The study was conducted over brains of 165 people. While participants were alive, physical frailty measurements were taken yearly including grip strength, time to walk eight feet, body composition and tiredness.
After death, the brains of these participants were checked for the plaques and tangles that are signs of Alzheimer's disease (AD) pathology. Thirty six percent of the study participants had dementia, or showed signs of memory loss.
The team found that that the level of frailty was nearly two times higher in people with high level of AD pathology.
"Interestingly, Alzheimer's disease pathology was associated with physical frailty in older persons both with and without dementia," said study author Aron S. Buchman, MD, with Rush University Alzheimer's Disease Center in Chicago and member of the American Academy of Neurology.
"The level of frailty was approximately two times higher in a person with a high level of AD pathology compared with a person with a low level of AD pathology," Buchman added.
Previous study on the same group while they were alive showed that eople who are physically frail with no cognitive impairment appear to be at higher risk of developing Alzheimer's disease as compared to those who were less frail.
"Together both of these studies suggest that frailty can be an early indicator of Alzheimer's disease pathology and may appear before memory loss," said Buchman.
The study is published in the August 12, 2008, issue of Neurology, the medical journal of the American Academy of Neurology.