WHO Says Nearly Half of Dementia Cases Could Be Prevented With Lifestyle Changes and Cleaner Air

The World Health Organization (WHO) has released updated global guidelines suggesting that up to 45 per cent of dementia cases could be prevented or delayed by tackling a range of modifiable risk factors. The revised recommendations place greater emphasis on healthy lifestyles, management of chronic diseases and, for the first time, reducing exposure to air pollution as an important strategy for protecting brain health.

Dementia affects more than 57 million people worldwide, with nearly 10 million new cases diagnosed every year. Alzheimer’s disease accounts for around 60 to 70 per cent of these cases. While there is currently no cure, WHO says growing scientific evidence shows that many people can significantly lower their risk by making healthier choices throughout life.

The updated guidance is the first major revision since 2019 and reflects advances in research on brain health. According to WHO, risk factors including smoking, excessive alcohol consumption, physical inactivity, social isolation, high blood pressure, diabetes and high cholesterol all contribute to cognitive decline. The organisation has now added air pollution to this list after emerging evidence linked long term exposure to polluted air with an increased risk of dementia.

The inclusion of air pollution is particularly relevant for rapidly urbanising countries where millions of people are exposed to poor air quality every day. Recent studies have suggested that pollutants such as fine particulate matter may contribute to inflammation, blood vessel damage and changes in brain structure that increase the likelihood of cognitive decline over time.

WHO recommends a combination of practical interventions that support overall health while reducing dementia risk. These include engaging in regular physical activity, following a balanced diet, avoiding tobacco, limiting alcohol intake and staying socially active. Adults are also encouraged to participate in mentally stimulating activities that keep the brain engaged, particularly as they grow older. Effective management of hypertension, diabetes and high cholesterol is equally important, as cardiovascular health is closely linked with brain health.

The guidance also highlights the importance of hearing health. Where clinically appropriate, hearing aids may help lower dementia risk by improving communication and reducing social isolation, which has been identified as another modifiable factor associated with cognitive decline.

One notable recommendation is what WHO advises against. Based on current evidence, the organisation does not recommend routine use of vitamin B supplements, vitamin E, omega 3 fatty acids or multivitamin supplements for dementia prevention in individuals who do not have a diagnosed nutritional deficiency. Researchers found insufficient evidence that these supplements provide meaningful protection against cognitive decline.

The economic impact of dementia continues to grow alongside the ageing global population. WHO estimates that dementia costs the global economy around US$1.3 trillion each year, with approximately half of this burden resulting from unpaid care provided by family members and friends. Delaying the onset of dementia could therefore improve quality of life while reducing healthcare costs and easing pressure on caregivers.

Health experts believe the latest recommendations reinforce a broader message that protecting the brain begins long before old age. Healthy habits adopted during midlife, combined with cleaner environments and effective management of chronic conditions, could help millions of people maintain cognitive health and independence for longer.