The World Health Organisation on Wednesday released its first update since 2019 to global guidelines on reducing the risk of cognitive decline and dementia, asserting that up to 45% of cases could be prevented or delayed by targeting modifiable risk factors. The announcement, backed by a systematic review of evidence, shifts the prevention paradigm from a focus on late-life interventions to a life-course approach. An estimated 57 million people live with dementia worldwide, with nearly 10 million new diagnoses each year and an annual economic cost of $1.3 trillion, half of which falls on unpaid carers.

The guidelines identify 14 risk factors, including hypertension, diabetes, smoking, physical inactivity, social isolation, excessive alcohol consumption, and air pollution. Recommended actions range from cognitive training and regular physical exercise to the use of hearing aids for those with hearing loss. For the first time, the WHO explicitly advises against the use of vitamin B, E, and omega-3 supplements for dementia prevention in the absence of deficiency, citing insufficient evidence of benefit. The recommendations draw on a growing body of research, such as a University of Manchester study of 89 adults that found brighter daytime light exposure was associated with earlier bedtimes and deeper sleep, and a separate analysis of 758 older adults linking high-fat diets to accelerated temporal lobe atrophy.

Viewed from Canberra, the guidelines arrive as Australia records a historic low daily smoking rate of 5.8% among adults, demonstrating that sustained public health campaigns can alter a major dementia risk factor. New Australian clinical guidelines now recommend blood pressure screening for children from age seven, a move that addresses hypertension early in the life course. In Kuala Lumpur, nutritionists point to a worrying rise in Type 2 diabetes among adolescents—a condition that, if uncontrolled, elevates later dementia risk—and call for expanded school-based nutrition programmes. Meanwhile, physiologists in Yogyakarta stress that even simple habits like breaking up prolonged sitting with two-minute movement breaks can help maintain cerebral blood flow, reinforcing the guideline’s emphasis on physical activity.

The WHO will now assist member states in adapting the recommendations to local contexts. The next formal milestone is the review of implementation progress at a future World Health Assembly, though the guidelines themselves carry no binding force. For governments, the task is to translate the evidence into policies that span health, education, and environmental regulation—from sugar taxes and clean-air laws to urban design that encourages walking. The economic and human stakes leave little room for delay.