It's expected that seniors slow down physically as they age, but this could be a sign of more than just lost muscle strength, a new study suggests. In some, it may be a harbinger of dementia.
Australian researchers said the findings may help health professionals to identify dementia risk in patients earlier.
"Both grip strength and TUG tests [for balance and mobility] aren't commonly performed in clinical practice, but both are inexpensive and simple screening tools," said senior researcher Marc Sim, from Edith Cowan University in Australia.
"Incorporating muscle function tests as part of dementia screening could be useful to identify high-risk individuals, who might then benefit from primary prevention programs aimed at preventing the onset of the condition such as a healthy diet and a physically active lifestyle," Sim said in a university news release.
His team used data from the Perth Longitudinal Study of Aging in Women to examine the relationship between muscle function and dementia. About 1,000 women were included in the study, with an average age of 75.
The researchers measured the women's grip strength and the time it took for them to rise from a chair, walk 3 meters (roughly 10 feet), turn around and sit back down. This is the "TUG" test (short for "timed-up-and-go"). The women then repeated these tests five years later.
Over the next 15 years, almost 17% of women involved in the study were found to have had a dementia event, including dementia-related hospitalization or death. Lower grip strength and slower TUG were significant risk factors for having dementia, independent of genetic risks and lifestyle factors such as smoking, alcohol intake and physical activity levels.
Those with the weakest grip strength were more than twice as likely to have a late-life dementia event when compared to the strongest women in the study. Similarly, those with the slowest TUG test were more than twice as likely to experience dementia as the fastest women.
Also notable is that women with the biggest drops in TUG performance were more than four times more likely to have a dementia-related death than the fastest women.
Grip strength can be easily measured using a handheld device known as a dynamometer, Sim said. He noted that this may be a measure of brain health due to the overlapping nature of cognitive and motor decline.
"Possibly due to a range of underlying similarities, grip strength may also present as a surrogate measure of cardiovascular disease, inflammation and frailty, which are known risk factors for dementia," Sim said.
"The exciting findings were that decline in these measures was associated with substantially higher risk, suggesting that if we can halt this decline, we may be able to prevent late-life dementias," he added. "However, further research is needed in this area."
The research was published recently in the Journal of Cachexia, Sarcopenia and Muscle.