The bi-national study, published on medRxiv and conducted by researchers from the University of Southern Denmark, Norwegian Institute of Public Health, and the University of Copenhagen, leveraged nationwide health registries to investigate the link between semaglutide and NAION. The findings suggest that Type 2 diabetes patients using Ozempic for two decades could have a 0.3% to 0.5% chance of developing NAION.

"We leveraged the nationwide Danish and Norwegian health registries to further investigate this association," said the study authors. "The vision loss is usually irreversible and there is no treatment. Given the serious nature of this potential adverse effect of semaglutide, it is crucial to weigh the potential risk of NAION against the substantial therapeutic benefits of semaglutide."

This study follows similar findings from a Harvard University study published in July, which also raised concerns about the association between semaglutide use and NAION. The new findings have shaken the pharmaceutical industry, with Novo Nordisk shares sliding as much as 5.4% in Copenhagen.

According to Dr. Jimena Hathaway, lead author of the JAMA study, "The study found people with diabetes who had been prescribed semaglutide by their physician and then filled the prescription were more than four times more likely to be diagnosed with NAION."

The authors of the Danish-Norwegian study emphasized that while semaglutide has shown significant benefits in managing both diabetes and obesity, the potential risk of NAION cannot be overlooked. "Given the well-established effects of semaglutide in managing both diabetes and obesity, it is crucial to weigh the potential risk of NAION against the substantial therapeutic benefits of semaglutide," they concluded.

The findings have significant implications for public health, as millions of Americans are currently using Ozempic and Wegovy. A separate study investigating the mechanism of semaglutide's side effects has raised concerns about its origins in reptile venom peptides and the potential for systemic damage. As the use of these drugs continues to rise, the need for further research and vigilant monitoring of their side effects becomes increasingly urgent.