Type 2 diabetes has been associated with an increased risk for various types of cognitive impairment.

These include:

  • Alzheimer’s disease
  • vascular dementia
  • mild cognitive impairment, a condition that precedes dementia

Cognitive impairment is when a person has trouble concentrating, learning new things, remembering information, or making decisions.

Researchers are still working to fully understand how diabetes and dementia are connected. They hope to answer questions such as:

  • How does high blood sugar or insulin harm the brain?
  • What’s the risk of having both diabetes and dementia?
  • What’s the life expectancy for those with diabetes and dementia?
  • How can both conditions be managed?

Read on to understand the answers to these important questions.

Dementia can be caused by a variety of illnesses or injuries. In general, dementia is a result of degeneration of neurons or disruptions in other body systems that affect how brain cells function.

Researchers still don’t fully understand if diabetes causes dementia. Scientists, however, do know that high blood sugar or insulin can harm the brain by:

  • increasing the risk for heart disease and stroke, which may damage blood vessels in the brain
  • causing an imbalance in certain chemicals in the brain
  • causing chronic inflammation in the body, which can damage brain cells over time

Research has also shown a correlation between Alzheimer’s disease and high blood sugar levels.

Studies suggest that people with high blood sugar levels show a substantial increase in beta-amyloid, a protein that’s toxic to cells in the brain. Clumps of beta-amyloid protein have been shown to build up in the brains of people with Alzheimer’s disease.

People with diabetes often have comorbidities (other conditions) that could also play a role in contributing to the development of dementia. Other risk factors for dementia include:

  • hypertension (high blood pressure)
  • obesity
  • lack of physical activity
  • smoking
  • depression

Your risk of having type 2 diabetes depends on several factors, including:

  • overweight or obesity
  • lack of physical activity
  • high blood pressure
  • high cholesterol

Risk of dementia depends on many factors as well, including genetics and age.

One study estimated that a 70-year-old man had roughly a 27 percent probability of developing dementia and a 70-year-old woman had about a 35 percent probability.

Another study found that older adults with type 2 diabetes experience cognitive decline twice as fast as those without type 2 diabetes over a 5-year period. Likewise, other research suggested that there’s a 56 percent increased risk for Alzheimer’s disease among people with type 2 diabetes.

Research from 2009 also suggested that the risk for having dementia is higher in people diagnosed with diabetes before age 65 compared to those diagnosed later in life.

Life expectancy for someone living with diabetes and dementia will vary depending on many factors. Both diabetes and dementia are complex illnesses. There are many variables and potential complications that can affect an individual’s life expectancy.

For example, people who don’t manage their glucose levels effectively, don’t exercise, or who smoke will likely have a shorter life expectancy than a person with a healthier lifestyle and stable blood glucose levels.

Still, having diabetes appears to accelerate mortality rate in people with dementia. One study found that people with both dementia and diabetes died almost twice as fast as those without diabetes.

In one Canadian study, life expectancy was shown to be significantly lower for people with diabetes compared to those without the condition. Life expectancy for women without diabetes was 85 years and life expectancy for men was about 80.2 years. Diabetes was associated with a loss in life expectancy of about 6 years for women and 5 years for men.

On average, people with Alzheimer’s disease live for 8 to 10 years after symptoms begin. It’s possible for someone to not even start to experience symptoms of Alzheimer’s disease until they’re in their 90s.

People with vascular dementia live for about 5 years after symptoms begin, on average. This is a bit less than the average for Alzheimer’s disease.

Taking steps to manage diabetes may not stop dementia from developing, but you may be able to cut your risk with a few lifestyle changes. These include:

  • maintaining a healthy weight
  • exercising at least 30 minutes a day
  • eating a healthy diet with fruits, vegetables, whole grains, and lean proteins
  • avoiding processed foods and foods high in sugars and carbohydrates

If you’re diagnosed with diabetes, it’s important that you work with your doctor to develop a treatment plan.

Your doctor may prescribe medications to help manage your blood sugar, such as metformin or insulin. Diabetes medications are meant to be taken around the same time every day. Missing a dose will likely cause an increase in blood sugar levels.

A growing body of evidence suggests a link between diabetes and cognitive impairment, including dementia. Though the exact ways that diabetes contributes to dementia aren’t fully understood, scientists suspect that diabetes damages brain cells in a few different ways.

As researchers learn more about the connection between diabetes and dementia, it’s important to take steps to prevent or treat both diseases. This includes following a healthy diet, monitoring your cholesterol and blood pressure levels, exercising, and taking your prescribed medications.