· Lee Chee Cheow, M.Sc. Dip CMP · Cognitive Health · 4 min read
12 Modifiable Risk Factors for Dementia — and How Much Each One Matters
Up to 45% of dementia cases may be linked to factors you can actually influence. Here is the life-stage breakdown, and which risk factors carry the biggest relative risk.
Age and genetics are the two dementia risk factors most people have heard of — and neither can be changed. What gets far less attention is that a substantial share of dementia risk comes from factors that, in principle, can be addressed. According to the 2024 report of the Lancet Standing Commission on dementia prevention, intervention and care, up to 45% of dementia cases could potentially be delayed or prevented by addressing modifiable risk factors.
This builds on the Commission’s influential 2020 report, which first consolidated the evidence into a list of 12 modifiable risk factors spanning early life, midlife and late life. The 2024 update expanded that framework further and raised the overall estimate to 45%. Either way, the core message has not changed: dementia risk is not fixed at birth.
The life-stage breakdown
The Lancet Commission’s model organises modifiable risk factors by the point in life at which they exert their influence, with each factor assigned an individual contribution to overall dementia risk:
| Life stage | Modifiable risk factor | Estimated contribution |
|---|---|---|
| Early life | Less education | 5% |
| Midlife | Hearing loss | 7% |
| Midlife | High LDL cholesterol | 7% |
| Midlife | Depression | 3% |
| Midlife | Traumatic brain injury | 3% |
| Midlife | Physical inactivity | 2% |
| Midlife | Diabetes | 2% |
| Midlife | Smoking | 2% |
| Midlife | Hypertension | 2% |
| Midlife | Obesity | 1% |
| Midlife | Excessive alcohol use | 1% |
| Late life | Social isolation | 5% |
| Late life | Air pollution | 3% |
| Late life | Untreated vision loss | 2% |
Early-life factors contribute around 5% of overall risk, midlife factors add up to roughly 30%, and late-life factors contribute a further 10% — together totalling the headline 45% figure. Two things stand out from this table: hearing loss and high LDL cholesterol are individually the largest single contributors at midlife (7% each), and social isolation is the single largest late-life factor (5%).
Which factors carry the most relative risk?
The life-stage table shows how much each factor contributes to the population-wide dementia burden, but a separate way to look at the evidence is relative risk — how much more likely an individual with a given risk factor is to develop cognitive impairment compared with someone without it. Drawing on the Lancet Commission’s earlier 2020 analysis, the relative risks reported were:
| Risk factor | Relative risk of cognitive impairment |
|---|---|
| Smoking | 1.4 |
| Physical inactivity | 1.4 |
| Obstructive sleep apnoea | 1.45 |
| Diabetes | 1.6 |
| Traumatic brain injury | 1.66 |
| Depression | 1.82 |
| Hearing loss (mild) | 2.0 |
| Hearing loss (moderate) | 3.0 |
| Hypertension (Stage 2) | 3.7 |
| Hypertension (Stage 3) | 8.6 |
The gap here is notable: uncontrolled, severe hypertension carries a relative risk more than six times higher than smoking or physical inactivity. Hearing loss also stands out — its relative risk climbs sharply with severity, from 2.0 for mild loss to 3.0 for moderate loss, which is one reason hearing health has moved from an afterthought to a genuine dementia-prevention priority in recent years.
Why “modifiable” doesn’t mean “easy”
It is worth being honest about what “modifiable” means in practice. Some of these factors — smoking cessation, physical activity, treating hypertension — are within an individual’s direct control with support from a healthcare provider. Others, like educational access in early life or air pollution exposure, are shaped by policy and environment as much as personal choice. The Lancet Commission’s framing is population-level: it estimates how much dementia burden could theoretically shift if these factors were addressed across a whole population, not a guarantee for any one person.
That said, the practical takeaway holds regardless of which factor you focus on: managing blood pressure, protecting your hearing, staying physically active, maintaining social connections, and treating depression are all supported by decades of separate research as good for overall health — and this evidence gives an additional, brain-specific reason to prioritise them.
Frequently asked questions
Does addressing all 12–14 modifiable risk factors guarantee I won’t develop dementia? No. The 45% figure is a population-level estimate of how much dementia risk could theoretically be reduced across a whole population if these factors were fully addressed — it is not a personal guarantee, and non-modifiable factors like age and genetics still play a substantial role.
Which single modifiable risk factor matters most? It depends on how you measure it. By relative risk, severe (Stage 3) hypertension stands out at 8.6 times the risk. By population-level contribution, hearing loss and high LDL cholesterol are the largest individual midlife factors, each estimated at around 7%.
Is it too late to address these risk factors if I’m already over 65? The Lancet Commission’s late-life factors — social isolation, air pollution exposure, and untreated vision loss — are specifically framed as risks that continue to matter well into older age, suggesting it is not simply a “midlife-only” window.
Why did the estimate rise from 12 factors to 45% risk reduction in the 2024 report, compared with earlier reports? The Lancet Commission’s most recent 2024 update expanded its earlier framework and incorporated newer evidence, which increased the overall estimated contribution of modifiable factors compared with the Commission’s 2020 report.
This article is for general information only and does not constitute medical advice. If you are concerned about your personal dementia risk, speak to a doctor about which of these factors are most relevant to your health history.