Risk factors


What are risk factors?

Risk factors are characteristics of your lifestyle, environment and genetic background that increase your likelihood of getting a disease.

Risk factors are not causes of disease on their own. Instead, they represent an increased chance—not a certainty—that a disease such as dementia will develop.

At the same time, having little or no exposure to known risk factors does not necessarily protect you from developing the disease.


How can you reduce your risk of developing dementia?

The best way to reduce your risk is by minimizing the risk factors that could affect you. However, it’s important to know which risk factors you can change.

There are some risk factors that you can control, which means that you can change them to reduce your chance of developing dementia. There are other risk factors that you cannot control, and they cannot be changed.

By knowing the risk factors you can change, you can reduce your risk of dementia.

Why a healthy lifestyle matters

As many of the risk factors you can change involve your physical and mental health, the best way to reduce the risk of Alzheimer’s disease and other dementias is to lead a healthy lifestyle that takes care of both your body and your brain.

For more tips and strategies regarding healthy lifestyle choices that can reduce your risk of dementia, visit our Brain health section.


Risk factors you can change

Depression

Many researchers believe that depression is a risk factor for dementia, whereas others believe it may be an early symptom of the disease, or both.

Depression

Diabetes

On average, people with type 2 diabetes are twice as likely to develop dementia compared to those without diabetes.

Diabetes

Head injuries

Experiencing severe or repeated head injuries increases a person’s risk of developing dementia.

Head injurie

Hearing loss

It’s still unclear how exactly hearing loss increases the risk of dementia, but it can also lead to social isolation, loss of independence and problems with everyday activities.

Hearing loss

High alcohol consumption

People who drink excessively have the highest risk of dementia compared to people who drink moderately or not at all.

High alcohol consumption

High blood pressure

People who have high blood pressure or hypertension in mid-life are on average more likely to develop dementia compared to those with normal blood pressure.

High blood pressure

High cholesterol

People with high cholesterol levels in mid-life are more likely to develop dementia compared to those with normal cholesterol.

High cholesterol

Living near busy roads

The impact on the brain from vehicle pollution is still being studied by researchers, but it’s estimated that people who live within 50 metres of a busy road are more likely to develop dementia.

Living near busy roads

Low levels of formal education

People who actively use their brains throughout their life may be building a ‘cognitive reserve’ that can provide more protection against brain cell damage caused by dementia.

Low levels of formal education

Obesity and lack of physical activity

In addition to dementia, obesity and lack of physical activity increase the risk of developing diabetes and high blood pressure. Obesity in mid-life is also a risk factor for dementia.

Obesity and lack of physical activity

Poor diet

An unhealthy diet, high in saturated fat, sugar and salt, can increase the risk of developing many illnesses including type 2 diabetes, cardiovascular disease and dementia.

Poor diet

Smoking

Smokers are 45% more likely to develop Alzheimer’s disease compared to non-smokers or ex-smokers.

Smoking

Social isolation

Besides dementia, social isolation can also increase the risk of hypertension, coronary heart disease and depression.

Social isolation

Risk factors you cannot change

Age

Dementia is not a normal part of aging. However, age is the strongest known risk factor for dementia. The older you become, the higher the risk.

Age

One in 20 Canadians over age 65 has Alzheimer’s disease. After 65, the risk of developing Alzheimer’s disease doubles approximately every five years, with one in four Canadians over 85 having Alzheimer’s disease.

While rare, dementia can affect people under 65. This is known as young onset dementia.

Gender

Women have a higher risk of developing Alzheimer’s disease than men. While the reasons for this are still unclear, some of the potential contributors include women living longer on average than men and changes in estrogen levels over a woman’s lifetime.

Gender

For types of dementia other than Alzheimer’s, men and women have the same risk.

For more information on the differences in risk between women and men, watch the webinar on Women and Dementia: Understanding sex/gender differences in the brain. Hosted by brainXchange in partnership with the Alzheimer Society of Canada and the Canadian Consortium of Neurodegeneration in Aging (CCNA).

Genetics

We don’t yet fully understand the role of genes in the development of dementia. We do know that most cases of Alzheimer’s disease are sporadic—they do not run in families. Only rare instances of Alzheimer’s disease are inherited or familial, accounting for 2-5% of all cases.

Genetics

Scientists have found over 20 genes that may increase the risk of developing Alzheimer’s disease. Three of these genes directly cause Alzheimer’s disease: PS1, PS2, and APP.

If a person has an alteration in any of these genes they will almost certainly develop familial Alzheimer’s disease, often well before the age of 65. If a parent has any of these faulty genes, their children have a 50% chance of inheriting the disease.

The other 17 genes associated with Alzheimer’s disease increase the risk, but don’t guarantee that Alzheimer’s disease will develop.

For more information about genetics and Alzheimer’s disease, including genetic testing, read our Understanding Genetics and Alzheimer’s Disease information sheet.


More information and resources


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Last Updated: 01/22/2020