Type 1 Diabetes May Carry Higher Dementia Risk

New research published in Neurology explores an important question: how different types of diabetes (Type 1 and Type 2) may affect the risk of developing dementia later in life. While it’s already well known that diabetes overall increases dementia risk, most previous studies have focused on Type 2 diabetes. This study aimed to better understand whether Type 1 diabetes may carry a similar, or even greater, risk.

“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 investigator 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.”

Investigators analyzed health data from 283,772 adults aged 50 and older (with a mean age of 64 years) who were part of a large U.S. research program. Among this group, 5,442 were diagnosed with Type 1 diabetes and 51,511 had Type 2 diabetes.

The team followed participants for an average of about 2.4 years, using electronic health records to track who developed dementia over time. Importantly, they separated participants into three groups: those without diabetes, those with Type 1 diabetes and those with Type 2 diabetes. During that period, 2,348 people developed dementia (2.6% with Type 1 diabetes, 1.8% with Type 2 diabetes and 0.6% of those without diabetes).

The findings showed that both types of diabetes were linked to a higher risk of developing dementia, but the risk was highest in people with Type 1 diabetes. Compared with people without diabetes:

• Those with Type 1 diabetes had nearly three times the risk of developing dementia
• Those with Type 2 diabetes had about double the risk

These patterns were consistent across different groups, including men and women and people of different racial and ethnic backgrounds.

For patients, this highlights an important takeaway: Diabetes doesn’t just affect blood sugar; it can also impact brain health over time. While the study doesn’t prove that diabetes directly causes dementia, it does show a strong association, especially for Type 1 diabetes, which has been less studied in this context.

The good news is that there are steps patients can take now. Managing diabetes carefully, through medication, healthy eating, physical activity and regular monitoring, may help reduce overall health risks, including those related to the brain. It also reinforces the importance of routine checkups and discussing cognitive health with your health care provider as you age.

Investigators noted an important limitation of the study: Diabetes and dementia were identified using electronic health records and survey data, so they may not have recognized every diagnosis.

Overall, this study adds to growing evidence that protecting your metabolic health may also help protect your brain — and that both Type 1 and Type 2 diabetes deserve attention when it comes to long-term cognitive health.

“Type 1 diabetes is not common, so this condition accounts for a small fraction of all dementia cases,” said Weuve. “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.”