Tiny blood vessels in the eye show pollution-heart disease link

WASHINGTON - By digitally photographing tiny blood vessels in our eyes, researchers have found a way to link exposure to air pollution with a higher risk of heart disease.

New digital photos of the retina revealed that otherwise healthy people exposed to high levels of air pollution had narrower retinal arterioles, an indication of a higher risk of heart disease.

The new study is the first known to examine relationships between pollution and extremely tiny blood vessels (microvasculature) in humans, said Sara Adar, research assistant professor at the University of Michigan School of Public Health.

Researchers found that participants who were exposed to low level of pollution in a short time period showed the microvascular blood vessels of someone three years older, while people who faced longer term exposure to high levels of pollution had the blood vessels of someone seven years older.

“Such a change would translate to a 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,” said Adar.

The study examined retinal vessels because they are an example of the very small vessels that exist in the heart and throughout the body, but are easily visible without needing scalpels, probes, or anesthesia.

Researchers took digital retinal photographs of blood vessels of 4,607 people aged 45 to 84 with no history of heart disease.

They measured air pollution levels in their homes for two years prior to the eye exams. They also checked pollution levels on the day before the eye exam to calculate short-term exposure.

Even though pollution levels in the study were generally below the level that the EPA considers acceptable, these levels still appeared to negatively affect the tiny blood vessels, said Adar.

Although the narrowing in the vessels amounted to about 1/100s of a hair’s width, this could have important health consequences if all of the microvasculature in the body is affected in the same way, he added.

Lead author Joel Kaufman at the University of Washington, Seattle said the research ‘provides a strong potential link between the epidemiological observations of more cardiovascular events like fatal heart attacks with higher pollution exposures and a verifiable biological mechanism’.he study is published in PLoS Medicine. (ANI)