A study published March 18 2026 in Neurology (American Academy of Neurology) found that people with type 1 diabetes have a higher risk of developing dementia — nearly three times higher than people without diabetes. Type 2 diabetes was also linked to higher risk, about twice as high as those without diabetes.
The research involved 283,772 people (average age 64), including 5,442 with type 1 diabetes and 51,511 with type 2 diabetes, followed for about 2.4 years. During that period, 2.6% of those with type 1 diabetes developed dementia, compared with 1.8% of those with type 2 diabetes and 0.6% of those without diabetes. After adjusting for factors like age and education, the authors estimate roughly 65% of dementia cases among people with type 1 diabetes could be attributed to the condition.
Study author Jennifer Weuve noted that while type 1 diabetes is rare (≈5% of diabetes cases), people with it are living longer, so understanding its link to dementia is increasingly important. The study shows an association, not causation, and its limitation is that diagnoses came from electronic health records and surveys, which may miss some cases.