There may be a causal link between physical frailty and dementia, reported a recent study published in Neurology.
“We’ve known that frailty is associated with a higher risk of dementia, but our study provides evidence that frailty may be an actual cause of dementia. On the other hand, despite this new evidence, we can’t rule out the possibility that frailty is instead a marker of the early changes in the disease process,” study author Yacong Bo, PhD, of Zhengzhou University in China, said in a press release.
The study involved data from just under 490,000 participants from the UK Biobank with an average age of 57 years old. They were followed for a median of 13.6 years, and none had dementia at enrollment.
Physical frailty was defined by five criteria: weight loss, exhaustion, physical inactivity, slow walking speed, and low grip strength. Altogether, 4.6% of patients met criteria for frailty- having three or more symptoms- while 43.9% had one or two symptoms, characterized as pre-frailty. The remaining 51.5% of patients had no symptoms and were deemed 'not frail'.
Over the course of the study, 8,900 people developed dementia. Of those with frailty, 4.6% developed dementia compared to 2.2% of those with pre-frailty and 1.3% of those without the condition.
The researchers wrote that those with frailty had a 182% higher risk of dementia than those without, and that those with prefrailty had a 50% higher risk. They further found that those with frailty and a higher genetic risk for dementia had an almost four times higher risk of dementia than those with low genetic risk and nonfrailty.
Brain imaging suggested a potential causal link between physical frailty and dementia, and that dementia is unlikely to increase risk of frailty. The researchers noted in their study, however, that the link requires further research as frailty may also be a correlative marker of dementia vulnerability.
Sources: Neurology, EurekAlert