New Study Compares Air Pollution to “Smoking a Pack of Cigarettes per Day”
While we know that heart disease is the leading cause of death for both men and women, physicians still debate what causes atherosclerosis (hardening of the arteries). This “stiffening” gives rise to what we see clinically as heart attack, stroke, and peripheral vascular disease. Approximately one-half of all Americans have at least one of the following “key” risk factors of heart disease (CDC, 2011):
High Blood Pressure
High LDL Cholesterol
Cigarette smoking
But these risk factors are an oversimplification. Recognizing that blood pressure, LDL-C, and smoking status weren’t enough to explain heart disease, researchers found that certain medical conditions and lifestyle choices also put people at a higher risk, including: Diabetes, Overweight/Obesity, Poor Diet, Lack of Exercise, Excessive Alcohol Consumption.
Even still, this is missing the bigger picture. Despite all the years and money spent in research, do we really believe we’re any closer to solving heart disease?
In the U.S., someone has a heart attack every 34 seconds, and each minute, more than one person dies from a heart disease-related event (Heron, 2016). This equates to around 630,000 lives lost from heart disease each year, which is 1 in every 4 deaths (CDC & NCHS, 2017).
Why? Because we are not thinking differently about this real crisis. First, heart disease does not discriminate. Heart disease is, in fact, the leading cause of death for people of most racial and ethnic groups in the United States, including African Americans, Hispanics, and whites. For Asian Americans, Pacific Islanders, American Indians, and Alaska Natives, heart disease is second only to cancer (Benjamin et al., 2017). More on this later…
Maybe 1 out of 4 of us are supposed to die from heart disease? Maybe that’s just the way it is. However, our genes haven't changed. Our environment has. Could it be that there is a profound mismatch between our polluted environment and previous circumstances that have produced the aberrant health outcomes we see today?
Thinking differently, if you asked our ancestors what were life’s top two most vital elements, air and water would have been the unanimous answers. Without water, you would only survive for a few days. Without air, a few minutes.
Given these simple truths, wouldn’t it make sense that, because every person inhales thousands of gallons of air each day, air would be the greatest potential source of toxicant exposure known to humankind?
As a dated example, we’ve known for generations that occupational exposure to air contaminated with chemical compounds in coal or radioactive dust can lead to black lung disease or lung cancer. More recently, similar protections were put in place after major cities’ air quality decreased due rising concentrations of gaseous lead found in gasoline exhaust. Unfortunately, lead-containing fuel is still sold for “off-road uses” to this day.
Sometimes we can’t see what’s around us. Out of sight, out of mind. This is why many of us assume that we can simply avoid poor air quality by refraining from occupational exposure or, at most, steering clear of tobacco use and second-hand smoke. But the truth is, even at home, the air you breathe inside is the same air you breathe outside. This is why we all have to care about air pollution.
Environmental Health Perspectives recently published a study that followed a sizable population (6,619 adults, between 45-84 years old) without cardiovascular disease or other health conditions to understand if there was an association between ground ozone exposure (i.e. vehicular exhaust emissions, smoke from nearby factories, etc.) and atherosclerosis. After almost a decade of follow-up, researchers found a strong association between long-term ozone exposure and an increased rate of carotid wall thickness progression and risk of new plaque formation (Wang et al., 2019).
What Happens When You Breathe Ground-level Ozone?
According to the American Lung Association, ground-level ozone (i.e. gas molecules) likely damages lungs when inhaled. One suggested pathway is the production of reactive oxidative species (ROS) from the interaction of ozone with cellular membranes (i.e. lipids) in the lung. These ROS are then released into the circulatory system where they can damage other cells throughout the body. ROS propagates a systemic inflammatory response. It’s like a domino effect—a cascade of injury we can’t initially feel. Persistent exposure to ground-level ozone and/or repeated activation of this pathway is likely the mechanism that leads to the development of arterial injury (Cosselman et al., 2015).
Obviously, it would be incredibly unethical to expose populations of humans to varying degrees of toxic air; hence, much of what we know depends on associations between ambient air quality and human diseases. In addition to respiratory effects of long-term exposure to ground-level ozone, higher concentrations were associated with total mortality and cardiovascular mortality and its subtypes, ischemic heart disease, cerebrovascular disease, and mortality risk among people with congestive heart failure.
Read more about how to protect your lungs here:
How To Keep Your Lungs Healthy and Respiratory Health
References
Benjamin, E. J., Blaha, M. J., Chiuve, S. E., Cushman, M., Das, S. R., Deo, R., ... & Jiménez, M. C. (2017). Heart disease and stroke statistics-2017 update: a report from the American Heart Association. Circulation, 135(10), e146-e603.
Centers for Disease Control and Prevention (CDC, 2011). Million hearts: strategies to reduce the prevalence of leading cardiovascular disease risk factors--United States, 2011. MMWR. Morbidity and mortality weekly report, 60(36), 1248.
Chuang, G. C., Yang, Z., Westbrook, D. G., Pompilius, M., Ballinger, C. A., White, C. R., ... & Ballinger, S. W. (2009). Pulmonary ozone exposure induces vascular dysfunction, mitochondrial damage, and atherogenesis. American Journal of Physiology-Lung Cellular and Molecular Physiology, 297(2), L209-L216.
Cosselman, K. E., Navas-Acien, A., & Kaufman, J. D. (2015). Environmental factors in cardiovascular disease. Nature Reviews Cardiology, 12(11), 627.
Di, Q., Wang, Y., Zanobetti, A., Wang, Y., Koutrakis, P., Choirat, C., ... & Schwartz, J. D. (2017). Air pollution and mortality in the Medicare population. New England Journal of Medicine, 376(26), 2513-2522.
Heron, M., & National Vital Statistics Reports. (2016). Deaths: Leading causes. National Vital Statistics Report, 65(5).
Jerrett, M., Burnett, R. T., Beckerman, B. S., Turner, M. C., Krewski, D., Thurston, G., ... & Gapstur, S. M. (2013). Spatial analysis of air pollution and mortality in California. American journal of respiratory and critical care medicine, 188(5), 593-599.
U.S. Environmental Protection Agency. (EPA, 2013). Integrated Science Assessment (ISA) for Ozone and Related Photochemical Oxidants. EPA/600/R-10/076F. Washington, DC:U.S. EPA.
AUTHOR
Dr. Payal Bhandari M.D. is one of U.S.'s top leading integrative functional medical physicians and the founder of SF Advanced Health. She combines the best in Eastern and Western Medicine to understand the root causes of diseases and provide patients with personalized treatment plans that quickly deliver effective results. Dr. Bhandari specializes in cell function to understand how the whole body works. Dr. Bhandari received her Bachelor of Arts degree in biology in 1997 and Doctor of Medicine degree in 2001 from West Virginia University. She the completed her Family Medicine residency in 2004 from the University of Massachusetts and joined a family medicine practice in 2005 which was eventually nationally recognized as San Francisco’s 1st patient-centered medical home. To learn more, go to www.sfadvancedhealth.com.