Alzheimer’s disease is caused by parts of the brain wasting away, which damages the structure of the brain and how it works. The medical name for wasting away is atrophy.
The atrophy mainly affects the cerebral cortex, which is the layer of grey matter that covers the brain. Grey matter is responsible for processing thoughts.
Plaques and tangles
As the cerebral cortex wastes away, clumps of protein, known as ‘plaques’ and ‘tangles’, start to form in the brain. The plaques and tangles start to destroy more brain cells, which makes the condition worse. They also affect the neurotransmitters (chemicals that carry messages to and from the brain).
Risk factors
It is still unknown what actually causes the deterioration of brain cells, although there are several factors that are known to affect the development of Alzheimer's disease. These are described in more detail below.
Age
Age is the greatest factor in the development of Alzheimer's disease. The likelihood of developing the condition doubles every five years after you reach 65 years of age. However, it is not just older people who are at risk of developing Alzheimer's disease.
Family history
Alzheimer's disease can also be inherited (run in the family), although the risk is only marginally higher than that of someone who has no family history of the condition.
In cases where Alzheimer's disease is inherited, the symptoms may start to develop at a relatively early age (between 35 and 60 years of age).
Down's syndrome
People with Down's syndrome (a genetic disorder that affects physical appearance, as well as the ability to learn and develop mentally) are at a higher risk of developing Alzheimer's disease.
This is because people with Down's syndrome have an extra copy of chromosome 21, which contains a protein found in the brain of those with Alzheimer's disease. Therefore, people with Down's syndrome have a higher-than-average amount of this protein, which could contribute to developing Alzheimer's disease.
Whiplash and head injuries
People who have had a severe head injury, or severe whiplash (a neck injury caused by a sudden movement of the head forwards, backwards or sideways), have been found to have a higher risk of developing Alzheimer's disease.
Aluminium
Aluminium is a naturally occurring substance found in food and plants. It is also added to products, such as pans, packaging and medicines. The body only absorbs a minimal amount of aluminium, which is usually passed out of the body in urine.
It has been suggested that aluminium could be a possible cause of Alzheimer's disease because research found that the plaques and tangles in the brain contain aluminium. However, further research has failed to prove a link between aluminium and Alzheimer's disease.
