A large long-term study by the researchers from University Colege London reveals that air pollution is linked to an increased risk of developing progressive and irreversible blindness, known as age-related and macular degeneration (AMD).
According to their findings, people who live in places with high air pollution rates are at least 8% more likely to report having AMD. They published their findings in the British Journal of Ophthalmology.
The researchers said that the findings could pave the way for developing new treatments for AMD, which is the leading cause of irreversible loss of sight among people in their 50s in high-income countries projected to reach up to 300 million cases by 2040.
Living in Air Polluted Area Heightens Risk of Developing Eye Disease
Age-related macular degeneration (AMD) is one of the causes of blindness in older age, but risk factors like smoking and genetic makeup could also play a role.
Since it is common knowledge already that air pollution increases risks of heart and respiratory diseases, the researchers investigated if the same is true in terms of eye health, according to Medical Xpress.
They collected the data from a 2006 study of 115,954 UK Biobank (UKBB) study participants aged 40-69 with no eye problems when the study started. The participants were asked to report any formal diagnosis of AMD. By 2012, over 50,000 of them reported structural changes in the thickness and numbers of light receptors in their retina, which indicates AMD.
"Here we have identified yet another health risk posed by air pollution, strengthening the evidence that improving the air we breathe should be a key public health priority. Our findings suggest that living in an area with polluted air, particularly fine particulate matter or combustion-related particles that come from road traffic could contribute to eye disease," lead author Professor Paul Foster of the university's Institute of Ophthalmology said.
He added that even relatively low exposure to polluted air increases AMD's risk, which suggests that it is a crucial risk factor that can impact the eye health of a large number of people.
Air pollution includes particulate matter (PM2.5), nitrogen oxide (NO), and nitrogen dioxide (NO2). The mall Area Health Statistics Unit, as part of the BioSHaRE-EU Environmental Determinants of Health Project, provides estimates for these measures of air pollution.
The annual average air pollution levels at the location of the participants' homes were calculated using the official information on traffic, land use, and topography. About 75% of more than 50,000 participants had a clinical diagnosis of AMD.
Meanwhile, the data also showed that higher particulate matter (PM2.5) exposure is linked to an 8% risk of AMD, adding the influential factors like underlying health conditions and lifestyle.
No Causal Relationship
Despite the findings, the researchers noted that this observational study does not point to a causal relationship between the two factors, EurekAlert! reported. However, the findings align with evidence from other studies.
The researchers suggest that ambient air pollution could heighten developing progressive and irreversible blindness or AMD through oxidative stress or inflammation.
"Higher exposure to air pollution was also associated with structural features of AMD. This may indicate that higher levels of air pollution may cause the cells to be more vulnerable to adverse changes and increase the risk of AMD," said the paper's first author Dr. Sharon Chua.
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