Type 3 Diabetes and Alzheimer’s Disease:

What You Need to Know

What is type 3 diabetes?

Diabetes mellitus (also called DM or diabetes for short) refers to a health condition where your body has difficulty converting sugar to energy. Typically, we think of three kinds of diabetes: 

• Type 1 diabetes (T1DM) is a chronic health condition in which your body’s endocrine part of the pancreas does not produce enough of the hormone insulin, and your blood sugar (glucose) level becomes too high.
• Type 2 diabetes (T2DM) is a chronic condition in which your body develops resistance to insulin, and your blood sugar level becomes too high as a result.
• Gestational diabetes (GDM) is DM that occurs during a pregnancy, and the blood sugar level is too high during this time.

Some research studies have proposed that Alzheimer’s disease should also be classified as a type of diabetes, called type 3 diabetes. Type 3 diabetes is known as the "other" category. The Type 3 category is divided into 8 sub-categories that include countless disorders such as specific known genetic mutations, rare genetic syndromes, multiple different pancreatic diseases, other hormonal disorders, toxin and drug effects, infections, and other autoimmune diseases.

This “type 3 diabetes” is a term that has been put forward to describe the hypothesis that Alzheimer’s disease, which is a major cause of dementia, is triggered by a type of insulin resistance and insulin-like growth factor dysfunction that occurs specifically in the brain.

This condition also has been used by some to describe people who have type 2 diabetes and are also diagnosed with Alzheimer’s disease dementia. Now, having said all of the above, it should be noted that the classification of type 3 diabetes is highly controversial, and it is not yet widely accepted by the medical community as a clinical diagnosis. If you have more questions, please make an appointment with us at Palmetto Endocrinology to discuss your concerns.

The link between diabetes and Alzheimer’s

According to the Mayo Clinic, there’s already an established link between Alzheimer’s and type 2 diabetes. It has been suggested that Alzheimer’s may be triggered by insulin resistance in your brain. Some people say that Alzheimer’s is simply “diabetes in your brain.” This claim has some science behind it, but it’s a bit of an oversimplification.

Over time, untreated diabetes can cause damage to your blood vessels, including vessels in your brain. Many people who have type 2 diabetes do not know that they have the condition, which may delay diagnosis and appropriate treatment measures.

Therefore, those with type 2 diabetes, especially undiagnosed diabetes, have a higher risk of this kind of damage. Diabetes may also cause chemical imbalances in your brain, which may trigger Alzheimer’s.

Also, high blood sugar levels lead to inflammation, which may damage brain cells. For these reasons, diabetes is considered a risk factor for a condition called vascular dementia. Vascular dementia is a stand-alone diagnosis with symptoms of its own, or it can be a warning sign of what will develop into an overlap with Alzheimer’s disease.

The science of this process is uncertain. For now, what has been established is that there are cases of Alzheimer’s disease and other forms of dementia that do not have any demonstrated link to insulin resistance.

Causes and risk factors for type 3 diabetes

According to a 2016 study, people who have type 2 diabetes may be up to 60 percent more likely to develop Alzheimer’s disease or another type of dementia, such as vascular dementia. This study, conducted by Trusted Source involved more than 100,000 people living with dementia. It showed that women with type 2 diabetes had a higher probability of developing vascular dementia than men. Risk factors for type 2 diabetes include: a family history of diabetes, high blood pressure (hypertension), being overweight or obese and certain chronic health conditions, such as depression and polycystic ovarian syndrome (PCOS).

Symptoms of type 3 diabetes

The symptoms of type 3 diabetes are described as the symptoms of dementia, such as those seen in early Alzheimer’s disease. According to the Alzheimer’s Association, these symptoms include: memory loss that affects daily living and social interactions, difficulty completing familiar tasks, misplacing things often, decreased ability to make judgements based on information, sudden changes in personality or demeanor.

Diagnosis of type 3 diabetes

There is no specific test for type 3 diabetes. Alzheimer’s disease is diagnosed based on: a neurological examination, medical history, and neurophysiological testing. Your primary care provider will ask several questions about your family history and your symptoms. If he or she thinks that type 3 diabetes may be a possibility, they will refer you to Palmetto Endocrinology and or neurology for further testing.

If you have symptoms of type 2 diabetes and Alzheimer’s and haven’t been diagnosed with either one, your healthcare provider may order a fasting blood sugar test and a glycated hemoglobin test.

If you do have type 2 diabetes, it is important that you begin treatment for it immediately. Treating type 2 diabetes could minimize damage to your body, including your brain, and slow the progression of Alzheimer’s or dementia.

Treatment for type 3 diabetes

There are separate treatment options for people who have: pre-type 2 diabetes, type 2 diabetes and Alzheimer’s. Lifestyle changes, such as making changes to your diet and including exercise in your daily routine, may be a big part of your treatment.

Here are some additional treatment tips: If you’re overweight, try to lose 5 to 7 percent of your body mass, according to the Mayo Clinic. This can help stop organ damage caused by high blood sugar and may prevent the progression of pre-DM2 to DM2.

A diet low in fat and rich in fruits and vegetables can help improve symptoms.

If you smoke, quitting is recommended because it can also help manage your condition.

If you have both type 2 diabetes and Alzheimer’s, treatment for your type 2 diabetes is important to help slow the progression of dementia.

Prescription medications are available to treat cognitive symptoms of Alzheimer’s dementia, but there’s uncertainty about whether they have a noticeable impact on the symptoms of Alzheimer’s disease.

Outlook for type 3 diabetes

Type 3 diabetes is a way of describing Alzheimer’s that is caused by insulin resistance inside the brain. So, your outlook will vary according to several factors, including your diabetes treatment and the severity of your dementia.

If you can treat your diabetes with diet, exercise, and medication, researchers who promote the diagnosis of type 3 diabetes suggest that you may be able to slow the progression of Alzheimer’s or vascular dementia, but evidence is uncertain.

Your outlook will also vary according to how soon your symptoms were discovered and what your healthcare provider thinks about your specific case. The sooner treatment begins, it is likely the better your outlook will be. Please make an appointment with us at Palmetto Endocrinology if you have further questions.

Author

Joseph Mathews, MD, FACP, FACE, ECNU, CCD Joseph W. Mathews M.D., a board certified Endocrinologist and Medical Director of Palmetto Endocrinology, was born and raised in South Carolina. He earned his Bachelor of Science in Biology from the College of Charleston, Cum Laude. He then achieved his M.D. at the Medical University of South Carolina where he also completed his residency in Internal Medicine and a Fellowship in Endocrinology, Diabetes, and Metabolism. Dr. Mathews is also a Fellow of both the American College of Endocrinology and the American College of Physicians, holds an Endocrine Certification in Neck Ultrasound (ECNU) and is a Certified Clinical Densitometrist (CCD). He has extensive experience performing ultrasound guided fine needle aspiration biopsies. His practice includes a range of specializations including prescribing and fitting patients with insulin pumps. Dr. Mathews' practice has drawn patients from out of state to benefit from his expertise in thyroid disorders, diabetes, cortisol problems and their Endocrine disorders.