World Alzheimer's Day: What you need to know about the most common cause of dementia

Today marks World Alzheimer's Day, observed on 21 September to raise awareness of the most common cause of dementia, a term that describes a set of symptoms that can include memory loss and difficulties with thinking, problem solving or language. The symptoms occur when the brain is damaged by certain diseases, such as Alzheimer's.

What is Alzheimer's?

Alzheimer's is a progressive disease, meaning more parts of the brain will be damaged over time and the symptoms become more severe.

It is caused by parts of the brain wasting away, a process called atrophy. During the course of the disease, proteins build up in the brain to form structures known as "plaques" and "tangles" – which leads to the loss of connections between nerve cells and their eventual death.

According to Alzheimer's Research UK, people with the disease also have a shortage of some chemicals in their brain, which help to transmit signals. When there is a shortage, the signals are not transmitted as effectively.

How does the disease impact women?

Dementia has a huge impact on women in Britain. Dementia is the leading cause of death among women in the UK – and they are also far more likely to become carers of those with dementia, such as spouses or other family members. Without adequate support, this can lead to emotional and physical stress as well as job losses.

Is there a cure?

There is currently no cure for Alzheimer's, although research into the disease is uncovering more about the condition. Although there have been trials for different drugs, none have so far been successful – and those that do exist only treat the symptoms of the disease and slow down its progression.

Some progress has been made, though. In August, an antibody therapy designed to reduce the build-up of amyloid plaques in the brains of patients with a mild form of the disease showed promising results in early clinical trials.

Is age a risk factor?

What triggers the condition is still unknown, but there are several risk factors associated with developing Alzheimer's. Age is the most significant factor, as the likelihood of developing the condition doubles every five years after the age of 65. However, a number of people develop early-onset Alzheimer's, which can affect people from around 40 years of age.

What about other risk factors?

Studies have shown smoking, obesity, high cholesterol, high blood pressure and diabetes can be risk factors in developing the disease, as can some head injuries. Family history is also a factor and genes can contribute to your risk of developing Alzheimer's – although the actual increase in risk is small if you have a close family member with the condition. Visit the Alzheimer's Society website for more information on genetics and dementia. People with Down's syndrome can also be at increased risk of developing Alzheimer's.