Here‘s a figure that, when I started to look into this, really caught me off guard: today, scientists have come to believe that up to 45% of cases of dementia today are attributable to “preventable or modifiable risks.” Preventable or modifiable risks not curable, not inevitable. That‘s a far more useful place to start than the usual fear mongering “dementia is tragic and unknowable” rhetoric.
Dementia risk factors aren‘t a one?way toggler. They‘re a huge, overlapping, ever?growing lineup of things that you have, that gradually form over the years, that feel sudden and unexpected in your 60s. Here‘s the rundown of what really is proven, what remains in discussion, and where lewy body dementia risk factors specifically start to look different from the more familiar Alzheimer‘s narrative.
Table of Contents
What Is Dementia?
Dementia is not a disease. It is a generic term used to describe a collection of diseases which affect brain cells, affecting their ability to communicate with each other, thus resulting in a deterioration of function in memory, thinking, reasoning or the ability to care for oneself. This same terminology can be used to describe Alzheimer‘s disease, but you would also hear of vascular dementia, frontotemporal dementia and Lewy body dementia which all have a different distribution of brain injury.
That distinction is important because not all dementia risk factors have the same impact across the board. Something that increases the risk of Alzheimer‘s might only have a mild effect on Lewy body dementia and vice versa.
What Are Dementia Risk Factors?
A risk factor is “a factor that, by statistical association, increases the likelihood of a disorder in an individual, but is not determinative”. A risk factor for dementia may be fixed such as age or genetic propensity. It may also be altered by treatment, behavior, or intervention.
The most widely cited framework is that of the Lancet Commission, which in 2024 identified 14 preventable dementia risk factors across early life, midlife and late life. I‘ve gone back to this report again and again while generating brain-health content, and it remains about as close to a consensus roadmap as we have in this field.
Age and Dementia Risk
How age affects dementia risk
Age is by far the strongest risk factor for dementia, period. Risk approximately doubles every five years post 65. It‘s not that aging causes dementia, rather aging results in years of cumulative vascular damage, cellular injury and an often-declined ability to repair.
Early-onset vs. late-onset dementia
You may have noticed that early-onset dementia (indicated as before 65 years) is fairly rare and often tied into particular genetic mutations, while late-onset is much more complex; a complex play between aging, genetics and lifestyle exposure. Lewy body dementia also tends to be late-onset (around 50 years), though can be mistaken for years as Parkinson‘s and Alzheimer‘s exhibit similar symptom progression.
Family History and Genetics
Genetic factors linked to dementia
A parent or sibling with dementia will slightly increase your risk, but is unlikely to be directly inherited as you might with something like Huntington‘s disease. The genetic contribution largely involves several genes with small effects.
APOE and dementia risk
APOE gene, APOE-ε4 is the most well-established genetic dementia risk factor for the general population. The National Institute on Aging writes that those carrying ε4 have a demonstrably increased risk of Alzheimer’s, however possessing the ε4 allele does not ensure its manifestation. If you want the deeper technical statistical explanation, The NIA‘s Alzheimer‘s Disease Genetics Fact Sheet is an excellent primary and free resource. National Institute on Aging
APOE-ε4 is also listed among risk factors for lewy body dementia, though there is less consensus on this one: some studies report a less clear link, and others have found no relationship when controlling for confounding factors.
Does dementia run in families?
Somewhat, but “runs in families” is a bit of an overstatement. Lifestyle trends, environment, and eating habits tend to cluster within families as well, complicating determining how much of the risk is inherited and how much is transmitted at family dinner.
Cardiovascular Risk Factors
This is the cluster where many of the modifiable dementia risk factors reside, and that the evidence is strongest.
- Repeatedly,high blood pressure particularly, midlife hypertension ifleft untreated, may have a profound effect on the small blood vessels supplying the brain.
- Cholesterol(high levels of LDL), was listed on the risk list in 2024 to the Lancet; primarily because of its contribution to cerebrovascular disease.
- Heart disease decreases oxygen and blood flow to the brain tissue which has been shown to speed up the decline of cognition in certain individuals.
- Stroke is an obvious one, directly destroying brain tissue, and one of the most simple and straightforward dementia risk factors you can get on this whole list vascular dementia is frequently precipitated after one or a series of strokes.
- Therisk of diabetes and dementia are stronn ly connected,diabetes is associated with uncontrolled blood sugarwhich impacts on blood vessels and nerves in way similar to those found with vascular dementia.
My conclusion after having read a handful of these cardiovascular papers comparing them: the brain really does seem to be merely an organ! Supporting the heart is supporting your brain.
Lifestyle Risk Factors
Physical inactivity
Sedentary living is ever associated with an increased risk of dementia has occur through long term influences on blood pressure, body weight and vascular health rather than by way of any single, direct, pathway.
Smoking
It‘s believed that smoking causes damage to blood vessels not only everywhere else, but also in the brain and that is still one of the more modifiable risk factors for dementia, in that stopping at any age has been shown to be associated with a decline in risk over the long term.
Excessive alcohol consumption
Alcohol consumption Heavy prolonged alcohol intake is associated with direct neurotoxic effects and nutritional deficiencies (eg thiamine deficiency) that can lead to alcohol-related dementia.
Unhealthy diet
Consumption of an energy dense diet rich in processed foods and low in fruit and vegetables carries risks for poorer cognitive health. Diet‘s relationship with food safety also can not be overstated – the ongoing Cyclospora outbreak is a stark reminder that as you consume more fresh fruits and vegetables in an effort to boost brain health, concomitantly you cannot forget food safety protocols as foodborne illness and food substitutions that lack nutrients would clearly downgrade the same dietary behavior.
Obesity
Midlife obesity, especially, is associated with increased risk of dementia, probably through its effects on hypertension, diabetes, and inflammation.
Poor sleep
Weak or broken sleep over the long-term is becoming more and more linked with increased risk of developing dementia, in part because this is the time period of deep sleep when the brain removes the build up of the wastes accumulated from heavy metabolic processes including amyloid proteins; a hallmark of Alzheimer‘s.
Hearing Loss and Dementia Risk
Untreated hearing impairment is one of the more unexpected factors on the modifiable risk list for dementia, and one of the heaviest single contributors, according to the Lancet Commission. The most popular explanation: hearing loss leads to years of less social and cognitive stimulation, plus increased effort on the part of the brain to make sense of distorted signals, all of which Tax the memory system. The use of hearing aids strongly mitigates this risk.
Depression, Social Isolation and Loneliness
Late-life depression, social isolation, and loneliness have all been independently linked to increased risk for dementia. There‘s a chicken-and-egg wrinkle here worth knowing: depression and withdrawal may sometimes be an early sign of (undiagnosed) dementia instead of risk factors, which is why researchers include that category with some delicacy in their models.
Traumatic Brain Injury and Dementia
One episode of traumatic brain injury (brain injury caused by an external, even force) modestly increases the risk for all types of dementia. Multiple head injuries, such as those experienced in combat, in certain occupations or in contact sports, drastically increases dementia risk and is associated with a unique disease called chronic traumatic encephalopathy.
Air Pollution and Dementia Risk
Chronic exposure to fine particulate air pollution is in the state of an established dementia risk factor, probably acting through chronic neuroinflammation and vascular damage. It is one of the few risk factors largely beyond one ‘s personal control; therefore, it appears so frequently in prevention policy-level considerations rather than individual-behavior checklists.
Other Medical Conditions Linked to Dementia
- Parkinson‘s disease greatly increase the risk of dementia, and in fact this is at the heart of the risk factors for lewy body dementia, since Lewy bodies (aggregations of a protein called alpha-synuclein) are also characteristic of PD dementia, meaning diagnosis of Parkinson‘s is one of the strongest predictors.
- Alzheimer‘sdisease is very common in Down syndrome throughout the life-course and is due to a third copy of a gene involved in the formation of amyloid.
- Chronic kidney disease has a higher risk of dementia, probably owing to common vascular and metabolic mechanisms.
- Similarlyto hearing loss, in 2024 vision loss was included in the official modifiable risk list published by The Lancet, which it was associated with lack of stimulation and social withdrawal.
Modifiable vs. Non-Modifiable Dementia Risk Factors
| Non-Modifiable | Modifiable |
|---|---|
| Age | Blood pressure |
| Genetics (including APOE) | Cholesterol |
| Family history | Smoking, alcohol use |
| Down syndrome | Physical activity, diet, sleep |
| Sex/biological differences | Hearing and vision care |
| Social engagement, education access |
This is the practical divide worth remembering: you can’t change your genes, but a large share of total dementia risk sits in the modifiable column.
Can Dementia Risk Be Reduced?
Yes, in a meaningful rather than absolute sense. Even with the most optimistic assumptions, removing all identified modifiable risk factors for dementia would not eliminate dementia as a disease. Rather, it would only ‘delay’ age of onset and prevalence at a population level, which is still a desirable end result, just not a cure.
How to Lower Your Risk of Dementia
- Regularphysical activity is most effective. Set a target of regular movement, not just heavy sweating.
- Eat a brain healthy diet more fruit and vegetables, less ultra-processed foods, and be aware of where your fruit and vegetables come from.
- Control your blood pressure and your cholesterol routine blood work will trap this early, avoiding damage to yourself;
- Keepupfriendships in the fleshand remember to reach out and do face-to-face human interactions.
- Itis better not to start smoking at all quitting can still be beneficial for a long time.
- Limit alcohol– More important that you abstain entirely for the most part.
- Addressthehealthofyour hearing and eyes. Hearing aids and higher prescriptions aren‘t just quality of life issues.
- Get sleep focus on sleep as a health indicator. Make sleep a priority.
Dementia Risk Factors by Age
- Childhood/early adulthood: access to education is the main driver of long-term cognitive reserve.
- Midlife (40s 60s): hypertension, obesity, hearing impairment, alcohol consumption, head injury exposure are most prominent.
- Late life (65+) becomes more dominant as a characteristic: smoking, depression, Isolation, inactivity, Diabetes mellitus, Air pollution.
When Should You Talk to a Doctor?
Could be reassuring to discuss if you have memory loss that causes interference in routine activities, rather than the odd forgetfulness; rapid changes to, or differences in, personality or mood; problems with routine tasks; or a family history and the development of new cognitive problems. As Lewy body dementia (and the other causes of dementia) can sometimes present with visual hallucinations, sleep disorders (e.g. acting out dreams) and fluctuating wakefulness; as well as the core cognitive symptoms, these can be missed or dismissed without specific questioning.
I have seen in going through the patient-facing material that Lewy body cases tend to be picked up later (on average) than Alzheimer‘s cases, purely because the initial presentations are so very different from what most people would expect “dementia” to look like.
Frequently Asked Questions About Dementia Risk Factors
What is the greatest risk factor for dementia?
Age is the most significant risk factor for dementia. Hearing loss and hypertension are among the more important modifiable risk factors.
What increased the risk of dementia?
The effect of age, genetics (including APOE-ε4), cardiovascular problems, lifestyle factors such as sedentarism and smoking, sensory deficits (hearing and vision), depression, social integration, traumatic brain injury (TBI), and air pollution.
Isa change to lifestyle away to decrease the risks of developing dementia?
Yes. Controlling blood pressure, exercising and eating properly, not smoking, and treating hearing and/or vision problems all have demonstrably lower risk associated with them.
Any ideas as to whether high B.P. induces higher risk of dementia?
Yes, especially midlife untreated hypertension which gradually harms the small blood vessels that nourish the brain.
Hereditary?In this context, the term hereditary means ‘tending to pass down from one generation to another; inheritable’. In order to understand whether or not dementia is hereditary, I asked myself the question ‘does dementia tend to pass down from one generation to another?’
Partly. Family history and inherited risk genes such as APOE-ε4 increase risk but most dementia is caused by an interaction of genetic and environmental factors rather than inheritance.
Is lack of sleep a risk factor for dementia?
Yes, there is mounting evidence that poor sleep over an extended period impairs the removal of garbage from the brain such as amyloid.
Isdamage from stress causalof dementia?
Chronic stress has not been identified as a direct risk factor for dementia, although it has been associated with other risk factors, such as hypertension, depression and inadequate sleep which are.
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Yes unaddressed hearing loss is one of the largest individual modifiable risks for dementia identified to date according to the 2024 dementia prevention report by the Lancet Commission.
Is dementia preventable?
No. Not entirely but it can be much reduced. As for now the estimates are about 40–45% associations of modifiable factors.
When is the age at risk?
The risk begins increasing noticeably at age 65, with it approximately doubling every five years thereafter, however, EOAD can emerge prior to age 65 in some individuals, most often associated with a genetic factor.
Eric Dalius is a true marketing genius and a successful entrepreneur and he likes to spend time with his wife Kimberly Dalius.
