Risk factors for Alzheimer's disease
There are many different things that can increase a person’s chances of getting Alzheimer’s. These are known as ‘risk factors’. Some of these risk factors cannot be changed, but many others can.
Risk factors that can’t be changed
Age is the biggest risk factor for Alzheimer’s, as it is for most types of dementia. This means that a person is more likely to get Alzheimer’s as they get older. Above the age of 65, a person’s risk of developing Alzheimer’s doubles about every five years.
Although most people with Alzheimer’s are over 65, younger people can also get it. Around one in three people with young-onset dementia have Alzheimer’s.
There are about twice as many women over 65 with Alzheimer’s as there are men over 65 with the condition. This is mostly because women tend to live longer than men.
However, women over the age of 80 still have a slightly higher risk of getting Alzheimer’s than men their age. We don’t know the exact reasons for this.
There has been a lot of interest in how menopause may increase a person’s risk of getting Alzheimer’s. While it seems that very early menopause caused by medical treatment can increase risk, it’s still unclear if it’s also a risk factor when it happens more naturally.
There are certain genes that may be passed down (inherited) from a parent that can affect a person’s chances of getting Alzheimer’s. There are two types of these genes: ‘familial’ genes and ‘risk’ genes.
Familial genes will definitely cause Alzheimer’s if they are passed down from a parent to a child. Out of 1000 people who have Alzheimer’s, less than ten of those people will have it because of a familial gene.
Risk genes increase a person’s chances of developing Alzheimer’s. They are much more common than familial genes. However, unlike familial genes, risk genes do not always cause a person to develop the condition. Most of them only slightly increase a person’s risk.
People with Down’s syndrome have a much higher risk of developing Alzheimer’s disease because of a difference in their genes.
The most important risk gene for Alzheimer’s is called apolipoprotein E (APOE). Certain versions of the APOE gene can make a person up to four times more likely to develop Alzheimer’s.
Nearly two out of three people in the UK who get Alzheimer’s disease have this version of APOE so it’s one of the biggest contributors to a person’s risk. However, the APOE gene only increases a person’s chances of getting dementia.
It doesn’t cause the condition in everyone who has it. In fact, most people with the higher-risk versions of the APOE gene don’t develop dementia.
Risk factors that can be controlled
People who live a healthy lifestyle, especially from mid-life (age 40–65) onwards, are less likely to develop Alzheimer’s. This includes not smoking, not drinking too much alcohol, and eating a healthy balanced diet.
Keeping physically, mentally and socially active may help a person to reduce their risk of developing Alzheimer’s.
Protecting the head from injuries throughout a person’s life may potentially reduce the risk of Alzheimer’s. Traumatic brain injuries (TBIs) are caused by a blow or jolt to the head, especially if the person is knocked out unconscious.
There are lots of health conditions that increase a person’s risk of developing Alzheimer’s disease (as well as vascular dementia). These include:
- diabetes, stroke and heart problems
- risk factors for heart and blood vessel disease, such as high blood pressure, high cholesterol and obesity in mid-life
- age-related hearing loss
Managing these conditions and getting support from health professionals as early as possible may help you to reduce your risk.
What can increase a person's risk of dementia?
There are different types of risk factors for dementia, including medical, lifestyle and environmental factors. It is possible to avoid some risk factors, while others cannot be controlled.
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