Air pollution linked to increased risk of irreversible vision loss
Air pollution is associated with an increased risk of progressive and irreversible sight loss, known as Age-related Macular Degeneration (AMD), according to a long-term study published in the British Journal of Opthalmology. The study could pave the way for new treatment options for the disorder. Researchers noted that AMD is the leading cause of irreversible blindness among the age-group over 50's in high-income countries.
AMD-linked blindness to affect 300 million people by 2040
The researchers, including those from the University College London, said, "Known risk factors include older age, smoking, and genetic make-up." They further noted that the numbers of those affected with the blindness caused by AMD are projected to reach 300 million by 2040.
Study analyzed association between ambient air pollution and AMD
Given that ambient air pollution is associated with heightened risks of heart and respiratory diseases, the study analyzed if it might also be associated with a heightened risk of AMD. Researchers drew on data from 115,954 UK Biobank (UKBB) study participants aged 40-69 with no eye problems at the start of the study in 2006. Of the total participants, 1,286 were diagnosed with AMD.
Measures of ambient air pollution used in the study
Measures of ambient air pollution included those for particulate matter (PM2.5), nitrogen dioxide (NO2), and nitrogen oxides (NOx). "Among the 52,602 people whose eyes had been assessed, 75 percent of those with a clinical diagnosis of AMD had signs of AMD on retinal imaging compared to only 12 percent of those without a clinical diagnosis of AMD," they said.
It is an observational study; can't establish cause
Analysis of the data showed that higher fine particulate matter (PM2.5 ) exposure was associated with a higher (8 percent) risk of AMD, while all other pollutants, except coarse particulate matter, were associated with changes in retinal structure. The researchers noted that it is an observational study, and as such, can't establish cause, adding the findings, however, echo those found elsewhere in the world.
Air pollution associated with AMD through oxidative stress or inflammation
Researchers suggest ambient air pollution could plausibly be associated with AMD through oxidative stress or inflammation. "Overall, our findings suggest that ambient air pollution, especially fine particulate matter or those of combustion-related particles, may affect AMD risk," the researchers noted.