Type 1 diabetes associated with higher risk of dementia, finds research

Having type 1 diabetes is associated with a higher risk of developing dementia, according to a study published March 18, 2026, in Neurology®, the medical journal of the American Academy of Neurology. Type 2 diabetes is also associated with a higher risk of dementia compared with not having diabetes. This study shows an association and does not prove that diabetes causes dementia.

Type 1 diabetes is rare, accounting for about 5% of diabetes cases.

“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, of 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 involved 283,772 people with an average age of 64. Of those, 5,442 had type 1 diabetes and 51,511 had type 2 diabetes. The participants were followed for an average of 2.4 years. During that time, 2,348 people developed dementia, including 144 of the people with type 1 diabetes, or 2.6%; 942 of the people with type 2 diabetes, or 1.8%; and 1,262 of the 226,819 people who did not have diabetes, or 0.6%.

After accounting for factors, such as age and education level, the researchers estimated that people with type 1 diabetes were nearly three times as likely to develop dementia as people without diabetes. People with type 2 diabetes were twice as likely to develop dementia as people without diabetes. Weuve added that in this study, an estimated 65% of dementia cases among people with type 1 diabetes could be attributed to the condition itself.

“Type 1 diabetes is not common, so this condition accounts for a small fraction of all dementia cases. But for the growing number of people with type 1 diabetes who are over 65 years old, these findings underscore the urgency of understanding the ways in which type 1 diabetes influences dementia risk and how we can prevent or delay it,” Weuve said.

A limitation of the study is that diabetes and dementia were identified using electronic health records and survey data, which may not capture every diagnosis.

Reference:

Audrey R. Murchland, Jingxuan Wang, Alana T. Brennan, M. Maria Glymour, and Jennifer Weuve, Type 1 Diabetes and Incident Dementia An Analysis in the All of Us Cohort, Neurology, https://doi.org/10.1212/WNL.0000000000214805