The World Health Organization (WHO) has launched its first ever guidelines on how people can help avoid getting dementia. It looked at the evidence of what works and what doesn’t for lowering risk. Things to avoid include smoking and drinking too much alcohol.While eating a healthy diet is beneficial, popping vitamin pills makes no difference to dementia risk, it advises.

There is no good evidence that brain training works but some studies suggest it may be worthwhile, says the WHO.

Dementia affects around 50 million people around the world and is becoming more common.While there is no treatment that can cure it, there are things people can do to lower their risk of the disease or slow its onset. Old age is the strongest risk factor, but it is not a natural or inevitable consequence of ageing.Genetics also play a role, but many risk factors are modifiable.

Experts have previously suggested lifestyle changes could prevent around a third of dementia cases.