Part 1: What is my baseline risk of dementia?
September 7 2024 | Last Updated: Feb 4 2025
This content is provided for general education and information only. It does not provide individualized medical advice, diagnosis, or treatment, and does not establish a doctor–patient relationship. Always seek the advice of your own physician or qualified healthcare provider regarding personal medical decisions.
Table of Contents
We all have a unique situation when it comes to our brain health.
Where your situation sits is dependent on two things:
Baseline risk — your starting point for dementia risk
Lifestyle-related risk — the part that can shift brain health over time
In this article, we’ll focus on baseline risk, not to predict your future, but to help you understand yourself more fully. Risk is only ever an estimate, not an outcome.
In Part 2, we talk about lifestyle factors that can influence long term brain health.
What is your starting point - or baseline - for brain health?
What does “baseline risk” really mean?
Baseline risk is simply a starting estimate, based on things that are largely outside your control including your:
Age
Family history / genetics
Gender
Environment
Looking at large populations over time, the average lifetime chance of developing dementia is estimated to be around 1 in 10 people (or 10%).
This means that across a group of 100 people, roughly 10 will develop dementia at some point during their lifetime - and 90 will not! - before considering lifestyle-related factors.
Your age, gender, and family history are linked to your risk of dementia.
1.Age
As people get older, dementia becomes more common.
When you’re 60, the chances of you having dementia is very low — only about 1-2%. When you’re in your 90’s, that number goes up to 30-40%.
That might sound like a scary number, but there’s good news: age itself does not cause dementia.
Saying dementia risk goes up with age is over simplified – it’s not age that’s necessarily doing the damage, it’s all those years of daily habits that catch up to us the longer we live.
The association with age likely has more to do with the accumulation of other diseases and lifestyle factors (like the Aldora 18) over a lifetime, which themselves lead to dementia, rather than age being a direct cause itself.
Or in other words, think of dementia like a tree falling in a forest. While older trees are more likely to fall, it's not because the tree's age alone causes it to collapse. Instead, it’s the storms and other environmental factors that weaken the tree over time. There are trees standing for 1000s of years while other trees fall after only a few hundred.
Similarly, as we age, it’s not just the years themselves that cause dementia, but the accumulation of health challenges - like high blood pressure, poor diet, or lack of exercise - over the course of a lifetime that can eventually lead to disease.
If you prevent storms (health conditions) from weakening your tree (body), you’ll have a good chance aging with independence and staving off symptoms of disease.
Read this for more on age vs time as the cause of disease.
The science is clear. Dementia is NOT an inevitable part of aging.
2. Family History / Genetics
Family history influences dementia risk in two very different ways:
Genetics (what you inherit)
Habits (the patterns you learn
We’ll briefly summarize genetics here again, or refer back to this article for a more detailed discussion.
1) GENETICS
A) One of the most well-studied genetic risk factors for dementia is a gene called APOE ε4.
This is because APOE ε4 is believed to cause more beta-amyloid and tau proteins to build up in the brain than in people without this gene (read this for what beta-amyloid and tau have to do with dementia).
The impact?
One APOE ε4 allele: Increases lifetime risk by 2-3 times.
Two APOE ε4 alleles: Increases lifetime risk by 8-12 times.
In practical terms, having one APOE4 gene turns your lifetime risk of dementia into about 25%.
However, many people with APOE ε4 never develop dementia.
The gene increases susceptibility - it does not determine your future. Lifestyle continues to play a meaningful role even with genetic risk.
Understanding genetics isn’t about predicting outcomes.
It’s about understanding where extra support helps most. Read more here.
B) In only 1% of people who develop Alzheimer’s dementia the disease is caused by 3 special genes (APP, PSEN1, and PSEN2).
The chances of developing dementia before age 65 with these genes is unfortunately almost 100%, although some people with the genes have not developed dementia until later in life. This type of genetic link is extremely rare.
We discuss what to do in this scenario in this article.
Certain genes can make us more susceptible to the build-up of dementia proteins in the brain, but it’s not a guarantee.
2) FAMILY HABITS
For most of us with a family history of dementia, it is our shared habits, not genes, that are responsible.
If you and your family don’t have the APOE4 gene but a lot of people in your family have gotten dementia later in life (meaning after the age of 65), this often is not actually related to unchangeable genes.
Families tend to share patterns across generations around diet, physical activity, sleep, stress, depression, etc. They may also share broader influences such as education, income, neighborhood safety, and access to healthy food. Over decades, these shared factors can shape health in very similar ways.
If we continue these same habits our risk roughly doubles, to about a 20% lifetime risk.
The good news is this kind of family pattern can be changed.
Think of it like copying the same diagram over and over again – if we use the same pencils, the picture will look pretty similar every time. If we change the tools we’re using, we can change the design.
Through a combination of socioeconomic advocacy and personal lifestyle habits it is in our control to avoid the preventable diseases that our parents encountered during their lifetimes.
The environment in which we live and the habits we pick up from our parents can increase our risk for dementia - which is often in our power to change.
3. Gender
Women are at higher risk of dementia than men.
The risk of having dementia at age 90 is closer to 40% for women vs 30% for men.
The reason women have a higher risk is likely from a few things, including the fact that women
Tend to live longer (hence more women make it into that 90 age-bracket with higher dementia risk)
Have hormonal changes after menopause with the loss of estrogen,
Have historically had less education than men until more recent generations (with low education being one of those “lifestyle” risk factors).
Tend to be caregivers for others, leading to increased stress (another lifestyle factor).
This list highlights that even when it comes to gender risk, there are aspects that can be traced back to modifiable daily habits.
Supporting sleep, stress recovery, education, movement, and self-care helps women remain strong, capable, and independent well into later life.
As women move into roles with more power and education, we may see dementia risk equalize with men.
4. Environment
Your environment plays a role in shaping your baseline risk for dementia, often in ways we don’t even realize.
“Environment” means both your physical surroundings and your broader social conditions, including:
where you live,
your exposure to air pollution,
access to education and healthcare,
your neighbourhood safety,
the foods available to you, and
the social networks you’re a part of.
Studies show that people who live in areas with higher levels of air pollution, fewer green spaces, or limited access to healthy foods have higher rates of cognitive decline and dementia later in life.
For example, chronic exposure to air pollutants can lead to inflammation in the brain and blood vessel damage, accounting for 3% of dementia cases in the world (read the research here).
The good news? Environmental influence on dementia risk is also modifiable. Public health efforts that reduce pollution, improve neighbourhood walkability, increase access to education and healthcare, and foster strong community ties can lower a whole community’s dementia rates.
On a personal level, even if you grew up in a challenging environment, creating a new one for yourself as an adult can provide major benefits.
Think of environment like the soil a tree grows in: better soil leads to a stronger, longer-lived tree. It’s possible to bring in new resources to nourish it at any time.
Where we live can have a role in our exposure to air pollution and other lifestyle factors.
Putting it all together
Your baseline risk is just a prediction. It’s not set in stone.
For everything that goes into your baseline risk - age, family history/genetics, gender, and environment - only genetics is truly outside our control. The others are heavily linked to the accumulation of modifiable lifestyle factors.
In general:
No family history → baseline risk ~10%
Family history or one APOE ε4 → ~20%
Two APOE ε4 copies → higher, but still modifiable
Research now shows that at least 50% of all dementia cases in Canada could be prevented, mostly through lifestyle changes (and this number keeps going up every few years).
Compare this to the fact that only about 7% of dementia cases in the world come from the APOE4 gene.
This means that you risk of dementia is SIGNIFICANTLY in your control.
You have so much power. Aldora will show you how to wield it.
Ready for Part 2?
More Like This…
Key References
Livingston G et al. Dementia prevention, intervention, and care: 2024 report of the Lancet standing Commission. The Lancet, 2024; 404:572 - 628.
Son S, Speechley M, Kivipelto M, et al. Potentially Modifiable Dementia Risk Factors in Canada: An Analysis of Canadian Longitudinal Study on Aging with a Multi-Country Comparison. J Prev Alz Dis 2024; 5(11):1490-1499.
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Aldora Health was founded by a Canadian physician specializing in cognitive health and dementia prevention. Content is informed by clinical experience, large population studies, and current prevention research, and is designed to support informed, thoughtful health decisions over time.
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