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Air pollution’s link to heart disease

Doctors and researchers have known for a long time that smoking, high blood pressure, high cholesterol, diabetes, being overweight, and being physically inactive increase a person’s chances of heart disease and stroke. Common prevention and treatment strategies include lifestyle changes (not smoking, eating a healthy diet, and exercise) and taking medications to control cholesterol and blood pressure.

Less well known is the link between heart disease and exposure to high levels of air pollution, especially air pollution that involves fine particulate matter (air pollution particles having a diameter approximately 1/30th the width of a human hair). This type of air pollution is mainly produced during combustion, such as from cars or power plants. During MESA clinical examinations, participants completed a questionnaire and some participants allowed researchers to visit their homes in order to take measurements of air pollution levels.

One of the recent major findings in MESA is the discovery of a link between air pollution, the small blood vessels in the body, and the toll pollution may take on your heart. MESA Investigator Dr. Sara Adar (from the University of Michigan, School of Public Health) and Dr. Joel Kaufman (from the University of Washington, School of Public Health) studied this potential link using photographs of MESA participants’ eyes taken as part of the eye tests during the second clinic visit. The photos taken were of the retina, which is the light-sensitive membrane layer at the back of the eye that contains many microscopic-sized blood vessels.

MESA retinal camera station Retinal scan

We already know that narrowing of the heart’s arteries reduces the flow of blood that nourishes the heart muscle, which is a cause of heart attacks, stroke, etc. It has been found that the tiny vessels carrying blood to the eyes mimic those found in other parts of the body, including the heart. Looking at the smaller vessels in the retinas of the eyes can give us a good idea about what is going on in the heart, since the smaller vessels in the heart are so difficult to see.

Dr. Adar and her colleagues wanted to know if exposure to air pollution narrowed the smaller blood vessels in our bodies. What they found was people living in areas of high air pollution had narrower arterioles in their eyes than people living in cleaner areas. The vessels in people’s eyes were also narrower on days with high air pollution as compared to days with low air pollution Dr. Adar: "People with short exposures to increased levels of pollution had the blood vessels of someone three years older and people exposed chronically to high pollution had the vessels of a person seven years older. These changes translate to an approximate three percent increase in heart disease for a woman living with high levels of air pollution as compared to a woman in a cleaner area."

Dr. Adar’s and her colleagues’ work was published in the prestigious journal, PLoS Medicine (Public Library of Science Medicine) and has had far-reaching effects since publication. Their paper was also spotlighted on several news shows and publications such as Science Daily, ABC Science, Medical News Today-online, Yahoo News, as well as sites as far away as India and New Zealand.

Dr. Adar continues, "This study suggests that living in an area with high levels of air pollution or having brief exposures to high levels of air pollution can increase

Anatomy of the eye

your risk of heart disease. The study shows that whether it’s a short-term or long-term exposure, air pollution does have an effect on one’s heart."

Some things you can do to lessen your exposure to air pollution are staying indoors during high-pollution days and using an air filter in your home and/or at work.

A pollution source

Through the MESA studies on air pollution, and the help of the MESA participants, we can expect to learn much more about the effect of

air pollution on the heart over the next few years. Studies like this provide valuable new insights into possible causes of heart disease and suggest new ways to prevent it – by clearing the air!

Some things you can do to lessen your exposure to air pollution are staying indoors during high-pollution days and using an air filter in your home and/or at work.

Link to Dr. Adar’s article - www.plosmedicine.org/article/info%3Adoi%2F10.1371%2Fjournal.pmed.1000372

Sara Adar, "Tiny Blood Vessels Show Pollution, Heart Disease Link," Yahoo News, November 30, 2010
Sara Adar, "Photos of Tiny Blood Vessels in the Eye Link Air Pollution to Heart Disease," Science Daily, November 30, 2010
Sara Adar, "Tiny Blood Vessels Show Pollution, Heart Disease Link," The Independent - online, December 03, 2010
Sara Adar, "Blood Vessels Show Pollution, Heart Disease Link," ABC Science, December 01, 2010
Sara Adar, "Blood Vessels in Eye Reveal Connection Between Heart Disease and Air Pollution," Daily Tech, December 01, 2010
Sara Adar, "Heart Disease, Pollution Link Seen in Blood Vessels ," Arab Times - online, December 02, 2010
Sara Adar, "Link Between Heart Disease And Air Pollution," Medical News Today - online, December 02, 2010
Sara Adar, "Photos Of Tiny Blood Vessels In The Eye Link Air Pollution To Heart Disease," redOrbit - online, December 02, 2010

Links to Dr. Adar’s paper in selected publications:

http://www.abc.net.au/science/articles/2010/12/01/3081483.htm

http://www.dnaindia.com/health/report_tiny-blood-vessels-in-the-eye-show-pollution-heart-disease-link_1475131

http://www.downtoearth.org.in/content/retina-visuals-capture-heart

http://newstrackindia.com/newsdetails/193323

http://www.thenewage.co.za/mobi/Detail.aspx?NewsID=4684&CatID=12

http://www2.canada.com/edmontonjournal/news/story.html?id=c000226b-8311-43f0-96b0-39cf3d0bb499