Dementia Risk Factors: What Actually Raises Your Risk

Last updated on September 12th, 2026 at 06:48 am

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 are attributable to “preventable or modifiable risks.” Preventable or modifiable risks aren’t curable or 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.

What Is Dementia?

Dementia is not a disease. It is a generic term for a group of diseases that affect brain cells and their ability to communicate, resulting in deterioration of memory, thinking, reasoning, or the ability to care for oneself. This same terminology can be used to describe Alzheimer’s disease. Still, you would also hear of vascular dementia, frontotemporal dementia, and Lewy body dementia, which all have a different distribution of brain injury.

That distinction matters because not all dementia risk factors affect all dementias equally. 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 dementia risk factor 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 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 (before 65 years) is fairly rare and often tied to particular genetic mutations, while late-onset is much more complex: a complex interplay between aging, genetics, and lifestyle exposure. Lewy body dementia also tends to be late-onset (around 50 years), though it 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 it 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

The APOE gene, particularly APOE-ε4, is the most well-established genetic dementia risk factor in the general population. The National Institute on Aging writes that those carrying ε4 have a demonstrably increased risk of Alzheimer’s; however, having the ε4 allele does not ensure it will manifest. For a deeper technical statistical explanation, the NIA’s Alzheimer’s Disease Genetics Fact Sheet is an excellent primary, free resource. National Institute on Aging

APOE-ε4 is also listed among risk factors for Lewy body dementia. However, consensus is less clear: some studies report a weaker link, and others find 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 also tend to cluster within families, complicating efforts to determine how much risk is inherited and how much is transmitted at family dinner.

Cardiovascular Risk Factors

This cluster includes many modifiable dementia risk factors, and the evidence is strongest here.

• Repeatedly, high blood pressure, particularly midlife hypertension if left 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 in The Lancet, primarily because of its contribution to cerebrovascular disease.
• Heart disease decreases oxygen and blood flow to brain tissue, which has been shown to speed up cognitive decline in certain individuals.
• Stroke is an obvious one, directly destroying brain tissue, and one of the most straightforward dementia risk factors you can get on this whole list. Vascular dementia is frequently precipitated after one or a series of strokes.
• The risk of diabetes and dementia are strongly connected; diabetes is associated with uncontrolled blood sugar, which impacts blood vessels and nerves in a way similar to those found with vascular dementia.

My conclusion after reading a handful of these cardiovascular papers is that the brain is 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. It occurs through long-term influences on blood pressure, body weight, and vascular health rather than through any single, direct pathway.

Smoking

It’s believed that smoking causes damage to blood vessels not only elsewhere in the body, but also in the brain, and that is still one of the more modifiable risk factors for dementia, in that stopping at any age is 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

Consuming an energy-dense diet rich in processed foods and low in fruit and vegetables increases the risk of 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 common explanation is that hearing loss leads to years of less social and cognitive stimulation, plus increased effort by the brain to make sense of distorted signals, all of which Tax the memory system. Using 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 increase dementia risk and are 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 increases 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’s disease 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.
• Similarly to hearing loss, in 2024 vision loss was included in the official modifiable risk list published by The Lancet, where it was associated with lack of stimulation and social withdrawal.

Modifiable vs. Non-Modifiable Dementia Risk Factors

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 result, just not a cure.

How to Lower Your Risk of Dementia

• Regular physical 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 catch this early, avoiding damage to yourself;
• Keep up friendships in the flesh, and remember to reach out and do face-to-face human interactions.
• It is better not to start smoking at all; quitting can still be beneficial for a long time.
• Limit alcohol- more importantly, abstain entirely for the most part.
• Address your hearing and eye health. Hearing aids and higher prescriptions aren’t just quality-of-life issues.
• Get sleep; treat it 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, and 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?

It may be reassuring to discuss memory loss that interferes with routine activities, rather than occasional forgetfulness; rapid changes 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 increases 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.

Is there a lifestyle way to decrease the risks of developing dementia?
Yes. Controlling blood pressure, exercising and eating properly, not smoking, and treating hearing and/or vision problems are all associated with demonstrably lower risk.

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’. 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, mounting evidence shows that poor sleep over an extended period impairs the removal of waste from the brain, such as amyloid.

Is damage from stress causal of dementia?
Chronic stress has not been identified as a direct risk factor for dementia. However, it has been associated with other risk factors, such as hypertension, depression, and inadequate sleep.

He does hear from here [sic], then aging playing a part I as I replied it then task has a time period [sic] to senile dementia too. The thing is, because a lot of time I coming because loss our because of then gamble that risk and and of the time you feeling.
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 significantly reduced. For now, estimates suggest about 40–45% of cases are associated with modifiable factors.

When is the age at risk?
Risk begins increasing noticeably at age 65, approximately doubling every five years thereafter; however, EOAD can emerge before age 65 in some individuals, most often associated with a genetic factor.

karen Anthony

Eric Dalius is a true marketing genius and successful entrepreneur, and he likes to spend time with his wife, Kimberly Dalius.