New study finds higher dementia risk in insulin-requiring diabetes patients

Individuals with diabetes are at an increased risk of developing dementia but those with insulin-requiring type 2 diabetes and type 1 diabetes have the greatest risk, according to research presented at the 28th European Congress of Endocrinology in Prague. Specifically, these higher-risk individuals were over twice as likely to develop the neurological disease. The findings suggest that dementia risk is not the same for all types of diabetes and future prevention strategies, such as continuous glucose monitoring, should be implemented in routine diabetes management.

In this study, researchers from Kyung Hee University Hospital at Gangdong and Samsung Medical Center examined over 1.3 million adults in South Korea, aged 40 and older, without dementia, and grouped them according to their diabetes status: no diabetes, type 2 diabetes using oral anti-diabetic medications, type 2 diabetes using insulin and type 1 diabetes. They followed the individuals from 2013 to 2024, or until a diagnosis of dementia, and found that those with diabetes had a higher risk of developing dementia compared to those without diabetes.

In particular, those with type 2 diabetes taking oral anti-diabetic medications were almost 1.3 times more likely to develop dementia, while the rate of dementia onset was 2.1 times as great among those with type 2 diabetes taking insulin and 2.4 times more in those with type 1 diabetes. Similar trends were observed for Alzheimer’s disease and vascular dementia.

“This is surprising because it suggests that not all types of diabetes carries the same risk, and that people with more intensive or insulin-dependent treatment may be particularly vulnerable to cognitive decline,” said lead author, Professor Ji Eun Jun from Kyung Hee University Hospital at Gangdong.

Professor Jun added: “Recognising diabetes as a potential risk factor for brain health and not just a metabolic condition could help identify a group of patients who may benefit from earlier monitoring for cognitive decline. Improving long-term glucose control and reducing large fluctuations in glucose levels could play a role in lowering dementia risk.”

“Our findings may be partly explained by recurrent hypoglycemia and greater glucose fluctuations in insulin-treated patients, thus we are planning further studies to better understand these mechanisms. Ultimately, we hope to identify high-risk patients and determine whether improving glucose stability can help prevent dementia,” said Professor Jun.

Previous studies have mainly focused on type 2 diabetes and have consistently shown an increased risk of dementia, but evidence for type 1 diabetes has been more limited and sometimes inconsistent, largely due to smaller study populations. “Our study adds new insight by directly comparing type 1 diabetes, type 2 diabetes, and treatment intensity within a large nationwide population,” said Professor Jun.

The results of this study were recently published in Diabetes, Obesity and Metabolism.

Reference:

J. E.Jun, S.Kim, I.-K.Jeong, and J. H.Kim, “Dementia Risk in Type 1 and 2 Diabetes: A Nationwide Population-Based Comparison,” Diabetes, Obesity and Metabolism28, no. 6 (2026): 4915–4925, https://doi.org/10.1111/dom.70677.