Associations Between Handgrip Strength and Dementia Risk, Cognition, and Neuroimaging Outcomes in the UK Biobank Cohort Study

Peripheral GFAP and NfL as early biomarkers for dementia: longitudinal insights from the UK Biobank

BACKGROUND

Peripheral glial fibrillary acidic protein (GFAP) and neurofilament light chain (NfL) are sensitive markers of neuroinflammation and neuronal damage. Previous studies with highly selected participants have shown that peripheral GFAP and NfL levels are elevated in the pre-clinical phase of Alzheimer's disease (AD) and dementia. However, the predictive value of GFAP and NfL for dementia requires more evidence from population-based cohorts.

METHODS

This was a prospective cohort study to evaluate UK Biobank participants enrolled from 2006 to 2010 using plasma GFAP and NfL measurements measured by Olink Target Platform and prospectively followed up for dementia diagnosis. Primary outcome was the risk of clinical diagnosed dementia. Secondary outcomes were cognition. Linear regression was used to assess the associations between peripheral GFAP and NfL with cognition. Cox proportional hazard models with cross-validations were used to estimate associations between elevated GFAP and NfL with risk of dementia. All models were adjusted for covariates.

RESULTS

A subsample of 48,542 participants in the UK Biobank with peripheral GFAP and NfL measurements were evaluated. With an average follow-up of 13.18 ± 2.42 years, 1312 new all-cause dementia cases were identified. Peripheral GFAP and NfL increased up to 15 years before dementia diagnosis was made. After strictly adjusting for confounders, increment in NfL was found to be associated with decreased numeric memory and prolonged reaction time. A greater annualized rate of change in GFAP was significantly associated with faster global cognitive decline. Elevation of GFAP (hazard ratio (HR) ranges from 2.25 to 3.15) and NfL (HR ranges from 1.98 to 4.23) increased the risk for several types of dementia. GFAP and NfL significantly improved the predictive values for dementia using previous models (area under the curve (AUC) ranges from 0.80 to 0.89, C-index ranges from 0.86 to 0.91). The AD genetic risk score and number of APOE*E4 alleles strongly correlated with GFAP and NfL levels.

CONCLUSIONS

These results suggest that peripheral GFAP and NfL are potential biomarkers for the early diagnosis of dementia. In addition, anti-inflammatory therapies in the initial stages of dementia may have potential benefits.

Association of grip strength and walking pace with the risk of incident Parkinson's disease: a prospective cohort study of 422,531 participants

BACKGROUND

Muscle weakness is a prominent feature of Parkinson's disease, but whether the occurrence of this deficit in healthy adults is associated with subsequent PD diagnosis remains unclear.

OBJECTIVE

This study sought to examine the relationship between muscle strength, represented by grip strength and walking pace, and the risk of incident PD.

METHODS

A total of 422,531 participants from the UK biobank were included in this study. Longitudinal associations of grip strength and walking pace with the risk of incident PD were investigated by Cox proportional hazard models adjusting for several well-established risk factors. Subgroup and sensitivity analyses were also conducted for further validation.

RESULTS

After a median follow-up of 9.23 years, 2,118 (0.5%) individuals developed incident PD. For per 5 kg increment of absolute grip strength, there was a significant 10.2% reduction in the risk of incident PD (HR = 0.898, 95% CI [0.872-0.924], P < 0.001). Similarly, per 0.05 kg/kg increment of relative grip strength was related to a 9.2% reduced risk of incident PD (HR = 0.908, 95% CI [0.887-0.929], P < 0.001). Notably, the associations remained consistent when grip strength was calculated as quintiles. Moreover, participants with a slower walking pace demonstrated an elevated risk of incident PD (HR = 1.231, 95%CI [1.075-1.409], P = 0.003). Subgroup and sensitivity analyses further validated the robustness of the observed associations.

CONCLUSION

Our findings showed a negative association of grip strength and walking pace with the risk of incident PD independent of important confounding factors. These results hold potential implications for the early screening of people at high-risk of PD.

Cognitive trajectories in older adults and the role of depressive symptoms: A 7-year follow-up study

OBJECTIVES

To examine different trajectories of cognitive changes in elderly adults and explore the mediating role of depressive symptoms.

DESIGN

A 7-year, community-based, prospective cohort study.

SETTING

The downtown neighborhood of Shanghai, China.

PARTICIPANTS

A cohort of 394 older adults, with an average age of 71.8 years, was recruited in 2015 and has been reassessed every two years until 2021.

METHODS

Latent Class Growth Analysis was used to model aging trajectories and Linear Mixed-Effect Models for Repeated Measures were used to estimate the least squares mean changes of cognition between subjects with depression (DEP+) and without (DEP-) across all visits.

RESULTS

Three cognitive trajectories were identified: the "successful aging" (SA) trajectory had the best and most consistent performance (n=229, 55.9%); the "normal aging" (NA) trajectory showed lower but stable cognition (n=141, 37.3%); while the "cognitive decline" (CD) trajectory displayed poor and declining cognition (n=24, 6.8%). Depressive symptoms were found to be influential across all trajectories. In the CD trajectory, the MoCA scores of the DEP+ group increased in within-group comparisons and were significantly higher than those of the DEP- group at visits 1 and 3 in between-group comparisons. A similar trend was observed in the NA trajectory, though it did not reach statistical significance.

CONCLUSIONS

Our research suggests that mild and decreasing depressive symptoms can be a reversible factor that might slow down the irreversible cognitive decline in the elderly. Therefore, we suggest that even mild depressive symptoms in the elderly should be monitored and detected.

Anti-Inflammatory Diet and Protein-Enriched Diet Can Reduce the Risk of Cognitive Impairment among Older Adults: A Nationwide Cross-Sectional Research

BACKGROUND

Cognitive impairment (CI) is a common mental health disorder among older adults, and dietary patterns have an impact on cognitive function. However, no systematic researches have constructed anti-inflammatory diet (AID) and protein-enriched diet (PED) to explore their association with CI among older adults in China.

METHODS

The data used in this study were obtained from the 2018 waves of the China Longitudinal Health and Longevity Survey (CLHLS). We construct AID, PED, and calculate scores for CI. We use binary logistic regression to explore the relationship between them, and use restrictive cubic splines to determine whether the relationships are non-linear. Subgroup analysis and sensitivity analysis were used to demonstrate the robustness of the results.

RESULTS

A total of 8692 participants (mean age is 83.53 years) were included in the analysis. We found that participants with a higher AID (OR = 0.789, 95% confidence interval: 0.740-0.842, p < 0.001) and PED (OR = 0.910, 95% confidence interval: 0.866-0.956, p < 0.001) score showed lower odds of suffering from CI. Besides, the relationship between the two dietary patterns and CI is linear, and the results of subgroup analysis and sensitivity analysis are also significant.

CONCLUSION

Higher intakes of AID and PED are associated with a lower risk of CI among older adults, which has important implications for future prevention and control of CI from a dietary and nutritional perspective.

Sarcopenia as a Risk Factor for Alzheimer's Disease: Genetic and Epigenetic Perspectives

Sarcopenia, defined as the age-associated loss of muscle mass and increased fragility with age, is increasing worldwide. The condition often precedes the development of Alzheimer's disease, thereby decreasing the levels of mobility and physical activity in those affected. Indeed, the loss of muscle mass has, in some studies, been associated with an increased risk of Alzheimer's disease and other dementias. However, a detailed understanding of the interplay between both conditions is not available and needs to be thoroughly addressed. In the following review, we focus on several genes, specifically APOE, BDNF, ACE, FTO, and FNDC5, that have been associated with both conditions. We also discuss the epigenetic regulation of each of these genes along with non-coding RNAs (ncRNAs) that may have a role in the development of both the sarcopenic and Alzheimer's disease phenotypes. Finally, we assert that the application of systems biology will unravel the relationship between sarcopenia and Alzheimer's disease and believe that the prevention of muscle loss in older age will reduce the incidence of debilitating cognitive decline.

Mediation role of DNA methylation in association between handgrip strength and cognitive function in monozygotic twins

Handgrip strength is a crucial indicator to monitor the change of cognitive function over time, but its mechanism still needs to be further explored. We sampled 59 monozygotic twin pairs to explore the potential mediating effect of DNA methylation (DNAm) on the association between handgrip strength and cognitive function. The initial step was the implementation of an epigenome-wide association analysis (EWAS) in the study participants, with the aim of identifying DNAm variations that are associated with handgrip strength. Following that, we conducted an assessment of the mediated effect of DNAm by the use of mediation analysis. In order to do an ontology enrichment study for CpGs, the GREAT program was used. There was a significant positive association between handgrip strength and cognitive function (β = 0.194, P < 0.001). The association between handgrip strength and DNAm of 124 CpGs was found to be statistically significant at a significance level of P < 1 × 10-4. Fifteen differentially methylated regions (DMRs) related to handgrip strength were found in genes such as SNTG2, KLB, CDH11, and PANX2. Of the 124 CpGs, 4 within KRBA1, and TRAK1 mediated the association between handgrip strength and cognitive function: each 1 kg increase in handgrip strength was associated with a potential decrease of 0.050 points in cognitive function scores, mediated by modifications in DNAm. The parallel mediating effect of these 4 CpGs was -0.081. The presence of DNAm variation associated with handgrip strength may play a mediated role in the association between handgrip strength and cognitive function.

Identifying a group of factors predicting cognitive impairment among older adults

BACKGROUND

Cognitive impairment has multiple risk factors spanning several domains, but few studies have evaluated risk factor clusters. We aimed to identify naturally occurring clusters of risk factors of poor cognition among middle-aged and older adults and evaluate associations between measures of cognition and these risk factor clusters.

METHODS

We used data from the National Health and Nutrition Examination Survey (NHANES) III (training dataset, n = 4074) and the NHANES 2011-2014 (validation dataset, n = 2510). Risk factors were selected based on the literature. We used both traditional logistic models and support vector machine methods to construct a composite score of risk factor clusters. We evaluated associations between the risk score and cognitive performance using the logistic model by estimating odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Using the training dataset, we developed a composite risk score that predicted undiagnosed cognitive decline based on ten selected predictive risk factors including age, waist circumference, healthy eating index, race, education, income, physical activity, diabetes, hypercholesterolemia, and annual visit to dentist. The risk score was significantly associated with poor cognitive performance both in the training dataset (OR Tertile 3 verse tertile 1 = 8.15, 95% CI: 5.36-12.4) and validation dataset (OR Tertile 3 verse tertile 1 = 4.31, 95% CI: 2.62-7.08). The area under the receiver operating characteristics curve for the predictive model was 0.74 and 0.77 for crude model and model adjusted for age, sex, and race.

CONCLUSION

The model based on selected risk factors may be used to identify high risk individuals with cognitive impairment.

Prevention of Vascular Contributions to Cognitive Impairment and Dementia: The Role of Physical Activity and Exercise

Vascular contributions to cognitive impairment and dementia, specifically cerebral small vessel disease (CSVD), are the second most common cause of dementia. Currently, there are no specific pharmacological treatments for CSVD, and the use of conventional antidementia drugs is not recommended. Exercise has the potential to prevent and mitigate CSVD-related brain damage and improve cognitive function. Mechanistic pathways underlying the neurocognitive benefits of exercise include the control of vascular risk factors, improving endothelial function, and upregulating exerkines. Notably, the therapeutic efficacy of exercise may vary by exercise type (ie, aerobic versus resistance training) and biological sex; thus, studies designed specifically to examine these moderating factors within a CSVD context are needed. Furthermore, future research should prioritize resistance training interventions, given their tremendous therapeutic potential. Addressing these knowledge gaps will help us refine exercise recommendations to maximize their therapeutic impact in the prevention and mitigation of CSVD.

Can motor decline be a modifiable marker of clinical progression in subjective cognitive decline? A national prospective cohort study

OBJECTIVES

Subjective cognitive decline represents a critical stage for preventing mild cognitive impairment and dementia, but the links between clinical progression in the subjective cognitive decline stage and various motor functions remain inconclusive. This cohort study aimed to elucidate the independent and joint associations between the clinical progression of subjective cognitive decline and motor functions.

METHODS

We enrolled 4880 community-dwelling elderly participants from a national cohort and used Cox proportional hazard regression model and restricted cubic spline models to explore the longitudinal associations between motor functions (gait, strength, balance, and endurance) and the clinical progression of subjective cognitive decline.

RESULTS

During 5-years follow-up, 1239 participants experienced clinical progression. After adjusting for demographics, vascular burden, body components, and polypharmacy, gait speed [hazard ratios (HRs)= 0.96, 95% confidence interval (CI) 0.94-0.99], chair stand test (HRs=1.02, 95%CI 1.01-1.03), and endurance limitation in jogging 1 kilometer (HRs=1.18, 95%CI 1.04-1.34) were significantly associated with clinical progression. Among all participants, individuals characterized by poor upper- and lower-body strength, as well as those with slow pace and reduced endurance, faced the highest risk of cognitive impairment.

CONCLUSIONS

This study emphasizes the potential of gait speed, muscle strength, and endurance as non-cognitive indicators of clinical progression in subjective cognitive decline. Understanding their combined effectiveness may reveal primary physiological mechanisms contributing to the dual decline of motor and cognition.

Linking sarcopenia, brain structure and cognitive performance: a large-scale UK Biobank study

Sarcopenia refers to age-related loss of muscle mass and function and is related to impaired somatic and brain health, including cognitive decline and Alzheimer's disease. However, the relationships between sarcopenia, brain structure and cognition are poorly understood. Here, we investigate the associations between sarcopenic traits, brain structure and cognitive performance. We included 33 709 UK Biobank participants (54.2% female; age range 44-82 years) with structural and diffusion magnetic resonance imaging, thigh muscle fat infiltration (n = 30 561) from whole-body magnetic resonance imaging (muscle quality indicator) and general cognitive performance as indicated by the first principal component of a principal component analysis across multiple cognitive tests (n = 22 530). Of these, 1703 participants qualified for probable sarcopenia based on low handgrip strength, and we assigned the remaining 32 006 participants to the non-sarcopenia group. We used multiple linear regression to test how sarcopenic traits (probable sarcopenia versus non-sarcopenia and percentage of thigh muscle fat infiltration) relate to cognitive performance and brain structure (cortical thickness and area, white matter fractional anisotropy and deep and lower brain volumes). Next, we used structural equation modelling to test whether brain structure mediated the association between sarcopenic and cognitive traits. We adjusted all statistical analyses for confounders. We show that sarcopenic traits (probable sarcopenia versus non-sarcopenia and muscle fat infiltration) are significantly associated with lower cognitive performance and various brain magnetic resonance imaging measures. In probable sarcopenia, for the included brain regions, we observed widespread significant lower white matter fractional anisotropy (77.1% of tracts), predominantly lower regional brain volumes (61.3% of volumes) and thinner cortical thickness (37.9% of parcellations), with |r| effect sizes in (0.02, 0.06) and P-values in (0.0002, 4.2e-29). In contrast, we observed significant associations between higher muscle fat infiltration and widespread thinner cortical thickness (76.5% of parcellations), lower white matter fractional anisotropy (62.5% of tracts) and predominantly lower brain volumes (35.5% of volumes), with |r| effect sizes in (0.02, 0.07) and P-values in (0.0002, 1.9e-31). The regions showing the most significant effect sizes across the cortex, white matter and volumes were of the sensorimotor system. Structural equation modelling analysis revealed that sensorimotor brain regions mediate the link between sarcopenic and cognitive traits [probable sarcopenia: P-values in (0.0001, 1.0e-11); muscle fat infiltration: P-values in (7.7e-05, 1.7e-12)]. Our findings show significant associations between sarcopenic traits, brain structure and cognitive performance in a middle-aged and older adult population. Mediation analyses suggest that regional brain structure mediates the association between sarcopenic and cognitive traits, with potential implications for dementia development and prevention.

Shared and Distinct Associations of Manual Dexterity and Gross Motor Function With Brain Atrophy

BACKGROUND

Poor motor function is associated with brain atrophy and cognitive impairment. Less is known about the relationship between motor domains and brain atrophy and whether associations are affected by cerebrovascular burden and/or physical activity.

METHODS

We analyzed data from 726 Baltimore Longitudinal Study of Aging participants (mean age 70.6 ± 10.1 years, 56% women, 27% Black), 525 of whom had repeat MRI scans over an average of 5.0 ± 2.1 years. Two motor domains, manual dexterity and gross motor, were operationalized as latent variables. Associations between the latent variables and cortical and subcortical brain volumes of interest were examined using latent growth curve modeling, adjusted for demographics, white matter hyperintensities, and physical activity.

RESULTS

Both higher manual dexterity and gross motor function were cross-sectionally associated with smaller ventricular volume and greater white matter volumes in the frontal, parietal, and temporal lobes (all p < .05). Manual dexterity was also cross-sectionally associated with parietal gray matter (B = 0.14; 95% CI: 0.05, 0.23), hippocampus (B = 0.10; 95% CI: 0.01, 0.20), postcentral gyrus (B = 0.11; 95% CI: 0.01, 0.20), and occipital white matter (B = 0.10; 95% CI: 0.01, 0.21) volumes, and gross motor function with temporal gray matter volume (B = 0.16; 95% CI: 0.05, 0.26). Longitudinally, both higher manual dexterity and gross motor function were associated with less temporal white matter and occipital gray matter atrophy (all p < .05). Manual dexterity was also associated with a slower rate of ventricular enlargement (B = -0.17; 95% CI: -0.29, -0.05) and less atrophy of occipital white matter (B = 0.39; 95% CI: 0.04, 0.71).

CONCLUSIONS

Among cognitively normal middle- and older-aged adults, manual dexterity and gross motor function exhibited shared as well as distinct associations with brain atrophy over time.

Targeted brain-specific tauopathy compromises peripheral skeletal muscle integrity and function

Tauopathies are neurodegenerative disorders in which the pathological intracellular aggregation of the protein tau causes cognitive deficits. Additionally, clinical studies report muscle weakness in populations with tauopathy. However, whether neuronal pathological tau species confer muscle weakness, and whether skeletal muscle maintains contractile capacity in primary tauopathy remains unknown. Here, we identified skeletal muscle abnormalities in a mouse model of primary tauopathy, expressing human mutant P301L-tau using adeno-associated virus serotype 8 (AAV8). AAV8-P301L mice showed grip strength deficits, hyperactivity, and abnormal histological features of skeletal muscle. Additionally, spatially resolved gene expression of muscle cross sections were altered in AAV8-P301L myofibers. Transcriptional changes showed alterations of genes encoding sarcomeric proteins, proposing a weakness phenotype. Strikingly, specific force of the soleus muscle was blunted in AAV8-P301L tau male mice. Our findings suggest tauopathy has peripheral consequences in skeletal muscle that contribute to weakness in tauopathy.

Comparative study of machine learning methods for modeling associations between risk factors and future dementia cases

A substantial portion of dementia risk can be attributed to modifiable risk factors that can be affected by lifestyle changes. Identifying the contributors to dementia risk could prove valuable. Recently, machine learning methods have been increasingly applied to healthcare data. Several studies have attempted to predict dementia progression by using such techniques. This study aimed to compare the performance of different machine-learning methods in modeling associations between known cognitive risk factors and future dementia cases. A subset of the AGES-Reykjavik Study dataset was analyzed using three machine-learning methods: logistic regression, random forest, and neural networks. Data were collected twice, approximately five years apart. The dataset included information from 1,491 older adults who underwent a cognitive screening process and were considered to have healthy cognition at baseline. Cognitive risk factors included in the models were based on demographics, MRI data, and other health-related data. At follow-up, participants were re-evaluated for dementia using the same cognitive screening process. Various performance metrics for all three machine learning algorithms were assessed. The study results indicate that a random forest algorithm performed better than neural networks and logistic regression in predicting the association between cognitive risk factors and dementia. Compared to more traditional statistical analyses, machine-learning methods have the potential to provide more accurate predictions about which individuals are more likely to develop dementia than others.

Low Handgrip Strength (Possible Sarcopenia) With Insulin Resistance Is Associated With Type 2 Diabetes Mellitus

Context

Older adults with sarcopenic obesity are at high risk for type 2 diabetes mellitus (T2DM). However, few East Asians have sarcopenic obesity. Since many East Asians have insulin resistance (IR) without obesity, it is possible that older East Asians with sarcopenia and IR might be at high risk for T2DM. However, this relationship has not been studied.

Methods

This cross-sectional study included 1629 older adults aged 65 to 84 years registered in the Bunkyo Health Study. All underwent a 75-g oral glucose tolerance test and handgrip strength measurement. Participants were classified into 4 groups by possible sarcopenia (handgrip strength <28 kg in men and <18 kg in women) and IR status (triglyceride glucose [TyG] index ≥8.79 for men and ≥8.62 for women [third quartile]). Modified Poisson regression was used to estimate relative risk (RR) and 95% CIs for T2DM with adjustment for confounding factors.

Results

The mean age was 73.1 ± 5.4 years. T2DM was diagnosed in 212 (13.0%) participants. After adjusting for age, sex, body mass index, use of lipid-lowering medications, hypertension, and cardiovascular disease, possible sarcopenia and IR were associated with T2DM, with their coexistence showing a notably stronger association (control: RR, 1.00 [Reference]; possible sarcopenia: RR, 1.55 [95% CI, 1.04-2.30]; IR: RR, 2.69 [95% CI, 1.99-3.65]; and IR possible sarcopenia: RR, 4.76 [95% CI, 3.34-6.79]).

Conclusion

Possible sarcopenia based on low handgrip strength and IR based on the TyG index are independently associated with T2DM in older Japanese individuals. Their coexistence shows a particularly strong association with T2DM.

Bridging Reduced Grip Strength and Altered Executive Function: Specific Brain White Matter Structural Changes in Patients with Alzheimer's Disease

Objective

To investigate the correlation between specific fiber tracts and grip strength and cognitive function in patients with Alzheimer's disease (AD) by fixel-based analysis (FBA).

Methods

AD patients were divided into AD with low grip strength (AD-LGS, n=29) and AD without low grip strength (AD-nLGS, n=25), along with 31 normal controls (NC). General data, neuropsychological tests, grip strength and cranial magnetic resonance imaging (MRI) scans were collected. FBA evaluated white matter (WM) fiber metrics, including fiber density (FD), fiber cross-sectional (FC), and fiber density and cross-sectional area (FDC). The mean fiber indicators of the fiber tracts of interest (TOI) were extracted in cerebral region of significant statistical differences in FBA to further compare the differences between groups and analyze the correlation between fiber properties and neuropsychological test scores.

Results

Compared to AD-nLGS group, AD-LGS group showed significant reductions in FDC in several cerebral regions. In AD patients, FDC values of bilateral uncinate fasciculus and left superior longitudinal fasciculus were positively correlated with Clock Drawing Test scores, while FDC of splenium of corpus callosum, bilateral anterior cingulate tracts, forceps major, and bilateral inferior longitudinal fasciculus were positively correlated with the Executive Factor Score of Memory and Executive Screening scale scores.

Conclusion

Reduced grip strength in AD patients is associated with extensive impairment of WM structural integrity. Changes in FDC of specific WM fiber tracts related to executive function play a significant mediating role in the reduction of grip strength in AD patients.

The Role of Different Weakness Cut-Points for Future Cognitive Impairment in Older Americans

OBJECTIVES

New absolute and normalized handgrip strength (HGS) cut-points may not yield similar predictive value for cognitive performance. We sought to determine the associations of (1) each absolute and normalized weakness cut-point, and (2) compounding weakness on future cognitive impairment in older Americans.

DESIGN

Longitudinal panel.

SETTING AND PARTICIPANTS

The analytic sample included 11,116 participants aged ≥65 years from the 2006 to 2018 waves of the Health and Retirement Study. Participants from the Health and Retirement Study completed detailed interviews that included physical measures and core interviews.

METHODS

The modified Telephone Interview of Cognitive Status assessed cognitive function and persons scoring <11 were classified as having a cognitive impairment. A handgrip dynamometer measured HGS. Men were considered weak if their HGS was <35.5 kg (absolute), <0.45 kg/kg (body mass normalized), or <1.05 kg (body mass index normalized), whereas women were classified as weak if their HGS was <20.0 kg, <0.337 kg/kg, or <0.79 kg. Compounding weakness included those below 1, 2, or all 3 cut-points. Generalized estimating equations quantified the associations.

RESULTS

Persons considered weak under the absolute cut-point had 1.62 (95% CI 1.34-1.96) greater odds for future cognitive impairment, but no significant associations were observed for those classified as weak under the body mass [odds ratio (OR) 1.12, CI 0.91-1.36] and body mass index normalized (OR 1.17, CI 0.95-1.43) cut-points. Older Americans below all 3 weakness cut-points had 1.47 (CI 1.15-1.88) greater odds for future cognitive impairment, but no significant associations were found for persons classified as weak under 1 (OR 1.08, CI 0.83-1.42) or 2 (OR 1.19, CI 0.91-1.55) cut-points.

CONCLUSIONS AND IMPLICATIONS

Our findings suggest that each weakness cut-point has differential prognostic value for future cognitive impairment, and aggregating weakness cut-points may improve their predictive utility. Consideration should be given to how weakness categories are uniquely linked to cognitive function.

Biological ageing and the risk of decreased handgrip strength among community-dwelling older adult Indians: a cross-sectional study

BACKGROUND

Evidence from the literature demonstrates that the risk of decreased handgrip strength is associated with various health issues, particularly in older persons. To make judgments regarding their general health condition that are well-informed for longevity, it is crucial to assess the risk level of decreased handgrip strength among community-dwelling older adult Indians. However, no study has examined the relationship between biological aging and the risk of decreased handgrip strength in Indian men and women aged 60 and older. The goal of the current study was to fill this gap in the literature.

METHODS

In this cross-sectional study, we included 31,464 (15,098 men and 16,366 women) community-dwelling older adult Indians aged 60 years and older using data from the Longitudinal Aging Study in India (LASI). The LASI is the world's most extensive and India's first multidisciplinary, internationally harmonized, longitudinal aging study. It has enrolled 72,250 individuals aged 45 and above across all 28 states and 8 union territories of India. Secondary analysis of biological ageing was performed by stratifying for age groups (60-64, 65-69, 70-74, 75-79, 80-84, and 85 + years) for both genders. The dominant right and nondominant left handgrip strength was assessed using the portable Smedley's Hand Dynamometer. All individuals had a dominant right hand. The adjusted logistic regression analysis assessed the association between biological ageing and the risk of decreased handgrip strength for both genders.

RESULTS

Compared to those between the ages of 60-64, those at age 65 and those aged 85 and above had 1-fold and 12-fold odds of decreasing handgrip strength, respectively. Men 85 years or older had a 12-fold higher chance than women in the same age group of having decreased handgrip strength.

CONCLUSIONS

The results indicate that community-dwelling older adult Indians aged 65 years and older are significantly associated with a higher risk of decreased handgrip strength, especially among older men. The results of this study can help assess and implement handgrip strength measurement in medicine for older Indians as part of regular admission assessment, particularly for older men.

Cardiorespiratory Fitness and Muscular Strength Do Not Predict Social Cognitive Capacity in Older Age

OBJECTIVES

Social cognitive function often declines in older age but the mechanisms underlying these declines are not completely clear. Cardiorespiratory fitness (CRF) and muscular strength are positively associated with broader cognitive function in older adults, yet surprisingly, no study has examined whether a similar relationship exists between CRF or muscular strength and social cognition in older age.

METHODS

We assessed whether higher CRF and muscular strength were associated with enhanced social cognitive function in a sample of fifty older adults (Mage = 70.08, standard deviation = 3.93). Participants completed a gold-standard cardiopulmonary exercise test to assess CRF, an isometric handgrip strength test to index muscular strength, and validated measures of social cognition to index emotion perception and theory of mind (ToM).

RESULTS

The results showed that CRF and muscular strength did not explain any unique variance in older adults' social cognitive performance. Bayesian analyses confirmed that the evidence for the null hypothesis was moderate for all tested relationships, except for the relationship between CRF and cognitive ToM where the evidence for the null was anecdotal.

DISCUSSION

This study has provided the first evidence to suggest that CRF and muscular strength-two important modifiable lifestyle factors-are not associated with social cognition in healthy older adults. However, replication studies are now needed to cross-validate these findings and to clarify whether any moderating variables may be important for understanding the relationship between fitness and social cognition in older age.

White matter hyperintensities: a possible link between sarcopenia and cognitive impairment in patients with mild to moderate Alzheimer's disease

PURPOSE

Alzheimer's disease (AD) has been reported to be associated with sarcopenia. White matter hyperintensities (WMH) are common in AD patients. However, the effect of WMH on sarcopenia in AD remains unclear. We hence aimed to investigate the possible association between regional WMH volumes and sarcopenic parameters in AD.

METHODS

57 mild to moderate AD patients and 22 normal controls (NC) were enrolled. Sarcopenic parameters were assessed, including appendicular skeletal mass index (ASMI), grip strength, 5-times sit-to-stand (5-STS) time, and gait speed. The volumes of periventricular hyperintensities (PVH) and deep white matter hyperintensities (DWMH) were quantified using 3D-slicer software.

RESULTS

AD subjects exhibited a lower ASMI, a slower gait speed, an increased 5-STS time, and larger volumes of PVH and DWMH than those in the NC group. In AD subjects, total WMH and PVH volumes were related to cognitive impairment, particularly executive function decline. Moreover, total WMH volume and PVH volume were negatively correlated with gait speed across various clinical stages of AD. Multiple linear regression analysis showed that PVH volume was independently associated with 5-STS time and gait speed, whereas DWMH volume was only independently associated with gait speed.

CONCLUSION

WMH volume was associated with cognitive decline and various sarcopenic parameters. It thereby suggested that WMH may serve as the connection between sarcopenia and cognitive dysfunction in AD. Further studies are needed to confirm these findings and to determine whether sarcopenia interventions reduce WMH volume and improve cognitive function in AD.

The association of handgrip strength with all-cause and cardiovascular mortality: results from the National Health and Nutrition Examination Survey database prospective cohort study with propensity score matching

Objective

To investigate the association between handgrip strength (HGS) with all-cause and cardiovascular disease (CVD) mortality in US adults.

Method

We analyzed data from the National Health and Nutrition Examination Survey (NHANES) prospective cohort study (2011-2014) with 10,470 participants. The cox regression analysis, Kaplan-Meier survival curves, fitted curves, ROC curves, and propensity score-matched analysis (PSM) with inverse probability of treatment weighting (IPTW), SMRW (PSM with repeated weights), PA (pairwise algorithm), and OW (overlap weighting) regression analysis were performed to assess the relationship between HGS and all-cause and CVD mortality.

Results

The low HGSs (men <37.4 kg, women <24 kg), was found to be associated with higher all-cause and CVD mortality in a reverse J-shaped curve (p < 0.05). Adjusting for multiple covariates including age, BMI, race, education level, marriage status, smoking and alcohol use, and various comorbidities, the hazard ratio (HR) for all-cause mortality in the lowest HGS quintile 1 (Q1) was 3.45 (2.14-5.58) for men and 3.3 (1.88-5.79) for women. For CVD mortality, the HR was 2.99 (1.07-8.37) for men and 10.35 (2.29-46.78) for women. The area under the curve (AUC) for HGS alone as a predictor of all-cause mortality was 0.791 (0.768-0.814) for men and 0.780 (0.752-0.807) for women (p < 0.05), while the AUC for HGS and age was 0.851 (0.830-0.871) for men and 0.848 (0.826-0.869) for women (p < 0.05). For CVD mortality, the AUC for HGS alone was 0.785 (95% CI 0.738-0.833) for men and 0.821 (95% CI 0.777-0.865) for women (p < 0.05), while the AUC for HGS and age as predictors of all-cause mortality was 0.853 (0.861-0.891) for men and 0.859 (0.821-0.896) for women (p < 0.05). The HGS Q1 (men <37.4 kg and women <24 kg) was matched separately for PSM. After univariate, multivariate Cox regression models, PSM, IPTW, SMRW, PA, and OW analyses, women had 2.37-3.12 and 2.92-5.12 HRs with low HGS for all-cause and CVD mortality, while men had 2.21-2.82 and 2.33-2.85 for all-cause and CVD mortality, respectively (p < 0.05).

Conclusion

Adults with low HGS exhibited a significantly increased risk of both all-cause and CVD mortality, regardless of gender. Additionally, low HGS served as an independent risk factor and predictor for both all-cause and CVD mortality.

Protracted CLN3 Batten disease in mice that genetically model an exon-skipping therapeutic approach

Genetic mutations that disrupt open reading frames and cause translation termination are frequent causes of human disease and are difficult to treat due to protein truncation and mRNA degradation by nonsense-mediated decay, leaving few options for traditional drug targeting. Splice-switching antisense oligonucleotides offer a potential therapeutic solution for diseases caused by disrupted open reading frames by inducing exon skipping to correct the open reading frame. We have recently reported on an exon-skipping antisense oligonucleotide that has a therapeutic effect in a mouse model of CLN3 Batten disease, a fatal pediatric lysosomal storage disease. To validate this therapeutic approach, we generated a mouse model that constitutively expresses the Cln3 spliced isoform induced by the antisense molecule. Behavioral and pathological analyses of these mice demonstrate a less severe phenotype compared with the CLN3 disease mouse model, providing evidence that antisense oligonucleotide-induced exon skipping can have therapeutic efficacy in treating CLN3 Batten disease. This model highlights how protein engineering through RNA splicing modulation can be an effective therapeutic approach.

One-Year Handgrip Strength Change in Kindergarteners Depends upon Physical Activity Status

Free play in kindergarten can be roughly divided into fine and gross motor activities, but the effects of these activities on improving handgrip strength are unknown. Therefore, we aimed to compare one-year changes in handgrip strength and forearm flexor muscle size in children separated by preferred play in a kindergarten. One hundred and eleven children were recruited from a local kindergarten. They underwent handgrip strength and forearm muscle thickness measurements, and 95 (49 boys and 46 girls) underwent a second measurement one year after the first measurement. Class teachers assessed the physical activity of everyone in their class after the second measurement. Using three evaluation scores by the class teachers, we divided children into three groups based on the children's preference to play in kindergarten (fine movement vs. gross motor movement). Handgrip strength did not change differently between groups across one year. However, children who liked active playing outside (i.e., gross motor activity) were stronger than others. Furthermore, children who like playing outside observed greater changes than the other groups in the ulna (right hand) and radius muscle thickness (left hand), suggesting that changes in forearm muscle size might be incongruent with changes in handgrip strength among the three activity groups.

Identifying modifiable factors and their joint effect on dementia risk in the UK Biobank

Previous hypothesis-driven research has identified many risk factors linked to dementia. However, the multiplicity and co-occurrence of risk factors have been underestimated. Here we analysed data of 344,324 participants from the UK Biobank with 15 yr of follow-up data for 210 modifiable risk factors. We first conducted an exposure-wide association study and then combined factors associated with dementia to generate composite scores for different domains. We then evaluated their joint associations with dementia in a multivariate Cox model. We estimated the potential impact of eliminating the unfavourable profiles of risk domains on dementia using population attributable fraction. The associations varied by domain, with lifestyle (16.6%), medical history (14.0%) and socioeconomic status (13.5%) contributing to the majority of dementia cases. Overall, we estimated that up to 47.0%-72.6% of dementia cases could be prevented.

The Relationship between Handgrip Strength, Timed Up-and-Go, and Mild Cognitive Impairment in Older People during COVID-19 Pandemic Restrictions

The COVID-19 lockdown restrictions affected physical performance and cognitive function in older people as they were confined to their homes. There is an association between physical and cognitive functions. Mild Cognitive Impairment (MCI) is a condition that risks progressing to dementia. This study aimed to identify the relationship between handgrip strength (HGS), Timed Up-and-Go (TUG), and MCI in older people during the COVID-19 pandemic restrictions. The cross-sectional study recruited 464 eligible participants for an interview and anthropometric measurement. The Montreal Cognitive Assessment-Basic (MoCA-B), HGS, and TUG were measured in addition to demographic and health characteristics. A total of 398 participants (85.8%) were found to have MCI when screened with the MoCA-B. Their mean age was 71.09 ± 5.81 years. Forward multiple regression analysis demonstrated that HGS (β = 0.032, p < 0.001), education level (β = 2.801, p < 0.001), TUG (β = -0.022, p = 0.013), Thai Geriatric Depression Score, TGDS (β = -0.248, p = 0.011), and age (β = -1.677, p = 0.019) were associated with MCI. A decrease in HGS and an increased TUG might allow for the early detection of MCI and promote physical training in order to reduce the risk of MCI. Further studies can investigate multidomain indicators for MCI, for example, fine motor skills and pinch strength as components of the motor abilities.

Nativity differences in the relationship between handgrip strength and cognitive impairment in older Mexican Americans over 20 years of follow-up

PURPOSE

To examine nativity differences in the relationship between handgrip strength (HGS) and cognitive impairment among Mexican Americans aged ≥ 65 years with normal or high cognitive function at baseline over a 20-year period.

METHODS

Prospective cohort study of 2,155 non-institutionalized Mexican Americans aged ≥ 65 years from the Hispanic Established Population for the Epidemiological Study of the Elderly) who scored ≥ 21 in the Mini Mental State Examination (MMSE) at baseline. Measures included socio-demographics, body mass index, medical conditions, depressive symptoms, physical function, disability, HGS quartiles (sex-adjusted), and MMSE. We used generalized estimating equation models to estimate the odds ratio (OR) and 95% Confidence Interval (CI) of cognitive impairment (MMSE < 21) as a function of HGS quartile by nativity and adjusted for covariates.

RESULTS

US-born and foreign-born participants in the 4th quartile (highest) of HGS at baseline had lower odds of cognitive impairment over time compared with those in the 1st (lowest) HGS quartile (OR=0.95, 95% CI=0.90-0.99 and OR=0.93, 95% CI=0.89-0.98, respectively), after controlling for all covariates. When we analyzed HGS quartiles as time-varying, we found that US-born participants in the 3rd and 4th HGS quartile had 25% and 30% lower odds of cognitive impairment, respectively, while foreign-born participants in the 3rd and 4th HGS quartile had 27% and 49% lower odds of cognitive impairment over time, respectively, after controlling for all covariates.

CONCLUSION

Foreign-born older Mexican Americans who performed high in HGS experienced 7% lower odds of cognitive impairment over time compared with US-born older Mexican Americans.

The Relationship Between Sarcopenia, Cognitive Impairment, and Cerebral White Matter Hyperintensity in the Elderly

Purpose

To explore the relationship between sarcopenia-related indices, cognitive impairment and cerebral white matter hyperintensities.

Patients and methods

Ninety-five hospitalized older adults aged 60 years and older were used in this study. Three sarcopenia-related indicators were measured: hand grip strength (Measured with a spring-type dynamometer), gait speed (6m step speed method), and appendicular skeletal muscle mass (ASM, bioelectrical impedance). Sarcopenia was defined according to the Asian Working Group for Sarcopenia (AWGS) criteria. Cognitive function was assessed using Montreal Cognitive Assessment (MoCA). Cerebral white matter hyperintensity was assessed using 3.0T superconducting magnetic resonance imaging.

Results

In both men and women, these three indices of sarcopenia were significantly and negatively correlated with WMH grades, except for appendicular skeletal muscle mass and WMH grades in women. Scores on the MoCA scale were significantly positive correlated with grip strength, and ASM, both in men and women. After adjusting for confounders and WMHs, regression analyses showed an increased incidence of cognitive impairment in patients with sarcopenia relative to those without sarcopenia.

Conclusion

Lower sarcopenia-related indices were significantly associated with cognitive impairment. WMHs may be one of the factors linking sarcopenia and cognitive function.

Grip strength, gait speed, and trajectories of cognitive function in community-dwelling older adults: A prospective study

Introduction

This study investigated whether grip strength and gait speed predict cognitive aging trajectories and examined potential sex-specific associations.

Methods

Community-dwelling older adults (n = 19,114) were followed for up to 7 years, with regular assessment of global function, episodic memory, psychomotor speed, and executive function. Group-based multi-trajectory modeling identified joint cognitive trajectories. Multinomial logistic regression examined the association of grip strength and gait speed at baseline with cognitive trajectories.

Results

High performers (14.3%, n = 2298) and low performers (4.0%, n = 642) were compared to the average performers (21.8%, n = 3492). Grip strength and gait speed were positively associated with high performance and negatively with low performance (P-values < 0.01). The association between grip strength and high performance was stronger in women (interaction P < 0.001), while gait speed was a stronger predictor of low performance in men (interaction P < 0.05).

Discussion

Grip strength and gait speed are associated with cognitive trajectories in older age, but with sex differences.

Highlights

There is inter-individual variability in late-life cognitive trajectories.Grip strength and gait speed predicted cognitive trajectories in older age.However, sex-specific associations were identified.In women, grip strength strongly predicted high, compared to average, trajectory.In men, gait speed was a stronger predictor of low cognitive performance trajectory.

Grip strength is inversely associated with DNA methylation age acceleration

BACKGROUND

There is a large body of evidence linking muscular weakness, as determined by low grip strength, to a host of negative ageing-related health outcomes. Given these links, grip strength has been labelled a 'biomarker of aging'; and yet, the pathways connecting grip strength to negative health consequences are unclear. The objective of this study was to determine whether grip strength was associated with measures of DNA methylation (DNAm) age acceleration.

METHODS

Middle age and older adults from the 2006 to 2008 waves of the Health and Retirement Study with 8-10 years of follow-up were included. Cross-sectional and longitudinal regression modelling was performed to examine the association between normalized grip strength (NGS) and three measures of DNAm age acceleration, adjusting for cell composition, sociodemographic variables and smoking. Longitudinal modelling was also completed to examine the association between change in absolute grip strength and DNAm age acceleration. The three DNAm clocks used for estimating age acceleration include the established DunedinPoAm, PhenoAge and GrimAge clocks.

RESULTS

There was a robust and independent cross-sectional association between NGS and DNAm age acceleration for men using the DunedinPoAm (β: -0.36; P < 0.001), PhenoAge (β: -8.27; P = 0.01) and GrimAge (β: -4.56; P = 0.01) clocks and for women using the DunedinPoAm (β: -0.36; P < 0.001) and GrimAge (β: -4.46; P = 0.01) clocks. There was also an independent longitudinal association between baseline NGS and DNAm age acceleration for men (β: -0.26; P < 0.001) and women (β: -0.36; P < 0.001) using the DunedinPoAm clock and for women only using the PhenoAge (β: -8.20; P < 0.001) and GrimAge (β: -5.91; P < 0.001) clocks. Longitudinal modelling revealed a robust association between change in grip strength from wave 1 to wave 3 was independently associated with PhenoAgeAA (β: -0.13; 95% CI: -0.23, -0.03) and GrimAgeAA (β: -0.07; 95% CI: -0.14, -0.01) in men only (both P < 0.05).

CONCLUSIONS

Our findings provide some initial evidence of age acceleration among men and women with lower NGS and loss of strength over time. Future research is needed to understand the extent to which DNAm age mediates the association between grip strength and chronic disease, disability and mortality.

Walking pace, handgrip strength, age, APOE genotypes, and new-onset dementia: the UK Biobank prospective cohort study

BACKGROUND

The independent and additive associations of walking pace and grip strength on dementia risk and the potential modifying effects of age, APOE phenotypes, and other dementia risk factors on the walking pace and dementia relationships demand further clarification. We aimed to investigate the independent and additive relationships of walking pace and handgrip strength on the risk of new-onset dementia and examine the potentially modifying effects of age, APOE phenotypes, lifestyle factors, and family history of dementia in the relationships.

METHODS

A total of 495,700 participants from the UK Biobank, who were free of dementia at baseline, were included in this study. Walking pace was self-defined as slow, average, or brisk. Handgrip strength was assessed by dynamometer and was divided into sex-specific quartiles. The APOE genotypes were determined by a combination variant of rs429358 and rs7412. Other dementia risk factors, including education, physical activity, hypertension, depression, diabetes, and family history of dementia, were also collected. The primary outcome was new-onset all-cause dementia.

RESULTS

Over a median follow-up duration of 12.0 years, 3986 (0.8%) participants developed new-onset all-cause dementia. Compared with those with slow walking pace, participants with average (HR, 0.61; 95%CI: 0.55-0.68) or brisk (HR, 0.59; 95%CI: 0.52-0.67) walking pace had a significantly lower risk of new-onset all-cause dementia. Moreover, compared with those with both slow walking pace and lower handgrip strength (the first quartile), the lowest risk of new-onset all-cause dementia was observed in participants with both average or brisk walking pace and higher handgrip strength (the 2-4 quartiles) (HR, 0.45; 95%CI: 0.40-0.52). Notably, the negative relationship between walking pace and the risk of new-onset all-cause dementia was significantly reduced as APOE ε4 dosage increased (APOE ε4 dosages = 0 or 1: brisk vs. slow: HR, 0.55; 95%CI: 0.48-0.63; vs. APOE ε4 dosages = 2: brisk vs. slow: HR, 1.14; 95%CI: 0.77-1.68; P for interaction = 0.001) or age increased (< 58 [median]: brisk vs. slow: HR, 0.27; 95%CI: 0.18-0.41; vs. ≥ 58 years: brisk vs. slow: HR, 0.55; 95%CI: 0.48-0.63; P for interaction = 0.007).

CONCLUSIONS

Walking pace was inversely associated with new-onset dementia in the general population, especially in younger participants and those with lower APOE ε4 dosage. Participants with both faster walking pace and higher handgrip strength had the lowest risk of dementia, suggesting that maintaining both high handgrip strength and fast walking pace may be a more comprehensive strategy for preventing dementia risk.