NEW DELHI: WHO has issued new global guidelines saying up to 45% of dementia cases could be prevented or delayed by tackling risk factors such as high blood pressure, diabetes, smoking, physical inactivity and, for the first time, air pollution, while advising against the routine use of vitamin and omega-3 supplements for dementia prevention in people without a diagnosed deficiency.The updated recommendations, the first major revision since 2019, reflect growing scientific evidence that lifestyle choices, management of chronic diseases and environmental exposures can significantly influence brain health. The inclusion of air pollution marks a key addition to WHO’s dementia prevention guidance, reflecting mounting evidence linking long-term exposure to polluted air with cognitive decline.Dementia is a progressive brain disorder that impairs memory, thinking and the ability to perform everyday activities. Alzheimer’s disease accounts for an estimated 60-70% of all dementia cases. Although there is no cure, WHO says a substantial proportion of the risk can be reduced through healthier lifestyles and better management of chronic diseases.The recommendations are particularly relevant for India, where the burden of dementia is expected to rise as the population ages. A nationally representative study published in the peer-reviewed journal Alzheimer’s & Dementia estimated that about 8.8 million Indians aged 60 years and above are living with dementia, based on a prevalence of 7.4% among older adults.The WHO guidelines on air pollution are supported by a growing body of evidence. The 2024 Lancet Commission on Dementia Prevention, Intervention and Care identified air pollution as one of 14 modifiable risk factors that together could account for up to 45% of dementia cases, while a 2024 study in BMJ Public Health identified both outdoor and indoor air pollution as important dementia risk factors in the Indian population.Globally, more than 57 million people live with dementia and nearly 10 million new cases are diagnosed every year.The guidelines recommend regular physical activity, quitting tobacco, limiting alcohol consumption, adopting a healthy diet, maintaining social engagement and cognitive stimulation, along with effective management of high blood pressure, diabetes and high cholesterol. The use of hearing aids, where clinically indicated, may also help reduce dementia risk.“We know more today than ever before about what drives dementia risk, and these guidelines translate that knowledge into action,” WHO director general Dr Tedros Adhanom Ghebreyesus said. “Countries now have clear, evidence-based recommendations they can put into practice immediately to protect people’s cognitive health.”WHO also advises against routine supplementation with vitamins B or E, omega-3 fatty acids or multivitamin-mineral preparations to prevent dementia in people without a diagnosed deficiency, citing insufficient evidence of benefit.Dementia also imposes a heavy economic burden. WHO estimates the disease costs the global economy about $1.3 trillion annually, with around half of that burden borne through unpaid care provided by family members and friends.