Midlife is a crucial period since this is when dementia and other neurocognitive disorders start to manifest. That means it is vital to examine the notable changes in muscle strength among middle-aged and older adults.
News Medical Life Sciences reported that a recent study showed a correlation between handgrip strength (HGS), dementia, and neurocognitive outcomes among men and women in the UK. The results add to the evidence that strength training has benefits for delaying dementia or age-related cognitive decline.
Handgrip Strength Associated with Dementia Risk, Neurocognitive Brain Health Among Older Adults
Neurocognition Associatied With Handgrip Strength
Kate A. Duchowny, Ph.D., from the University of California in San Francisco, together with her colleagues, examined how handgrip strength is linked to dementia, reduced cognition, and poorer neuroimaging outcomes. They used the data of 190,406 adults aged 39 to 73 enrolled in the UK Biobank from 2006 to 2010. They were followed up for dementia diagnoses until December 2020.
The team found that a 5-kilogram decrement or reduction in handgrip strength in middle age is associated with higher dementia risk among men and women with a median of 11.7 years, Medpage Today reported. More so, they found that a 5-kilogram decrement in HGS is associated with the following:
- Lower fluid intelligence in men and women
- Both men and women have worse odds of correctly responding to a memory task
- Greater white matter hyperintensity volume in men and women
Handgrip strength was measured using a hydraulic hand dynamometer that participants used to grip their left and right hands. Meanwhile, fluid intelligence and memory were assessed using touch screen tests and a subset of them were subjected to brain imaging.
Researchers said grip strength was linked to neurocognition in people under 65 years old and older. But they found no correlation between Alzheimer's disease genetic risk score with HGS. Overall, researchers found a strong correlation between neurocognitive outcomes and vascular mechanisms in midlife and late-life for both men and women.
They described their findings in full in the study titled "Associations Between Handgrip Strength and Dementia Risk, Cognition, and Neuroimaging Outcomes in the UK Biobank Cohort Study," published in the journal JAMA Network.
Muscle Strength and Cognitive Performance
Alzheimer's disease is a type of neurodegenerative disorder characterized by cognitive decline, especially in memory, cognitive deficits, and non-cognitive symptoms.
According to a separate study published on Frontiers in Neurology, reduced muscle strength is common among people with Alzheimer's disease, but an understanding of their relationship is limited. However, the study showed that moderate-to-severe Alzheimer's disease presented lower HGS.
HGS was also linked to overall neurocognitive functioning, attentional and memory performance among those with Alzheimer's disease and mild cognitive impairment. That means reduced HGS in patients with late-stage Alzheimer's disease is associated with worse cognitive performance.
Both studies show important implications of HGS on neurocognitive outcomes and dementia risk that may have something to do with vascular mechanisms. Therefore, interventions should be designed to improve muscle strength, paramount to one's neurocognitive brain health.
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