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Dementia Causes and Risk Factors

Dementia is not a specific disease, but rather a group of symptoms caused by a number of different disorders that affect the brain. The symptoms include loss of memory, changes in mood, personality and behavior.

People with dementia may have trouble controlling their emotions or behaving appropriately in social situations. It usually gets worse over time, which means that you have to rely on other people more and more.

Dementia is often occurs in people who are 65 and older. The older you get, the greater your chances of developing dementia. Dementia is also more common in women than in men. It is estimated that 1 in 6 women and 1 in 10 men, who live past the age of 65 will develop dementia in their lifetime.

What Causes Dementia?

Dementia can be caused by many conditions, which result in brain damage. Some causes of dementia can be reversed, but most can not.

Causes of Dementia that can’t be reversed or stopped

  • Alzheimer’s Disease
    Alzheimer’s disease is the most common cause of dementia, accounting for 50%-70% of all dementia cases. Although the exact cause of Alzheimer’s disease isn’t known, but it is likely due to plaques and tangles in the brain. Plaques are deposits of beta-amyloid protein that accumulate between nerve cells, and tangles are deposits of tau protein that accumulate in the nerve cells.
  • Vascular Dementia
    Vascular Dementia is the second most common form of dementia, accounting for as many as 40% of all cases. This dementia is caused by reduced blood flow to the brain — usually due to hardening of the arteries (atherosclerosis). When blood flow is reduced, brain cells can’t function properly, causing damage to the cortex of the brain – the area that is associated with memory, language, and learning.
  • Lewy Body Dementia
    Lewy body dementia (LBD) is one of the most common types of progressive dementia, affecting approximately 20 percent of people with dementia. This dementia is caused by small protein deposits in the brain called Lewy bodies. These deposits also found in the brains of people with Alzheimer’s or Parkinson’s disease. This means that these three diseases may be linked in some way. If a family member has Parkinson’s disease, there may be a higher risk of developing Alzheimer’s disease or dementia. Currently, there is no cure for LBD. Treatments aim to control the cognitive, psychiatric, and motor symptoms of the disorders.
  • Fronto-temporal Dementia
    Fronto-temporal dementia (FTD) is a rare form of dementia, accounting for only 2 to 5 percent of all dementia cases. This less common cause of dementia tends to occur at a younger age than Alzheimer’s disease does, generally between the ages of 40 and 70. This is a group of disorders that primarily affect the frontal and temporal lobes of the brain – the areas generally associated with personality, behaviour, emotions, language, thinking and movement.

    In many cases, people with FTD have inherited a genetic mutation from their parents. These genetic mutations are thought to have a negative effect on a protein called tau protein. All brain cells contain tau proteins that help to keep them stable. However, if tau proteins stop working properly, they can damage brain cells.

  • Parkinson Disease
    People with Parkinson disease usually have speech problems, rigidity, and tremors (shaking at rest). Dementia may occur late in the disease, but not all people with Parkinson’s disease have dementia. Memory, speech, and judgement are more likely to be affected. Like Alzheimer disease and Lewy body dementia, Parkinson disease can’t be cured, however drugs can help control or relieve the symptoms.

Dementia causes that can be reversed (if caught early)

  • Head injuries
  • Brain tumour
  • Brain infections, such as meningitis, encephalitis and lyme disease.
  • Huntington’s disease, a rare inherited disease that causes progressive brain damage.
  • Creutzfeldt-Jakob disease (CJD), a rare, fatal degenerative brain disorder.
  • Dehydration
  • Lack of vitamin B in the blood
  • Poisoning, such as from lead or pesticides
  • Having heart and lung problems that interrupt the supply of blood and oxygen to the brain.

Risk Factors for Dementia

There are a number of risk factors that can lead to the cause of dementia. Some can be controlled and some can not.

Dementia risk factors that can’t be controlled

  • Age
  • Family history of dementia
  • Down syndrome, a genetic condition that causes lifelong mental retardation and other problems.

Dementia risk factors that can be controlled

  • Diabetes
  • Smoking
  • High blood pressure (hypertension)
  • High blood cholesterol
  • Atherosclerosis
  • Excessive alcohol intake
  • High homocysteine levels in the blood

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