Who is more likely to develop dementia? The 14 risk factors identified by research

Summary — The characteristics of people more likely to develop dementia fall into two groups: factors that cannot be changed, such as age and genes, and factors that can be changed through lifestyle and health care. In its 2024 report, the Lancet Commission on dementia set out 14 modifiable risk factors and estimated that eliminating all of them could, in theory, prevent or delay about 45% of dementia. This article explains each risk factor and when in life it matters.

Risk factors that cannot be changed

The biggest risk factor is age. Dementia rises steeply after 65, which is one reason case numbers keep growing in ageing societies such as Korea and Japan. The second is genetics: the ε4 form of apolipoprotein E (APOE) is the best-known gene raising Alzheimer's risk, and rare familial Alzheimer's disease caused by specific gene variants can begin before 60. Alzheimer's dementia is also more common in women, with women's longer average life expectancy considered an important reason.

Having these factors does not mean dementia is inevitable; recent research agrees that managing the factors that can be changed is important for lowering risk.

The 14 modifiable risk factors

The Lancet Commission set out 12 risk factors in its 2020 report and added high LDL cholesterol and vision loss in 2024, giving 14. The Commission groups them by stage of life.

• Childhood and adolescence — less education. Education and intellectual activity are described as building the brain's 'cognitive reserve', so symptoms appear later even when brain changes occur.
• Midlife (roughly 45–65) — hearing loss, high LDL cholesterol, depression, traumatic brain injury, physical inactivity, diabetes, smoking, hypertension, obesity and excessive alcohol. Hearing loss and high LDL cholesterol were highlighted as having large effects.
• Later life — social isolation, air pollution and vision loss.

Why hearing and vision matter

One explanation is that reduced hearing or vision lowers stimulation reaching the brain, reduces conversation and social activity, and makes the brain spend more resources interpreting sounds or images. The Commission suggested that compensating for sensory loss, for example with hearing aids or cataract treatment, may be a way to reduce risk. These associations come mainly from observational studies, however, and do not mean the same effect for every individual.

Vascular health and dementia

High blood pressure, diabetes, high LDL cholesterol, smoking and obesity can all damage blood vessels in the brain. Damage to small brain vessels not only raises the risk of vascular dementia but is also thought to influence the progression of Alzheimer's disease. Managing blood pressure, glucose and cholesterol in midlife is therefore treated as important for dementia prevention as well.

Risk management recommended by international guidelines

In 2019 the World Health Organization (WHO) published guidelines on reducing the risk of cognitive decline and dementia, recommending regular physical activity, stopping smoking, a balanced diet, reducing harmful drinking, and managing hypertension, diabetes and dyslipidaemia. These are closer to overall health care than to a specific treatment.

Points to keep in mind about risk factors

Risk factors describe a tendency for dementia to be more common across a population; they do not predict an individual's future. Some people with many risk factors never develop dementia, and some with few do. The 45% figure is a theoretical estimate assuming every risk factor disappears completely. If changes in memory or judgement are a concern, an accurate assessment at a medical institution is important.

Relation to stem cell research

Stem cell research in Alzheimer's dementia is currently at an early clinical stage. Managing risk factors is meaningful because it is evidence-based and can be practised now, independent of stem cell research. The state of stem cell research is covered on the 'Alzheimer's Dementia' topic page.

Frequently asked questions

Q. Which risk factors should I tackle first?
International reports highlight midlife hearing loss, high LDL cholesterol and hypertension as high-impact factors. Checking blood pressure, glucose and cholesterol at regular health check-ups and having a hearing test if hearing is a problem can be a starting point.

Q. Do hearing aids prevent dementia?
Many observational studies report less cognitive decline among hearing-aid users. In a randomised trial published in 2023 (ACHIEVE), no difference was found across all participants, while slower cognitive decline was reported in a subgroup at higher cardiovascular risk. Hearing care is also worthwhile for communication and quality of life.

Q. Do puzzles or brain games prevent dementia?
Education and intellectual activity are linked to cognitive reserve, but evidence that specific brain games prevent dementia is limited. A broad range of activities that involve other people and learning new things is more widely recommended.

How to look up clinical trial information

Ongoing and completed clinical trials can be checked on public registries. ClinicalTrials.gov, run by the U.S. National Library of Medicine, and jRCT, run by Japan's Ministry of Health, Labour and Welfare, publish each study's purpose, eligibility criteria, intervention, outcomes, institutions and status. Results are later published as journal papers, and the reference links below this article lead to the original information. It is also worth knowing that interventions not publicly registered are difficult to verify from outside, in both design and results.

The above summarises published papers and public-agency materials. Organisation names are given to identify sources, not to introduce or recommend any medical institution. Individual diagnosis and management are decided by the medical team.

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