Weakening muscles may point to Alzheimer’s

[Posted: Thu 12/11/2009 by Olivia Fens]

Older people with weak muscles appear to be at a higher risk of developing Alzheimer’s disease and mild cognitive impairment, as well as a more rapid rate of cognitive decline, a new study has found.

According to researchers at Rush University Medical Center in the US, the study shows that impaired muscle strength comes before the development of cognitive impairment in aging, and may be an early clinical marker.

“However, decreased strength may not be a true risk factor.  Rather, loss of muscle strength may be the result of an underlying disease process that also leads to cognitive decline and clinical symptoms of Alzheimer’s,” the researchers said.

Alzheimer’s and related dementia currently affects approximately 38,000 people in Ireland but, due to Ireland’s rapidly ageing population, that number is predicted to rise to 58,000 by 2021 and 104,000 by 2036.

Alzheimer's disease is the most common form of dementia and is a progressive and irreversible disease of the brain, characterised by loss of intellectual function, chronic memory loss, language deterioration and personality change.

In the study of more than 970 older adults (with an average age of 80.3 years), participants with the best muscle strength scores had about a 61% reduced risk of developing Alzheimer’s disease compared to those with the lowest strength score.

The association between muscle strength and risk for Alzheimer’s disease remained significant even after adjustment for many other potentially important factors, including body mass index and physical activity level.

The researchers found a similar association between muscle strength and the risk of developing mild cognitive impairment, the earliest sign of Alzheimer’s disease. 

The study also reported that the course of cognitive decline was more rapid in individuals with weaker muscle strength. Individuals who were stronger at the beginning of the study experienced a slower rate of decline.

The researchers concluded that the basis for the association between muscle strength and cognitive decline was likely complex – and that more studies were needed. 

The study was published in the journal Archives of Neurology.

For more information on Alzheimer's disease and dementia, click on
http://www.irishhealth.com/clin/alzheim/index.html