112,725 older adults. That's roughly the population of a mid-sized American city. And researchers from New York University wanted to know: could a common diabetes medication help protect some of these seniors from dementia?
The study, published in the journal JAMA Network Open, focused on people 65 and older who also lived with mood disorders like depression or bipolar disorder, or psychotic disorders like schizophrenia — conditions that already put people at higher risk for thinking and memory problems later in life. The participants had a median age of 74.1 years.
Researchers gave some participants SGLT2 inhibitors, which are drugs commonly used to treat diabetes. They work by helping the kidneys remove extra sugar from the body through urine. Then the scientists tracked who developed dementia over time.
The results were striking. Older adults who took SGLT2 inhibitors had significantly lower odds of developing all-cause dementia compared to those who didn't take the drug. The medication was also linked to fewer psychiatric emergency room visits and fewer psychiatric hospital stays — suggesting possible benefits beyond just diabetes management.
The research team, led by Dr. David T. Liebers from NYU Grossman School of Medicine, used data from the U.S. Department of Veterans Affairs to conduct what scientists call a "target trial emulation" — a method designed to closely mimic a real clinical trial using existing health records. About 6.8 percent of the 112,725 participants had been exposed to SGLT2 inhibitors.
The researchers now believe there may be a shared link between metabolic health and both psychiatric and brain-degenerative diseases. "These findings support the hypothesis of shared metabolic vulnerability across psychiatric and neurodegenerative diseases," they wrote.
The team is calling for more research into whether SGLT2 inhibitors could one day be used as treatments not just for diabetes, but as a way to protect brain health in people at higher risk. More studies in broader populations will be needed to confirm the findings and understand exactly how the drugs might help. But for now, this research offers a promising clue in the fight against dementia — and a reminder that the connections between body and brain may run deeper than scientists once thought.