Dementia is a brain disease that affects approximately 55 million people worldwide and is characterized by the loss of cognitive functions such as memory and reasoning.
The classic, early cognitive symptoms of dementia — like misplacing valuables, forgetting names, and having trouble planning — can slowly get worse over time.
But there are other more visible body changes that correlate with dementia risk that can be detected more than a decade before diagnosis. Recent research has shown that hearing difficulties can be a warning sign of dementia that occurs years before other symptoms of the disease.
Now, a study by Australian researchers suggests that measuring grip strength and mobility are two potentially useful and inexpensive ways to assess dementia risk in older women.
In the study, about 1,200 women in their 60s were tested for grip strength using a hand-held dynamometer and for mobility using a timed test where the person stands up from a chair, walks 3 meters (9.8 feet), turns around and sits back on the chair.
These tests were carried out in 1998 as part of the Perth Longitudinal Study of Aging in Women and repeated five years later.
Participants’ health was tracked using linked health records for the next 14.5 years. During this period, almost 17% of the women had been hospitalized for dementia or had died from a dementia-related cause.
Although the observational study could not show cause and effect, the researchers found a clear, linear relationship between physical strength and mobility and dementia events occurring more than a decade later.
Women who fell into the lowest quartile for grip strength or mobility were more than twice as likely as women in the top quartile to be hospitalized or die of dementia later in life.
Women with the greatest decline in grip strength and upward measures over five years were at highest risk of dementia.
These trends were independent of other risk factors, such as a genetic predisposition to Alzheimer’s disease, type of dementia and cardiovascular disease risk scores, which were measured at the start of the study.
“Grip strength tests and timed tests are not commonly performed in clinical practice, but both are simple and inexpensive screening tools,” says Marc Sim, lead author and exercise and sport scientist at Edith Cowan University in Perth. , Australia.
The decline in neurological function characteristic of dementia may have a cognitive and motor component. Grip strength may be a surrogate measure of cardiovascular disease, inflammation and frailty, known risk factors for dementia.
“Incorporating muscle function testing as part of dementia screening could be useful in identifying those at high risk, who could then benefit from primary prevention programs aimed at preventing the onset of the disease, such as a healthy eating and a physically active lifestyle,” says Sim.
People with one copy of the APOE4 gene have a 2 to 3 times higher risk of developing Alzheimer’s disease, a form of dementia. This risk increases 10 to 15 times for people with two copies of the gene.
In the study, about 23% of the women had at least one copy of the APOE4 gene. Compared to strong and agile women without the APOE4 gene, carriers of the gene were at even greater risk of dementia if they also had muscle weakness or sluggishness.
By 2050, the number of people with dementia is expected to reach 152 million worldwide, at an estimated cost of US$1 trillion.
It may be possible to change this trajectory. According to a 2020 report by The Lancetthe main preventable risk factors for dementia are physical inactivity, poor social contact, lack of education in early life, hypertension, diabetes, hearing loss, smoking, obesity, depression, excessive alcohol consumption, traumatic brain injury and air pollution.
This article was published in the Journal of cachexia, sarcopenia and muscle.