[DigitalToday AI Reporter] The World Health Organization (WHO) issued new guidance saying dementia could be prevented or delayed in up to 45 percent of cases worldwide.

Medical News Today reported on July 17 (local time) that WHO presented evidence-based recommendations in a second edition of its guidance, updating its first advice issued in 2019, to reduce the risk of cognitive decline and dementia.

WHO set out four pillars for dementia prevention: healthy lifestyles; management of existing diseases and biological conditions; addressing environmental risk factors; and tailored combined interventions that manage multiple risk factors together. WHO explained that the number of people living with dementia worldwide has exceeded 57 million, and that the disease burden is growing, especially in low- and middle-income countries.

Healthy lifestyles include cognitive activities, social activities, physical activity, reduced drinking, quitting smoking and a balanced diet. WHO recommended cognitively stimulating activities such as reading, playing musical instruments and board games, and said social interaction could help both adults with normal cognitive function and adults with mild cognitive impairment. It also estimated that about 1 in 4 older people feel socially isolated, and that reducing loneliness could prevent about 5 percent of dementia cases.

Physical activity remained a key recommendation in the guidance. WHO said the longer physical activity is sustained and the higher its intensity, the clearer its effect in reducing the risk of Alzheimer's disease, cognitive decline and dementia overall. It also recommended interventions to help people reduce or stop harmful drinking, and suggested that abstaining from alcohol for 6 to 12 months could be linked to improved cognitive function.

On diet, it did not recommend vitamin B, vitamin E, omega-3, or multivitamin and mineral supplements for people without nutritional deficiencies. It cited insufficient evidence and the possibility of unexpected side effects. Instead, it recommended a balanced diet that includes sufficient essential nutrients.

For managing existing conditions, it identified obesity, type 2 diabetes, high blood pressure, dyslipidaemia and hearing loss as key targets. Hearing loss occurs in about 1 in 5 adults, and if it can be prevented or managed, it could cut global dementia incidence by about 7 percent. WHO also introduced findings from observational studies suggesting that hearing aid use could be linked to reduced dementia risk.

The revised edition added air pollution as a new risk factor. WHO said reducing exposure to outdoor air pollution, including fine particulate matter (PM2.5), and indoor air pollution could lower the risk of cognitive decline and dementia. It judged that evidence is still insufficient to support associations with dementia and cognitive decline for depression, stroke, traumatic brain injury, vision loss, chronic sleep deprivation and HIV.

WHO also newly recommended tailored combined interventions that manage multiple risk factors at the same time based on individual or group characteristics. It is a prevention strategy that manages various risk factors together rather than addressing a single risk factor.