Those who want to avoid dementia in later life should "think positive" about growing old, according to new research.
A US study published in journal PLOS ONE has found older people with more positive beliefs about ageing are less likely to develop dementia, even if they are genetically predisposed.
"We found that positive age beliefs can reduce the risk of one of the most established genetic risk factors of dementia," lead researcher Becca Levy at the Yale School of Public Health said.
One of the strongest risk factors for dementia is a variant of the gene APOE, yet many who carry it never develop the condition.
To understand why this might be, the study examined for the first time whether positive age beliefs that are acquired from the culture may reduce the risk of developing the brain disease.
The researchers looked at almost 5000 people with an average age of 72, who did not have dementia when the study began.
Of these, 26 per cent carried a variant of the gene APOE, which has previously been identified as a high risk factor for the debilitating condition.
During the four-year study, researchers found those who carried the gene variant but developed positive ideas about growing old from the culture around them had a 2.7 per cent risk of developing dementia.
Those with who carried the gene variant and felt grumpy about old age had a 6.1 per cent risk.
The study provides evidence that cultural beliefs about age may contribute to the development of dementia in older individuals, the authors wrote.
"This makes a case for implementing a public health campaign against ageism and negative age beliefs," said Ms Levy.
The study comes after earlier research identified the E4 variant of the APOE gene as a high-risk factor for dementia.
Only 47 per cent of APOE E4 carriers develop dementia and Ms Levy says why the other 53 per cent don't remains a mystery that the research hoped to help answer.
