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Iluka Medical Centre

GP Clinic · Iluka WA 6028

Evidence-Based Health Education

Dementia: Separating Myths from Facts

Dementia is one of the most misunderstood conditions in medicine. Here is what the current evidence actually shows about risk, prevention, and why your daily choices matter more than most people think.

Published  11 July 2026
AHPRA & RACGP Compliant
4 peeir-reviewed references
General health information only. This article is educational and is not a substitute for personal medical advice. If you are worried about memory, thinking, or your dementia risk, please speak with your GP for advice tailored to you.

Numbers at a glance

45%[1]

Of dementia cases could potentially be prevented or delayed by addressing 14 modifiable risk factors.

Potentially preventable
60%[3]

Lower risk of Alzheimer’s dementia in people with 4–5 healthy lifestyle factors versus 0–1.

Lower risk
152.8M[2]

People worldwide are projected to be living with dementia by 2050, up from approximately 57 million in 2019.

Rising with ageing
15–20 yrs[1]

Brain changes linked with dementia can begin years before memory or thinking symptoms become noticeable.

Silent early phase

Five Things the Evidence Tells Us

A quick visual summary of the key messages in this guide.

Not
ageing

Not inevitable

Dementia is caused by specific brain diseases, not normal ageing.

45%

Often modifiable

A large share of risk is linked to factors people can influence.

14

Risk factors

Risk can accumulate across early, mid and later life.

Genes
≠ fate

Genes aren’t destiny

Lifestyle can offset part of inherited risk for many people.

Heart
= brain

Heart–brain link

What protects your heart also tends to protect your brain.

Five Common Myths, and What the Science Says

Myth vs fact

Myth Dementia is a normal part of getting older.

Fact Age is the strongest risk factor, but dementia results from diseases that damage the brain. Many people live into their nineties with their thinking abilities intact. [1]

Myth Nothing can be done to reduce dementia risk.

Fact Managing blood pressure, hearing loss, cholesterol, smoking, inactivity and social isolation may reduce or delay a significant proportion of cases.

Myth A family history means dementia is unavoidable.

Fact Genes can affect risk, but most cases are influenced by a combination of age, health, environment and lifestyle.

Myth Dementia always begins with severe memory loss.

Fact Early symptoms can also involve language, planning, judgement, mood, behaviour or visual processing.

Myth Alzheimer’s disease and dementia are the same thing.

Fact Dementia is a general term for symptoms affecting thinking and daily life. Alzheimer’s disease is the most common underlying cause.

Five Common Myths, and What the Science Says

Myth vs Fact
Myth

Dementia is a normal part of getting older.

Fact

Age is the strongest risk factor, but dementia results from specific diseases that damage the brain, most often Alzheimer’s disease (around 50–60% of cases), followed by vascular dementia. Many people live into their 90s with intact thinking. [1]

Myth

Nothing can be done to prevent it.

Fact

The 2024 Lancet Commission estimates that up to 45% of dementia cases could potentially be prevented or delayed by tackling 14 modifiable risk factors. [1]

Myth

Dementia only affects memory.

Fact

Memory loss is common, but dementia also affects judgement, language, visual perception, mood, behaviour and the ability to manage everyday tasks. [1]

Myth

If you carry the “Alzheimer’s gene”, you will definitely get dementia.

Fact

Genes such as APOE ε4 raise risk but do not make dementia certain. In one large study, people at high genetic risk who followed a healthy lifestyle had about a 32% lower risk than those with an unhealthy lifestyle. [4]

Myth

There is already a cure for dementia.

Fact

There is currently no treatment that reverses or stops dementia. Newer anti-amyloid antibodies only modestly slow progression in early Alzheimer’s disease, which is why reducing risk matters. [1]

Quick clarification:

“Dementia” is an umbrella term for a group of symptoms. Alzheimer’s disease is the most common cause of it, not a separate condition. Vascular dementia, Lewy body dementia and frontotemporal dementia are other causes. [1]

It is not only an older person’s condition.

Young-onset dementia, which starts before age 65, is less common but real. In younger people, the first sign is often something other than memory, such as changes in behaviour, language or coordination.

The takeaway:

Dementia is not simply “old age”. It is caused by disease processes, and a meaningful share of the risk is open to change.

What Raises Dementia Risk: The 14 Modifiable Factors

The Evidence

The 2024 Lancet Commission identified 14 risk factors that, if fully addressed across the whole population, are linked to around 45% of dementia cases. The bars below show each factor’s estimated share of preventable risk, known as its population attributable fraction. [1]

Hearing loss (midlife)
7%
High LDL cholesterol
7%
Low education (early life)
5%
Social isolation (later life)
5%
Depression
3%
Traumatic brain injury
3%
Air pollution
3%
Hypertension
2%
Obesity
2%
Physical inactivity
2%
Diabetes
2%
Smoking
2%
Vision loss (untreated)
2%
Excessive alcohol
1%

Bars are scaled to each factor’s estimated share of preventable risk. These are population-level estimates, not individual guarantees. Several factors, including weight, blood pressure and cholesterol, are areas you and your GP can act on.

Worth knowing:

Two factors were added in the 2024 update: high LDL cholesterol and untreated vision loss, based on new large-scale evidence. [1]

Your Heart and Your Brain Are Connected

Cardiovascular Health

Several of the biggest modifiable risks—high blood pressure, high cholesterol, diabetes, smoking and obesity—are the same factors that damage the heart and blood vessels. They appear to raise dementia risk through vascular damage and through effects on the brain’s own disease processes.[1]

This is encouraging, because it means the everyday steps a GP already helps patients with for heart health— managing blood pressure, cholesterol, blood sugar and weight, plausibly support brain health at the same time.[1]

One message, two organs:

Looking after your heart is one of the most practical things you can do for your brain.

What Helps Protect the Brain

Prevention That Has Evidence Behind It

No single habit prevents dementia, and nothing removes risk entirely. But the evidence points consistently to a set of choices that, especially in combination, are linked to lower risk. [1][3]

Protective factor Why it may help Strength of link
Physical activity Supports brain blood flow, plasticity and mood Strong
Mediterranean / MIND-style diet Plant-forward eating linked to slower decline Good
Treating hearing & vision loss Maintains sensory input and social contact Good
Staying socially connected Reduces isolation, a recognised risk factor Moderate
Mentally engaging activity Builds cognitive reserve over life Moderate
Good quality sleep Supports the brain’s overnight waste clearance Emerging
Not smoking Quitting is linked to lower risk over time Strong

The power is in the combination.

People with 4–5 healthy lifestyle factors had a 60% lower risk of Alzheimer’s dementia than those with 0–1, and every extra healthy habit counted.

[3]
The Bottom Line

Dementia is not inevitable, and midlife is a key window.

Genetics matter, but so do the things within your control. Because the underlying brain changes can begin many years before symptoms, the choices you make in your 40s, 50s and 60s carry real weight. [1]

The same habits that protect your heart—staying active, eating well, not smoking, and keeping blood pressure, cholesterol and diabetes in check—also help protect your brain. Add good sleep, treated hearing and vision, and staying socially and mentally engaged. [1][2]

It is never too early, or too late, to start. If you have questions about your own risk, your GP is the right place to begin.

References

  1. Livingston G, Huntley J, Liu KY, et al. Dementia prevention, intervention, and care: 2024 report of the Lancet Standing Commission. Lancet. 2024;404(10452):572–628. doi:10.1016/S0140-6736(24)01296-0
  2. GBD 2019 Dementia Forecasting Collaborators. Estimation of the global prevalence of dementia in 2019 and forecasted prevalence in 2050: an analysis for the Global Burden of Disease Study 2019. Lancet Public Health. 2022;7(2):e105–e125. doi:10.1016/S2468-2667(21)00249-8
  3. Dhana K, Evans DA, Rajan KB, Bennett DA, Morris MC. Healthy lifestyle and the risk of Alzheimer dementia: findings from 2 longitudinal studies. Neurology. 2020;95(4):e374–e383. doi:10.1212/WNL.0000000000009816
  4. Lourida I, Hannon E, Littlejohns TJ, et al. Association of lifestyle and genetic risk with incidence of dementia. JAMA. 2019;322(5):430–437. doi:10.1001/jama.2019.9879
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