|
The
exact cause of Alzheimer's is unknown. However, several risk factors
have been identified.
Age
Age is the greatest risk factor for developing Alzheimer's and the
incidence increases with age. Men and women are affected equally. At
any given point in time there are more women with Alzheimer's than
men but this is due to the fact that women have a longer life
expectancy.
Genetics
The risk of Alzheimer's is three times greater in individuals with
first degree relatives who suffered from Alzheimer's than in the
normal population. A genetic predisposition towards the disease is
found in five to ten percent of people with Alzheimer's and
mutations in certain genes have also been identified in individuals
with a familial type of Alzheimer's disease. Studies looking at
identical and fraternal twins support the presence of a genetic
predisposition of developing the condition.
Environmental
factors
A number of environmental factors have been linked to Alzheimer's
disease:
| • |
Exposure to aluminium; |
| • |
Alcohol; |
| • |
Head
injury; |
| • |
Family
history of psychiatric illness. |
However, the studies in
this area are controversial, with some studies showing clear
relationships between the disease and certain environmental factors
and other studies refuting the relationship.
Brain damage
The brain of a person with Alzheimer's dementia shows characteristic
changes. Large plaques consisting of the protein amyloid are found
outside dying brain cells. Other abnormal structures called
neurofibrillary tangles consisting of a protein called tau protein
are also found in the brain. |
