Healthy living may cut dementia risk for older people by more than 22 per cent

The prevalence of brain diseases such as Alzheimer’s has fallen by more than 22 per cent in 20 years, possibly because of healthier lifestyles and better education.

About 850,000 Britons have dementia but the new research, funded by the Medical Research Council, suggests the number could be as much as 300,000 higher if not for the dip in prevalence.
The Cambridge University study looked at the prevalence of dementia two decades ago, finding it affected 8.3 per cent of over-65s. However, when the researchers looked at people in that age bracket now, they found it had fallen to 6.5 per cent – a 22 per cent decline.

“Such reductions could be the outcomes from earlier population-level investments such as improved education and living conditions, and better prevention and treatment of vascular and chronic conditions,” said research leader Carol Brayne.

Brayne concluded the same trend was emerging across Europe: “In a review of dementia occurrence in five studies … we found none that supported headlines about dramatic increases in dementia. They report stable or reduced prevalence – despite ageing populations.”

Dementia has several different causes, with Alzheimer’s triggering 62 per cent of cases, and vascular dementia, which is caused by restriction in the brain’s blood supply, accounting for 17 per cent.

Ten per cent of sufferers have both conditions while the other 11 per cent are caused by rarer diseases.

Rates of smoking, a major risk factor, have more than halved since 1974, and the prevention and treatment of high blood pressure and cholesterol, which also increase the risk of dementia, have improved.

Dr Matthew Norton, head of policy at Alzheimer’s Research UK, said: “Although the proportion of older people with dementia has not increased according to these studies, age is the biggest known risk factor for dementia and with an ageing population in the UK, current estimates show the overall number of people with dementia is still projected to rise.

“Encouragingly, this research suggests that healthier behaviours may have helped reduce dementia risk in later-born generations.

“Current trends in risk factors such as obesity and diabetes mean we should not be complacent, but measures to help people adopt healthy lifestyles now could have a real impact on the numbers of people living with dementia in the future.”