Understanding the Connection Between Diabetes and Dementia

Diabetes and dementia each affect millions of older adults in the United States. But did you know that they can be connected? A growing body of research shows that diabetes is a significant risk factor for developing dementia.  

Let’s dive deeper into the link between these two conditions, considerations for caregivers of loved ones with both diabetes and dementia, and lifestyle changes that can help lower your risk of diabetes.

Diabetes is a dementia risk factor

The connection between diabetes and dementia is complex. While it’s challenging to unpack all of the details in one blog post, here’s what we do know: having diabetes increases your risk of developing dementia. Here’s what else we know: researchers are still working to explore the details of this connection.

Some research suggests that diabetes can directly cause Alzheimer’s disease by contributing to the buildup of amyloid and tau proteins in the brain, which are key markers of the disease. Other research suggests a more indirect link, where diabetes complications like heart disease and cerebrovascular disease account for the increased risk of dementia.  

While research indicates that diabetes is a risk factor for Alzheimer’s disease, the most common type of dementia, there may be a stronger connection between diabetes and vascular dementia.

Vascular dementia is dementia caused by damage to the brain from impaired blood flow. Large strokes can cause this damage, but it is more commonly caused by multiple very minor silent strokes or other conditions like hypertension (high blood pressure) that affect the blood vessels in the brain. Diabetes can also contribute to this damage. For example, high blood sugar can harm small blood vessels in your body, including your brain. Certain diabetes complications, such as heart disease, can also strain blood vessels.  

Regardless of the cause, extensive research has established that if you have diabetes, you have a heightened risk of developing dementia compared to someone without diabetes. Moreover, those who develop diabetes earlier in life have a higher risk of developing dementia compared to individuals who develop diabetes later in life. 

Blood sugar, glucose, and your brain 

Both type 1 and type 2 diabetes are risk factors for dementia, and there’s not enough data to say whether one is more of a risk factor than the other. However, the link to dementia may be less about the type of diabetes you have and more about how well-controlled your blood sugar is.  

One study found that older adults with type 1 diabetes who had been hospitalized for both high blood sugar (hyperglycemic) and low blood sugar (hypoglycemic) events had a six times greater risk of dementia than those who hadn’t been hospitalized for either. Any hospitalization related to blood sugar was linked to an increased risk of dementia.

Your brain is unique because it requires a constant supply of glucose, the main type of sugar in your blood and a major energy source for your body’s cells. While the rest of your body can store glucose for later, the brain has limited capability to do this, making your brain particularly sensitive to blood sugar fluctuations.

Very low levels of glucose will impair brain functioning, while sustained very high levels can damage small blood vessels over time, contributing to the development of vascular dementia.

Insulin resistance and brain health

Both type 1 and type 2 diabetes revolve around insulin, the hormone produced by your pancreas that helps glucose enter your cells. If you have type 1 diabetes, your pancreas does not produce insulin. If you have type 2 diabetes, the cells in your body don’t use insulin effectively — a condition known as insulin resistance. As type 2 diabetes progresses, your pancreas becomes less capable of producing insulin.

Insulin resistance can even impact your brain, a condition known as brain insulin resistance. Research has indicated that brain insulin resistance can impair cognition and affect mood. Brain insulin resistance may also contribute to the faster buildup of amyloid and tau proteins.  

The connection between insulin resistance in the body and brain led some researchers to develop the unofficial term “type 3 diabetes,” highlighting insulin’s crucial role in brain function and memory.

Diabetes complications like heart disease may strengthen the link

One of the reasons it’s challenging for researchers to determine whether the link between diabetes and dementia is direct or indirect is because diabetes is associated with complications that are themselves linked to dementia. For example, diabetes is closely related to your heart health and increases your risk of cardiovascular disease.

Research has shown that cardiovascular disease, which affects both the heart and blood vessels, is associated with a higher risk of developing vascular dementia. Other studies have found a connection between cardiovascular disease and Alzheimer’s disease.

Caregiving for someone with both dementia and diabetes

If you’re caring for someone who has both dementia and diabetes, there are some special considerations you should keep in mind. As their dementia progresses, their diabetes regimen might become difficult for them to manage on their own, especially if it involves complicated steps such as regularly checking their blood sugar and taking insulin.

It will become important for you to learn more about their diabetes management needs and flag areas you will eventually need to assist with or take over. You may eventually need to make sure your loved one isn’t taking too much or too little insulin as their cognitive decline progresses. Managing their diabetes will become a team effort, particularly if they have a complex regimen.

For those who don’t use insulin but manage diabetes with oral medications and a healthy diet, you may have less to manage. Still, educating yourself on their dietary and medication needs will be important to continue their diabetes management.

It may also be worth asking their doctor if the regimen can be simplified. How often do they need blood sugar checks? Do they need meal-time insulin, or is long-acting insulin okay? It may be possible to balance managing diabetes while also recognizing the unique challenges that arise when it is paired with a dementia diagnosis. 

Lifestyle choices can reduce your diabetes and dementia risk

While diabetes is a risk factor for dementia, it is a modifiable risk factor! That means you can take steps to reduce your chances of developing it. Here are a few lifestyle changes you can take to manage both your diabetes and dementia risk:  

• Stay physically active. Aim for around 30 minutes of moderate to vigorous activity five days a week, but do whatever you can. You don’t have to do those 30 minutes all at once; break it up throughout the day if you have to.
• Maintain a healthy weight. Weight loss can be an effective way to control your blood sugar. It doesn’t have to be dramatic! Even a 5-7% reduction in body weight can reduce your risk of diabetes. Always talk  with your doctor before trying to lose weight. 
• Eat a balanced diet. Healthy, unprocessed foods are both heart- and brain-healthy. Anti-inflammatory diets like the Mediterranean and MIND diets can be great choices. 
• Stay socially engaged. Regular social interaction can keep your mind active and promote healthy aging. If you’re feeling isolated and not sure how to change that, our blog post on how to make new friends offers some tips you might find helpful.

Personalized dementia treatment at the Deanna and Sidney Wolk Center for Memory Health

If you or a loved one has noticed memory changes you are concerned about, consider contacting the Wolk Center for Memory Health. We offer comprehensive outpatient care related to brain health, including memory loss assessment, testing, and diagnosis; clinical treatment for dementia; and family and caregiver support.  

Our geriatricians provide evidence-based treatment for many different forms of cognitive decline and dementia, including mild cognitive impairment, Alzheimer’s disease, vascular dementia, and more. The earlier you seek care, the more options you have for treatment and lifestyle interventions.

For more information or to schedule an initial consultation, message us online or call us at 617-363-8600 today.

Join Our Community: Subscribe to the Hebrew SeniorLife blog for weekly insights on healthy aging and senior living.