Reduced Muscle Strength Is Associated with a Higher Risk of Dementia

A study published in JAMA found that a reduction in muscle strength is associated with an increased risk of dementia. Researchers in this study analyzed data from the UK Biobank on patients between 39 and 73 years old. Handgrip strength (HGS) was used as a muscle strength measurement and examined on its association with dementia, cognition, and neuroimaging outcomes.  

The study looked at participants from 2006 to 2010 with no dementia diagnosis. Neuropsychological assessments were conducted, and for some participants, information was gathered from their primary care physician and hospital records.  

Three analyses were done, including dementia, neuroimaging, and cognition analyses. For each category, participants were determined through different exclusionary criteria, meaning that the sample size for each study was different.  

To measure HGS, a Jamar J00105 hydraulic hand dynamometer (Jamar) was used. Patients were asked to squeeze the Jamar as hard as they could for 3 seconds. Data was collected for each hand up to 4 times, and the maximum score was included.  

For dementia analysis, only patients with primary care linkage were analyzed. Dementia diagnosis data was attained through primary care, hospital, and death registry records. It was found that reduced hand grip strength was associated with an increased risk of dementia.  

In men, a 5 kg decrease in HGS was associated with a 16% increased risk of developing all-cause dementia. A similar trend was seen in women with all-cause dementia risk increasing by 14% with every 5 kg decrease in HGS.  

The researchers also concluded a stronger association between HGS and the likelihood of developing vascular dementia than any other kind of dementia.  

Understanding the odds of developing dementia has many implications for treatment and diagnosis. Globally, 55 million people have dementia, according to the WHO. Many sources, including Alzheimer’s Disease International, project that this number will double every 20 years.  

The Alzheimer’s Society in England states that early-stage dementia can be challenging to identify because the symptoms are minimal, and patients typically do not require assistance at this stage. Despite the difficulty of an early-stage diagnosis, the Alzheimer’s Society of Canada lists multiple benefits of an early diagnosis, including more effective interventions and life planning.  

Early diagnosis of dementia has an impact on patient prognosis. Understanding potential risk factors can assist physicians in advanced testing and treatment for this disorder. Further research needs to be conducted to understand how this data can contribute to treatment regimens.  

“Our findings add to a small but growing body of research indicating that the association between muscle strength and dementia may be due to vascular mechanisms and that interventions designed to increase muscle strength, particularly among middle-aged adults, may hold promise for the maintenance of neurocognitive brain health,” concluded the researchers in the study.