A new investigation involving over 157,000 participants revealed an unprecedented effect of GLP-1-based drugs, such as Ozempic and Wegovy. In a clinical trial, these medications were correlated with a decrease in the risk of age-related macular degeneration (AMD), which is the main cause of irreversible blindness in older people.
The individuals included in the study were 60 years or older and obese, but not diabetic. This selection allowed scientists to exclude glycemic influences that could distort the results.
The group was divided into two equal parts. One group used GLP-1 class medications for weight control, such as liraglutide, semaglutide, or tirzepatide. The second group consisted of people using other weight loss medications that did not belong to this category.
After a seven-year monitoring period, the data showed that patients treated with GLP-1 had a significantly lower incidence of AMD compared to the other group. The use of GLP-1 was linked to an estimated 18% reduction in the risk of developing AMD during the follow-up.
Medications like Ozempic contain semaglutide as the active ingredient, a substance that mimics the function of the GLP-1 hormone, responsible for signaling satiety. Unlike natural GLP-1, which remains in the body for only a few minutes, semaglutide has a more lasting effect, promoting weight loss and suppressing appetite for an extended period.
Although the exact mechanism by which GLP-1 drugs might protect the elderly from vision loss remains uncertain, researchers raised a possibility: the drug class could have a neuroprotective effect. This would occur through the reduction of inflammation in the retina via a protein complex known as the NLRP3 inflammasome, which protects the body.
However, there is another plausible explanation. Obese individuals using GLP-1 tend to lose more weight than those using other weight loss treatments. Thus, the reduced risk of AMD may be linked to the weight loss process itself, and not directly to GLP-1. The authors clarify that 'weight loss itself already reduces systemic inflammation and oxidative stress, which can decrease the risk of AMD independently.'
If this second theory is confirmed, the finding corroborates a study conducted ten years before semaglutide was introduced to the market, which already indicated a 2% increase in the risk of AMD for every additional kilogram per square meter in the body mass index (BMI) of overweight or obese people.
The researchers themselves admit that it is premature to draw final conclusions. The observation time of the study was relatively short, with only one year for GLP-1 users and two and a half years for the comparison group. More research will be necessary to confirm and better understand the underlying processes of this effect, including studies with younger age groups, starting from 50 years old.
