The causes of dementia can include:

  • Alzheimer’s disease, a brain disease that causes abnormal changes that kill brain cells.
  • Blockages in blood vessels in the brain that limit blood flow to parts of the brain or trigger mini-strokes. These cause a type of vascular dementia.
  • Abnormal brain proteins which cause Lewy body dementia.
  • Side effects of drugs, thyroid disease, low levels of some vitamins, and other conditions. These are reversible dementias.
  • Other health problems. For example, Parkinson’s disease and the virus that causes AIDs can cause dementia, and obstructive sleep apnea can worsen symptoms of dementia.
  • Serious head injuries.
  • Brain tumors.
  • Sustained heavy drinking.

People can have more than one type of dementia. For example, they can have Alzheimer’s and vascular dementia at the same time. These two types of dementia are most common in older adults.

No cures exist for most types of dementia. However, some treatments can improve how you carry out your daily activities and your quality of life.  

Risks Related to Dementia

A risk factor for a health problem is something that increases the likelihood, that you will get it.  However, having a risk factor doesn’t mean you’ll develop the problem. Risk factors for dementia include:

  • Age: the older you are the more likely you are to have dementia.
  • Family history of dementia
  • Depression and stress
  • Down Syndrome
  • Serious head injury
  • High blood pressure and high levels of bad cholesterol
  • Smoking or alcohol use
  • Diabetes and obesity
  • Inactive lifestyle
  • Low levels of education
  • Delirium

Many of these risk factors are the same as those that relate to heart disease. Visit the Prevention section to get easy-to-follow information about living a heart healthy lifestyle.

Possible protections against dementia include: controlling blood pressure, following a healthy diet, and being physically active. Staying mentally and socially active may also lower your risk of developing dementia.

Mild Cognitive Impairment

Mild cognitive impairment is a condition where people have problems with memory, language, planning, and other mental abilities. These problems are noticeable and show up on medical tests. However, they, don’t disrupt a person’s daily life. So, mild cognitive impairment isn’t considered a form of dementia. However, people with this problem have a higher risk of developing dementia.


Last Updated February 2023

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