There are 14 modifiable risk factors for dementia that researchers have identified as changeable through lifestyle choices, medical treatment, or environmental improvements. According to the landmark 2024 Lancet Commission report, addressing these 14 factors could prevent or delay up to 45% of dementia cases worldwide — a figure revised upward from 40% in their previous 2020 estimate. That means nearly half of all dementia cases are not inevitable. They are, at least in part, products of conditions we can act on.
For someone in their 40s managing untreated high blood pressure, or a retiree who has been putting off getting hearing aids, these are not abstract statistics — they represent real decisions with real neurological consequences. The 14 factors span every stage of adult life, from the quality of education a child receives to whether an older adult is socially isolated. Some are familiar: smoking, obesity, physical inactivity. Two are newly added to the 2024 report: uncorrected vision loss and high LDL cholesterol. This article walks through all 14, explains how each one damages the brain, identifies the strongest risk factors for Americans specifically, and addresses what the research actually says about whether changing these factors makes a meaningful difference at the individual level.
Table of Contents
- Which Modifiable Risk Factors for Dementia Can You Actually Change?
- How Midlife Risk Factors Do the Most Damage to the Brain
- The Two Risk Factors Added to the List in 2024
- Practical Steps to Address the Modifiable Risk Factors
- Social Isolation, Depression, and the Mental Health Dimension
- What the Harvard Research on Shared Risk Factors Adds
- What a 45% Prevention Estimate Actually Means for the Future
- Conclusion
- Frequently Asked Questions
Which Modifiable Risk Factors for Dementia Can You Actually Change?
The 14 modifiable risk factors identified by the 2024 Lancet Commission are organized by life stage because the brain’s vulnerability shifts over time. In early life (ages 0–18), the most impactful factor is low educational attainment — education builds what researchers call “cognitive reserve,” a kind of neural buffer that allows the brain to sustain damage before symptoms emerge. In midlife, factors like hearing loss, hypertension, obesity, smoking, depression, physical inactivity, diabetes, excessive alcohol consumption, and traumatic brain injury carry the greatest overall weight. Later life introduces additional threats: air pollution, social isolation, and the two newly recognized factors — uncorrected vision loss and high LDL cholesterol. What makes these “modifiable” is that they are either preventable or treatable. Hypertension can be brought under control with medication and diet. Smoking can be stopped. Hearing aids can correct hearing loss.
None of these are genetic inevitabilities. Compare this to non-modifiable risk factors like age, family history, or the APOE-e4 genetic variant — those cannot be changed. The distinction matters because it shifts the conversation from prognosis to action. A 50-year-old with elevated blood pressure and untreated hearing difficulty is not simply “at risk” — they are carrying two simultaneous, addressable contributors to future cognitive decline. It is worth noting that not all 14 factors carry equal weight. An analysis of over 600 studies, highlighted by AARP, identified high blood sugar, hearing loss, and low educational attainment as the strongest and most consistent risk factors specifically in the United States. A November 2025 report from AARP and a coalition of research organizations confirmed high blood sugar as the single top modifiable risk factor for American adults. This does not mean the other 12 factors are unimportant — it means the risk landscape has regional patterns, and interventions may need to be prioritized accordingly.
How Midlife Risk Factors Do the Most Damage to the Brain
The Lancet Commission’s analysis found that addressing midlife risk factors — the cluster spanning hearing loss, hypertension, obesity, smoking, depression, physical inactivity, diabetes, alcohol, and TBI — had the greatest overall impact in their modeling. This makes intuitive sense: midlife is when chronic disease tends to take hold, often without symptoms, and the brain is still several decades away from when dementia typically manifests. The lag between exposure and outcome is long, which is both discouraging (damage accumulates silently) and encouraging (there is time to intervene). High blood pressure in midlife is a particularly well-documented driver of brain damage. Chronically elevated pressure stiffens blood vessels and reduces cerebral blood flow, contributing to small vessel disease and white matter lesions — the kind of structural changes that show up on MRI scans years before any cognitive symptoms. Someone who normalizes their blood pressure at 45 through medication, reduced sodium intake, and exercise is potentially protecting hippocampal volume they would not have otherwise kept into their 70s. The window for intervention matters enormously.
Research suggests that treating hypertension in late life, while still beneficial, has a smaller effect on dementia risk than treating it in midlife. However, a critical caveat applies here: these risk factor associations are largely drawn from epidemiological studies, not randomized controlled trials of long-term interventions. A 2025 PubMed study noted that evidence for individual-level interventions reducing cognitive decline is “modest at best” according to the Global Brain Health Institute. Population-level projections showing millions of prevented cases are robust because even small individual risk reductions, applied across hundreds of millions of people, add up. But a single person eliminating multiple risk factors cannot be guaranteed a dementia-free future. Genetics, random biological variation, and factors science has not yet identified all play a role. This is not a reason for fatalism — it is a reason for realistic expectations.
The Two Risk Factors Added to the List in 2024
The 2024 Lancet Commission expanded its list from 12 to 14 by adding uncorrected vision loss and high LDL cholesterol. These additions reflect accumulating evidence that both conditions, when left unaddressed, accelerate neurodegenerative processes through distinct but related mechanisms. Uncorrected vision loss likely damages the brain through pathways similar to hearing loss. When sensory input is degraded or absent, the brain regions that process that input receive less stimulation. Neural networks that are understimulated tend to atrophy over time — a phenomenon sometimes described as “use it or lose it” at the cellular level.
There is also a social component: people who cannot see or hear well tend to withdraw from complex social and cognitive activities, compounding the isolation that is itself a separate risk factor. A concrete example: an older adult who can no longer read comfortably without glasses they do not have, who stops attending book clubs and evening events because navigating unfamiliar environments feels difficult, is experiencing a cascade of risk factor accumulation that began with an uncorrected prescription. High LDL cholesterol joins the list based on evidence linking elevated low-density lipoprotein to amyloid plaque accumulation and vascular disease in the brain. LDL contributes to atherosclerosis in cerebral blood vessels, reducing oxygen delivery to brain tissue. The connection is particularly relevant given that statins — widely prescribed cholesterol-lowering medications — have been studied for their potential neuroprotective effects, though research on statins and dementia prevention specifically remains ongoing and does not yet support prescribing them solely for that purpose. Still, the fact that elevated LDL is now formally recognized as a modifiable dementia risk factor gives additional weight to existing cardiovascular guidelines about cholesterol management.
Practical Steps to Address the Modifiable Risk Factors
Addressing 14 different risk factors simultaneously is not realistic for most people. The evidence suggests prioritizing the factors with the strongest associations and the most accessible interventions. For American adults specifically, this means focusing first on blood sugar control, hearing health, and — where relevant — educational engagement for younger family members. A practical starting point is a metabolic panel at an annual physical to identify prediabetes or elevated LDL, combined with a hearing evaluation if there are any signs of difficulty following conversation or reliance on closed captions. Physical inactivity and obesity are worth addressing together because exercise addresses both simultaneously and also independently reduces depression risk — meaning a single intervention can move three factors at once. The comparison matters: medication can control hypertension, diabetes, and cholesterol, but only physical activity reduces all three while also improving mood, sleep quality, and social engagement.
This does not mean medication is inferior — for many people, it is essential — but the risk factor framework makes visible how lifestyle changes can be unusually leveraged interventions with broad-spectrum effects. Aerobic exercise specifically has the strongest evidence base for cognitive benefit; 150 minutes per week of moderate-intensity activity is the threshold most guidelines cite. The tradeoff worth acknowledging is that behavioral change is far harder than pharmacological management for most people. Telling a sedentary, overweight, socially isolated 60-year-old to exercise more, eat less, and make new friends is not a medical plan — it is a wish list. Public health researchers have increasingly emphasized structural interventions: walkable neighborhoods, subsidized hearing aids, clean air regulations, and accessible mental health treatment. Air pollution, notably, is listed as a later-life risk factor that the individual cannot meaningfully address through personal behavior alone. Living near a highway or in a city with chronically poor air quality is a dementia risk factor that requires policy solutions, not just personal ones.
Social Isolation, Depression, and the Mental Health Dimension
Depression and social isolation appear on the Lancet Commission’s list as distinct factors, but they interact heavily in practice. Depression is one of the most underrecognized dementia risk factors because it is both a prodromal symptom of dementia — meaning it can appear years before cognitive decline — and an independent causal contributor. The directionality is genuinely difficult to untangle at the individual level. What is clearer is that treating depression reduces neuroinflammatory signaling and restores behavioral engagement in ways that are neurologically protective, regardless of which came first. Social isolation is more significant in later life, according to the Lancet Commission’s life-stage framework. This is when people retire, when spouses and close friends die, when mobility decreases and spontaneous social contact becomes rare. Cognitive stimulation derived from conversation, shared problem-solving, and navigating social expectations is substantial — and its absence is measurable in longitudinal brain imaging studies.
Older adults who maintain regular social contact show slower rates of hippocampal atrophy than those who do not. One example: a 2024 analysis found that widowhood, when not followed by new social connection, is associated with a significantly elevated dementia risk — not primarily because of grief, but because of the structural loss of a daily conversational partner and joint decision-making relationship. A warning about the evidence here: the fact that social isolation is a modifiable risk factor has sometimes been overcommunicated as a simple fix (“join a club, prevent dementia”). The reality is more complicated. Not all social contact is equally cognitively stimulating. Passive contact — watching others socialize, attending events without genuine participation — does not produce the same neurological benefits as engaged, reciprocal interaction. Quality matters more than quantity, and forced social programming for older adults in institutional settings has not consistently shown cognitive benefits in clinical trials. The goal is meaningful engagement, which is harder to prescribe than attendance.
What the Harvard Research on Shared Risk Factors Adds
In April 2025, Harvard researchers published findings identifying 17 risk factors shared across dementia, stroke, and late-life depression — three conditions that have long been studied separately but that share substantial neurological overlap. The addition of stroke and late-life depression to the shared risk factor model matters because it suggests that interventions targeting cerebrovascular health protect against multiple forms of cognitive and mental decline, not just dementia specifically. Hypertension, diabetes, obesity, smoking, and physical inactivity all appear on the shared list, reinforcing that the cardiovascular-brain health connection is one of the most durable findings in neuroscience research.
For people making decisions about their health priorities, this convergence is practically useful. Managing blood pressure does not just reduce dementia risk — it reduces stroke risk, which is also a major cause of cognitive impairment, and it reduces the risk of the kind of late-life depression that further accelerates brain aging. These are not competing priorities. They are the same intervention producing overlapping benefits.
What a 45% Prevention Estimate Actually Means for the Future
The statistic that up to 45% of dementia cases could be prevented or delayed is striking, but it is a population-level projection based on theoretical complete elimination of all 14 risk factors globally. No country or population has achieved anything close to that. Still, the estimate is directionally important: it establishes that dementia is substantially a disease of modifiable conditions, not an inevitable consequence of aging. That framing has driven major shifts in dementia research funding and public health policy over the past decade.
Looking forward, Harvard’s identification of 17 shared risk factors, the Lancet’s expanded list, and the November 2025 AARP coalition report all point toward a maturing scientific consensus: the brain is vulnerable to chronic disease, sensory deprivation, social circumstance, and environmental exposure in ways that are addressable. Research on interventions — particularly multimodal approaches combining exercise, cognitive training, diet, and cardiovascular management — is ongoing, and results from large trials in Finland, France, and Australia are expected to refine individual-level recommendations over the coming years. The science is not finished. But the direction is clear.
Conclusion
Dementia is not fully preventable, and no one who addresses every modifiable risk factor can be guaranteed cognitive health in old age. But the 14 factors identified by the 2024 Lancet Commission — from low education in childhood to uncorrected vision loss in older age — collectively account for nearly half of all dementia cases worldwide.
That figure represents an extraordinary opportunity for individuals and health systems alike. The strongest individual interventions, based on current evidence, involve controlling blood sugar and blood pressure, correcting hearing and vision loss, staying physically active, avoiding smoking and excessive alcohol, and maintaining meaningful social connection. The most honest framing of this research is not “do these things and you won’t get dementia.” It is “these things shift probabilities in measurable ways, and the cumulative effect of shifting probabilities across millions of people is enormous.” For anyone with a family history of dementia or a current diagnosis of prediabetes, hypertension, hearing loss, or depression, the 2024 Lancet report is not just a scientific document — it is a list of doors that are still open.
Frequently Asked Questions
Is it too late to address these risk factors if I’m already in my 60s or 70s?
No. While midlife interventions appear to have the greatest impact, the Lancet Commission’s framework includes later-life factors specifically because addressing them in older age still reduces risk. Treating hearing loss, managing blood pressure, reducing social isolation, and correcting vision loss all remain relevant in later life.
Which modifiable risk factor is the most important to address?
In the United States, high blood sugar has been identified as the single strongest modifiable risk factor by both AARP research and a November 2025 coalition report. Globally, hearing loss and low educational attainment also rank among the most impactful. The relative weight depends on individual circumstances — someone who smokes heavily and is physically inactive may gain more from addressing those factors first.
Does treating depression reduce dementia risk, or is depression just an early symptom?
Both are true, and that makes it complicated. Depression can be an early symptom of neurodegeneration, but it also appears to independently accelerate cognitive decline through neuroinflammatory pathways. Treating depression is warranted regardless of which came first, and there is evidence that effective treatment reduces dementia risk separate from any diagnostic question.
Is air pollution really something an individual can address as a dementia risk factor?
Not meaningfully at the individual level. Air pollution is primarily a structural and policy problem. While personal choices like air purifiers or avoiding outdoor exercise during high-pollution days may offer marginal benefit, this risk factor requires regulatory and environmental intervention to address at scale.
What are the two newly added risk factors in the 2024 Lancet report?
Uncorrected vision loss and high LDL cholesterol were added to the Lancet Commission’s list in 2024, expanding it from 12 to 14 modifiable risk factors.
If I eliminate all 14 risk factors, will I definitely avoid dementia?
No. The 45% prevention estimate is a population-level projection assuming complete elimination of all factors — a theoretical scenario. At the individual level, genetics, unknown biological variables, and factors not yet identified by science all play a role. The evidence suggests that addressing modifiable factors shifts probabilities meaningfully, but cannot guarantee outcomes.
