Having type 1 diabetes may be linked to a higher risk of developing dementia later in life, according to a study published March 18, 2026, in Neurology®. The study also found an increased risk of dementia among people with type 2 diabetes compared to those who do not have diabetes.
Type 1 diabetes is rare, making up about 5 percent of all diabetes cases, and is usually diagnosed earlier in life than type 2 diabetes. Advances in medical care are helping people with type 1 diabetes live longer, so researchers say understanding its long-term effects on brain health is becoming more important.
“As advances in medical care have extended the lives of people with type 1 diabetes, it’s becoming increasingly important to understand the relation of type 1 diabetes to the risk of dementia,” said study author Jennifer Weuve, MPH, ScD, a professor at Boston University. “We have known that type 2 diabetes is linked to an increased risk of dementia, but this new research suggests that, unfortunately, the association may be even stronger for those with type 1 diabetes.”
The study followed more than 280,000 people with an average age of 64 for about two and a half years. During the study period, 2,348 people developed dementia, including 144 people with pre-existing type 1 diabetes (2.6%), 942 people with pre-existing type 2 diabetes (1.8%), and 1,262 people without pre-existing diabetes (0.6%).
After taking factors such as age and education level into consideration, researchers estimated that people with type 1 diabetes were nearly three times as likely to develop dementia than those without diabetes. People with type 2 diabetes were about twice as likely to develop dementia.
The researchers emphasize that these results show an association, not proof that diabetes causes dementia. They note that the study relied on health records and survey data, which may not capture every diagnosis.
The Key Takeaways:
- This study shows that people with diabetes may have a higher risk of dementia.
- In this study, people with type 1 diabetes were nearly three times as likely to develop dementia.
- In this study, people with type 2 diabetes were about twice as likely to develop dementia.
- This study does not prove that diabetes causes dementia.
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