A large international review concluded that around 45% of dementia cases worldwide are associated with risk factors that can, in principle, be modified. The biggest single one in mid-life is untreated hearing loss. That is not a guarantee — you cannot choose not to get dementia, and genetics and age matter enormously. But the idea that nothing can be done is out of date.
If you take one action from this article, get your hearing tested and treat the loss if you have it.
The modifiable risks
Roughly in order of when they matter:
Mid-life (40s–60s):
- Hearing loss — the largest single modifiable factor. Use hearing aids if you need them.
- High LDL cholesterol
- High blood pressure — treating hypertension in mid-life is one of the best-evidenced protections
- Depression — treat it, don’t endure it
- Head injury — helmets, and fall prevention later
- Physical inactivity
- Diabetes
- Smoking
- Obesity
- Excessive alcohol
Later life (65+):
- Social isolation
- Untreated vision loss — get cataracts fixed and glasses updated
- Air pollution
What jumps out is how much overlap there is with cardiovascular risk. Blood pressure, cholesterol, blood sugar, smoking, activity, and weight protect your brain and your heart through the same mechanism — healthy blood vessels. Vascular contribution to dementia is substantial, and the things that keep your arteries healthy keep your brain supplied.
The practical version
Treat your hearing and vision. These are the two most overlooked and among the most actionable. Hearing loss appears to accelerate cognitive decline partly through reduced stimulation and partly through social withdrawal. Hearing aids are not a cosmetic decision.
Control blood pressure. Aim for under 120/80 if that is safe for you. This is the most strongly evidenced pharmacological protection available.
Move. 150 minutes a week of moderate activity, plus strength work. Exercise is associated with lower dementia risk and better cognition, and it also protects against the vascular risks above.
Sleep properly, and get apnoea treated. During deep sleep the brain clears metabolic waste, including amyloid. Chronic short sleep and untreated sleep apnoea are both associated with higher risk. If you snore heavily and wake unrefreshed, get tested.
Stay socially engaged. Isolation is a genuine risk factor, not a soft one. Conversation is cognitively demanding in a way that passive entertainment is not.
Keep learning something difficult. Novelty and challenge matter more than repetition — a new language, an instrument, a craft, bridge. Doing the same crossword every day is pleasant but not the same stimulus.
Eat a Mediterranean-style pattern. Fish, olive oil, vegetables, nuts, whole grains, less processed meat and refined carbohydrate. The MIND diet variant was designed for brain health specifically and has supportive evidence.
Protect your head. Helmets for cycling; fall prevention as you age. Repeated head injury matters.
Do not smoke. Keep alcohol modest. Heavy drinking is directly neurotoxic.
Be sceptical of supplements. No supplement has been shown to prevent dementia. If you have a documented vitamin B12 deficiency, correcting it matters — and we can test for it. Beyond that, the money is better spent on hearing aids and a gym membership.
Normal ageing versus something worth checking
Everyone forgets things. The distinction is about pattern and function, not the occasional lapse.
| Ordinary ageing | Worth an evaluation |
|---|---|
| Forgetting a name and recalling it later | Forgetting the names of close family, or recently met people repeatedly |
| Occasionally misplacing keys | Putting things in illogical places, and being unable to retrace steps |
| Needing a moment to find a word | Frequent difficulty following or joining a conversation |
| Forgetting which day it is, then working it out | Losing track of seasons, or the passage of time |
| Making an occasional bad decision | A pattern of poor judgement, especially with money |
| Sometimes needing help with a new device | Struggling with familiar tasks — a well-known recipe, a familiar route, paying bills |
| Feeling weary of obligations | Withdrawing from work, hobbies, and social life |
| Being irritable when routine is disrupted | Marked changes in mood or personality; new suspicion or fearfulness |
Repeating the same question in one conversation, getting lost in a familiar place, and difficulty managing money are three that particularly warrant assessment.
Why an evaluation is worth having
People delay because they assume nothing can be done. Three reasons that is wrong.
Some causes are reversible. Vitamin B12 deficiency, an underactive thyroid, depression, medication side effects, sleep apnoea, alcohol, infection, and normal-pressure hydrocephalus can all cause cognitive symptoms — and treating them can reverse the problem entirely. That possibility alone justifies the appointment.
Newer treatments need early diagnosis. The anti-amyloid therapies now available for Alzheimer’s disease are only appropriate in early disease, which means finding it early or not at all.
Planning is easier early. Legal and financial arrangements, care preferences, and family conversations are far better handled while someone can fully participate.
An evaluation typically involves a history — often with a family member present, who frequently notices what the patient does not — cognitive testing, blood work, medication review, and sometimes imaging and specialist referral.
For families
Caring for someone with dementia is one of the hardest things people do, and caregiver burnout is a genuine medical issue. Ask us about local resources, respite options, and support groups, and get your own health looked after. The Alzheimer’s Association helpline runs 24 hours a day on 1-800-272-3900 and is genuinely useful, including at 3am.
A note specific to our community: if a relative spends part of the year in Arizona, changes are often noticed by family at the start of the season, after months apart. That observation is valuable clinical information. If you have arrived and thought “something is different,” bring them in rather than waiting to see how the season goes.
Where to go
Book our Medical Clinic for a cognitive assessment, a medication review, blood work to rule out reversible causes, or a hearing referral. Call (602) 671-7981.
Come to our Emergency Room — open 24 hours — for sudden confusion, which is a different matter entirely. Abrupt change in mental state can mean stroke, infection, low blood sugar, dehydration, or a medication problem, and needs assessing now: (602) 671-7990. Sudden confusion is not dementia; dementia develops over months and years.
Related: heart health · healthy ageing and fall prevention · sudden fatigue and weakness
Sources
- Lancet Commission — Dementia prevention, intervention, and care: 2024 report01296-0/fulltext)
- Alzheimer’s Association — 10 early signs and symptoms
- National Institute on Aging — Preventing Alzheimer’s disease: what do we know?
- CDC — Healthy brain initiative