Handgrip strength appears to be associated with several markers of cognitive aging, such as neuroimaging markers of cerebral small vessel disease and subtypes of dementia. These are the findings of an analysis published in the journal JAMA Network Open.
The researchers sought to evaluate the relationship between handgrip strength and dementia, reduced cognition, and poor neuroimaging outcomes in a population of middle-aged adults from the United Kingdom. Although the link between muscle strength and cognitive outcomes has generated interest in devising interventions that increase muscle strength for the prevention of dementia, the associations between muscle strength and cognitive aging remain to be elucidated, especially among middle-aged adults.
The current cohort study assessed UK Biobank participants aged 39 to 73 years who had been enrolled in the study from 2006 to 2010. All participants had their handgrip strength measured and were prospectively followed for dementia diagnosis. All of the resulting data were analyzed between October 2021 and April 2022. Handgrip strength was calculated by a trained research staff member with use of a hydraulic hand dynamometer, following standardized procedures.
Study outcomes included cognitive test scores (fluid intelligence and prospective memory); brain resonance imaging measures (total brain volume, hippocampal volume, and white matter hyperintensity); and incident dementia (all-cause, vascular, and Alzheimer disease [AD] from primary care, hospital, or death records) — over a median of 11.7 years (range, 11.0 to 12.4 years) of follow-up.
The study comprised a subsample of 190,406 adult participants in the UK Biobank. The mean participant age was 56.5±8.1 years. A total of 54% (102,735 of 190,406) of the individuals evaluated were women. Overall, 95.6% (182,073 of 190,406) of the participants were White.
Study findings revealed that a 5-kg decrement in handgrip strength was associated with slightly lower fluid intelligence scores in men (95% CI, –0.010 to –0.003) than in women
(95% CI, –0.05 to –0.04). Further, every 5-kg lower decrement in handgrip strength was associated with a 9% lower likelihood of recalling a prospective memory task item correctly among men (odds ratio [OR], 0.91; 95% CI, 0.90-0.92) and a 12% lower likelihood among women (OR, 0.88; 95% CI, 0.87-0.90).
A 5-kg decrement in handgrip strength was also linked to greater white matter hyperintensity volume in men (95% CI, 31.09-153.35) and in women (95% CI, 13.54-153.58). Additionally, a 5-kg decrement in handgrip strength was associated with incident dementia in men (hazard ratio [HR], 1.20; 95% CI, 1.12-1.28) and in women (HR, 1.12; 95% CI, 1.00-1.26). The AD genetic risk score, however, did not demonstrate a significant association with handgrip strength.
Several limitations of the current analysis should be noted. Since the sample was highly selected with documented healthy volunteer bias, generalizability to other populations may be limited. Further, as the researchers could assess only cross-sectional differences in handgrip strength, this hampered the ability to evaluate change within an individual relative to cognition.
The researchers concluded that “interventions designed to increase muscle strength, particularly among middle-aged adults, may hold promise for the maintenance of neurocognitive brain health.”
Disclosure: One of the study authors has declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of the author’s disclosures.
Duchowny KA, Ackley SF, Brenowitz WD, et al. Associations between handgrip strength and dementia risk, cognition, and neuroimaging outcomes in the UK Biobank Cohort Study. JAMA Netw Open. Published online June 23, 2022. doi:10.1001/jamanetworkopen.2022.18314