Could preserved vision be part of the growing list of health benefits associated with GLP-1 drug use?
New research suggests that in patients without diabetes, GLP-1 medications may lower the risk of age-related macular degeneration (AMD), the leading cause of vision loss in older US adults.
AMD is a disease that gradually damages the macula, the part of the retina responsible for sharp, central vision. As it worsens, people find it increasingly difficult to see things directly in front of them, while their peripheral vision remains largely unaffected.
Nearly 20 million US adults have AMD. The slower-moving, dry form of the condition accounts for about 80% of cases. It occurs when the macula thins with age, often due to the buildup of yellow protein deposits called drusen.
Wet AMD, while less common, is far more aggressive, causing rapid and severe vision loss.
As the name implies, AMD risk increases with age. About 2% of adults aged 40-44 are living with AMD, and in adults over 85, that rate shoots up to 35%.
Knowing that GLP-1 drugs have proven effective at reducing inflammation and improving vascular health, Oregon Health & Science University researchers were interested in how the meds would affect AMD, which is classified as an inflammatory disease.
The team followed roughly 91,000 participants over 10 years. Participants were over 55 with no history of diabetes. Of this cohort, half were taking a GLP-1 for weight loss, and the other half were prescribed a non-GLP-1 weight loss drug.
Five years into the study, the GLP-1 group had an 84% lower risk of developing dry AMD than the non-GLP-1 group.
Better yet, the risk continued to drop over time. After seven years, GLP-1 users had an 87% lower risk; at 10 years, the risk was 91% lower.
“We were quite surprised by the strength of the association between GLP-1 medication use and the lower risk of developing macular degeneration,” said Dr. Benjamin Young, a corresponding study author and an assistant professor of ophthalmology at OHSU Health in Portland, Oregon.
However, the team found that in participants who already had dry AMD, GLP-1 meds did not slow the progression to wet AMD.
Experts note that the absence of diabetes among participants and the strict use of GLP-1s for weight loss is a critical caveat, as diabetes is a substantial risk factor for AMD.
In fact, a separate study found that after one year, diabetic GLP-1 users were more than twice as likely to develop wet AMD than those who were not taking the drugs.
Young notes that his study only shows an association, not a cause-and-effect relationship, between GLP-1 medications and a reduced risk of AMD.
“We can’t say that these medications directly caused the reduction in AMD risk. The findings suggest a possible link that should be tested in a randomized clinical trial,” he said.
Young believes that reduced inflammation resulting from GLP-1 use could contribute to a reduced risk of AMD, noting that this reduction could translate into alleviation of other eye issues.
“We also recently published that GLP-1s might reduce the incidence of cataracts, which we also speculate may be related to reduced ocular [eye] inflammation,” said Young.
Despite these promising findings, Young cautioned against physicians recommending GLP-1 meds as a treatment for, or preventative measure against, AMD or other vision issues.
“I don’t think this study should play any role in physicians recommending weight loss drugs to prevent macular degeneration. If a patient asks if it’s safe to take if they think they are at risk for macular degeneration, I think these results might help physicians suggest it is likely safe to take in that situation,” said Young.
He acknowledged that more research is needed to confirm these findings and to further explore the relationship between GLP-1 medications and overall eye health.
“There are many different eye diseases; macular degeneration is only one. We hope further studies shed more light on this complicated picture,” said Young.
