Older adults with strong muscles are at lower risk of developing Alzheimer's disease and mild cognitive impairment than their weaker peers, researchers report in Archives of Neurology. The study builds on previous research showing a link between grip strength and Alzheimer's risk.
In this study, researchers at the Rush University Alzheimer's Disease Center in Chicago measured a wide range of cognitive skills and muscle strength throughout the body in 970 participants with an average age of 80 years. During nearly 4 years of follow-up, 138 people developed Alzheimer's disease. After adjusting for age and other variables, the researchers found that the strongest 10 percent of participants had a 61 percent lower risk of developing Alzheimer's, compared with the weakest 10 percent of study participants. Muscle strength and mild cognitive impairment, a condition that often precedes Alzheimer's, were similarly but less closely linked. Stronger muscles were also associated with a slower rate of cognitive decline.
The authors surmise that a common underlying disease process could account for the association between muscle weakness and declining cognition. Replication of the results in a population-based study is important, they add.
Boyle, P.A., et al. Association of muscle strength with the risk of Alzheimer's disease and the rate of cognitive decline in community-dwelling older persons. Archives of Neurology. 2009. 66(11):1339-44.