Frail people carry a higher risk of developing dementia than their healthier counterparts, a large-scale study has shown.
More than 196,000 adults aged over 60 were analysed by researchers who took into account factors including genetic risk, frailty score and healthy lifestyle behaviours.
Over a 10-year, some 1,762 participants who were diagnosed with dementia were found to have a high degree of frailty compared to those who did not develop the syndrome.
People who were frail and also genetically at risk of dementia were found to be six times more likely to have a diagnosis than their counterparts without either risk factor.
Common indicators of frailty include weakness, weight loss, exhaustion, low physical activity and slow movements.
The team comprising experts from Dalhousie University and Nova Scotia Health in Canada and the University of Exeter in the UK worked with data from thousands of elderly adults in the UK Biobank, a giant biomedical database and research source.
Dr David Ward, lead author of the study published in the Journal of Neurology, Neurosurgery and Psychiatry, said the findings represented a “major step” in how health professionals understand dementia.
“We’re seeing increasing evidence that taking meaningful action during life can significantly reduce dementia risk,” said Dr Ward, who works at the Division of Geriatric Medicine at Dalhousie University.
“Our research is a major step forward in understanding how reducing frailty could help to dramatically improve a person’s chances of avoiding dementia, regardless of their genetic predisposition to the condition.
“This is exciting because we believe that some of the underlying causes of frailty are in themselves preventable.
“In our study, this looked to be possible partly through engaging in healthy lifestyle behaviours.”
Using hospital admission records of older patients, researchers highlighted the importance of healthy habits with their examination of the impact of genetic risk in people with different degrees of frailty.
While genetic risk factors exerted their expected effect on risk of dementia in participants who were healthy, genes were noticeably less important in those who were the frailest.
Frail men and women were found to carry a high risk of dementia regardless of their genetic make-up.
Among those who were genetically at high risk of dementia, experts found that if a person was in poor health they were more likely to have a diagnosis.
When frailty was combined with a high genetic risk it proved to be particularly detrimental, with participants six times more likely to develop dementia than people with neither risk factor.
And even after controlling for multiple genetic detriments of dementia, the number of frail people who developed dementia was 268 per cent higher than those who were in more robust health.
Study participants who reported more engagement in healthy lifestyle behaviours were less likely to develop dementia, partly because they had a lower degree of frailty.
“The risk of dementia reflects genetic, neuropathological, lifestyle, and general health factors that in turn give rise to a range of abnormalities in the brain,” said Dr Kenneth Rockwood, a professor of geriatric medicine and neurology and the Kathryn Allen Weldon professor of Alzheimer research at Dalhousie University, and the senior medical director of the newly formed Frailty and Elder Care Network at Nova Scotia Health.
“Our study is an important step forward on the role of frailty, which appears to have a unique and potentially modifiable pathway in influencing dementia risk.
“That’s an incredibly exciting prospect that we must urgently explore to potentially benefit the growing number of people worldwide affected by dementia.”
Co-author Dr Janice Ranson, from the University of Exeter Medical School, said the study findings would have “extremely positive implications” for efforts to prevent dementia and showed “it’s not the case that dementia is inevitable”.
“We can take meaningful action to reduce our risk; tackling frailty could be an effective strategy to maintaining brain health, as well as helping people stay mobile and independent for longer in later life,” she added.
The paper, titled Frailty, lifestyle, genetics and dementia risk, is published in the Journal of Neurology, Neurosurgery and Psychiatry.