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 In a study of nearly 40,000 people in Taiwan, researchers found that
high levels of exhaust could nearly double the risk of the
age-related eye condition, which damages the macula, the part of the
eye needed for sharp, central vision. People with AMD have trouble
seeing straight ahead.
Only people with the highest exposure to exhaust had an increased
risk of age-related macular degeneration (AMD), meaning that "if we
can reduce exposure and try not to be in the highest exposure group,
the risk can be significantly reduced," said study coauthor Dr. Suh-Hang
Hank Juo, a distinguished professor at the China Medical University
in Taiwan.
"Therefore, do not go jogging on the road side when there are lots
of cars and try not to go outside during the heavy traffic hours,"
Juo said in an email.
To investigate whether vehicle pollution, which has previously been
tied to increased risks for respiratory and cardiovascular diseases,
also impacts the risk for AMD, Juo and his colleagues turned to two
large data sets: The Longitudinal Health Insurance Database (LHID)
and the Taiwan Air Quality Monitoring Database (TAQMD).
From the insurance database, the researchers selected patients who
were aged 50 or older when they were enrolled, who did not have
signs of AMD at that point, and who lived in areas where there were
air-quality monitoring stations.
As reported in the Journal of Investigative Medicine, the
researchers divided the patients into four groups depending on the
level of pollutant exposure. Of the 39,819 patients in the study,
1,442 developed AMD during 11 years of follow-up. After accounting
for other factors that might influence the risk of AMD, such as age,
gender, household income and underlying illnesses, the researchers
determined that people living in areas with the highest levels of
vehicle-generated pollution were 84% more likely to develop AMD
compared to those exposed to the lowest levels.
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The new research is interesting but "it is a longitudinal
observational study and can only show an association but not prove a
cause-effect relationship," said Dr. Fernando Arevalo, a professor
of ophthalmology at the Johns Hopkins University School of Medicine
and chairman of ophthalmology at the Johns Hopkins Bayview Medical
Center, both in Baltimore, Maryland. "AMD is multifactorial and many
genetic as well as environmental factors play a role in its
development and that may confound the results. Further studies are
needed."
While the study doesn't prove pollution causes AMD, "it's very, very
intriguing," said Dr. Avnish Deobhakta, an assistant professor of
ophthalmology at the Icahn School of Medicine and the Eye and Ear
Infirmary at Mount Sinai in New York.
Scientists already know that smoking increases the risk of AMD,
Deobhakta said, adding that "smoking is the highest controllable
risk factor." Inhaled pollutants may work in a similar way, he
added.
Dr. Joseph Martel, an assistant professsor of ophthalmology at the
University of Pittsburgh, suspects that, as with smoking, air
pollution may lead to oxidative damage, which "in the eye is known
to be associated with macular degeneration."
That's why doctors often prescribe an antioxidant concoction of
vitamins and minerals to help slow AMD, Martel said. It's also
suggested that people with AMD consume lots of green, leafy
vegetables, like spinach, he added.
SOURCE: http://bit.ly/2KKC02p Journal of Investigative Medicine,
online August 20, 2019.
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