Staying optimistic can reduce your risk of dementia, researchers say

The Harvard researchers found that those with a more sanguine outlook had a 15 per cent lower risk of developing dementia after adjusting for age, sex, race, ethnicity, education, depression and other major health conditions.

The team sought to account for reverse causality - the possibility that indications of or worries about dementia onset could understandably leave even a usually cheerful person feeling down and in turn exacerbate cognitive decline.

The researchers conceded that it is "not clear exactly" how the findings can be used as part of "future dementia prevention initiatives", recommending future research into the matter given the dearth of "effective treatments" for the condition, which affects an estimated 57 million people worldwide.

Previously published research suggests a link between depression and dementia, while other work found that people who reported loneliness while young were more likely than others to face the dread-inducing prospect of developing Alzheimer’s disease as ageing takes hold.