOPD, stroke, and MI, and the adverse influences of PM2.5 on these diseases were generally stronger than that of PM10. The incremental increased concentrations of gaseous pollutants including SO2, NO2, and O3 were significantly associated with increased risk of hospitalization of stroke and MI in this population.Air pollution has significant adverse effects on hospitalization rates of individuals with AECOPD, stroke, and MI in Jinan, China.

Evaluation of a meta-analysis of air quality and heart attacks, a case study

It is generally acknowledged that claims from observational studies often fail to replicate. An exploratory study was undertaken to assess the reliability of base studies used in meta-analysis of short-term air quality-myocardial infarction risk and to judge the reliability of statistical evidence from meta-analysis that uses data from observational studies. A highly cited meta-analysis paper examining whether short-term air quality exposure triggers myocardial infarction was evaluated as a case study. The paper considered six air quality components - carbon monoxide, nitrogen dioxide, sulphur dioxide, particulate matter 10 μm and 2.5 μm in diameter (PM10 and PM2.5), and ozone. The number of possible questions and statistical models at issue in each of 34 base papers used were estimated and p-value plots for each of the air components were constructed to evaluate the effect heterogeneity of p-values used from the base papers. Analysis search spaces (number of statistical tests possible) in the base papers were large, median = 12,288 (interquartile range = 2496 - 58,368), in comparison to actual statistical test results presented. Statistical test results taken from the base papers may not provide unbiased measures of effect for meta-analysis. Shapes of p-value plots for the six air components were consistent with the possibility of analysis manipulation to obtain small p-values in several base papers. Results suggest the appearance of heterogeneous, researcher-generated p-values used in the meta-analysis rather than unbiased evidence of real effects for air quality. We conclude that this meta-analysis does not provide reliable evidence for an association of air quality components with myocardial risk.

Impact of smoke-free legislation on acute myocardial infarction and stroke mortality: Tianjin, China, 2007-2015

BACKGROUND

Smoke-free legislation is an effective way to protect the population from the harms of secondhand smoke and has been implemented in many countries. On 31 May 2012, Tianjin became one of the few cities in China to implement smoke-free legislation. We investigated the impact of smoke-free legislation on mortality due to acute myocardial infarction (AMI) and stroke in Tianjin.

METHODS

An interrupted time series design adjusting for underlying secular trends, seasonal patterns, population size changes and meteorological factors was conducted to analyse the impact of the smoke-free law on the weekly mortality due to AMI and stroke. The study period was from 1 January 2007 to 31 December 2015, with a 3.5-year postlegislation follow-up.

RESULTS

Following the implementation of the smoke-free law, there was a decline in the annual trends of AMI and stroke mortality. An incremental 16% (rate ratio (RR): 0.84; 95% CI: 0.83 to 0.85) decrease per year in AMI mortality and a 2% (RR: 0.98; 95% CI: 0.97 to 0.99) annual decrease in stroke mortality among the population aged ≥35 years in Tianjin was observed. Immediate postlegislation reductions in mortality were not statistically significant. An estimated 10 000 (22%) AMI deaths were prevented within 3.5 years of the implementation of the law.

CONCLUSION

The smoke-free law in Tianjin was associated with reductions in AMI mortality. This study reinforces the need for large-scale, effective and comprehensive smoke-free laws at the national level in China.

Cytotoxicity induced by fine particulate matter (PM2.5) via mitochondria-mediated apoptosis pathway in human cardiomyocytes

Although the strongly causal associations were between fine particulate matter (PM_2.5) and cardiovascular disease, the toxic effect and potential mechanism of PM_2.5 on heart was poorly understood. Thus, the aim of this study was to evaluate the cardiac toxicity of PM_2.5 exposure on human cardiomyocytes (AC16). The cell viability was decreased while the LDH release was increased in a dose-dependent way after AC16 exposed to PM_2.5. The reactive oxygen species (ROS) generation and production of malondialdehyde (MDA) were increased followed by the decreasing in superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). The damage of mitochondria was observed by ultra-structural analysis and MMP measurement. The apoptotic rate of AC16 were markedly elevated which was triggered by PM_2.5. In addition, the proteins involved in mitochondria- mediated apoptosis pathway were measured. The protein levels of Caspase-3, Caspase-9 and Bax were up-regulated while the anti-apoptotic protein, Bcl-2 was down-regulated after AC16 exposed to PM_2.5. In summary, our results demonstrated that mitochondria-mediated apoptosis pathway played a critical role in PM_2.5-induced myocardial cytotoxicity in AC16, which suggested that PM_2.5 may contribute to cardiac dysfunction.

Eliminating systematic bias from case-crossover designs

Case-crossover designs have been widely applied to epidemiological and medical investigations of associations between short-term exposures and risk of acute adverse health events. Much effort has been made in literature on understanding source of confounding and reducing systematic bias by reference-select strategies. In this paper, we explored the nature of bias in the ambi-directional and time-stratified case-crossover designs via simulation using actual air pollution data from urban Edmonton, Alberta, Canada. We further proposed a calibration approach for eliminating systematic bias in estimates (coefficient estimate, 95% confident interval, and p-value). Bias check for coefficient estimation, size check and power check for significance test were done via simulation experiments to show advantages of the calibrated case-crossover studies over the ones without calibration. An application was done to investigate associations between air pollutants and acute myocardial infarction hospitalizations in urban Edmonton. In conclusion, systematic bias in a case-crossover design is often unavoidable, leading to an obvious bias in the estimated effect and an unreliable p value in the significance test. The proposed calibration technique provides an efficient approach to eliminating systematic bias in a case-crossover study.

The association between exposure to air pollutants including PM10, PM2.5, ozone, carbon monoxide, sulfur dioxide, and nitrogen dioxide concentration and the relative risk of developing STEMI: A case-crossover design

BACKGROUND

Unfavorable associations between air pollution and myocardial infarction are broadly investigated in recent studies and some of them revealed considerable associations; however, controversies exists between these investigations with regard to culprit components of air pollution and significance of correlation between myocardial infarction risk and air pollution.

METHODS

The association between exposure to PM₁₀, PM_2.5, ozone, carbon monoxide, sulfur dioxide, and nitrogen dioxide concentration of background air that residents of Tehran, the capital city of Iran, which is ranked as the most air polluted city of Iran and the relative risk of developing ST-elevation myocardial infarction (STEMI) were investigated by a case-crossover design. Our study included 208 patients admitted with a diagnosis of STEMI and undergone primary percutaneous intervention. Air pollutant concentration was averaged in 24-h windows preceding the time of onset of myocardial infarction for the case period. Besides, the mean level of each element of air pollution of the corresponding time in one week, two weeks and three weeks before onset of myocardial infarction, was averaged separately for each day as one control periods. Thus, 624 control periods were included in our investigation such that. Each patient is matched and compared with him/herself.

RESULTS

The mean level of PM₁₀ in case periods (61.47µg/m³) was significantly higher than its level in control periods (57.86µg/m³) (P-value = 0.019, 95% CI: 1.002-1.018, RR = 1.010). Also, the mean level of PM_2.5 in case periods (95.40µg/m³) was significantly higher than that in control days (90.88µg/m³) (P-value = 0.044, 95% CI: 1.001-1.011, RR = 1.006). The level of other components including NO₂, SO₂, CO and O₃ showed no significant differences between case and control periods. A 10µg/m³ increase in PM₁₀ and PM_2.5 would result in 10.10% and 10.06% increase in STEMI event, respectively. Furthermore, the results of sub-group analysis showed that older patients (equal or more than 60 year-old), diabetic patients, non-hypertensive ones and patients with more than one diseased vessel may be more vulnerable to the harmful effect of particular matters including PM₁₀ and PM_2.5 on development of STEMI.

CONCLUSION

Air pollution is a worldwide pandemic with great potential to cause terrible events especially cardiovascular ones. PM_2.5 and PM₁₀ are amongst ambient air pollutant with a high risk of developing STEMI. Thus, more restrictive legislations should be applied to define a safe level of indoor and outdoor air pollutant production.

Exploratory Temporal and Spatial Analysis of Myocardial Infarction Hospitalizations in Calgary, Canada

Spatial and temporal analyses are critical to understand the pattern of myocardial infarction (MI) hospitalizations over space and time, and to identify their underlying determinants. In this paper, we analyze MI hospitalizations in Calgary from 2004 to 2013, stratified by age and gender. First, a seasonal trend decomposition analyzes the seasonality; then a linear regression models the trend component. Moran's I and hot spot analyses explore the spatial pattern. Though exploratory, results show that most age and gender groups feature a statistically significant decline over the 10 years, consistent with previous studies in Canada. Decline rates vary across ages and genders, with the slowest decline observed for younger males. Each gender exhibits a seasonal pattern with peaks in both winter and summer. Spatially, MI hot spots are identified in older communities, and in socioeconomically and environmentally disadvantaged communities. In the older communities, higher MI rates appear to be more highly associated with demographics. Conversely, worse air quality appears to be locally associated with higher MI incidence in younger age groups. The study helps identify areas of concern, where MI hot spots are identified for younger age groups, suggesting the need for localized public health policies to target local risk factors.

Seasonal Effect on Association between Atmospheric Pollutants and Hospital Emergency Room Visit for Stroke

BACKGROUND

The relationship between air pollution and stroke is conflicting. This study was conducted to document the relationship between daily changes in atmospheric pollutants and hospital emergency room visits (ERVs) for stroke.

METHODS

Data of daily hospital ERVs for stroke and atmospheric pollutants in Changsha city between 2008 and 2009 were collected. Using a time-stratified bidirectional case-crossover design, we analyzed the association between atmospheric pollutants and stroke incidence in 4 seasons.

RESULTS

In the single-pollutant model, we found changes in sulfur dioxide (SO₂), nitrogen dioxide (NO₂), and particulate matters (PM₁₀) were significantly associated with cerebral hemorrhage and cerebral infarction (P < .05) in lags of 0-2 days in autumn. A 10-µg/m³ increase in SO₂ in autumn was significantly associated with ERVs for both cerebral hemorrhage (odds ratio [OR], 1.166; 95% confidence interval [CI], 1.012-1.343) and cerebral infarction (OR, 1.214; 95% CI, 1.018-1.448). NO₂ in autumn was significantly associated with ERVs for cerebral hemorrhage and infarction with OR = 1.162 (95% CI, 1.005-1.344) and OR = 1.137 (95% CI, 1.011-1.279), respectively. PM₁₀ in autumn was significantly associated with ERVs for cerebral hemorrhage and infarction with OR = 1.147 (95% CI, 1.045-1.259) and OR = 1.091 (95% CI, 1.019-1.168), respectively. Results of the multipollutant model showed that in autumn after PM₁₀ and NO₂ adjustment, only a 10-µg/m³ increase in SO₂ was significantly associated with ERVs for cerebral infarction (OR, 1.158; 95% CI, 1.006-1.333; P < .05). SO₂, NO₂, and PM₁₀ were not associated with ERVs for cerebral hemorrhage (P > .05).

CONCLUSIONS

This study demonstrates that the change in atmospheric SO₂ levels in Changsha is significantly associated with the stroke incidence in autumn.

Health risk of inhalation exposure to sub-10 µm particulate matter and gaseous pollutants in an urban-industrial area in South Africa: an ecological study

OBJECTIVE

To assess the health risks associated with exposure to particulate matter (PM10), sulphur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO) and ozone (O3).

DESIGN

The study is an ecological study that used the year 2014 hourly ambient pollution data.

SETTING

The study was conducted in an industrial area located in Pretoria West, South Africa. The area accommodates a coal-fired power station, metallurgical industries such as a coke plant and a manganese smelter.

DATA AND METHOD

Estimate of possible health risks from exposure to airborne PM10, SO2, NO2, CO and O3 was performed using the US Environmental Protection Agency human health risk assessment framework. A scenario-assessment approach where normal (average exposure) and worst-case (continuous exposure) scenarios were developed for intermediate (24-hour) and chronic (annual) exposure periods for different exposure groups (infants, children, adults). The normal acute (1-hour) exposure to these pollutants was also determined.

OUTCOME MEASURES

Presence or absence of adverse health effects from exposure to airborne pollutants.

RESULTS

Average annual ambient concentration of PM10, NO2 and SO2 recorded was 48.3±43.4, 11.50±11.6 and 18.68±25.4 µg/m3, respectively, whereas the South African National Ambient Air Quality recommended 40, 40 and 50 µg/m3 for PM10, NO2 and SO2, respectively. Exposure to an hour's concentration of NO2, SO2, CO and O3, an 8-hour concentration of CO and O3, and a 24-hour concentration of PM10, NO2 and SO2 will not likely produce adverse effects to sensitive exposed groups. However, infants and children, rather than adults, are more likely to be affected. Moreover, for chronic annual exposure, PM10, NO2 and SO2 posed a health risk to sensitive individuals, with the severity of risk varying across exposed groups.

CONCLUSIONS

Long-term chronic exposure to airborne PM10, NO2 and SO2 pollutants may result in health risks among the study population.

Myocardial infarction, ST-elevation and non-ST-elevation myocardial infarction and modelled daily pollution concentrations: a case-crossover analysis of MINAP data

Objectives

To investigate associations between daily concentrations of air pollution and myocardial infarction (MI), ST-elevation MI (STEMI) and non-ST-elevation MI (NSTEMI).

Methods

Modelled daily ground-level gaseous, total and speciated particulate pollutant concentrations and ground-level daily mean temperature, all at 5 km×5 km horizontal resolution, were linked to 202 550 STEMI and 322 198 NSTEMI events recorded on the England and Wales Myocardial Ischaemia National Audit Project (MINAP) database. The study period was 2003–2010. A case-crossover design was used, stratified by year, month and day of the week. Data were analysed using conditional logistic regression, with pollutants modelled as unconstrained distributed lags 0–2 days. Results are presented as percentage change in risk per 10 µg/m³ increase in the pollutant relevant metric, having adjusted for daily mean temperature, public holidays, weekly influenza consultation rates and a sine-cosine annual cycle.

Results

There was no evidence of an association between MI or STEMI and any of O₃, NO₂, PM_2.5, PM₁₀ or selected PM_2.5 components (sulfate and elemental carbon). For NSTEMI, there was a positive association with daily maximum 1-hour NO₂ (0.27% (95% CI 0.01% to 0.54%)), which persisted following adjustment for O₃ and adjustment for PM_2.5. The association appeared to be confined to the midland and southern regions of England and Wales.

Conclusions

The study found no evidence of an association between the modelled pollutants (including components) investigated and STEMI but did find some evidence of a positive association between NO₂ and NSTEMI. Confirmation of this association in other studies is required.

Potential Harmful Effects of PM2.5 on Occurrence and Progression of Acute Coronary Syndrome: Epidemiology, Mechanisms, and Prevention Measures

The harmful effects of particulate matter with an aerodynamic diameter of <2.5 µm (PM_2.5) and its association with acute coronary syndrome (ACS) has gained increased attention in recent years. Significant associations between PM_2.5 and ACS have been found in most studies, although sometimes only observed in specific subgroups. PM_2.5-induced detrimental effects and ACS arise through multiple mechanisms, including endothelial injury, an enhanced inflammatory response, oxidative stress, autonomic dysfunction, and mitochondria damage as well as genotoxic effects. These effects can lead to a series of physiopathological changes including coronary artery atherosclerosis, hypertension, an imbalance between energy supply and demand to heart tissue, and a systemic hypercoagulable state. Effective strategies to prevent the harmful effects of PM_2.5 include reducing pollution sources of PM_2.5 and population exposure to PM_2.5, and governments and organizations publicizing the harmful effects of PM_2.5 and establishing air quality standards for PM_2.5. PM_2.5 exposure is a significant risk factor for ACS, and effective strategies with which to prevent both susceptible and healthy populations from an increased risk for ACS have important clinical significance in the prevention and treatment of ACS.

Evaluation of Chronic Obstructive Pulmonary Disease (COPD) attributed to atmospheric O3, NO2, and SO2 using Air Q Model (2011-2012 year)

Chronic obstructive pulmonary disease (COPD) is an important disease worldwide characterized by chronically poor airflow. The economic burden of COPD on any society can be enormous if not managed. We applied the approach proposed by the World Health Organization (WHO) using the AirQ2.2.3 software developed by the WHO European Center for Environment and Health on air pollutants in Tabriz (Iran) (2011-2012 year). A 1h average of concentrations of ozone (O3), daily average concentrations of nitrogen dioxide (NO2) and sulfur dioxide (SO2) were used to assess human exposure and health effect in terms of attributable proportion of the health outcome and annual number of excess cases of Hospital Admissions for COPD (HA COPD). The results of this study showed that 2% (95% CI: 0.8-3.1%) of HA COPD were attributed to O3 concentrations over 10 μg/m(3). In addition, 0.7 % (95% CI: 0.1-1.8%) and 0.5% (95% CI: 0-1%) of HA COPD were attributed to NO2 and SO2 concentrations over 10 μg/m(3) respectively. In this study, we have shown that O3, NO2 and SO2 have a significant impact on COPD hospitalization. Given these results the policy decisions are needed in order to reduce the chronic pulmonary diseases caused by air pollution and furthermore better quantification studies are recommended.