Illness and disease do not exist in silos: often, one can cause or exacerbate another. Emerging evidence paints a clearer, more urgent picture: The global diabetes epidemic may be one of the strongest, but most serious, risk factors for dementia. Far from being two distinct conditions, researchers are increasingly seeing them as a single, integrated metabolic disorder that affects both the body and the brain.
What is diabetes?
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Before we talk about how diabetes and dementia are connected, we must understand each disease. Diabetes mellitus is a group of diseases characterized by high levels of glucose (sugar) in the blood, resulting from the body’s inability to produce or use insulin properly. Insulin is a hormone produced by the pancreas that acts as a key, allowing glucose (the body’s main source of energy) to enter the cells. There are two types of diabetes:
- Type 1 (T1D): An autoimmune condition in which the body does not produce insulin.
- Type 2 (T2D): A condition, usually developed later in life, where the body does not produce enough insulin or, more commonly, the cells become resistant to insulin.
Uncontrolled blood sugar over time can damage blood vessels and nerves throughout the body, leading to complications such as heart disease, kidney failure, and nerve damage (neuropathy).
What is dementia?
Dementia is not a specific disease but an umbrella term for a group of symptoms caused by damage to brain cells. It involves a decline in memory, thinking, problem solving, and language that is severe enough to interfere with daily life. While aging is the biggest risk factor, dementia is not a normal part of aging. The most common types of dementia include:
- Alzheimer’s disease: It is caused by the abnormal formation of proteins (beta-amyloid plaques and taumples) in the brain, which leads to cell death.
- Vascular Dementia: caused by impaired blood flow to the brain, usually from a stroke or damage to small blood vessels. This results in brain cells dying due to lack of oxygen.
The compound problem: Diabetes and dementia are linked
The connection between diabetes and dementia is so strong that some researchers have Alzheimer’s disease “Type 3 diabetes. This link is operated in several ways.
Traumatic injuries
Both diabetes and dementia are largely driven by heart problems. Diabetes damages blood vessels, including those in the brain, which is a direct cause of vascular dementia. This damage is exacerbated by existing conditions such as high blood pressure, high cholesterol, and obesity.
Brain insulin resistance
Like muscle and fat cells, brain cells depend on insulin to regulate energy use and promote cellular health. In people with diabetes, brain cells can become resistant to insulin, inhibiting their ability to use glucose efficiently. This loss of energy is thought to promote the accumulation of amyloid and tau proteins associated with Alzheimer’s.
Chronic inflammation
Diabetes involves a chronic, low-grade inflammatory state throughout the body. This affects the brain, too. In the brain, this inflammation can damage neurons and disrupt communication networks that are important for healthy cognition.
Recent evidence: Learning outcomes linking diabetes and dementia
Recent findings presented at the European Association for the Study of Diabetes in Vienna, Austria, confirm the connection between these two conditions. They also highlight the groups that pose the greatest risk. These include:
Increased risk of death from T2D
A 20-year study involving millions of people found that dementia-related deaths increased significantly after age 80. There was an increased risk among people with type 2 diabetes compared to this disease.
Increased risk of dementia in T1D
Research from the Swedish National Register found that people with type 1 diabetes had twice the risk of the elderly. In addition, these people have almost four times the risk of vascular dementia. This risk was strongly related to poor glycemic control (high A1C levels) and long disease duration. This suggests that blood sugar management is important for brain health.
The Role of Body Markers
The Revadiab study investigates the connection between glycemic variability, cognitive function, and circulating body markers in T1D. It found a significant connection between certain physical symptoms, suggests chronic inflammation, and low cognitive function. This is further support for the idea that diabetes-related inflammation negatively affects the brain.
The Many Faces of Dementia: Some Causes and Risk Factors
Just because you don’t have diabetes, doesn’t mean you have nothing to worry about when it comes to preventing dementia. While the link to diabetes is strong, many other factors can lead to cognitive decline. Dementia is multifactorial, meaning it is often caused by a combination of problems:
Neurodegenerative causes
The most common is Alzheimer’s disease itself, which involves plaque and tangle pathology. There are other neurodegenerative conditions that cause dementia. Lowy body dementia is another, which involves the deposition of abnormal proteins called lew bodies in the brain. Also, prototemporal dementia, which involves damage to the frontal and temporal lobes.
Lifestyle and health risks
In addition to diabetes, there are many things, the most common, factors that contribute to the risk of dementia. These include:
- Age and Genetics (so-called invariant traits)
- High blood pressure and high cholesterol
- Lack of physical activity and poor diet
- Smoking and excessive alcohol consumption
- Frustration
- Hearing loss
- Traumatic brain injury
Read more: Can your eyes reveal diabetes or cancer? Don’t miss the signs
Undiagnosed: why you may be at risk without diabetes
It is important to understand that a diagnosis of diabetes is not the only risk factor for dementia. The real danger is often in a subset of medical conditions known as metabolic syndrome (Mets). Mets are defined as having excess fat and at least two of the following:
- High blood pressure
- High blood sugar (even if you don’t have full blood sugar yet)
- High triglycerides (a type of fat in the blood)
- “Good” HDL Cholesterol HDL
Even if your blood sugar is not good enough to diagnose diabetes, these individual things are very painful for your vascular system and brain. Research shows that acne in midlife is associated with a higher risk of dementia, including Alzheimer’s and vascular dementia. This means the silent, unhealthy metabolic processes that lead to diabetes are already active and damaging the brain years before a person gets the diabetes label.
What does this mean for us?
For those of us with diabetes, regardless of this type, this means that it is very important that blood sugar is kept under control. The facts are here and clear: Uncontrolled diabetes will eventually lead to dementia. For all of us, including those with diabetes, dealing with the individual aspects of metabolic syndrome is very important. This includes managing blood pressure, losing weight if necessary, and controlling cholesterol.
Bottom line
In fact, living a healthy lifestyle is the most powerful strategy to reduce the risk of dementia, regardless of your diabetes status. Weight management, stress management, healthy eating, regular movement and exercise, and proper sleep hygiene will all work to reduce your risk of dementia. While you can’t control everything, a healthy lifestyle will make the uncontrollable risk factors less worth it.
Disclaimer: This information is not intended to be a substitute for professional medical advice, diagnosis or treatment and is for information only. Always seek the advice of your doctor or other qualified health care provider with any questions about your medical condition and/or current medication. Do not disregard qualified medical advice or delay seeking advice or treatment because of what you have read here.
Read more: 5 early behavioral changes that signal dementia
