It’s natural to worry about developing dementia—particularly Alzheimer’s disease, the most common form— especially if it runs in your family. However, the most dominant risk factor for Alzheimer’s disease is age, meaning the risk increases as we get older, regardless of family history.
The good news? Most cases are not directly inherited, and there are proactive steps you can take today to reduce your risk.
Genetics: A Piece of the Puzzle
Most cases of Alzheimer’s disease are not inherited. While genetics play a role, they are not the sole determinant of whether someone will develop Alzheimer’s, and having a parent or grandparent with the condition only slightly increases your odds.
The APOE gene—particularly the APOE4 variant—is associated with higher risk, but it’s not a definitive predictor. Many individuals with APOE4 never develop Alzheimer’s, and conversely, those without it can still be affected.
“In 99% of cases, Alzheimer’s is not caused by the genes received from a person’s parents.” — Professor Nick Fox, Institute of Neurology, London
APOE4 does not cause Alzheimer’s. Instead, it increases the likelihood slightly—for a 50-year-old, the lifetime risk might shift from 1 in 1,000 to 2 in 1,000. And even then, many with this gene never go on to develop the disease. Only about half of people diagnosed with Alzheimer’s have the APOE4 variant.
There are rare exceptions that are clearly inherited, such as Huntington’s disease. This is an autosomal dominant disorder, meaning only one faulty copy of the gene is needed to inherit it.
Some other forms of dementia—such as frontotemporal dementia (FTD)—can be partially inherited. In FTD, about 30–50% of cases are linked to family history.
So what should you do?
Stop worrying—and start being proactive about looking after your brain health and memory. Here’s how:
Building Cognitive Reserve: Your Brain’s Resilience
Cognitive reserve is your brain’s ability to adapt, compensate, and stay functional even as it ages or experiences damage. Enhancing this reserve is one of the best things you can do at any age to delay—or even prevent—the symptoms of dementia.
Ways to build cognitive reserve:
- Engage in lifelong learning: Take up new skills, hobbies, or educational courses.
- Stay socially active: Maintain relationships and participate in your community.
- Challenge your mind: Play strategy games, solve puzzles, read widely, and embrace mental novelty.
Lifestyle Choices: Your Action Plan
Research shows that up to 45% of dementia cases could be prevented or delayed through changes in lifestyle. There are 14 modifiable risk factors but these are the most impactful:
Key strategies include:
- Regular physical activity: Aim for at least 150 minutes of moderate-intensity exercise each week.
- Balanced diet: Follow a diet rich in fruits, vegetables, whole grains, legumes, and healthy fats.
- Quality sleep: Aim for 7–9 hours of restorative sleep each night.
- Mental stimulation: Continuously challenge your brain with new and complex activities.
- Social engagement: Stay connected with friends, family, and support networks.
- Manage chronic conditions: Keep blood pressure, cholesterol, and blood sugar in check.
- Avoid harmful substances: Minimise alcohol intake and avoid smoking.
- Address hearing loss early: Even mild hearing loss can significantly increase dementia risk. Use hearing aids if needed, and get your hearing checked regularly.
The Role of Genetic Testing
Genetic testing for Alzheimer’s, particularly for the APOE gene, is available—but it is not routinely recommended.
As discussed above, the presence of risk genes doesn’t guarantee Alzheimer’s, and the absence doesn’t offer immunity. Moreover, test results can cause unnecessary anxiety without offering clear preventative solutions.
Taking Control: Your Next Steps
While you can’t change your DNA, you can absolutely influence how your brain ages.
By taking action now—adopting healthy habits, staying mentally engaged, and caring for your cognitive wellbeing—you reduce your risk of Alzheimer’s and improve your quality of life at every age.
It’s never too early or too late to make a change.
Your brain is adaptable and resilient – nurture it, and it will serve you well.
✅ Want to take the next step?
Explore our courses, books and resources, created by New Zealand memory experts Dr. Allison Lamont, PhD, and Gillian M. Eadie.
Need more support or resources? We’re here to help—just reach out.
Thank you for answers to questions. I find it very interesting .
I am the youngest of 8 children, my father diagnosed as old age senility, my mother dementia, 1 sister alzheimers, 1 brother lewy body dementia, 1 brother vascular dementia, 1 sister vascular dementia, 1 sister brain tumor, 1 brother cognitive disorder and early time dementia (69, living) and 1 brother killed at 34 years, so the likelihood of me aged 67 must be 99% chance of getting this terrible disease. DO YOU REALLY THINK IT IS NOT GENETIC??????
Thank you for your response and it is natural that you are worried! There is still a lot of research being done in this area, of course, but the current consensus is that having a close relative with the Alzheimer’s disease is NOT evidence of a genetic link. Even people who are influenced by risk factor genes have only a slightly increased risk of developing the disease than the average population.
Here is a summary of what research is telling us.
Researchers at the University of Reading in the UK indicate that the most important gene discovered to date is the Apolipoprotein E (APOE) gene, which is found in chromosome 19. This gene occurs in three forms in humans: types 2, 3 and 4. Every person in the world carries two APOE genes: they can be the same type (2,2; 3,3 or 4,4), or a mixture of two types (2,3; 2,4; 3,4).
What has been found is that people with at least one type 4 and especially those with two, such as 4,4, are at a slightly increased risk of developing Alzheimer’s disease earlier in life than those with the other types of Apolipoprotein E. Only 2% of the population (in the UK) have two type 4 genes. And it seems that less than half of the 2% show increased occurrence of AD.
People with type 2, especially 2,2, appear to be protected against developing Alzheimer’s disease, until much later in life. Researchers do not understand why this is so, and there is much research underway to find out why.
What it all means is that the type of Apolipoprotein a person has is not enough on its own to cause Alzheimer’s disease.
When Alzheimer’s Disease IS Genetic:
Very early onset Alzheimer’s Disease can be caused by a Genetic mutation; that is a permanent change in a gene that can be passed on to children. The rare, early-onset familial form of Alzheimer’s disease is associated with mutations in genes on chromosomes 21, 14, and 1. This condition is very rare indeed, and the families where it occurs are known to the medical profession in most countries. It is known as Familial Alzheimer’s Disease.
Lifestyle factors matter so looking after the basics is important for everyone. Daily exercise, a heart-healthy diet, giving up smoking and plenty of daily mental challenges.
My mother and two of her sisters had dementia. They said one had Alzheimer’s and my mother had dementia. What’s the difference?
Hello, Mary – yes these terms are often used as interchangeable, which they are not. Dementia is the overall term but there are several pathways to dementia – Alzheimer’s Disease being the most common. this article will help you understand the difference more clearly: https://www.brainfit.world/2013/11/03/is-it-dementia-or-alzheimers/
What about somebody who got diagnosed in 2017 at age of 57? Would this person’s child develop it? Neither that parent or child (under age of 30) are proactive…
You may be interested in a free online course that gives you the latest research that is going on. It is a very good course and would help you with the further queries you have. http://www.utas.edu.au/wicking/understanding-dementia It is open to everyone and starts next week (February 19th)
I have three generations of relatives who have all had Alzheimer’s. My Great grandfather, I don’t know many details about him. Then both his children, my Grandmother and her brother both died of Alzheimer’s and now my father (an only child) who had obvious symptoms of Alzheimer’s at 55 and is in late stages now at the age of 70. So my fear is, although I recognize that my family is small, to date 100% of the relatives on my fathers side have gotten it and fairly young. How can I not be worried? How can I get tested for the inherited form?
Dr Allison Lamont replies: ‘I can see how worrying this is for you. It is true that early onset Alzheimer’s has a little bit more of a genetic component, but it is very, very far from inevitable.
There is a lot that is in our own hands, too. The Lancet, a world-respected medical journal published a paper this month making it clear that we can lessen our risk factors for Alzheimer’s by up to 35%. This is by our lifestyle factors: keeping the brain humming along by a variety of brain challenges, moderate exercise, good nutrition, keeping socially engaged, having a positive and interested attitude to everything we do, making sure we have plenty of sleep, and definitely having self-belief that we can make a difference to our own futures. These things are definitely worth doing! As far as genetic testing goes, there isn’t a test that I am aware of that would give you the information you want. Any test will be for the presence of APOE-e4 gene but the results are very difficult to interpret and most specialists don’t recommend it. We can have two copies of the APOE-e4 gene and not develop Alzheimer’s so it can be really confusing. For all of us, we can do everything we can to lessen our risk factors. It is important we look after both our body and our brain.’
My husband aged 77 has Parkinson’s. He worries that he will develop dementia. Many of our friends assume because his mobility has declined that his thinking and memory have as well. But this is not the case at present.
Many people with Parkinson’s have no memory issues at all. In fact, a friend of mine with Parkinson’s has a sharper mind than most of us! Forgetting and other occasional memory lapses happen as we get older – that is quite normal and NOT an indicator of dementia. I only wish more people knew more about the brain! It is really hurtful to be treated differently because of visible mobility changes.