Dementia: Causes and risk factors

Ageing, lifestyle factors, genetics, and health conditions can all contribute to dementia.

Dementia is an umbrella term for a collection of symptoms that include memory loss and cognitive changes. Brain damage or various diseases can cause abnormal brain changes, which can cause dementia.

There are different types of dementia that can result from various causes. The different types of dementia link to certain forms of brain damage in specific areas of the brain.

Most types of dementia occur due to proteins accumulating in the brain. In Alzheimer’s disease, abnormal protein deposits called amyloid plaques and tangles form and damage nerve cells.

Parkinson’s disease, dementia, and Lewy body dementia occur due to abnormal protein deposits called Lewy bodies.

Vascular dementia occurs due to reduced blood flow to the brain, such as through a stroke, which damages brain cells. Certain infections, such as HIV, and high consumption of alcohol may contribute to the development of dementia.

It is not common to inherit dementia, but some rare types of dementia can be genetic. Traumatic brain injury may damage the brain and increase the risk of developing dementia.

Researchers are still not clear on what causes Alzheimer’s disease, but it is likely due to a combination of factors, which include:

Many brain changes occur in the development of Alzheimer’s disease. A key feature of Alzheimer’s disease is the formation of amyloid plaques and tau tangles, which disrupt communication between nerve cells in the brain.

Damage to blood vessels in the brain can cause vascular dementia. This damage disrupts the flow of oxygen and blood to the brain, leading to abnormal brain changes.

Researchers have not found the exact cause of Lewy body dementia. In most people with Lewy body dementia, there is no family history of the condition. So far, there is no definitive research linking any genes to Lewy body dementia.

Lewy body dementia occurs due to a buildup of abnormal protein deposits called Lewy bodies. This buildup contributes to the loss of nerve cells in the brain that produce neurotransmitters.

Neurotransmitters are chemical messengers that allow nerve cells to communicate. Neurotransmitters such as acetylcholine and dopamine are important for cognitive abilities, learning, memory, and movement.

In around a third of all frontotemporal dementia (FTD) cases, people inherit it. The only known risk factors for FTD are a family history of the condition or a similar disorder.

There are many different genes that can cause FTD, and each gene has its own inheritance pattern.

Most people with FTD do not inherit the condition directly, but in some cases, it can pass directly from a parent to a child. In around 40% of cases, people with FTD have at least one close relative who has a type of dementia.

Genetics, age, and certain health conditions can increase the risk of mild cognitive impairment (MCI). MCI increases the risk of developing dementia.

If people have concerns that they or someone else may have dementia, it is important to contact a doctor. Symptoms may include changes in behavior, mood, communication, and memory.

Other conditions may cause similar symptoms, but it is important to find the underlying cause and start any necessary treatment.

Various factors can cause changes in the brain that can lead to dementia. These can include ageing, health conditions, genetics, and lifestyle factors.

If people think they might have dementia, it is important to contact a doctor to find out the cause of symptoms.