Does diabetes cause dementia? Research links diabetes to a higher risk of dementia, including Alzheimer's disease and vascular dementia, but scientists are still working out why, and a higher risk does not mean dementia will happen. Age, blood vessel health, severe low blood sugar, and other factors all play a part, and only a clinician can assess memory changes.
Key takeaways
- ADA 2026 reports that people with diabetes have higher rates of all-cause dementia, Alzheimer's disease, and vascular dementia than people without diabetes.
- The link runs both ways, and why it happens is not fully understood. Blood vessel damage, blood sugar extremes, and aging are all being studied.
- Studies of intensive glucose or blood pressure control have not shown less cognitive decline. Blood pressure management and statins have been associated with a lower dementia risk.
- ADA 2026 recommends screening adults 65 and older for mild cognitive impairment or dementia at the first visit, then every year and as appropriate.
- Some memory problems have treatable causes, such as medicine side effects or thyroid problems, so new changes deserve a checkup.
What Is Dementia?
The Centers for Disease Control and Prevention (CDC) explains that dementia is not a specific disease. It is an overall term for a decline in mental ability that interferes with daily life, affecting memory, thinking, and behavior. Alzheimer's disease is the most common type.
In an NIDDK expert interview, José Luchsinger, MD, of Columbia University separates two stages. Mild cognitive impairment (MCI) means thinking problems that are mild and do not stop a person from functioning on their own. Dementia means the problems are severe enough to affect independent living, so the person needs help remembering things, keeping track of things, or handling daily activities.
Does Diabetes Raise the Risk of Dementia?
At the group level, yes. The American Diabetes Association's Standards of Care in Diabetes—2026, Section 13 says older adults with diabetes are at higher risk of cognitive decline and of moving into long-term care than older adults without diabetes. People with diabetes have higher rates of all-cause dementia, Alzheimer's disease, and vascular dementia.
The link appears to run both ways. ADA notes that people with Alzheimer's disease or other dementias are more likely to develop diabetes than people without dementia. ADA also reports that both high and low blood sugar are associated with a decline in cognitive function, and that a longer duration of diabetes is associated with worsening cognitive function.
These findings describe groups. A study can show that a group has higher rates of dementia without showing what will happen to you. For the wider picture of how diabetes can affect thinking, stroke risk, and blood sugar emergencies, see our guide to how diabetes affects the brain.
What Types of Dementia Are Linked to Diabetes?
Several types of dementia appear in research on diabetes. They can overlap, and only a clinician can tell them apart.
| Type | What is known | Link to diabetes |
|---|---|---|
| Alzheimer's disease | The most common type; NIA describes abnormal protein deposits called plaques and tangles in the brain | ADA reports higher rates in people with diabetes |
| Vascular dementia | Caused by strokes or other problems with blood flow to the brain; symptoms can begin gradually or suddenly | CDC lists diabetes, high blood pressure, and high cholesterol among conditions that raise risk |
| Mixed dementia | More than one type at the same time, such as Alzheimer's disease with vascular dementia | Not always obvious; a clinician considers all causes |
| Diabetes-related dementia | A newly recognized pattern that ADA describes as emerging as distinct from Alzheimer's and vascular dementia | Linked with older age, high A1C, long diabetes duration, frequent insulin use, frailty, and loss of muscle mass and strength |
ADA describes diabetes-related dementia as progressing more slowly and lacking the typical findings seen on brain scans. Because it is a newly recognized category, ask your clinician what it means for you rather than drawing conclusions from a description.
The National Institute on Aging (NIA) notes that major strokes can raise dementia risk, but not everyone who has had a stroke will develop dementia. Our guide to whether diabetes causes strokes covers stroke risk and warning signs.
Why Might Diabetes Be Linked to Dementia?
Researchers are still working out the reasons. Luchsinger says the reason people with diabetes are more likely to develop cognitive impairment is not well understood. Several ideas are being studied:
- Blood vessel damage. Luchsinger explains that diabetes causes cerebrovascular disease, meaning disease of the blood vessels in the brain, and that this damage can lead to different thinking problems.
- Blood sugar extremes. ADA reports that both high and low blood sugar are associated with cognitive decline, and that severe low blood sugar has been linked to a higher risk of dementia.
- Aging and shared conditions. Thinking problems become more common with age, and conditions such as high blood pressure can contribute to cognitive decline.
- Insulin signaling in the brain. Some researchers study how insulin works in the brain. This idea led to the term “type 3 diabetes,” which our guide to whether Alzheimer's is type 3 diabetes explains. It is a research label, not a diagnosis.
Low blood sugar and thinking can affect each other. ADA notes that cognitive decline has been associated with a higher risk of lows, because complex self-care tasks become harder. Severe lows, in turn, have been linked to a higher risk of dementia. Our guide to whether low blood sugar can cause brain damage covers what lows can and cannot do to the brain.
Does Controlling Blood Sugar Prevent Dementia?
Not on current evidence. ADA 2026 says studies of diabetes prevention or intensive glucose and blood pressure management have not shown a reduction in cognitive decline. Luchsinger describes the MIND sub-study of the ACCORD trial in people with type 2 diabetes: tight glucose control did not help prevent cognitive impairment or improve thinking compared with standard control.
That does not make glucose management unimportant. It still matters for avoiding dangerous highs and lows and other complications. ADA also notes that cognitive impairment can make it harder to reach glucose, blood pressure, and cholesterol goals.
ADA does report some associations worth discussing. Blood pressure management and cholesterol lowering with statins have been associated with a lower risk of dementia, which ADA calls particularly important in older adults with diabetes. ADA also notes that some glucose-lowering drug classes have shown small benefits on slowing cognitive decline in studies.
That evidence is still developing. In November 2025, Novo Nordisk reported that its phase 3 evoke trials of oral semaglutide did not slow disease progression in people with early Alzheimer's disease. These findings do not make any diabetes medicine a dementia treatment. Medicine choices belong to your care team, so do not start, stop, or switch a medicine based on this article.
Which Risk Factors Can You Discuss?
The 2024 Lancet Commission on dementia prevention listed 14 modifiable risk factors and estimated that about 45% of dementia cases worldwide might be prevented or delayed if they were eliminated. The factors are lower education, hearing loss, high LDL cholesterol, depression, traumatic brain injury, physical inactivity, diabetes, smoking, high blood pressure, obesity, excessive alcohol use, social isolation, air pollution, and untreated vision loss.
This is a population-level estimate, not a personal guarantee. The NIA page What Causes Alzheimer's Disease? adds that researchers cannot yet say for certain whether making positive changes in these areas can prevent dementia.
Topics to raise with your care team:
- Blood pressure and cholesterol goals. See what blood pressure should be for a diabetic and what cholesterol should be for a diabetic.
- Hearing and vision checks. See whether diabetes hearing loss can be reversed and how often diabetics should get an eye exam.
- Activity. Ask what movement fits your health. Our guide to whether exercise lowers blood sugar covers getting started safely.
- Mood and connection. Depression and social isolation are both on the list. See diabetes and depression.
- Smoking and alcohol. See whether smoking affects blood sugar and whether diabetics can drink alcohol.
- Lows. Ask whether your medicines can cause lows and what your plan is if one happens.
Vynleads is also developing Done With Alzheimer's (DWA), an upcoming brain-healthy habits program being designed as an educational companion to medical care. It is not yet available, and it is not a treatment for Alzheimer's disease or a way to prevent dementia.
How Is Dementia Screened For and Diagnosed?
ADA recommendation 13.3 calls for screening adults 65 and older for mild cognitive impairment or dementia at the first visit, every year after that, and as appropriate. Brief tools include the Mini-Cog, the Mini-Mental State Examination, and the Montreal Cognitive Assessment. ADA also advises screening when self-care becomes noticeably harder, such as insulin dosing errors, trouble counting carbohydrates, skipped meals or doses, or difficulty recognizing, preventing, or treating lows.
A screening tool is not a diagnosis. The NIA Alzheimer's Disease Fact Sheet explains that diagnosis may involve questions about health and daily activities, tests of memory and thinking, blood and urine tests, a check for depression, and sometimes brain scans or tests of proteins in spinal fluid or blood.
Some memory problems have causes that can be treated. CDC lists medicine side effects, increased pressure in the brain, vitamin deficiency, and thyroid hormone imbalance as examples. NIA adds stroke, tumors, sleep problems, and infections to the possible causes a clinician considers. That is one reason new changes deserve a checkup instead of a guess. If you need a clinician for this, our guide to finding a diabetes doctor near you explains where to start.
When thinking problems are found, ADA advises simplifying the care plan and involving support people. A daily type 2 diabetes checklist can keep routine tasks in one place, and our guide to supporting someone with diabetes covers how family members can help. Families weighing care settings can read about diabetes management programs for senior living.
When Should You Get Help?
Emergency: Call 911 for sudden confusion, trouble speaking or understanding, face drooping, one-sided weakness, vision loss, a severe headache, or a seizure, or if someone with diabetes cannot be woken or cannot swallow. Sudden changes need emergency care, not a wait-and-see approach.
Same day: Contact your care team the same day after any low that needed someone else's help, or if lows keep happening. ADA calls repeated level 2 lows and level 3 lows an urgent medical issue, and lows become more likely when thinking skills decline.
Prompt appointment: Book a visit for memory or thinking changes that last for weeks, get worse, or affect daily tasks such as bills, cooking, driving, or medicines, especially if family members notice them. If you are 65 or older, ask whether a memory screening is due.
Frequently Asked Questions
Does diabetes cause dementia?
Diabetes is linked to a higher risk of dementia, including Alzheimer's disease and vascular dementia, but scientists are still working out why. Blood vessel damage, blood sugar extremes, and aging are all being studied. A higher risk does not mean dementia will happen, and a clinician assesses any memory changes.
What is diabetes-related dementia?
ADA 2026 describes diabetes-related dementia as a newly recognized pattern emerging as distinct from Alzheimer's disease and vascular dementia. It tends to progress more slowly and lacks typical brain-scan findings. It is linked with older age, high A1C, long diabetes duration, frequent insulin use, frailty, and loss of muscle mass and strength.
Does controlling blood sugar prevent dementia?
Current evidence does not show that. ADA 2026 notes that studies of intensive glucose and blood pressure management have not shown less cognitive decline. Glucose management still matters for avoiding dangerous highs, lows, and other complications. Blood pressure management and statin treatment have been associated with a lower dementia risk.
Can low blood sugar increase dementia risk?
ADA 2026 reports that severe low blood sugar has been linked to a higher risk of dementia, and that cognitive decline has been linked to more lows. The two can affect each other. If you have had a severe low, ask your care team to review your plan and whether a memory screening fits.
At what age should people with diabetes be screened for dementia?
ADA 2026 recommends screening for mild cognitive impairment or dementia in adults 65 and older at the first visit, then every year and as appropriate. Screening is also advised when diabetes self-care becomes harder, such as insulin dosing errors or skipped meals. A screening result is not a diagnosis.
Can memory problems in diabetes be reversed?
It depends on the cause. CDC notes that some memory problems come from treatable conditions, such as medicine side effects, vitamin deficiency, or thyroid problems, and can be reversed when the cause is treated. For dementia, CDC notes that an earlier diagnosis means treatment to slow its progression can start sooner.
References
- American Diabetes Association Professional Practice Committee for Diabetes. “13. Older Adults: Standards of Care in Diabetes—2026.” Diabetes Care. 2026;49(Suppl. 1):S277–S296. Accessed October 2026.
- American Diabetes Association Professional Practice Committee for Diabetes. “6. Glycemic Goals, Hypoglycemia, and Hyperglycemic Crises: Standards of Care in Diabetes—2026.” Diabetes Care. 2026;49(Suppl. 1):S132–S149. Accessed October 2026.
- National Institute of Diabetes and Digestive and Kidney Diseases. “Can Diabetes Lead to Cognitive Impairment?” Diabetes Discoveries & Practice Blog. Accessed October 2026.
- Centers for Disease Control and Prevention. “About Dementia.” Accessed October 2026.
- National Institute on Aging. “Vascular Dementia: Causes, Symptoms, and Treatments.” Accessed October 2026.
- National Institute on Aging. “Alzheimer's Disease Fact Sheet.” Accessed October 2026.
- National Institute on Aging. “What Causes Alzheimer's Disease?” Accessed October 2026.
- Livingston G, et al. “Dementia prevention, intervention, and care: 2024 report of the Lancet standing Commission.” The Lancet. 2024;404(10452):572–628. Accessed October 2026.
- Wise J. “Dementia: Almost half of cases could be prevented by tackling 14 risk factors, says commission.” BMJ. 2024;386:q1723. Accessed October 2026.
- Novo Nordisk A/S. “Novo Nordisk A/S: Evoke phase 3 trials did not demonstrate a statistically significant reduction in Alzheimer's disease progression.” GlobeNewswire, November 24, 2025. Accessed October 2026.
- Bernard Becker Medical Library, Washington University School of Medicine. “Ear Trumpets.” How Did We Get Hear? Historic Hearing Devices, 1800–2000. Historical context only for the companion feature. Accessed October 2026.
Next Steps
If you are 65 or older, ask whether a memory screening is due. Bring notes on any memory or thinking changes, past lows, and your blood pressure and cholesterol questions to your next visit. Call 911 for sudden confusion, speech trouble, or weakness.
For adults with type 2 diabetes or prediabetes who want lifestyle education alongside clinical care, the Done With Diabetes™ program, a holistic approach to type 2 diabetes, organizes learning about meals, movement, sleep, and stress. It does not diagnose or treat diabetes, dementia, or other brain conditions, interpret symptoms or test results, change medicines, or replace your care team.