A recent study reveals that individuals with type 1 diabetes are around three times as likely to develop dementia as people without diabetes. Similarly, those with type 2 diabetes may be twice as likely to develop dementia. However, the study found a correlation rather than proof of causation, indicating that diabetes is associated with an increased risk of dementia but does not directly cause it.
Diabetes is a chronic condition that affects how the body regulates glucose, a key source of energy. Type 1 involves the immune system destroying insulin-producing cells, while type 2 results from insulin resistance or reduced insulin production. Both forms can cause long-term damage to the heart, kidneys, and nerves. However, researchers are increasingly examining their effects on the brain.
Emerging evidence suggests a strong link between metabolic health and dementia [1]. Diabetes may contribute to cognitive decline through mechanisms such as impaired brain glucose metabolism, vascular damage, and inflammation, all of which are associated with increased dementia risk [2, 3].
While much of the earlier research focused on type 2 diabetes, growing evidence suggests that type 1 diabetes may also increase dementia risk [4].
A recent large cohort study has revealed that patients with type 2 diabetes have an increased dementia risk, but the risk may be even higher for those with type 1 diabetes.
According to the findings, individuals with type 1 diabetes are three times more likely to develop dementia, while those with type 2 face roughly double the risk. The results show correlation, not causation, but highlight potential long-term neurological risks.
The journal Neurology published the recent research [5].
Type 1 Diabetes Associated with an Increased Dementia Risk
For this study, the researchers analyzed survey data and electronic health records from about 283,772 individuals in the ongoing All of Us Research Program. This national U.S. research project examines long-term health outcomes by connecting survey data with electronic health records.
Researchers examined the association between different types of diabetes and the development of dementia in individuals aged 50 and older.
They found 5,442 individuals with type 1 diabetes and 51,511 with type 2 diabetes among the participants in the investigation. The average follow-up period was 2.4 years, and the participants’ average age was 64. About 2,348 individuals experienced dementia during the study period.
Of the 2,348 participants who developed dementia during the follow-up period, 144 had type 1 diabetes (2.6%), and 942 had type 2 diabetes (1.8%). In contrast, among the 226,819 participants without diabetes, 1,262 (0.6%) developed dementia.
The researchers observed that those with type 1 diabetes were almost three times more likely to acquire dementia than those without the disease after adjusting for factors like age, sex, race and ethnicity, and education.
Participants with type 2 diabetes were roughly twice as likely to develop dementia as those without diabetes.
The correlation persisted even after adjusting for lifestyle factors, including alcohol consumption and smoking. Those with type 1 diabetes were still more than twice as likely to develop dementia as those without diabetes.
According to study author Annie Pederson, MPH, a research fellow at the Boston University School of Public Health, as life expectancy among individuals with type 1 diabetes continues to rise, this increased risk of dementia emphasizes the significance of comprehending the neurologic difficulties this population may encounter with aging. It highlights the need for increased awareness, monitoring, and focused prevention strategies [6].
Consistent Dementia Risk Across Demographic Groups
The researchers also discovered that the higher dementia risk associated with diabetes was largely consistent across demographic groups.
When researchers evaluated the data by sex, they discovered that type 1 diabetes was linked to an increased risk of dementia in both men and women.
Women with type 1 diabetes had a relatively increased risk compared to men, while both groups demonstrated strong connections.
All racial and ethnic groups—including non-Hispanic white, Hispanic/Latino, and other ethnic groups—also showed an increased risk.
High Dementia Burden Among People with Type 1 Diabetes
Type 1 diabetes is far less common than type 2, accounting for fewer than 5% of all cases [7]. These results, however, imply that type 1 diabetes may significantly increase the risk of dementia.
According to research estimates, type 1 diabetes may be the cause of dementia in approximately 64.5% of cases.
However, since type 1 diabetes is less prevalent in the general population, it was responsible for around 3.9% of total dementia cases in the study sample.
Exploring the Biological Links Between Diabetes and Dementia
Research has long established that diabetes increases the risk of dementia, although type 2 diabetes has been the subject of the majority of research.
These two types of diabetes may have different molecular mechanisms that lead to cognitive impairment.
Type 2 diabetes is frequently linked to insulin resistance, chronic hyperglycemia (high blood sugar levels), and metabolic problems that might damage blood vessels in the brain or cause protein buildup associated with Alzheimer’s disease.
In contrast, type 1 diabetes is an autoimmune disease where the body attacks and destroys the beta cells in the pancreas that produce insulin.
People with type 1 diabetes typically need to take insulin for the rest of their lives to control their illness, and they may occasionally have low blood sugar.
The researchers suggested that long-term metabolic disturbance, oxidative stress, inflammation, and recurrent hypoglycemia may all be factors in brain alterations that raise the risk of dementia.
According to Pederson, people with type 1 diabetes are usually diagnosed at younger ages, which results in a prolonged illness duration throughout life and may eventually increase the risk of dementia. Furthermore, while type 1 and type 2 diabetes share some biological processes, type 1 diabetes is biologically unique and may entail other mechanisms that need further research.
Although there may be increasing interest in the possibility that long-term blood glucose patterns and hypoglycemia episodes could contribute to the etiology of dementia, she continued, their study was not intended to examine these mechanisms directly. Therefore, further research is required to better understand how these factors may lead to dementia risk in individuals with type 1 diabetes.
A Novel Algorithm to Improve Diabetes Type Detection in Large Datasets
The creation of a novel algorithm to differentiate between type 1 and type 2 diabetes using electronic health records was a crucial component of the study.
Distinguishing diabetes subtypes in large datasets is challenging because diagnostic codes often overlap, and many patients with advanced type 2 diabetes may also require insulin.
The team addressed this challenge by using a classification approach based on the number of clinical encounters coded as type 1 diabetes.
The researchers used two reference standards to validate the approach: self-reported diabetes type and the quantity of C-peptide (a marker of pancreatic insulin production) in the individuals’ blood.
Using this technique, the researchers were able to examine dementia risk separately for each diabetes subtype in a sizable sample.
What were the limitations of the study?
Researchers identified diabetes and dementia diagnoses using electronic health records and survey data, which may not capture every case.
Additionally, individuals with type 1 diabetes may engage with healthcare systems more frequently, which could raise the possibility that dementia is detected earlier.
Furthermore, the results may not be entirely applicable to the larger U.S. population, as the All of Us cohort is not nationally representative and relies in part on convenience sampling through healthcare systems.
Therefore, it is important to interpret the results with caution. The study does not demonstrate that diabetes causes dementia directly, but it does indicate a connection between diabetes and dementia risk.
More study will be needed to understand better the underlying mechanisms that may link diabetes to cognitive loss, as well as to develop risk-reducing interventions.
Pederson pointed out that while the results shed light on the relationship between type 1 diabetes and dementia risk, there are still significant unanswered questions.
Future study, she continued, should look at the role of co-occurring clinical disorders and other potential “modifiable risk factors” that may assist in identifying subgroups at highest risk to better understand the heightened risk among people with type 1 diabetes.
She stated that research is required to better understand the biological mechanisms behind this link and to ascertain whether specific management or preventative techniques can lower the risk of dementia in people with type 1 diabetes. All of this could lead to more individualized treatment and preventative strategies.
Significance of the findings.
Notwithstanding these limitations, the researchers claim the results provide crucial evidence that diabetes subtype influences dementia risk assessment.
As the life expectancy of people with type 1 diabetes rises, an increasing number of them are reaching old age, which is the greatest known risk factor for dementia. Consequently, this study suggests that individuals with type 1 diabetes should undergo more frequent cognitive assessments.
Pederson continued that these results emphasize the need for increased awareness of dementia risk in patients with type 1 diabetes.
Given that persons with type 1 diabetes are living longer, this may require clinicians to take cognitive health into account while providing long-term diabetes care [6].
According to Pederson, these findings emphasize the importance of continued care, monitoring, and overall health management as individuals with type 1 diabetes grow older. They also imply an increased chance, but not a guarantee, of dementia.
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References
- Zhang, S., Zhang, Y., Wen, Z., Yang, Y., Bu, T., Bu, X. and Ni, Q., 2023. Cognitive dysfunction in diabetes: abnormal glucose metabolic regulation in the brain. Frontiers in endocrinology, 14, p.1192602.
- Chen, X., Huang, Y. and Xiong, X., 2025. Mechanisms underlying cognitive impairment and management strategies in type 2 diabetes. Frontiers in Endocrinology, 16, p.1655768.
- Raza, Ahmad, Shafaq Saleem, Samar Imran, Sarah Rahman, Muhammad Haroon, Azeen Razzaq, Ahmad Hussain, Javed Iqbal, and Brijesh Sathian. “From metabolic dysregulation to neurodegenerative pathology: the role of hyperglycemia, oxidative stress, and blood-brain barrier breakdown in T2D-driven Alzheimer’s disease.” Metabolic Brain Disease 40, no. 7 (2025): 276.
- Li, L., Wong, D., Fisher, C.A., Conn, J.J., Wraight, P.R., Davies, A., Barson, E. and Pike, K.E., 2025. Increased risk of dementia in Type 1 diabetes: A systematic review with meta-analysis. Diabetes Research and Clinical Practice, 222, p.112043.
- Pederson, A.M., Buto, P., Zimmerman, S.C., Velez, M., Sims, K.D., Murchland, A.R., Wang, J., Brennan, A.T., Glymour, M.M. and Weuve, J., 2026. Type 1 Diabetes and Incident Dementia: An Analysis in the All of Us Cohort. Neurology, 106(7), p.e214805.
- Morales-Brown, P. Type 1 diabetes linked to significantly higher dementia risk, large U.S. study finds. Medical News Today. https://www.medicalnewstoday.com/articles/diabetes-linked-to-higher-dementia-risk. Published Online: 19th March, 2026. Accessed: 9th April, 2026.
- Diabetes. World Health Organization. https://www.who.int/news-room/fact-sheets/detail/diabetes. Updated: 14th November, 2024. Accessed: 10th April, 2026.
- McKoy, J. Type 1 Diabetes Linked to Higher Risk of Dementia. BU School of Public Health. https://www.bu.edu/sph/news/articles/2026/type-1-diabetes-linked-to-higher-risk-of-dementia/. Published Online: 18th March, 2026. Accessed: 10th April, 2026.
- Both Type 1 and Type 2 Diabetes Linked to Increased Dementia Risk. Inside Precision Medicine. https://www.insideprecisionmedicine.com/topics/patient-care/both-type-1-and-type-2-diabetes-linked-to-increased-dementia-risk/. Published Online: 18th March, 2026. Accessed: 10th April, 2026.
