9 Habits Quietly Increasing Your Risk of Dementia
And what the research says to do instead
Dementia is one of the fastest-growing health challenges of our time.
By 2050, the number of people living with dementia worldwide is projected to triple to 150 million.
Age and genetics are key risk factors. But research now suggests that almost half of dementia cases could potentially be prevented or delayed through modifiable lifestyle factors.
This is an enormous opportunity that most people don’t know they have.
There is no guaranteed way to prevent dementia entirely. But the evidence behind certain preventative measures is now substantial.
And much of it comes down to ordinary, changeable habits.
Today, we’re covering 9 of the most evidence-backed ones that may be quietly increasing your risk of dementia.
Note: this is the final edition of the Brain Longevity Mini-Series - exploring the strategies that matter most for long-term brain health.
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1. High blood pressure
Midlife hypertension is one of the strongest modifiable risk factors for dementia.
Your brain runs on a dense, delicate network of tiny blood vessels.
Chronically elevated blood pressure - often driven by excess sodium, low physical activity, or stress - damages vessel walls, reduces cerebral blood flow, and disrupts the blood–brain barrier.
Over time, this increases microinfarcts (tiny areas of brain tissue damage) and is associated with increased amyloid accumulation linked to dementia.
2. Hearing loss
Midlife hearing loss is estimated to account for around 9% of dementia cases (as a modifiable risk factor).
When sound input is degraded, the brain has to work harder just to understand speech, which diverts cognitive resources away from memory and thinking.
It also increases social withdrawal, which reduces cognitive stimulation and accelerates decline over time.
If hearing loss is present, getting it tested and using hearing aids is protective - large studies show they likely help reduce dementia risk.
3. Smoking and alcohol
About 14% of Alzheimer’s cases worldwide may be attributable to smoking.
Smokers have a 45% higher risk of developing dementia than non-smokers, with long-term exposure linked to vascular damage, oxidative stress, and neuroinflammation.
Alcohol is more nuanced, but heavy and binge drinking clearly increase risk. Emerging evidence suggests there may be no completely safe level.
4. Poor blood sugar control
Type 2 diabetes - or simply poor blood sugar control over years - is linked to a higher risk of dementia.
Chronically high glucose damages blood vessels throughout the body, including the tiny vessels supplying the brain.
Insulin resistance - often driven by excess body fat, inactivity, and ultra-processed diets - impairs how brain cells use energy and is linked to greater accumulation of proteins associated with Alzheimer’s disease.
5. Persistently short sleep
Regularly getting less than 6 hours of sleep in midlife is linked to around a 30% higher dementia risk compared with getting 7 hours.
Deep sleep helps drive the brain’s glymphatic clearance system, clearing metabolic waste including amyloid-beta proteins associated with Alzheimer’s disease.
It also supports memory consolidation, inflammation control, and vascular health.
6. Letting your social life shrink
Social connection is one of the most cognitively stimulating activities available, recruiting multiple brain networks (language, memory, empathy, executive function) simultaneously, helping build neural resilience against dementia.
Chronic social isolation can increase a person’s risk of dementia by about 60%. It increases stress hormones, inflammation, and is linked to faster brain atrophy in memory regions like the hippocampus.
It really is one of the key pillars of long-term brain health. Aim for at least 3 meaningful interactions (calls, meetups, groups) per week.
7. Uncorrected vision loss
This is a newly recognised modifiable dementia risk factor.
Uncorrected vision impairment is linked with nearly twofold higher odds of cognitive decline.
Reduced sensory input forces the brain to work harder to interpret information and can lead to social withdrawal, accelerating cognitive decline.
Correcting vision (glasses or cataract surgery) appears to be protective in large studies.
8. Poor oral health
There is now a fairly well-established association between gum disease and increased dementia risk.
Chronic gum inflammation allows bacteria and inflammatory molecules to enter the bloodstream and may contribute to neuroinflammation.
Some studies have detected Porphyromonas gingivalis in Alzheimer’s brains.
It’s not 100% understood how oral health influences dementia risk, but maintaining good oral hygiene - through a mostly whole-food, low-refined sugar diet and promptly treating dental issues like cavities and gum disease - is likely protective.
9. Living on ‘cognitive autopilot’
A quiet risk factor: repetitive days with familiar routines and little novelty or mental challenge.
This may limit the amount of cognitive reserve the brain builds, which is its ability to cope with age or disease-related changes before symptoms appear.
Long periods with no demanding hobbies, no new skills, and no complex problem-solving at work or at home can gradually lower that reserve and may make the brain more vulnerable to dementia later in life.
Also of note are other established risk factors, including physical inactivity (covered in previous editions), high intake of ultra-processed foods, traumatic head injury, and air pollution.
Final Thoughts
Aging is inevitable. Cognitive decline isn’t always.
Brain longevity is shaped quietly, over decades. Not by one supplement, one “superfood”, or one good habit - but by the repeated behaviours that influence the brain day after day, year after year.
It’s never too early or too late to take action, with opportunities to make a meaningful impact at every stage of life.
This wraps up the Brain Longevity Mini-Series - for full access to all editions and the complete practical system for long-term brain health, join the paid community today.
Best wishes for the week ahead,
-Ollie
Disclaimer: This post provides educational information based on scientific research and is not medical advice. It does not establish a doctor-patient relationship. Always consult a qualified healthcare professional before making lifestyle changes, addressing medical conditions, or starting new treatments.
What stands out is how closely long-term brain health follows everyday vascular patterns shaped by things like blood pressure, sleep, movement, and staying socially and mentally engaged over time.
So clear and insightful, thank you!