What is the most common cause of dementia?
Vascular dementia. This second most common type of dementia occurs as a result of damage to the vessels that supply blood to your brain. Blood vessel problems can be caused by stroke or other blood vessel conditions. Lewy body dementia.
Causes and risk factors. Like all types of dementia, Alzheimer's is caused by brain cell death. It is a neurodegenerative disease, which means there is progressive brain cell death that happens over time. In a person with Alzheimer's, the tissue has fewer and fewer nerve cells and connections.
- Three cholinesterase inhibitors are commonly prescribed: Donepezil (Aricept) is approved to treat all stages of Alzheimer's. Rivastigmine (Exelon) is approved to treat mild to moderate Alzheimer's.
- But, as well as progressive brain cell death, like that seen in Alzheimer's disease, dementia can be caused by a head injury, a stroke, or a brain tumor, among other causes. This prevents normal blood flow, depriving brain cells of oxygen.
- Those who have a parent, brother or sister with Alzheimer's are more likely to develop the disease. The risk increases if more than one family member has the illness. When diseases tend to run in families, either heredity (genetics) or environmental factors, or both, may play a role.
High cholesterol levels in the blood, high blood pressure, diabetes, smoking and obesity are the major modifiable risk factors for cardiovascular diseases, including heart disease and stroke. The risk factors for cardiovascular disease represent risk factors for both Alzheimer's disease and vascular dementia.
- Types of dementias that progress and aren't reversible include:
- Alzheimer's disease. In people age 65 and older, Alzheimer's disease is the most common cause of dementia.
- Vascular dementia.
- Lewy body dementia.
- Frontotemporal dementia.
- Mixed dementia.
- Vascular dementia is a general term describing problems with reasoning, planning, judgment, memory and other thought processes caused by brain damage from impaired blood flow to your brain. You can develop vascular dementia after a stroke blocks an artery in your brain, but strokes don't always cause vascular dementia.
- The commonest factors significantly associated with delirium were dementia, older age, co-morbid illness, severity of medical illness, infection, 'high-risk' medication use, diminished activities of daily living, immobility, sensory impairment, urinary catheterisation, urea and electrolyte imbalance and malnutrition.
Age, family history and heredity are all risk factors we can't change. The risk of developing Alzheimer's or vascular dementia appears to be increased by many conditions that damage the heart and blood vessels. These include heart disease, diabetes, stroke, high blood pressure and high cholesterol.
- At present such predictive genetic testing is only possible for inherited Alzheimer's disease, in which very rare mutations in three genes are implicated, and frontotemporal dementia, which has known mutations in at least six genes. There are no approved predictive genetic tests for this form of the condition.
- Age, family history and heredity are all risk factors we can't change. The risk of developing Alzheimer's or vascular dementia appears to be increased by many conditions that damage the heart and blood vessels. These include heart disease, diabetes, stroke, high blood pressure and high cholesterol.
- It is rare for someone under 65 to have dementia, but it does occur at younger ages and we call this 'younger onset dementia'. People often wonder whether dementia is inherited. The answer for most of us is, no. The common forms of dementia are likely caused by a combination of genetic and environmental factors.
Updated: 2nd October 2019