Most people treat dementia like a coin toss. Either it runs in your family or it does not, and all you can do is wait to see which way it lands. It is one of the most common beliefs about the disease, and it is also one of the most mistaken.
An estimated 750,000 Canadians are living with dementia today, and the Alzheimer Society of Canada projects that number will climb toward one million by 2030. Sitting behind those figures is a finding that deserves far more attention than it gets. In 2024, the Lancet Commission on dementia, one of the most respected research groups in the field, concluded that nearly half of dementia cases worldwide could potentially be prevented or delayed by tackling 14 specific dementia risk factors. Not experimental drugs. Not gene editing. Fourteen ordinary things, most of which you can act on at your next doctor's appointment or in your own kitchen. This piece covers what they are, which ones surprise people, and what to do about each at every stage of life.
Is Dementia Hereditary, or Can You Change Your Odds?
The belief that it all comes down to genes is understandable. The first question most families ask is a version of is dementia hereditary, and for a small group the answer is yes. Some rare, early-onset forms are strongly genetic, and those are the dramatic stories that reach the news. Watching a parent or grandparent decline leaves a powerful impression that the same script is waiting for you, and for years doctors had little to offer beyond sympathy.
The far more common story is late-onset dementia, which shows up after 65, where genes are one input among many. Having a parent with Alzheimer's disease, the most common cause of dementia, nudges your risk up, but it is not a verdict. Researchers who followed hundreds of thousands of people for decades kept seeing the same pattern. The health of your heart, ears, eyes, and social life in midlife predicted the health of your brain later on. A family history loads the dice a little, and your daily choices still get to roll them.
Which 14 Modifiable Risk Factors Matter, and Why Do Two Surprise People?
When researchers say modifiable risk factors, they mean contributors you can change, as opposed to fixed ones like age or genes. The Commission's full list spans the whole lifespan: less education in early life, hearing loss, high LDL cholesterol, depression, traumatic brain injury, physical inactivity, diabetes, smoking, high blood pressure, obesity, drinking too much alcohol, social isolation, air pollution, and untreated vision loss. Together, these 14 dementia risk factors account for close to half of cases worldwide.
Some you would expect. Anything that damages blood vessels, such as high blood pressure, diabetes, and smoking, also damages the brain, because your brain runs on a dense network of tiny vessels delivering oxygen and fuel. High blood pressure in midlife is one of the clearest brain risks in the research, which is why it helps to understand what your blood pressure numbers are telling you and treat them if they run high. The two newest entries are the surprises: high LDL cholesterol (the type that furs up arteries) and untreated vision loss, both added in 2024 alongside longstanding factors like hearing loss.
Hearing deserves a moment of its own, because researchers rank it among the largest single contributors. When hearing fades and goes uncorrected, the brain strains to decode ordinary sound, borrowing effort from memory and thinking, and people pull back from conversation and company. That retreat matters, since social isolation is on the list too. Treating hearing loss appears to help, so if a hearing test has lived on your someday list, or a hearing aid has sat in a drawer, that is a good reason to reconsider. Air pollution made the list for a related reason, and new Canadian research on how wildfire smoke can reach the brain, not just the lungs, shows why the air you breathe belongs in a brain-health conversation.
Vision works the same way. Untreated vision loss, including correctable cataracts, is now on the list, most likely because it strains the brain and shrinks a person's world just as hearing loss does.
What Does Lowering Your Dementia Risk Look Like Decade by Decade?
Timing matters, but not in the discouraging way you might fear. The window does not slam shut at 50. Different factors take centre stage at different ages, so there is a way to lower your dementia risk at every one of them.
In your 40s and 50s, the vascular factors lead. Know your blood pressure and treat it if it is high. Know your cholesterol numbers. If you smoke, quitting is still the single best thing you can do for nearly every organ you own, brain included. Keep moving, because physical activity protects the brain directly and keeps blood pressure, blood sugar, and weight in a friendlier range. If a lot of your downtime is spent sitting, the research on what heavy nightly TV watching does to the brain is worth a look.
In your 60s and beyond, the sensory and social factors move front and centre. Get your hearing tested and act on what you learn. Keep up with eye exams and do not postpone cataract surgery if it is recommended. Guard your social life the way you would any prescription, because regular contact with people is genuinely protective. Protect your head as well, since a traumatic brain injury at any age raises risk, and falls are the leading cause of brain injury in older Canadians, so keeping your balance strong and preventing falls is more than a mobility issue. At every age, depression belongs on the list of things to treat rather than tough out, both because it is a risk factor in its own right and because it drags physical activity and social connection down with it.
Can You Really Prevent Dementia by Changing These Things?
It is worth being honest about the limits, because false hope helps no one. Addressing all 14 factors does not prevent dementia with any guarantee, and developing it does not mean you failed at prevention. Plenty of people who did everything right still become ill, and the half of risk that is not modifiable is real. Age itself remains the biggest risk factor, and nobody has a fix for that.
The point is not certainty. The point is odds, and the odds are worth improving. These are the same changes that lower your risk of heart attack, stroke, and diabetes, so the effort is never wasted. If Alzheimer's already runs in your family and you want to know where treatment is heading, the recent news on Alzheimer's drug coverage for people diagnosed early is a useful companion read. And unlike most health advice, much of this list is pleasant: seeing friends, going for walks, fixing your hearing so you can enjoy the conversation, getting cataract surgery so you can read again. Very little of it asks you to give things up.
When Should You Talk to a Doctor About Memory Changes?
If you have not had your blood pressure and cholesterol checked in the past year, that is the easiest first step, and it takes minutes. If you are over 60 and cannot recall your last hearing test or eye exam, book both. And if you are noticing memory changes in yourself or someone you love that go beyond misplacing keys, things like getting lost in familiar places, repeating the same question, or struggling with tasks that used to be automatic, do not sit on it. Early assessment matters, because some causes of memory trouble are treatable and early support changes the whole road ahead.
A quick brain-health check-in
Tick any of these you have not looked at in the past year. Each one is a lever from the 2024 Lancet Commission list, and each is a fair thing to raise with your doctor.
□ Blood pressure (hypertension)
□ Cholesterol (LDL)
□ Blood sugar / diabetes
□ Smoking
□ Alcohol intake
□ Physical activity
□ Weight
□ Hearing
□ Vision / cataracts
□ Mood / depression
□ Social connection
□ Head-injury and falls risk
□ Air quality / pollution
□ Staying mentally active
This is a personal check-in to guide a conversation, not a diagnosis. Based on the 2024 Lancet Commission on dementia.
Frequently Asked Questions About Dementia Risk
What are the main dementia risk factors you can change?
The 2024 Lancet Commission lists 14 dementia risk factors you can influence: hearing loss, high LDL cholesterol, high blood pressure, diabetes, smoking, obesity, physical inactivity, depression, excessive alcohol, social isolation, traumatic brain injury, air pollution, untreated vision loss, and less education early in life. Addressing them could prevent or delay nearly half of cases.
Is dementia inherited from your parents?
Usually not in a direct way. Rare early-onset forms are strongly genetic, but most dementia is late-onset, where a parent's diagnosis raises your risk modestly rather than guaranteeing it. Your blood pressure, hearing, activity, and social life in midlife shape your odds at least as much as family history.
At what age should you start protecting your brain?
Earlier than most people expect, though it is never too late. In your 40s and 50s, focus on blood pressure, cholesterol, not smoking, and staying active. In your 60s and beyond, prioritize hearing, vision, social connection, and protecting your head from falls.
Does treating hearing loss lower dementia risk?
Hearing loss is one of the largest modifiable contributors on the list, and evidence suggests treating it helps. Uncorrected hearing loss makes the brain strain to process sound and pushes people to withdraw socially, which compounds the risk. A hearing test, and using aids if advised, supports both connection and brain health.
Can you prevent dementia completely?
No approach guarantees prevention. Around half of dementia risk is not modifiable, and age remains the biggest factor of all. What you can do is meaningfully shift the odds. The same habits that protect your brain also lower your risk of heart attack, stroke, and diabetes, so the effort pays off regardless.
What memory changes are worth seeing a doctor about?
Occasional forgetfulness is normal. Worth a visit: getting lost in familiar places, repeating questions or stories within a short time, struggling with once-routine tasks, or changes that other people point out. Some causes are treatable, and early assessment opens the door to support, so ask sooner than later.
Where to Start Today
You can use Medimap to find a walk-in clinic near you with short wait times, whether you want your blood pressure checked, a hearing referral, or a first conversation about memory. When it comes to your brain, the best time to act is while everything still feels fine.
If this is a medical emergency, call 911 or go to your nearest emergency department.
This article is for general information only and is not medical advice. It does not replace a conversation with a qualified healthcare provider about your own health.
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