Up to 45% of dementia risk is not fixed - the WHO's updated advice, in short

What happened

On 2 September 2026, the World Health Organization published the executive summary of the second edition of its guidelines on reducing the risk of cognitive decline and dementia. It is worth being clear about the timeline. The full guidelines came out on 15 July 2026. What appeared on 2 September is the short version, designed so that busy people can read the main recommendations without working through the whole document. The first edition was published in 2019. A great deal of research has been done since, and the second edition reflects that. The headline figure is that up to 45 per cent of dementia risk is linked to things that can be changed. The WHO lists tobacco, alcohol, social isolation, physical inactivity, air pollution, and long-term conditions such as high blood pressure and diabetes. The second edition adds advice in areas the 2019 version did not cover: sleep, stroke, traumatic brain injury, vision impairment, HIV, and exposure to air pollution. It also does two newer things. It makes recommendations about reducing exposure to environmental risks, rather than only about personal habits. And it recommends tailored multidomain interventions, which means working on several risk factors at once rather than one at a time. The guidelines take a life-course view. They are aimed at adults who do not have dementia, including people with normal thinking and memory and people with mild cognitive impairment.

Why this matters

For a long time, dementia was talked about as something that simply happened to some people and not others. Bad luck, or family history, or age. Age and genes do matter, and nothing here changes that. But the idea that nothing can be done has not been the scientific position for some years now, and this update pushes it further. Up to 45 per cent is a large share. It does not mean 45 per cent of dementia cases can be prevented by individuals making better choices. It means that when you add up all the risk factors that could in principle be changed, across whole populations, they account for up to that proportion of the risk. That distinction matters, because several of the biggest factors are not really personal choices at all. Air pollution is not something you can opt out of. Nor is the quality of the housing you can afford, or whether your area has safe places to walk. That is why the WHO puts so much weight on equity and on what it calls multisectoral action. Some of this is for individuals. A good deal of it is for governments, councils and employers. The practical hope is straightforward. Even delaying the onset of dementia by a few years, across a population, would mean an enormous reduction in the number of people living with it at any one time.

What the evidence actually says

A few points of honesty are needed here. First, "up to 45 per cent" is an upper estimate from modelling, not a promise. It comes from adding up the estimated contribution of many risk factors. Modelling of this kind involves assumptions, and different research groups produce somewhat different numbers. Second, risk reduction is not prevention. Someone can do everything the guidelines suggest and still develop dementia. Someone else can ignore all of it and never develop it. What these recommendations change is the odds, across many people, over many years. Third, the strength of evidence varies a great deal between recommendations. Evidence that treating high blood pressure helps is much stronger than evidence for, say, specific brain-training exercises. Guidelines of this type usually grade each recommendation, and the graded detail sits in the full document rather than the summary. Fourth, most of the underlying research is observational. That means it watches what happens to people over time rather than assigning them to different lifestyles. Observational research is good at spotting associations. It is weaker at proving cause. People who exercise more also tend to differ in many other ways. Fifth, the WHO itself says gaps remain and sets out priorities for future research. That is a sign of a careful document, not a weak one. What is not in doubt is the direction. Hearing loss, high blood pressure, diabetes, smoking, heavy drinking, physical inactivity and social isolation are all associated with higher dementia risk, and all of them are addressable in some measure.

Qurexa perspective

Two of the biggest items on the WHO's list are conditions that are treated with everyday medicines: high blood pressure and diabetes. That is worth sitting with for a moment. Taking your blood pressure tablets as prescribed is not usually described as brain health. According to this evidence, it partly is. The difficulty is that blood pressure medicines make you feel no different. There is no reward for taking them and no immediate punishment for missing them. That is exactly the kind of medicine people drift away from, often without meaning to. Supporting people to keep taking medicines they cannot feel working is a large part of what community pharmacy does, and it is a large part of what we do at Qurexa across Lincolnshire. Repeat deliveries, blister packs where they help, and a person to ask when something is confusing. None of that is dramatic. But if the WHO is right that treating high blood pressure lowers dementia risk, then the unglamorous business of not running out of your tablets is genuinely part of brain health. If you have stopped taking a medicine, or keep forgetting it, speak to a pharmacist rather than saying nothing. There is often a practical fix.

Practical advice

Nothing on this list is exotic. That is rather the point. Keep your blood pressure checked and treated. If you have been prescribed medication for it, take it as directed, and go back to your GP if side effects are bothering you rather than simply stopping. If you have diabetes, keep to your reviews. Good control matters for more than your blood sugar. Get your hearing checked if you are struggling, and use hearing aids if you are offered them. Hearing loss is one of the more strongly linked factors, and untreated hearing loss also drives social isolation, which is itself on the list. Get your eyes tested. Vision impairment is new to this edition. Stop smoking, and keep alcohol within the UK low-risk guideline of no more than 14 units a week, spread over several days. Move regularly. Any activity is better than none, and walking counts. Stay socially connected, and take part in things that make you think: conversation, learning, hobbies, volunteering. Protect your head. Wear a helmet when cycling, and take falls prevention seriously if you are older. Pay attention to sleep. It is newly covered in this edition, and persistent poor sleep is worth mentioning to your GP. And if you are worried about your memory, or someone else's, get it checked. Many causes of memory problems are treatable, including some that have nothing to do with dementia.

What to know

The WHO published a short executive summary of its updated dementia risk-reduction guidelines on 2 September 2026. The full second edition was released on 15 July 2026, and replaces guidance from 2019. Up to 45 per cent of dementia risk is linked to factors that can be changed, including tobacco, alcohol, social isolation, physical inactivity, air pollution, high blood pressure and diabetes. New ground in this edition includes sleep, stroke, traumatic brain injury, vision impairment, HIV and air pollution, plus advice on environmental risks and on tackling several risk factors together. The 45 per cent figure is a modelled upper estimate across whole populations, not a personal guarantee. Risk reduction is not the same as prevention. Many of the strongest actions are ordinary ones: treating blood pressure, managing diabetes, using hearing aids, not smoking, moving more, and staying connected to other people. Some of the biggest factors, such as air quality, are not within any individual's control, which is why the WHO also addresses governments. Sources: World Health Organization, "Risk reduction of cognitive decline and dementia: WHO guidelines: executive summary, 2nd ed.", 2 September 2026, https://www.who.int/publications/i/item/B09867 | World Health Organization, "Risk reduction of cognitive decline and dementia: WHO guidelines, second edition", 15 July 2026, https://www.who.int/publications/i/item/9789240123557 | PAHO/WHO, "New WHO guidelines: up to 45% of dementia risk could be prevented or delayed", 16 July 2026, https://www.paho.org/en/news/16-7-2026-new-who-guidelines-45-dementia-risk-could-be-prevented-or-delayed This article is for general information and does not replace advice from a doctor, pharmacist or other qualified healthcare professional. Do not start or stop any medicine based on this article. If you are worried about memory or thinking changes in yourself or someone else, speak to your GP.