Dementia

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Causes

Causes of Dementia

  • Alzheimer’s disease, a brain disease that causes changes in the brain and leads to the death of brain cells.
  • Blockages in the brain’s blood vessels that reduce blood flow or cause small strokes. This leads to vascular dementia.
  • Abnormal brain proteins that cause Lewy body dementia.
  • Side effects of medications, thyroid disease, low vitamin levels, and other medical problems. These are sometimes called reversible dementias because they may improve with treatment.
  • Other health conditions. For example, Parkinson’s disease and the virus that causes AIDS can lead to dementia. Obstructive sleep apnea can make dementia symptoms worse.
  • Serious head injuries.
  • Brain tumors.
  • Long-term heavy alcohol use.

A person can have more than one type of dementia. For example, someone may have both Alzheimer’s disease and vascular dementia. These two types are the most common in older adults.

There is no cure for most types of dementia. However, treatments can help improve daily function and quality of life.

Risks Related to Dementia

A risk factor is something that increases your chance of developing a health problem. Having a risk factor does not mean you will definitely get the condition.

Risk factors for dementia include:

  • Age: The older you are, the higher your risk.
  • Family history of dementia
  • Depression and stress
  • Down syndrome
  • Serious head injury
  • High blood pressure and high levels of “bad” cholesterol
  • Smoking or heavy alcohol use
  • Diabetes and obesity
  • Lack of physical activity
  • Low level of education
  • Delirium

Many of these risk factors are the same as those for heart disease. Visit the Prevention section for easy steps to live a heart-healthy lifestyle.

Possible ways to lower your risk of dementia include controlling blood pressure, eating a healthy diet, and staying physically active. Staying mentally and socially active may also help lower your risk.

Mild Cognitive Impairment 

Mild cognitive impairment (MCI) is a condition in which a person has problems with memory, language, planning, or other thinking skills. These problems are noticeable and can be found on medical tests.

However, these changes do not strongly interfere with daily life. For this reason, mild cognitive impairment is not considered dementia.

People with mild cognitive impairment have a higher risk of developing dementia in the future.

 

Last Reviewed and Updated: August 2026
By: AGS/HiAF Public Education Committee, HealthinAging.org Content Reviewers

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