Concerned about your dementia risk? Dr Jamie Wilson, dementia specialist and founder of live-in care platform Hometouch, explains the causes of dementia and looks at whether it runs in the family.
What is dementia?
There’s no one disease or condition called dementia. Rather, it’s a term used for a collection of symptoms, which include memory loss and difficulties with language, problem-solving and other cognitive abilities. These symptoms can be brought about by a number of different causes, some of them more well understood than others.
This is the most common form of dementia. More than 60 per cent of dementia diagnoses are attributed to Alzheimer’s. The causes aren’t fully understood – there are hypotheses that proteins called amyloids accumulate in the brain, causing damage, or that a deficiency in a neurotransmitter called acetylcholine is responsible. Typically, the disease affects people aged over 65.
➡️ Is Alzheimer’s hereditary?
There does appear to be a genetic link to Alzheimer’s disease, as people with a particular variant of the ApoE allele are at an increased risk of developing the disease.
As many as 20 per cent of dementia cases are categorised as vascular dementia. Vascular dementia is caused by brain damage, resulting from small strokes (also known as infarcts) in the brain. The reduction in circulation causes oxygen deprivation and cell death in partsof the brain. Diagnosis of vascular dementia peaks in people in their 70s, though both later and early onset aren’t uncommon.
Unlike Alzheimer’s, which characteristically involves a slow, steady decline in cognitive function, vascular dementia progresses in a step-wise fashion, often due to further mini-strokes or TIAs (transient ischaemic attacks).
➡️ Is Vascular dementia hereditary?
Vascular dementia is not usually hereditary. The primary risk factors for vascular dementia are smoking, hypertension, high cholesterol, Type 2 diabetes, obesity and various heart conditions. These factors are primarily epigenetic, or lifestyle-based.
The best way to protect yourself from vascular dementia is to avoid smoking, eating a healthy, balanced diet, exercising regularly, keeping to a healthy weight and maintaining normal blood pressure. However, some rare genetic conditions, such as CADASIL, are linked to higher incidences of vascular dementia.
An individual is diagnosed as having mixed dementia when they have two or more different types of disease. Many of these conditions have similar risk factors, and so it is likely that more than one disease will co-exist.
The most common combination of dementias is Alzheimer’s and vascular dementia, which can result in both a steady worsening of symptoms punctuated by acute periods of deterioration.
This is also known as frontal lobe dementia. As with dementia generally, there are a number of causes of frontotemporal dementia. All are characterised by damage to the frontal lobes – the parts of the brain that regulate language and behaviour.
Instead of the problems with forgetfulness and short-term memory loss typically associated with Alzheimer’s, damage to the frontotemporal areas can lead to changes in personality, as well as struggles with speech and language. Frontotemporal dementia is most often diagnosed between the ages of 45 and 65, and it affects men and women roughly equally.
➡️ Is frontotemporal dementia hereditary?
One type of frontotemporal dementia, called familial frontotemporal dementia, has a particularly strong genetic link, and a variant in a gene called TMEM106B has been implicated in several forms of the condition.
Dementia with Lewy bodies (DLB)
Lewy bodies are tiny deposits of a protein that build up in the brain’s nerve cells, especially in the areas that affect the memory, thought and movement. They were named after the German doctor that discovered them and are implicated in causing a form of dementia and Parkinson’s disease.
Dementia with Lewy bodies (DLB) is characterised by memory and processing problems, hallucinations, tremor, sleep disturbance, and coordination and movement difficulties, also known as Parkinsonism.
➡️ Is (DLB) hereditary?
A number of gene mutations are linked to an increased risk of developing the condition. DLB has a strong incidence of inheritance in an autosomal dominant pattern – meaning if one parent carries a copy of a mutated gene, their offspring is likely to inherit it.
For more information on dementia charities that offer advice and support, try one of the following resources:
Alzheimer's Society has information on dementia causes, plus how to live well and find help and support near you.
National Dementia Helpline: call on 0300 222 11 22 for information and advice about dementia.
Dementia UK: is a national charity that aims to improve the quality of life for people with dementia.
Alzheimer's Research UK: carries out dementia research but also answers questions about dementia and dementia research.
Age UK: has advice on a range of topics, including advance care planning, benefits and choosing a care home.
The Carers Trust: provides information and advice on its website for carers, including how to get support for yourself.
Carers UK: is a national charity for carers, providing information and advice from benefits to practical support.