The organization substantially broadens its approach by integrating the environmental, social, and medical determinants of brain health.
Dementia: prevention begins long before the first symptoms
The number of people living with dementia continues to rise worldwide, while no widely accessible curative treatment currently exists that can sustainably alter its course. In response to this reality, the WHO published on July 15, 2026 the second edition of its recommendations dedicated to reducing the risk of cognitive decline and dementia. More than a mere update, this nearly 170-page document offers a refreshed vision of prevention, grounded in the scientific data accumulated since the first edition in 2019.
According to the United Nations agency, up to 45% of dementia risk could be avoided or delayed through interventions targeting modifiable risk factors identified across the lifespan. This estimate, drawn from The Lancet Commission 2024 work and incorporated into the new guidelines, confirms that prevention today is the most promising lever for limiting the progression of this condition, which already affected 57 million people worldwide in 2021, with more than 60% living in low- or middle-income countries, according to the WHO.
One of the major evolutions of these new recommendations is to view dementia as the result of the progressive accumulation of risk factors across the life course. The biological mechanisms leading to cognitive decline can take root decades before the first memory problems appear. This life-course approach leads experts to advocate for early actions, starting in mid-adulthood, or even earlier.
The guidelines now list 17 domains of intervention. Some were already well established, such as physical activity, smoking cessation, limiting alcohol intake, a balanced diet, or controlling hypertension and diabetes. Others appear in this new edition, including air pollution, traumatic brain injuries, strokes, sleep disorders, HIV, or visual impairments. The aim is to provide health professionals with a much more holistic view of the determinants of brain health.
This shift also reflects a change in philosophy. Up to now, the recommendations primarily targeted individual behaviors. Now, the WHO contends that public policies, living conditions, the urban environment, access to care, and social inequalities play an equally determining role in dementia prevention. Dévora Kestel, head of the WHO department of Mental Health, Brain Health and Substance Use, sums up this ambition by stating that these new recommendations constitute “an important step” as they propose “concrete, evidence-based actions to reduce the risk of dementia and promote brain health.”
The WHO broadens dementia risk factors to include the environment
Among the most notable additions is the introduction of specific recommendations concerning air quality. Until now, outdoor air pollution was rarely included in dementia prevention strategies. New scientific data have led the WHO to consider that chronic exposure, particularly to fine particulate matter PM2.5, could contribute to the development of cognitive decline.
The organization therefore recommends reducing exposure to outdoor pollution as much as possible, as well as to indoor air pollution. The authors, however, cautioned that the level of evidence remains weak and that this recommendation is issued with prudence. It nevertheless marks a significant shift: brain health no longer depends solely on individual choices but also on the quality of the environment in which people live.
This logic appears in several other chapters of the report. Experts believe that urban planning policies, transportation, access to spaces that encourage physical activity, the quality of education, the fight against inequality, and the strengthening of health systems are now essential components of any effective dementia strategy. Individual interventions, no matter how relevant, cannot reach their full potential without a favorable environment.
Finally, the WHO highlights so-called “multidomain” approaches. Rather than acting on a single risk factor, professionals are invited to propose personalized interventions that combine several levers simultaneously. A person with hypertension, overweight, physical inactivity, and social isolation can thus benefit from comprehensive care addressing all of these factors rather than treating them separately. This integrated strategy rests on a level of evidence judged to be moderate to high and stands as one of the principal scientific innovations of this new edition of the guidelines.
