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Healthy Heart Toolkit and Research: Results

EPA researchers and partners are learning more about how people can better protect their cardiovascular health from air pollution.

A large and robust body of research has been published in peer-reviewed journal articles by EPA and EPA-funded scientists on the health effects of air pollution, including the heart, nervous and vascular systems.  

This research has shown that exposure to fine particle pollution, known as PM2.5, can impact heart disease. Particles are emitted year-round from motor vehicles, power plants, industries, and naturally from forest fires. PM also develops from chemical reactions in sunlight from vapor and gaseous pollutants.

Published Research Highlights

The Health Burden of Air Pollution on the Cardiovascular System

In an article in the North Carolina Medical Journal, researchers observe that air pollution’s cardiovascular effects pose an even larger public health burden than its respiratory effects. Yet, the authors note that only three percent of patients with heart disease discuss guidance to reduce exposure with a health professional as shown in a study by the Centers for Disease Prevention and Control (CDC). The researchers explain the sources, exposures, and health effects of air pollution and discuss the potential for intervention strategies in the health care system to help reduce individual and population exposure and the attendant risk from the cardiovascular effects of air pollution.

Ambient Air Quality and Cardiovascular HealthTranslation of Environmental Research for Public Health and Clinical CareExit

New Study Finds Association Between Exposure to Wildland Fire Smoke and Heart and Stroke Related Emergency Room Visits

A new study published April 11, 2018 in the Journal of the American Heart Association, looked for possible associations between daily maximum smoke density (low, medium, and dense) and over a million hospital Emergency Department (ED) visits in northern and central California, over a five-month period in 2015 at a ZIP code level of resolution. The study found a positive association between ED diagnoses for heart, brain, blood vessel, and respiratory disease relative to days without wildland fire smoke exposure.  Impacts were greatest on medium and dense smoke days, and among adults 65 years and older. 

This new study is one of the few to investigate cerebrovascular outcomes explicitly and to find significant associations with exposure to smoke. The publication is a product of a multi-disciplinary collaboration between EPA researchers, the State of California Department of Public Health, and academic partners at the University of California, San Francisco.

Environmental and human health impacts of wildland fire continue to capture the attention of state and local governments, their officials and the public, yet sound decisions for many key policy issues related to wildland fire and land management are limited by a lack of sufficient health data, especially for wildfire smoke impacts on common and costly chronic diseases, such as cardiovascular disease. This study demonstrates the value of collaboration in closing knowledge gaps as we meet the needs of the states. 

Open access journal articleExit

Article in American Heart Association NewsExit

New Study Links Ozone Exposure and Cardiovascular Disease

 A large body of evidence has confirmed that fine particulate matter (PM2.5) is a major risk factor for cardiovascular disease. But what about ozone, another common air pollutant? Previous epidemiological studies suggest that there is a relationship between the air pollutant and cardiovascular health effects, but this work is inconclusive. In a recent study, EPA researchers investigated the ways in which ozone impacts the cardiovascular system and found that exposure altered several biological pathways associated with cardiovascular disease in coronary artery disease patients. The findings support the plausibility that ozone exposure can cause negative cardiovascular health effects in susceptible populations.

Ozone exposure is associated with acute changes in inflammation, fibrinolysis, and endothelial cell function in coronary artery disease patientsEXIT, published in Environmental Health on November 21, 2017.

Study examines possible mechanism linking pulmonary exposure to ultrafine particle pollution and heart disease 

In an animal study, findings suggest that ultrafine particle pollution may affect mitochondrial function important to regulating normal cardiac metabolism. Ultrafine Particulate Matter Increases Cardiac Ischemia/Reperfusion Injury via Mitochondrial Permeability Transition Pore, published in Cardiovascular Toxicology.Exit

Novel data clustering technique used to identify neighborhoods at risk of cardio-metabolic disease

A study investigated the relationship between neighborhood-level factors and cardio-metabolic disease by using hierarchical clustering of data.  A novel approach for measuring residential socioeconomic factors associated with cardiovascular and metabolic health, published in the Journal of Exposure Science & Environmental Epidemiolology. Exit 

Study shows microbes in lungs altered from smoke inhalation   

In a recent study, researchers from EPA and University of North Carolina in Chapel Hill, NC, used new molecular biology techniques to show that the colony of microorganisms (microbiota) living in the lungs is altered in burn patients with damaged airways from smoke inhalation. Not too long ago, the surface of the lung was considered to be sterile with no microorganisms. Now, studies indicate microbiota not only live in the lungs, but also play a role in their health. As a result, scientists are interested in learning what happens to the living colony when the airways are damaged such as by air pollutants. 

Lungs damaged by smoke may change the balance of good microbes and harmful ones such as bacteria that lead to respiratory disease. These bacteria cannot be detected by conventional techniques such as cell culturing, but have been identified with the molecular techniques. Ongoing research will explore whether the same or similar changes in microbiota observed in severe smoke inhalation cases occurs in individuals who are exposed to high pollution events or wildfires.   

Alterations in airway microbiota in patients with PaO2/FiO2 ratio ≤ 300 after burn and inhalation injury, published in PLoS One.Exit 

Biomarkers associated with short-term exposure to PM2.5

Doctor treating PatientResearchers from the Harvard Clean Air Research Center, funded by EPA, evaluated biomarkers of oxidative stress in blood and urine and their association to short-term exposure to fine particulate matter (PM2.5), black carbon, and other air pollutants. Biomarkers in blood were positively associated with PM2.5 and black carbon concentrations, and biomarkers in urine were positively associated with fine particulate matter and sulfate. These associations were stronger for participants with diabetes. Additional research is needed to fully understand the observed link.

Short‐Term Exposure to Air Pollution and Biomarkers of Oxidative Stress: The Framingham Heart Study, published in the Journal of American Heart Association.Exit

Do our genes make us more sensitive to air pollution? In a large study by EPA and Duke University, researchers identified several novel genes associated with coronary artery atherosclerosis in heart patients who have been exposed to traffic-related air pollution for a long time. Atherosclerosis results in plaque build-up in the arteries, which can lead to heart attacks and strokes. The research adds to the large body of evidence that shows the link between air pollution near roadways and cardiovascular disease. While other studies have looked at the gene-air pollution connection, this is the first to examine the entire genome and its potential to respond to emissions from traffic.   

 A genome-wide trans-ethnic interaction study links the PIGR-FCAMR locus to coronary atherosclerosis via interactions between genetic variants and residential exposure to traffic,  published in PLoS One in March 2017.Exit

Community Health Vulnerability Index can be used to identify those at risk from wildfire smoke. EPA scientists developed a Community Health Vulnerability Index that can be used to help identify communities at higher health risk from wildfire smoke. Smoke inhalation is a health threat, especially for people with lung or heart disease, diabetes and high blood pressure as well as older adults, and people in communities with poverty, unemployment and other indicators of social stress. State and local governments can use the tool, in combination with air quality forecasting models, to “map” areas where vulnerable populations are at higher risk from poor air quality, including areas prone to wildfires. Health officials can learn where to focus public health strategies to protect individuals living in areas where air quality is impaired, either by wildfire smoke or other sources of pollution.    

 Community vulnerability to health impacts of wildland fire smoke exposure, published in Environmental Science & Technology  in May 2017.Exit

PM2.5-related cardiac deaths: what we know and how to prevent them. A causal link between fine particulate matter (PM2.5) and cardiac death is well established, but what are the biological steps to adverse cardiopulmonary outcomes? And what makes certain individuals susceptible to PM2.5 ‘s adverse clinical effects? An article describes the physiological changes likely to occur in people with cardiovascular disease that can lead to cardiac arrest or sudden death with high levels of PM2.5. The article also explains the importance of direct and indirect health interventions to reduce the impacts of air pollution on heart health.

Proposed Pathophysiologic Framework to Explain Some Excess Cardiovascular Death Associated with Ambient Air Particle Pollution: Insights for Public Health Translation, published in special issue of the journal Biochimica et Biophysica Acta on air pollution in December 2016. 

Women/African Americans who live near roads may be at higher cardiovascular risk. Female and African-American patients had disproportionately high associations between residential proximity to roadways and known risk indicators for heart disease, including high sugar and cholesterol levels in blood. Air pollution from different types of roads—ranging from major highways to residential streets—also produced specific health responses. These findings are part of CATHGEN, a collaborative study by researchers at Duke University Medical Center and EPA.  

 Association of Roadway Proximity with Fasting Plasma Glucose and Metabolic Risk Factors for Cardiovascular Disease in a Cross-Sectional Study of Cardiac Catheterization Patients, published in Environmental Health Perspectives on March 24, 2015. CATHGEN Research Project Exit

VOCs from petroleum sources may impact the heart. Researchers found that volatile organic compounds (VOCs) in ambient air from petroleum sources resulted in observed cardiovascular health outcomes. The research suggests that VOC exposures may have rapid effects on cardiovascular systems.

Associations between Personal Exposures to VOCs and Alterations in Cardiovascular Physiology: Detroit Exposure and Aerosol Research Study (DEARS),  published in Atmospheric Environment on January 6, 2015.Exit

Smoke forecast models could cut health economic risks from wildfires. For a 2008 peat fire in North Carolina, researchers found that asthma and cardiac events declined after simulating adherence to smoke advisories for exposure from low and intermediate levels of particulate matter. The economic benefit of effective interventions exceeded $1 million in excess hospital visits for asthma and heart failure, $2 million in lost productivity, $100,000 in respiratory conditions in children, and $42 million due to excess mortality.

Forecast-Based Interventions Can Reduce the Health and Economic Burden of Wildfires,  published in Environmental Science and Technology on August 25, 2014.Exit

Biomarker for PM risk studied in highway workers. Overall, exposure to PM2.5 at work, but not noise, increased acute-phase markers of inflammation. Fine particles and work noise were independently associated with increased heart rate variability during sleep hours. The researchers concluded that noise and pollutants comprise a cardiovascular risk for highway maintenance workers, and that actions to reduce these exposures might lead to better health for this population.

Association of short-term particle and noise exposure with markers of cardiovascular and respiratory health among highway maintenance workers, published in Environmental Health Perspectives on July 1, 2014.Exit

Exposure to course particle pollution causes metabolic changes. Short-term exposure to rural coarse particulate matter leads to an increase in endothelial progenitor cell (EPC) levels, which is an indication of metabolic changes, according to an EPA-funded study.  The rising levels of EPC can contribute to the risk of cardiovascular disease and diabetes.

The effect of acute exposure to coarse particulate matter air pollution in a rural location on circulating endothelial progenitor cells: results from a randomized controlled study,  published in Inhalation Toxicology in August 2013.

Link found between air pollution and susceptibility to metabolic syndrome. Scientists found that short-term exposures to concentrated air pollutants and ozone in obese rodents resulted in inflammation and oxidative stress in the fat around the heart and kidney. Rodents on a high-fructose diet had a greater response. The findings may provide a link between air pollution exposure and accelerated susceptibility to metabolic syndrome, a group of risk factors that increases your risk for heart disease and other health problems such as diabetes and stroke. The research was funded by EPA’s STAR program.

Ambient fine particulate matter and ozone exposures induce inflammation in epicardial and perirenal adipose tissues in rats fed a high fructose diet (PDF), (2 pp, 34K)  published in Particle and Fibre Toxicology in 2013. Exit

Diesel exhaust can impact “good” cholesterol. Exposure to diesel emissions can change the function of high density lipoproteins (HDL) from good to bad. HDL is normally seen as the “good” cholesterol that helps moderate the bad effects of low density lipoproteins (LDL). The development of dysfunctional HDL resulting from exposure to diesel exhaust emissions could be a pathway by which air pollution leads to enhanced atherosclerosis and heart problems, according to the study funded by EPA’s STAR program.

Diesel exhaust induces systemic lipid peroxidation and development of dysfunctional pro-oxidant and pro-inflammatory high-density lipoprotein,  published in Arteriosclerosis, thrombosis, and vascular biology on April 4, 2013.Exit

Can controlling high blood pressure protect against air pollution? A study shows that when medication is used to reduce blood pressure in rodents who are genetically predisposed to hypertension, there is an extra benefit. Controlling blood pressure also reduced some of the negative health impacts of long-term exposure to diesel exhaust on the pulmonary and cardiovascular systems.

The research is making an important contribution to understanding how to improve public health since the World Health Organization estimates more than 30 percent of adults worldwide have high blood pressure. The paper was featured online by World Biomedical Frontiers, an organization that focuses on cutting-edge biomedical research from around the globe.

Diesel exhaust induced pulmonary and cardiovascular impairment: The role of hypertension intervention,  published in Toxicology and Applied Pharmacology on April 15, 2013. Exit

Nitrogen dioxide may enhance cardiac effects of fine particulate pollution. Recent epidemiology studies associated nitrogen dioxide (NO2) exposure with cardiovascular effects and suggest that the gas is merely a marker of traffic-related air pollution. A study by EPA and Duke University Medical Center scientists examined effects of a mixture of NO2 and fine particles (PM2.5). The study suggests NO2 exposure may produce and enhance acute cardiovascular effects of fine particulate matter exposure.

Synergistic effects of exposure to concentrated ambient fine pollution particles and nitrogen dioxide in humans,  published in Inhalation Toxicology on Oct. 24, 2012. Exit

Ozone may impact cardiovascular system. A clinical study by EPA found that ozone caused temporary changes in the cardiovascular system. The ozone exposure caused inflammation of the vascular system and resulted in a change in heart rate variability and a reduction in the ability of blood clots to dissolve, which are two risk factors for heart disease. This study shows ozone has the potential to impact the cardiovascular system.

Controlled Exposure of Healthy Young Volunteers to Ozone Causes Cardiovascular Effects,  published in the American Heart Association’s journal, Circulation,  on June 25, 2012. Exit

Higher health risk found for heart patients living near major highways. EPA’s Clean Air Research Center at Beth Israel Deaconess Medical Center has found that heart attack survivors face air pollution health risks associated with living near major highways. Over a study period of 10 years, heart attack survivors living less than 100 meters or 328 feet from a roadway were found to have a 27 percent higher health risk compared to survivors living at least 1,000 meters or 3,277 feet away. That risk lowered to 13 percent for those living between 200 and 1,000 meters or 656 to 3,277 feet from the roadway.

Residential Proximity to Major Roadway and 10-Year All-Cause Mortality After Myocardial Infarction,  published in the American Heart Association’s journal, Circulation, on May 7, 2012. Exit

Fish oil may help heart patients. In a study, EPA scientists found evidence that omega-3 fatty acids (the kind found in most fish oil supplements) may protect the cardiovascular system from the harmful effects of fine particle pollution. The study found that 3 grams of fish oil daily helped to prevent symptoms such as a change in heart rate variability and heart rhythm that could contribute to heart problems in people with heart disease. Always check with your personal doctor before starting a dietary supplement such as fish oil.

Omega-3 Fatty Acid Supplementation Appears to Attenuate Particulate Air Pollution Induced Cardiac Effects and Lipid Changes in Healthy Middle-Aged Adults, published in Environmental Health Perspectives on April 19, 2012. Exit

Cardiac effects found with ozone exposure. EPA scientists found that exposure to varying levels of ozone has both direct and indirect effects on the heart. Rats exposed to 0.8 parts per million (ppm) of ozone experienced immediate and clear changes in heart function including heart arrhythmias and abnormal electrocardiograms (ECG). While there were no direct changes in heart function when the rats were exposed to 0.2 ppm of ozone, they were more likely to have alterations in heart function when the heart was stressed 24 hours after exposure.

Overt and latent cardiac effects of ozone inhalation in rats: evidence for autonomic modulation and increased myocardial vulnerability,  published in Environmental Health Perspectives on Dec. 2, 2011. Exit

PM Training Course for Healthcare Professionals Available. EPA scientists collaborated to develop an evidence-based training course for healthcare professionals summarizing the scientific data linking exposures to particulate matter (PM) with a wide range of health effects including cardiovascular and respiratory effects and premature death. This course includes educational tools that physicians, nurses and others can share with their patients, especially those with pre-existing heart and lung disease, to help them understand how PM can affect their health and learn how to use the Air Quality Index to reduce their exposures to PM. 

Access the Training Course.

Residential Socioeconomic Factors Linked to Cardio-Metabolic Disease. EPA researchers applied a novel hierarchical clustering technique to identify residential areas with similar characteristics using demographic data from the US Census. An existing group of individuals with a previous cardiac catheterization already living in those areas was then examined for their cardio-metabolic health. After controlling for individual risk factors, the researchers found that individuals living in more disadvantaged areas are more likely to be obese and have diabetes, congestive heart failure, and hypertension compared with those living in the most-advantaged area. Future research will focus on whether living in disadvantaged areas confers a greater susceptibility to the adverse effects of air pollution. In addition, public health officials can use this information to target assistance for communities that are susceptible to cardiovascular and metabolic disorders due to their residential characteristics.  

A novel approach for measuring residential socioeconomic factors associated with cardiovascular and metabolic health, Exitpublished in the Journal of Exposure Science and Environmental Epidemiology on September 21, 2016.

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