Roadway proximity and risk of sudden cardiac death in women

Air Pollution and Temperature: a Systematic Review of Ubiquitous Environmental Exposures and Sudden Cardiac Death

PURPOSE OF REVIEW

Environmental exposures have been associated with increased risk of cardiovascular mortality and acute coronary events, but their relationship with out-of-hospital cardiac arrest (OHCA) and sudden cardiac death (SCD) remains unclear. SCD is an important contributor to the global burden of cardiovascular disease worldwide.

RECENT FINDINGS

Current literature suggests a relationship between environmental exposures and cardiovascular disease, but their relationship with OHCA/SCD remains unclear. A literature search was conducted in PubMed, Embase, Web of Science, and Global Health. Of 5138 studies identified by our literature search, this review included 30 studies on air pollution, 42 studies on temperature, 6 studies on both air pollution and temperature, and 1 study on altitude exposure and OHCA/SCD. Particulate matter air pollution, ozone, and both hot and cold temperatures are associated with increased risk of OHCA/SCD. Pollution and other exposures related to climate change play an important role in OHCA/SCD incidence.

[Effects of air pollution on cardiovascular events in cardiac intensive care units]

Many environmental factors influence the occurrence of cardiovascular events. Among these, air pollution is certainly the most harmful, due to its dual composition and effects. Air pollution is both particulate and gaseous, and can vary in concentration and composition according to its source and type of emission. Moreover, clinical effects are not only observed at long-term but also at short-term, following rapid deterioration in air quality. Air pollution must therefore be seen both as a risk factor for atherosclerotic disease, and as a trigger for cardiovascular events. These acute effects are essentially mediated by an increased risk of acute coronary syndromes and heart failure. The effects of air pollution on admissions for ventricular arrhythmias and arterial hypertension are also possible. The cardiotoxicity of pollution is mainly mediated by sympatho-vagal imbalance, by the initiation and amplification of an oxidative, inflammatory and pro-aggregatory cascade, and by endothelial dysfunction and activation of metalloproteinases. Although now well established, the consequences of air pollution on acute cardiovascular events require further investigation. Environmental cardiology is an emerging discipline whose current vision still fails to integrate qualitative aspects, such as the oxidative potential of particulate matter, and the joint effects of multiple environmental exposures.

Association of physical activity and PM2.5-attributable cardiovascular disease mortality in the United States

Objective

The study aimed to explore the association between physical activity (PA) and PM2. 5-attributable cardiovascular disease (CVD) mortality trends across the United States (US) at the state level.

Methods

We conducted a cross-sectional study using data from the Global Burden of Disease 2019 study for PM2.5-attributable CVD mortality and the Behavioral Risk Factor Surveillance System for PA prevalence. The study covered all 50 US states and the District of Columbia from 2001 to 2019. We utilized Joinpoint Regression to calculate AAPC from 2011 to 2019 and Pearson correlation coefficients to assess state-level associations between PA and PM2.5-attributable CVD mortality AAPC.

Results

During 2011-2019, a total of 244,318 PM2.5-attributable CVD deaths were recorded. The age-adjusted mortality rates (AAMR) of PM2.5-attributable CVD declined substantially from 2011 to 2019 across all US states, with the most pronounced reductions observed in industrialized states such as West Virginia (51% decline), Kentucky (32%), and Ohio (22%). AAMR ratios for the US states varied substantially, ranging from 0.1 in Hawaii to 1.7 in Arkansas. The AAPC ranged from -9.4% (West Virginia) to -1.7% (New Mexico) in the majority of states, while a few states such as Alaska, Wyoming, and Washington saw slight positive AAPCs from 0.9 to 2.9%. A significant correlation was found between PA and PM2.5-attributable CVD mortality trends (r = 0.454, p = 0.001), with similar results in subgroup analyses.

Conclusion

Our findings suggest a correlation between increased physical activity (PA) and increased PM2.5-attributable CVD mortality, highlighting the potential need to consider PM2.5 exposure when engaging in PA to mitigate adverse cardiovascular health impacts. However, further research is warranted to establish causality and underlying mechanisms in the relationship between PA and PM2.5-attributable CVD mortality. Potential limitations include reliance on self-reported PA data.

Air Pollution and Arrhythmias

Air pollution is commonly defined as the contamination of the air we breathe by any chemical, physical, or biological agent that is potentially threatening to human and ecosystem health. The common pollutants known to be disease-causing are particulate matter, ground-level ozone, sulphur dioxide, nitrogen dioxide, and carbon monoxide. Although the association between increasing concentrations of these pollutants and cardiovascular disease is now accepted, the association of air pollution and arrhythmias is less well established. In this review we provide an in-depth discussion of the association of acute and chronic air pollution exposure and arrhythmia incidence, morbidity, and mortality, and the purported pathophysiological mechanisms. Increases in concentrations of air pollutants have multiple proarrhythmic mechanisms including systemic inflammation (via increases in reactive oxygen species, tumour necrosis factor, and direct effects from translocated particulate matter), structural remodelling (via an increased risk of atherosclerosis and myocardial infarction or by affecting the cell-to-cell coupling and gap junction function), and mitochondrial and autonomic dysfunction. Furthermore, we describe the associations of air pollution and arrhythmias. There is a strong correlation of acute and chronic air pollutant exposure and the incidence of atrial fibrillation. Acute increases in air pollution increase the risk of emergency room visits and hospital admissions for atrial fibrillation and the risk of stroke and mortality in patients with atrial fibrillation. Similarly, there is a strong correlation of increases of air pollutants and the risk of ventricular arrhythmias, out-of-hospital cardiac arrest, and sudden cardiac death.

Fine Particulate Air Pollution and the "No-Multiple-Versions-of-Treatment" Assumption: Does Particle Composition Matter for Causal Inference?

Here we discuss possible violations of the "no-multiple-versions-of-treatment" assumption in studies of outdoor fine particulate air pollution (particulate matter with an aerodynamic diameter less than or equal to 2.5 μm (PM2.5)) owing to differences in particle composition, which in turn influence health. This assumption is part of the potential outcomes framework for causal inference, and it is needed for well-defined potential outcomes, as multiple versions of the same treatment could lead to different health risks for the same level of treatment. Since 2 locations can have the same outdoor PM2.5 mass concentration (i.e., treatment) but different chemical compositions (i.e., versions of treatment), violations of the "no-multiple-versions-of-treatment" assumption seem likely. Importantly, violations of this assumption will not bias health risk estimates for PM2.5 mass concentrations if there are no unmeasured confounders of the "version of treatment"-outcome relationship. However, confounding can occur if these factors are not identified and controlled for in the analysis. We describe situations in which this may occur and provide simulations to estimate the magnitude and direction of this possible bias. In general, violations of the "no-multiple-versions-of-treatment" assumption could be an underappreciated source of bias in studies of outdoor PM2.5. Analysis of the health impacts of outdoor PM2.5 mass concentrations across spatial domains with similar composition could help to address this issue.

Environmental exposure and the role of AhR in the tumor microenvironment of breast cancer

Activation of the aryl hydrocarbon receptor (AhR) through environmental exposure to chemicals including polycyclic aromatic hydrocarbons (PAHs) and polychlorinated dibenzo-p-dioxins (PCDDs) can lead to severe adverse health effects and increase the risk of breast cancer. This review considers several mechanisms which link the tumor promoting effects of environmental pollutants with the AhR signaling pathway, contributing to the development and progression of breast cancer. We explore AhR's function in shaping the tumor microenvironment, modifying immune tolerance, and regulating cancer stemness, driving breast cancer chemoresistance and metastasis. The complexity of AhR, with evidence for both oncogenic and tumor suppressor roles is discussed. We propose that AhR functions as a "molecular bridge", linking disproportionate toxin exposure and policies which underlie environmental injustice with tumor cell behaviors which drive poor patient outcomes.

Environmental Stressors and the PINE Network: Can Physical Environmental Stressors Drive Long-Term Physical and Mental Health Risks?

Both psychosocial and physical environmental stressors have been linked to chronic mental health and chronic medical conditions. The psycho-immune-neuroendocrine (PINE) network details metabolomic pathways which are responsive to varied stressors and link chronic medical conditions with mental disorders, such as major depressive disorder via a network of pathophysiological pathways. The primary objective of this review is to explore evidence of relationships between airborne particulate matter (PM, as a concrete example of a physical environmental stressor), the PINE network and chronic non-communicable diseases (NCDs), including mental health sequelae, with a view to supporting the assertion that physical environmental stressors (not only psychosocial stressors) disrupt the PINE network, leading to NCDs. Biological links have been established between PM exposure, key sub-networks of the PINE model and mental health sequelae, suggesting that in theory, long-term mental health impacts of PM exposure may exist, driven by the disruption of these biological networks. This disruption could trans-generationally influence health; however, long-term studies and information on chronic outcomes following acute exposure event are still lacking, limiting what is currently known beyond the acute exposure and all-cause mortality. More empirical evidence is needed, especially to link long-term mental health sequelae to PM exposure, arising from PINE pathophysiology. Relationships between physical and psychosocial stressors, and especially the concept of such stressors acting together to impact on PINE network function, leading to linked NCDs, evokes the concept of syndemics, and these are discussed in the context of the PINE network.

The Impact of Fine Particulate Matter 2.5 on the Cardiovascular System: A Review of the Invisible Killer

Air pollution exerts several deleterious effects on the cardiovascular system, with cardiovascular disease (CVD) accounting for 80% of all premature deaths caused by air pollution. Short-term exposure to particulate matter 2.5 (PM_2.5) leads to acute CVD-associated deaths and nonfatal events, whereas long-term exposure increases CVD-associated risk of death and reduces longevity. Here, we summarize published data illustrating how PM_2.5 may impact the cardiovascular system to provide information on the mechanisms by which it may contribute to CVDs. We provide an overview of PM_2.5, its associated health risks, global statistics, mechanistic underpinnings related to mitochondria, and hazardous biological effects. We elaborate on the association between PM_2.5 exposure and CVD development and examine preventive PM_2.5 exposure measures and future strategies for combating PM_2.5-related adverse health effects. The insights gained can provide critical guidelines for preventing pollution-related CVDs through governmental, societal, and personal measures, thereby benefitting humanity and slowing climate change.

Short-term exposure to traffic-related air pollution and STEMI events: Insights into STEMI onset and related cardiac impairment

AIMS

Evidence on the impacts of traffic-related air pollution (TRAP) on ST-segment elevation myocardial infarction (STEMI) events is limited. We aimed to assess the acute effects of TRAP exposure on the clinical onset of STEMI and related cardiac impairments.

METHODS AND RESULTS

We recruited patients who were admitted for STEMI and underwent primary percutaneous coronary intervention at Peking University Third Hospital between 2014 and 2020. Indicators relevant to cardiac impairments were measured. Concomitantly, hourly concentrations of traffic pollutants were monitored throughout the study period, including fine particulate matter, black carbon (BC), particles in size ranges of 5-560 nm, oxides of nitrogen (NO_X), nitrogen dioxide, and carbon monoxide. The mean (SD) age of participants was 62.4 (12.5) years. Daily average (range) concentrations of ambient BC and NO_X were 3.9 (0.1-25.0) μg/m³ and 90.8 (16.6-371.7) μg/m³. Significant increases in STEMI risks of 5.9% (95% CI: 0.1, 12.0) to 21.9% (95% CI: 6.0, 40.2) were associated with interquartile range increases in exposure to TRAP within a few hours. These changes were accompanied by significant elevations in cardiac troponin T levels of 6.9% (95% CI: 0.2, 14.1) to 41.7% (95% CI: 21.2, 65.6), as well as reductions in left ventricular ejection fraction of 1.5% (95% CI: 0.1, 2.9) to 3.7% (95% CI: 0.8, 6.4). Furthermore, the associations were attenuated in participants living in areas with higher residential greenness levels.

CONCLUSIONS

Our findings extend current understanding that short-term exposure to higher levels of traffic pollution was associated with increased STEMI risks and exacerbated cardiac impairments, and provide evidence on traffic pollution control priority for protecting vulnerable populations who are at greater risks of cardiovascular events.

European Society of Cardiology: cardiovascular disease statistics 2021

AIMS

This report from the European Society of Cardiology (ESC) Atlas Project updates and expands upon the widely cited 2019 report in presenting cardiovascular disease (CVD) statistics for the 57 ESC member countries.

METHODS AND RESULTS

Statistics pertaining to 2019, or the latest available year, are presented. Data sources include the World Health Organization, the Institute for Health Metrics and Evaluation, the World Bank, and novel ESC sponsored data on human and capital infrastructure and cardiovascular healthcare delivery. New material in this report includes sociodemographic and environmental determinants of CVD, rheumatic heart disease, out-of-hospital cardiac arrest, left-sided valvular heart disease, the advocacy potential of these CVD statistics, and progress towards World Health Organization (WHO) 2025 targets for non-communicable diseases. Salient observations in this report: (i) Females born in ESC member countries in 2018 are expected to live 80.8 years and males 74.8 years. Life expectancy is longer in high income (81.6 years) compared with middle-income (74.2 years) countries. (ii) In 2018, high-income countries spent, on average, four times more on healthcare than middle-income countries. (iii) The median PM2.5 concentrations in 2019 were over twice as high in middle-income ESC member countries compared with high-income countries and exceeded the EU air quality standard in 14 countries, all middle-income. (iv) In 2016, more than one in five adults across the ESC member countries were obese with similar prevalence in high and low-income countries. The prevalence of obesity has more than doubled over the past 35 years. (v) The burden of CVD falls hardest on middle-income ESC member countries where estimated incidence rates are ∼30% higher compared with high-income countries. This is reflected in disability-adjusted life years due to CVD which are nearly four times as high in middle-income compared with high-income countries. (vi) The incidence of calcific aortic valve disease has increased seven-fold during the last 30 years, with age-standardized rates four times as high in high-income compared with middle-income countries. (vii) Although the total number of CVD deaths across all countries far exceeds the number of cancer deaths for both sexes, there are 15 ESC member countries in which cancer accounts for more deaths than CVD in males and five-member countries in which cancer accounts for more deaths than CVD in females. (viii) The under-resourced status of middle-income countries is associated with a severe procedural deficit compared with high-income countries in terms of coronary intervention, ablation procedures, device implantation, and cardiac surgical procedures.

CONCLUSION

Risk factors and unhealthy behaviours are potentially reversible, and this provides a huge opportunity to address the health inequalities across ESC member countries that are highlighted in this report. It seems clear, however, that efforts to seize this opportunity are falling short and present evidence suggests that most of the WHO NCD targets for 2025 are unlikely to be met across ESC member countries.

The Lancet women and cardiovascular disease Commission: reducing the global burden by 2030

Cardiovascular disease is the leading cause of death in women. Decades of grassroots campaigns have helped to raise awareness about the impact of cardiovascular disease in women, and positive changes affecting women and their health have gained momentum. Despite these efforts, there has been stagnation in the overall reduction of cardiovascular disease burden for women in the past decade. Cardiovascular disease in women remains understudied, under-recognised, underdiagnosed, and undertreated. This Commission summarises existing evidence and identifies knowledge gaps in research, prevention, treatment, and access to care for women. Recommendations from an international team of experts and leaders in the field have been generated with a clear focus to reduce the global burden of cardiovascular disease in women by 2030. This Commission represents the first effort of its kind to connect stakeholders, to ignite global awareness of sex-related and gender-related disparities in cardiovascular disease, and to provide a springboard for future research.

Estimating exposure to fine particulate matter emissions from vehicle traffic: Exposure misclassification and daily activity patterns in a large, sprawling region

Vehicle traffic is responsible for a significant portion of toxic air pollution in urban areas that has been linked to a wide range of adverse health outcomes. Most vehicle air quality analyses used for transportation planning and health effect studies estimate exposure from the measured or modeled concentration of an air pollutant at a person's home. This study evaluates exposure to fine particulate matter from vehicle traffic and the magnitude and cause of exposure misclassification that result from not accounting for population mobility during the day in a large, sprawling region. We develop a dynamic exposure model by integrating activity-based travel demand, vehicle emission, and air dispersion models to evaluate the magnitude, components and spatial patterns of vehicle exposure misclassification in the Atlanta, Georgia metropolitan area. Overall, we find that population exposure estimates increase by 51% when population mobility is accounted for. Errors are much larger in suburban and rural areas where exposure is underestimated while exposure may be overestimated near high volume roadways and in the urban core. Exposure while at work and traveling account for much of the error. We find much larger errors than prior studies, all of which have focused on more compact urban regions. Since many people spend a large part of their day away from their homes and vehicle emissions are known to create "hotspots" along roadways, home-based exposure is unlikely to be a robust estimator of a person's actual exposure. Accounting for population mobility in vehicle emission exposure studies may reveal more effective mitigation strategies, important differences in exposure between population groups with different travel patterns, and reduce exposure misclassification in health studies.

Fine particle environmental pollution and cardiovascular diseases

Air pollution affects 90% of the world's population and has caused 9 million deaths in 2015, becoming the most important cause of premature deaths in the world. Exposure to fine particulate matter, a major component of urban air pollution, has been associated with an increase in cardiovascular risk and associated mortality. Impact of fine particles on the cardiovascular system includes inflammation, activation of prothrombotic pathways, oxidative stress, vascular dysfunction and remodeling, and neurological dysfunction. Genetic and epigenetic factors might also increase the susceptibility to air pollution. Consequently, epidemiologic studies have identified correlations between air particulate matter concentrations and acute coronary events, ischemic cardiomyopathy, acute heart failure, and stroke. Interestingly, these effects are present even for fine particulate matter concentrations below current US and EU regulatory standards, and seems to be more harmful in the most fragile population such as low-income or elderly subjects, or patients with previous cardiovascular disease. This review aims to summarize recent data on the pathophysiology and epidemiology of cardiovascular disease after particulate matter exposure. It will also discuss potential strategies to reduce the impact of air pollution on current and future populations' health.

Synthesis of Harvard Environmental Protection Agency (EPA) Center studies on traffic-related particulate pollution and cardiovascular outcomes in the Greater Boston Area

The association between particulate pollution and cardiovascular morbidity and mortality is well established. While the cardiovascular effects of nationally regulated criteria pollutants (e.g., fine particulate matter [PM_2.5] and nitrogen dioxide) have been well documented, there are fewer studies on particulate pollutants that are more specific for traffic, such as black carbon (BC) and particle number (PN). In this paper, we synthesized studies conducted in the Greater Boston Area on cardiovascular health effects of traffic exposure, specifically defined by BC or PN exposure or proximity to major roadways. Large cohort studies demonstrate that exposure to traffic-related particles adversely affect cardiac autonomic function, increase systemic cytokine-mediated inflammation and pro-thrombotic activity, and elevate the risk of hypertension and ischemic stroke. Key patterns emerged when directly comparing studies with overlapping exposure metrics and population cohorts. Most notably, cardiovascular risk estimates of PN and BC exposures were larger in magnitude or more often statistically significant compared to those of PM_2.5 exposures. Across multiple exposure metrics (e.g., short-term vs. long-term; observed vs. modeled) and different population cohorts (e.g., elderly, individuals with co-morbidities, young healthy individuals), there is compelling evidence that BC and PN represent traffic-related particles that are especially harmful to cardiovascular health. Further research is needed to validate these findings in other geographic locations, characterize exposure errors associated with using monitored and modeled traffic pollutant levels, and elucidate pathophysiological mechanisms underlying the cardiovascular effects of traffic-related particulate pollutants. Implications: Traffic emissions are an important source of particles harmful to cardiovascular health. Traffic-related particles, specifically BC and PN, adversely affect cardiac autonomic function, increase systemic inflammation and thrombotic activity, elevate BP, and increase the risk of ischemic stroke. There is evidence that BC and PN are associated with greater cardiovascular risk compared to PM_2.5. Further research is needed to elucidate other health effects of traffic-related particles and assess the feasibility of regulating BC and PN or their regional and local sources.

E-noise: An increasingly relevant health risk

This article briefly reviews and discusses the current status of major non-communicable diseases (mNCDs), definition of e-noise, its possible link as a risk factor for cardiovascular diseases and other mNCDs, and proposes possible mechanisms and hypotheses on that link, and how to control e-noise in the future. E-noise is defined as signal from electronic products and instruments that emit radiation and electromagnetic fields. It includes not only the acoustic but also non-acoustic noise. Just like road traffic and aircraft noises, e-noise may not only lead to hearing loss and health problems such as fatigue, stress, irritability, headache, and insomnia, but may also endanger cardiovascular health and result in hypertension, ischemic heart disease (myocardial infarction), arrhythmia (atrial fibrillation) and stroke; brain and metabolic problems such as obesity and diabetes; mental and cognitive impairment; as well as changing of humans' long-evolved cortisol and circadian rhythms after long-term exposure. Even short-term exposure to excessive e-noise may lead to heightened stress responses and low quality of life. In conclusion, e-noise is a potential danger in our world, and further studies are needed of its effects on mechanisms of aging, disease, and human health.

Aviation Noise and Cardiovascular Health in the United States: a Review of the Evidence and Recommendations for Research Direction

Purpose of the Review

In the USA, there is mounting pressure on aviation operators and regulators to address concerns about community impacts of aircraft noise given increasing evidence of adverse health impacts, continuing community complaints, availability of cost-effective programs to reduce exposures to aircraft noise, and more stringent international policies. In the USA, regulation of civil aviation noise is the responsibility of the Federal Aviation Administration (FAA), which requires a "significant body of scientific support," particularly applicable to the USA, to inform health-based policy and regulatory decisions. However, there have been very few studies investigating the relationship between noise and health in the USA and limited studies across the globe characterizing the effects of aviation noise specifically on cardiovascular health. This review focuses on recent findings on the relationship between aircraft noise and cardiovascular outcomes and directions for future research.

Recent Findings

Epidemiological studies generally report statistically significant associations between aircraft noise and adverse cardiovascular outcomes, although with limited evidence within the USA. Sleep disturbance, associated with nighttime noise, has been shown to be a risk factor for cardiovascular disease given associations with inflammatory markers and metabolic changes. Given numerous cardiovascular markers, the most appropriate choices depend on the ultimate objectives of the individual studies.

Summary

Given the state of the literature, future research should leverage emerging tools to estimate aviation, railway, and road traffic noise and apply noise estimates to a range of epidemiological study designs and endpoints to inform causal interpretation and help determine potential intervention strategies.

Aviation Noise and Cardiovascular Health in the United States: a Review of the Evidence and Recommendations for Research Direction

PURPOSE OF THE REVIEW

In the USA, there is mounting pressure on aviation operators and regulators to address concerns about community impacts of aircraft noise given increasing evidence of adverse health impacts, continuing community complaints, availability of cost-effective programs to reduce exposures to aircraft noise, and more stringent international policies. In the USA, regulation of civil aviation noise is the responsibility of the Federal Aviation Administration (FAA), which requires a "significant body of scientific support," particularly applicable to the USA, to inform health-based policy and regulatory decisions. However, there have been very few studies investigating the relationship between noise and health in the USA and limited studies across the globe characterizing the effects of aviation noise specifically on cardiovascular health. This review focuses on recent findings on the relationship between aircraft noise and cardiovascular outcomes and directions for future research.

RECENT FINDINGS

Epidemiological studies generally report statistically significant associations between aircraft noise and adverse cardiovascular outcomes, although with limited evidence within the USA. Sleep disturbance, associated with nighttime noise, has been shown to be a risk factor for cardiovascular disease given associations with inflammatory markers and metabolic changes. Given numerous cardiovascular markers, the most appropriate choices depend on the ultimate objectives of the individual studies.

SUMMARY

Given the state of the literature, future research should leverage emerging tools to estimate aviation, railway, and road traffic noise and apply noise estimates to a range of epidemiological study designs and endpoints to inform causal interpretation and help determine potential intervention strategies.

Residential distance to major roadways and semen quality, sperm DNA integrity, chromosomal disomy, and serum reproductive hormones among men attending a fertility clinic

OBJECTIVE

We examined associations of residential distance to major roadways, as a proxy for traffic-related air pollution exposures, with sperm characteristics and male reproductive hormones.

DESIGN

The cohort included 797 men recruited from Massachusetts General Hospital Fertility Center between 2000 and 2015 to participate in fertility research studies.

MATERIALS AND METHODS

Men reported their residential addresses at enrollment and provided 1-6 semen samples and a blood sample during follow-up. We estimated the Euclidean distance to major roadways (e.g. interstates and highways: limited access highways, multi-lane highways (not limited access), other numbered routes, and major roads) using information from the Massachusetts Department of Geographic Information Systems. Semen parameters (1238 semen samples), sperm DNA integrity (389 semen samples), chromosomal disomy (101 semen samples), and serum reproductive hormones (405 serum samples) were assessed following standard procedures.

RESULTS

Men in this cohort were primarily Caucasian (86%), not current smokers (92%), with a college or higher education (88%), and had an average age of 36 years and BMI of 27.7 kg/m2. The median (interquartile range) residential distance to a major roadway was 111 (37, 248) meters. Residential proximity to major roadways was not associated with semen parameters, sperm DNA integrity, chromosomal disomy, or serum reproductive hormone concentrations. The adjusted percent change (95% CI) in semen quality parameters associated with a 500 m increase in residential distance to a major roadway was -1.0% (-6.3, 4.5) for semen volume, 4.3% (-5.8, 15.7) for sperm concentration, 3.1% (-7.2, 14.5) for sperm count, 1.1% (-1.2, 3.4) for % total motile sperm, and 0.1% (-0.3, 0.5) for % morphologically normal sperm. Results were consistent when we modeled the semen parameters dichotomized according to WHO 2010 reference values.

CONCLUSION

Residential distance to major roadways, as a proxy for traffic-related air pollution exposure, was not related to sperm characteristics or serum reproductive hormones among men attending a fertility clinic in Massachusetts.

The Adverse Effects of Environmental Noise Exposure on Oxidative Stress and Cardiovascular Risk

Epidemiological studies have provided evidence that traffic noise exposure is linked to cardiovascular diseases such as arterial hypertension, myocardial infarction, and stroke. Noise is a nonspecific stressor that activates the autonomous nervous system and endocrine signaling. According to the noise reaction model introduced by Babisch and colleagues, chronic low levels of noise can cause so-called nonauditory effects, such as disturbances of activity, sleep, and communication, which can trigger a number of emotional responses, including annoyance and subsequent stress. Chronic stress in turn is associated with cardiovascular risk factors, comprising increased blood pressure and dyslipidemia, increased blood viscosity and blood glucose, and activation of blood clotting factors, in animal models and humans. Persistent chronic noise exposure increases the risk of cardiometabolic diseases, including arterial hypertension, coronary artery disease, diabetes mellitus type 2, and stroke. Recently, we demonstrated that aircraft noise exposure during nighttime can induce endothelial dysfunction in healthy subjects and is even more pronounced in coronary artery disease patients. Importantly, impaired endothelial function was ameliorated by acute oral treatment with the antioxidant vitamin C, suggesting that excessive production of reactive oxygen species contributes to this phenomenon. More recently, we introduced a novel animal model of aircraft noise exposure characterizing the underlying molecular mechanisms leading to noise-dependent adverse oxidative stress-related effects on the vasculature. With the present review, we want to provide an overview of epidemiological, translational clinical, and preclinical noise research addressing the nonauditory, adverse effects of noise exposure with focus on oxidative stress. Antioxid. Redox Signal. 28, 873-908.

Determinants of occurrence and survival after sudden cardiac arrest-A European perspective: The ESCAPE-NET project

AIMS

The ESCAPE-NET project ("European Sudden Cardiac Arrest network- towards Prevention, Education and New Effective Treatments") aims to study: (1) risk factors and mechanisms for the occurrence of sudden cardiac arrest (SCA) in the population, and (2) risk factors and treatment strategies for survival after SCA on a European scale.

METHODS

This is an Horizon2020 funded program of the European Union, performed by a European public-private consortium of 16 partners across 10 EU countries. There are 11 deep-phenotyped SCA cohorts for the study of risk factors and treatment strategies for survival after SCA, and 5 deep-phenotyped observational prospective population cohorts for the study of risk factors for occurrence of SCA. Personalized risk scores for predicting SCA onset and for predicting survival after SCA will be derived and validated.

RESULTS

The 11 clinical studies with SCA cases comprise 85,790 SCA cases; the 5 observational prospective population cohorts include 53,060 subjects. A total of 15,000 SCA samples will be genotyped for common and rare variants at the Helmholtz Zentrum München (Germany) using the Illumina Global Screening Array which contains > 770,000 SNPs, and after imputation, a database of an estimated > 9 million variants will be available for genome wide association studies. Standardization of risk factors definition and outcomes is ongoing. An Executive Committee has been created along with a Collaboration Policy document.

CONCLUSION

ESCAPE-NET will complement ongoing efforts on SCA outside Europe and within Europe including the EuReCa project.

Enhanced vasculotoxic metal excretion in post-myocardial infarction patients following a single edetate disodium-based infusion

Toxic metals have been associated with cardiovascular mortality and morbidity. We have hypothesized that enhanced excretion of vasculotoxic metals might explain the positive results of the Trial to Assess Chelation Therapy (TACT). The purpose of this study was to determine whether a single infusion of the edetate disodium- based infusion used in TACT led to enhanced excretion of toxic metals known to be associated with cardiovascular events.

METHODS

Twenty six patients (post-MI, age > 50 years, serum creatinine ≤ 2.0mg/dL) were enrolled in this open-label study. Urinary levels of 20 toxic metals normalized to urinary creatinine concentrations were measured at baseline in overnight urine collections, for 6h following a placebo infusion of 500mL normal saline and 1.2% dextrose, and for 6h following a 3g edetate disodium-based infusion. Self-reported metal exposure, smoking status, food frequency, occupational history, drinking water source, housing and hobbies were collected at baseline by a metal exposure questionnaire.

RESULTS

The mean age was 65 years (range 51-81 years). All patients were male. 50% had diabetes mellitus and 58% were former smokers. Mean (SD) serum creatinine was 0.95 (0.31) mg/dL. Toxic metals were detected in the baseline urine of >80% of patients. After placebo infusion there were no significant changes in total urinary metal levels. After edetate infusion, total urinary metal level increased by 71% compared to baseline (1500 vs. 2580µg/g creatinine; P<0.0001). The effect of edetate was particularly large for lead (3835% increase) and cadmium (633% increase).

CONCLUSIONS

Edetate disodium-based infusions markedly enhanced the urinary excretion of lead and cadmium, toxic metals with established epidemiologic evidence and mechanisms linking them to coronary and vascular events.

Cardiovascular effects of air pollution

Air pollution is composed of particulate matter (PM) and gaseous pollutants, such as nitrogen dioxide and ozone. PM is classified according to size into coarse particles (PM₁₀), fine particles (PM_2.5) and ultrafine particles. We aim to provide an original review of the scientific evidence from epidemiological and experimental studies examining the cardiovascular effects of outdoor air pollution. Pooled epidemiological studies reported that a 10μg/m³ increase in long-term exposure to PM_2.5 was associated with an 11% increase in cardiovascular mortality. Increased cardiovascular mortality was also related to long-term and short-term exposure to nitrogen dioxide. Exposure to air pollution and road traffic was associated with an increased risk of arteriosclerosis, as shown by premature aortic and coronary calcification. Short-term increases in air pollution were associated with an increased risk of myocardial infarction, stroke and acute heart failure. The risk was increased even when pollutant concentrations were below European standards. Reinforcing the evidence from epidemiological studies, numerous experimental studies demonstrated that air pollution promotes a systemic vascular oxidative stress reaction. Radical oxygen species induce endothelial dysfunction, monocyte activation and some proatherogenic changes in lipoproteins, which initiate plaque formation. Furthermore, air pollution favours thrombus formation, because of an increase in coagulation factors and platelet activation. Experimental studies also indicate that some pollutants have more harmful cardiovascular effects, such as combustion-derived PM_2.5 and ultrafine particles. Air pollution is a major contributor to cardiovascular diseases. Promotion of safer air quality appears to be a new challenge in cardiovascular disease prevention.

Environmental Determinants of Cardiovascular Disease

Many features of the environment have been found to exert an important influence on cardiovascular disease (CVD) risk, progression, and severity. Changes in the environment because of migration to different geographic locations, modifications in lifestyle choices, and shifts in social policies and cultural practices alter CVD risk, even in the absence of genetic changes. Nevertheless, the cumulative impact of the environment on CVD risk has been difficult to assess and the mechanisms by which some environment factors influence CVD remain obscure. Human environments are complex, and their natural, social, and personal domains are highly variable because of diversity in human ecosystems, evolutionary histories, social structures, and individual choices. Accumulating evidence supports the notion that ecological features such as the diurnal cycles of light and day, sunlight exposure, seasons, and geographic characteristics of the natural environment such as altitude, latitude, and greenspaces are important determinants of cardiovascular health and CVD risk. In highly developed societies, the influence of the natural environment is moderated by the physical characteristics of the social environments such as the built environment and pollution, as well as by socioeconomic status and social networks. These attributes of the social environment shape lifestyle choices that significantly modify CVD risk. An understanding of how different domains of the environment, individually and collectively, affect CVD risk could lead to a better appraisal of CVD and aid in the development of new preventive and therapeutic strategies to limit the increasingly high global burden of heart disease and stroke.

Proximity to major roadways and prospectively-measured time-to-pregnancy and infertility

We aimed to study the potential impact of proximity to major roadways on time-to-pregnancy and infertility in couples attempting pregnancy in the Longitudinal Investigation of Fertility and Environment (LIFE) study (2005-2009), a population-based, prospective cohort study. Couples attempting pregnancy (n=500) were enrolled and followed prospectively until pregnancy or 12months of trying and 393 couples (78%) had complete data and full follow-up. Time-to-pregnancy was based on a standard protocol using fertility monitors, tracking estrone-3-glucuonide and luteinizing hormone, and pregnancy test kits to detect human chorionic gonadotropin (hCG). The fecundability odds ratio (FOR) and 95% confidence interval (CI) were estimated using proportional odds models. Infertility was defined as 12months of trying to conceive without an hCG pregnancy and the relative risk (RR) and 95% CI were estimated with log-binomial regression. Final models were adjusted for age, parity, study site, and salivary alpha-amylase, a stress marker. Infertile couples (53/393; 14%) tended to live closer to major roadways on average than fertile couples (689m vs. 843m, respectively) but the difference was not statistically significant. The likelihood of pregnancy was increased 3% for every 200m further away the couples residence was from a major roadway (FOR=1.03; CI=1.01-1.06). Infertility also appeared elevated at moderate distances compared to 1000m or greater, but estimates lacked precision. Our findings suggest that proximity to major roadways may be related to reductions in fecundity. Prospective data from larger populations is warranted to corroborate these findings.

Residential Proximity to Major Roadways and Risk of Type 2 Diabetes Mellitus: A Meta-Analysis

Research indicates that higher levels of traffic-related pollution exposure increase the risk of diabetes, but the association between road proximity and diabetes risk remains unclear. To assess and quantify the association between residential proximity to major roadways and type 2 diabetes, a systematic review and meta-analysis was performed. Embase, Medline, and Web of Science were searched for eligible studies. Using a random-effects meta-analysis, the summary relative risks (RRs) were calculated. Bayesian meta-analysis was also performed. Eight studies (6 cohort and 2 cross-sectional) with 158,576 participants were finally included. The summary unadjusted RR for type 2 diabetes associated with residential proximity to major roadways was 1.24 (95% confidence interval [CI]: 1.07–1.44, p = 0.001, I² = 48.1%). The summary adjusted RR of type 2 diabetes associated with residential proximity to major roadways was 1.12 (95% CI: 1.03–1.22, p = 0.01, I² = 17.9%). After excluding two cross-sectional studies, the summary results suggested that residential proximity to major roadways could increase type 2 diabetes risk (Adjusted RR = 1.13; 95% CI: 1.02–1.27, p = 0.025, I² = 36.6%). Bayesian meta-analysis showed that the unadjusted RR and adjusted RR of type 2 diabetes associated with residential proximity to major roadways were 1.22 (95% credibility interval: 1.06–1.55) and 1.13 (95% credibility interval: 1.01–1.31), respectively. The meta-analysis suggested that residential proximity to major roadways could significantly increase risk of type 2 diabetes, and it is an independent risk factor of type 2 diabetes. More well-designed studies are needed to further strengthen the evidence.

Proposed pathophysiologic framework to explain some excess cardiovascular death associated with ambient air particle pollution: Insights for public health translation

The paper proposes a pathophysiologic framework to explain the well-established epidemiological association between exposure to ambient air particle pollution and premature cardiovascular mortality, and offers insights into public health solutions that extend beyond regulatory environmental protections to actions that can be taken by individuals, public health officials, healthcare professionals, city and regional planners, local and state governmental officials and all those who possess the capacity to improve cardiovascular health within the population. The foundation of the framework rests on the contribution of traditional cardiovascular risk factors acting alone and in concert with long-term exposures to air pollutants to create a conditional susceptibility for clinical vascular events, such as myocardial ischemia and infarction; stroke and lethal ventricular arrhythmias. The conceptual framework focuses on the fact that short-term exposures to ambient air particulate matter (PM) are associated with vascular thrombosis (acute coronary syndrome, stroke, deep venous thrombosis, and pulmonary embolism) and electrical dysfunction (ventricular arrhythmia); and that individuals having prevalent heart disease are at greatest risk. Moreover, exposure is concomitant with changes in autonomic nervous system balance, systemic inflammation, and prothrombotic/anti-thrombotic and profibrinolytic-antifibrinolytic balance. Thus, a comprehensive solution to the problem of premature mortality triggered by air pollutant exposure will require compliance with regulations to control ambient air particle pollution levels, minimize exposures to air pollutants, as well as a concerted effort to decrease the number of people at-risk for serious clinical cardiovascular events triggered by air pollutant exposure by improving the overall state of cardiovascular health in the population. This article is part of a Special Issue entitled Air Pollution, edited by Wenjun Ding, Andrew J. Ghio and Weidong Wu.

Pretreatment with Antioxidants Augments the Acute Arterial Vasoconstriction Caused by Diesel Exhaust Inhalation

RATIONALE

Diesel exhaust inhalation, which is the model traffic-related air pollutant exposure, is associated with vascular dysfunction.

OBJECTIVES

To determine whether healthy subjects exposed to diesel exhaust exhibit acute vasoconstriction and whether this effect could be modified by the use of antioxidants or by common variants in the angiotensin II type 1 receptor (AGTR1) and other candidate genes.

METHODS

In a genotype-stratified, double-blind, four-way crossover study, 21 healthy adult subjects were exposed at rest in a randomized, balanced order to diesel exhaust (200 μg/m(3) particulate matter with an aerodynamic diameter ≤ 2.5 μm [PM2.5]) and filtered air, and to pretreatment with antioxidants (N-acetylcysteine and ascorbate) and placebo. Before and after each exposure, brachial artery diameter (BAd) was assessed using ultrasound. Changes in BAd were compared across pretreatment and exposure sessions. Gene-exposure interactions were evaluated in the AGTR1 A1166C polymorphism, on which recruitment was stratified, and other candidate genes, including TRPV1 and GSTM1.

MEASUREMENTS AND MAIN RESULTS

Compared with filtered air, exposure to diesel exhaust resulted in a significant reduction in BAd (mean, -0.09 mm, 95% confidence interval [CI], -0.01 to -0.17; P = 0.03). Pretreatment with antioxidants augmented diesel exhaust-related vasoconstriction with a mean change in BAd of -0.18 mm (95% CI, -0.28 to -0.07 mm; P = 0.001). Diesel exhaust-related vasoconstriction was primarily observed in the variant alleles of AGTR1 and TRPV1. No association was found between diesel exhaust inhalation and flow-mediated dilation.

CONCLUSIONS

We confirmed that short-term exposure to diesel exhaust in healthy subjects is associated with acute vasoconstriction in a conductance artery and found suggestive evidence of involvement of nociception and renin-angiotensin systems in this effect. Pretreatment with an antioxidant regimen increased vasoconstriction.

Environmental factors in cardiovascular disease

Environmental exposure is an important but underappreciated risk factor contributing to the development and severity of cardiovascular disease (CVD). The heart and vascular system are highly vulnerable to a number of environmental agents--ambient air pollution and the metals arsenic, cadmium, and lead are widespread and the most-extensively studied. Like traditional risk factors, such as smoking and diabetes mellitus, these exposures advance disease and mortality via augmentation or initiation of pathophysiological processes associated with CVD, including blood-pressure control, carbohydrate and lipid metabolism, vascular function, and atherogenesis. Although residence in highly polluted areas is associated with high levels of cardiovascular risk, adverse effects on cardiovascular health also occur at exposure levels below current regulatory standards. Considering the widespread prevalence of exposure, even modest contributions to CVD risk can have a substantial effect on population health. Evidence-based clinical and public-health strategies aimed at reducing environmental exposures from current levels could substantially lower the burden of CVD-related death and disability worldwide.

Residential proximity to major roadways and incident hypertension in post-menopausal women

Living near major roadways has been associated with increased risk of cardiovascular morbidity and mortality, presumably from exposure to elevated levels of traffic-related air and/or noise pollution. This association may potentially be mediated through increased risk of incident hypertension, but results from prior studies are equivocal. Using Cox proportional hazards models we examined residential proximity to major roadways and incident hypertension among 38,360 participants of the Women's Health Initiative (WHI) Clinical Trial cohorts free of hypertension at enrollment and followed for a median of 7.9 years. Adjusting for participant demographics and lifestyle, trial participation, and markers of individual and neighborhood socioeconomic status, the hazard ratios for incident hypertension were 1.13 (95% CI: 1.00, 1.28), 1.03 (0.95, 1.11), 1.05 (0.99, 1.11), and 1.05 (1.00, 1.10) for participants living ≤50, >50-200, >200-400, and >400-1000 m vs >1000 m from the nearest major roadway, respectively (ptrend=0.013). This association varied substantially by WHI study region with hazard ratios for women living ≤50 m from a major roadway of 1.61 (1.18, 2.20) in the West, 1.51 (1.22, 1.87) in the Northeast, 0.89 (0.70, 1.14) in the South, and 0.94 (0.75, 1.19) in the Midwest. In this large, national cohort of post-menopausal women, residential proximity to major roadways was associated with incident hypertension in selected regions of the U.S. If causal, these results suggest residential proximity to major roadways, as a marker for air, noise and other traffic-related pollution, may be a risk factor for hypertension.

Exposure to ambient air pollution in Canada and the risk of adult leukemia

There is a paucity of studies investigating adult leukemia and air pollution. To address this gap, we analyzed data from a Canadian population-based case-control study conducted in 1994-1997. Cases were 1064 adults with incident leukemia and controls were 5039 healthy adults. We used data from satellites and fixed-site monitoring stations to estimate residential concentrations of NO2 and fine particulate matter (PM2.5) for the period prior to diagnosis, starting in 1975 and ending in 1994. We modeled the average annual exposure of each subject. Odds ratios (OR) and their 95% confidence intervals (CI) were estimated using logistic regression, adjusted for age, gender, province, smoking, education, body mass index, income, and self-reported exposures to ionizing radiation and benzene. We found an 'n-shaped' response function between exposure to NO2 and all forms of leukemia: from the tenth percentile to the median (4.51 to 14.66 ppb), the OR was 1.20; 95% CI: 0.97-1.48 and from the 75th percentile to the 90th (22.75 to 29.7 ppb), the OR was 0.79; 95% CI 0.68-0.93. For PM2.5 we found a response function consistent with a linear model, with an OR per 10 μg/m(3) of 0.97 (95% CI 0.75-1.26). For chronic lymphocytic leukemia we found response functions that were consistent with a simple linear model, with an OR per 5 ppb of NO2 of 0.93 (95% CI 0.86-1.00) and an OR per 10 μg/m(3) of PM2.5 of 0.62 (95% CI 0.42-0.93). In summary, for chronic lymphocytic leukemia we found no evidence of an association with air pollution and with all forms of leukemia we found weak evidence of an association only at low concentrations of NO2. It is possible that these inconsistent results may have arisen because of unaccounted urban/rural differences or possibly from a selection effect, especially among controls.

The spectrum of epidemiology underlying sudden cardiac death

Sudden cardiac death (SCD) from cardiac arrest is a major international public health problem accounting for an estimated 15%-20% of all deaths. Although resuscitation rates are generally improving throughout the world, the majority of individuals who experience a sudden cardiac arrest will not survive. SCD most often develops in older adults with acquired structural heart disease, but it also rarely occurs in the young, where it is more commonly because of inherited disorders. Coronary heart disease is known to be the most common pathology underlying SCD, followed by cardiomyopathies, inherited arrhythmia syndromes, and valvular heart disease. During the past 3 decades, declines in SCD rates have not been as steep as for other causes of coronary heart disease deaths, and there is a growing fraction of SCDs not due to coronary heart disease and ventricular arrhythmias, particularly among certain subsets of the population. The growing heterogeneity of the pathologies and mechanisms underlying SCD present major challenges for SCD prevention, which are magnified further by a frequent lack of recognition of the underlying cardiac condition before death. Multifaceted preventative approaches, which address risk factors in seemingly low-risk and known high-risk populations, will be required to decrease the burden of SCD. In this Compendium, we review the wide-ranging spectrum of epidemiology underlying SCD within both the general population and in high-risk subsets with established cardiac disease placing an emphasis on recent global trends, remaining uncertainties, and potential targeted preventive strategies.