Am I at risk of developing dementia?
Many people worry that they may be at risk of developing dementia, particularly if they have a close relative with the condition. This information sheet explains what we know about the risks associated with different types of dementia and gives some advice on how people can reduce their risk. Research is continuing.What is risk?
Risk is a person’s chance of getting a disease over a certain period of time. A person’s risk factors make up their individual risk. For example, an 80-year-old woman is more at risk of developing dementia than a 30-year-old man. This does not mean that the older woman will definitely develop dementia (she only has a slightly higher than one in five chance) or that the younger man will not.What is a risk factor?
A risk factor is anything that increases or reduces a person’s chance of developing a condition. Some of these factors can be controlled, but not all of them.What are the risk factors for dementia?
While there is still much to learn about the brain, researchers have highlighted some important factors that affect our risk of developing different types of dementia. Most researchers now believe that our risk of developing dementia depends upon a combination of genetic and environmental factors. We are all at some risk of developing dementia, but some of us more than others. A person who has some of the risk factors for dementia will not necessarily go on to develop the condition. And avoiding risk factors does not guarantee that you will be healthy, although it makes this more likely.Age
Age is the most significant known risk factor for dementia. While it is possible to develop dementia early in life, the chances of developing it increase dramatically as we get older. One in 50 people between the ages of 65 and 70 has a form of dementia, compared to one in five people over the age of 80. Factors associated with ageing may be responsible for this increased risk. These factors include high blood pressure, some diseases (for example, heart disease and stroke), changes to nerve cells, DNA and cell structure, and the weakening of natural repair systems.Gender
Women are slightly more likely to develop Alzheimer’s disease than men, even if the fact that women are more likely to live longer is discounted.A lack of the hormone oestrogen in women after the menopause has been suggested as one factor in the development of Alzheimer’s disease. Controlled studies have, however, suggested that hormone replacement therapy (HRT) has no beneficial effect on the development of Alzheimer’s disease and may even increase a person’s risk of developing the condition. We do not recommend that women take HRT as a way to reduce their risk of developing dementia.
Vascular dementia is more common in men than women. This may be because common risk factors for vascular dementia, such as heart problems and high blood pressure, are more common in men than women.
Genetics
Scientists have been aware for some time that our genetic background – the genes we inherit from our parents – may partly determine whether we will develop specific diseases. The role of genetics in the development of dementia is still not fully understood, but researchers have made some important advances in recent years.We do know that there are families where there is a very clear inheritance of dementia from one generation to the next. This is usually in families where the disease appears relatively early in life. Diseases which may cause dementia and may be hereditary in some cases include Huntington’s disease, Alzheimer’s disease and Niemann-Pick disease. In the majority of cases, however, the effect of inheritance seems to be small, such that if a parent or other relative has dementia your own chances of developing it are only a little higher than if there were no cases of dementia in the family.
Particular genes can effect a person’s risk of developing Alzheimer’s disease and scientists are learning more about these. For example, a gene called apolipoprotein E (APOE) has been shown to play a part in the development of Alzheimer’s disease and vascular dementia. For more information about genetics and dementia, please see the Society’s information sheet Genetics and dementia.
