Air pollution and its link to heart disease
Coronary heart disease is the leading cause of death in the western hemisphere.
While cardiac prevention has traditionally focused on controlling high blood pressure, diabetes, cholesterol levels, and smoking and making healthy choices in regard to diet and exercise, accumulating evidence indicates that air pollutants contribute to serious, even fatal damage to the cardiovascular system.
Whether one lives in a city where smog forecasts are routine or in a less populated place, tiny pollution particles in the air can still contribute to heart problems.
Air pollution can come from traffic, factories, power generation, and wildfires. One of the most common sources though remains indoor second-hand smoking.
In 2004, the American Heart Association issued a scientific statement concluding that exposure to air pollution contributes to cardiovascular illness and mortality. A 2010 update elaborated on those risks.
According to these two statements, short-term effects of air pollution tend to strike people who are elderly or who already have coronary disease. For instance, someone with plaque build-up in the coronary arteries could experience, thanks to some polluting particles, a rupture of one of these stable plaques, triggering a heart attack.
Pollution is also believed to have inflammatory effects on the heart (oxidative stress), causing long-term cardiovascular issues. Medical researchers are particularly concerned about pollution particles smaller than 2.5 microns, which are usually related to fuel combustion. Because they are so tiny, they can not be stopped by the nose and sinuses and more readily enter the human body. They then begin to irritate the lungs and coronary vessels.
Though anyone can be exposed, people who live near road intersections or factories or who direct traffic are particularly at risk. This risk is also greater, not only with more contact but with longer-term exposure.
The same above statements suggested a possible additional role of pollution in high blood pressure and diabetes development, but also in the heart failure epidemic. The latter effect was extensively studied by an Edinburgh-based research team. The team analysed data from 12 countries covering more than four million people living with heart failure, and found they had an increased risk of hospitalisation and death where air pollution levels were high.
Impact: A very large one
The increase in disease rates related to air pollution may appear to be small when viewed in percentage terms. For example, the studies cited above found cardiac hospital admissions increasing on the order of a single per cent. However, the large number of people who suffer from heart ailments translates the result into a very large effect when measured nationally or globally, in terms of total hospital admissions, numbers of illnesses, patient deaths and the costs to the economy of healthcare and days lost from work and school.
Research by the World Health Organisation claims that one in eight of total global deaths is a result of air pollution exposure.
This more than doubles previous estimates and confirms that air pollution is now the world's largest single environmental health risk.
Approach to the problem
Reducing exposure to air pollutants is an important aspect of improving cardiovascular health. For example, reductions in PM2.5 concentration in 51 metropolitan US areas were correlated with significant increases in life expectancy. Air quality improvements under the American Clean Air Act have measurably improved the health of the US population.
People with heart or lung disease should avoid spending long periods outdoors in areas where traffic pollution is likely to be high. Local air quality reports could help people understand when they might be most at risk.
However, for most people, the benefits of exercising outdoors outweigh the risks associated with pollution. While we are lucky to live in Bermuda and breathe its clean air, we cannot afford to be complacent about air quality and pollution in general, including land littering and ocean effluence.
• Joe Yammine is a cardiologist at Bermuda Hospitals Board. He trained at the State University of New York, Brown University and Brigham and Women's Hospital. He holds five American Board certifications. He was in academic practice between 2007 and 2014, when he joined BHB. During his career in the US, he was awarded multiple teaching and patients' care recognition awards. The information herein is not intended as medical advice nor as a substitute for professional medical opinion. Always seek the advice of your physician. You should never delay seeking medical advice, disregard medical advice or discontinue treatment because of any information in this article.