INS and Alzheimer disease: Despite the negligible difference in this study between AD risk with metformin compared to both sulfonylureas and insulin, patients on metformin were actually more likely to develop AD than those on GLP-1 receptor agonists (HR = 2.228, CI: 1.036, 4.794), which helps to underscore a recently published study in Nature Medicine that found GLP-1s to be protective to some degree against AD development due to several reducing impacts, including on neuroinflammation and oxidative stress levels [27].