Not all diabetes carries the same risk to the brain. Research presented at the 28th European Congress of Endocrinology in Prague found that adults with type 1 diabetes were 2.4 times more likely to develop dementia than people without diabetes, and those with type 2 diabetes treated with insulin were 2.1 times more likely. By comparison, people with type 2 diabetes managed with oral medications faced a more modest increase, at roughly 1.3 times the risk.
The work came from researchers at Kyung Hee University Hospital at Gangdong and Samsung Medical Center, who tracked more than 1.3 million South Korean adults aged 40 and older who were free of dementia at the start. Participants were sorted by diabetes status - none, type 2 on oral drugs, type 2 on insulin, or type 1 - and followed from 2013 to 2024 or until a dementia diagnosis. The same pattern held when the team looked separately at Alzheimer's disease and vascular dementia.
Lead author Professor Ji Eun Jun called the result surprising, noting it suggests patients on more intensive or insulin-dependent treatment may be particularly vulnerable to cognitive decline. Her point for clinical practice is straightforward: treating diabetes as a condition that affects brain health, not only metabolism, could flag a group of patients worth monitoring for cognitive changes earlier than usual.
The researchers suggest that better long-term glucose control and fewer large swings in blood sugar may matter for dementia risk, and they point to tools such as continuous glucose monitoring as a candidate for routine diabetes care. The findings were presented at a conference, which means they describe an association across a large population rather than proof that insulin dependence itself causes the added risk.