Combination of gait speed and grip strength to predict cognitive decline and dementia

Physical function is associated with cognitive status, brain amyloid-beta deposition, and blood biomarkers in Chinese Han population

BACKGROUND

The physical function of elderly individuals reflects whether they have had a history of regular physical activity over the long term. Such indicators have been found to have a certain connection with cognitive function these years. However, there is limited research that associates it with mechanisms such as cerebral Aβ deposition. We aim to investigate this relationship and unveil the underlying mechanisms.

METHOD

Physical function and cognition data of 4189 participants were obtained from the Chinese preclinical Alzheimer's disease study. Participants were divided into six groups according to disease severity. Among them, 1048 participants underwent the positron emission tomography-computed tomography (PET-CT) and plasma biomarker test. Grip strength and gait were combined into a score indicating physical function. Multiple linear regression models and logistic regression models were mainly used to conduct the analysis.

RESULTS

There was a significant positive correlation between physical function and cognitive function (R = 0.48, p < 0.001), independent of sex, age, apolipoprotein E-ε4 genotype, and disease stages (p < 0.001). Physical function was effective in distinguishing individuals with cognitive impairment from those without (AUC = 0.835). Physical function was negatively associated with brain Aβ deposition (p = 0.008) and brain Aβ had an intermediary effect (p < 0.01) on the association between physical function and cognition in women. This association was mainly evident in the lateral parietal, lateral temporal, posterior cingulate, frontal, occipital, and precuneus regions. Physical function was negatively associated with plasma neurofilament light-chain (Nfl) level (p < 0.001).

CONCLUSIONS

Physical function is strongly associated with cognitive function in the Chinese elderly, and brain Aβ deposition partly mediates the linkage in women. Plasma Nfl can be used as a potential target for exercise intervention in cognitive function. Improving physical function will contribute to the alleviation of cognition decline.

Cognitive function in different motor subtypes of Parkinson's disease: A systematic review protocol

Background and Aims

As the fastest-growing neurological disorder globally, a better understanding of Parkinson's disease (PD) is needed to improve patient outcomes and reduce the increasing economic and healthcare burden associated with the disease. Whilst classified as a movement disorder, this disease is highly heterogeneous, encompassing a broad range of both motor and non-motor symptoms (NMS). Cognitive impairment, presenting as either mild cognitive impairment or PD-dementia, is one of the most prevalent and disabling NMS. To better understand heterogeneity in PD, researchers have sought to identify subtypes of individuals who share similar symptom profiles. To date, this research has predominantly focused on motor subtyping, with many studies comparing these motor subtypes on non-motor outcomes, such as cognitive impairment. However, despite evidence of a motor-cognitive relationship in healthy aging, findings regarding the presence of a motor-cognitive relationship in PD are inconsistent. In our proposed systematic review, we will investigate motor subtyping studies that have evaluated the relationship between motor and cognitive function in PD. We aim to examine what is currently known about the relationship between motor and cognitive impairment in PD and evaluate the state of the field with respect to the subtyping methods and quality of cognitive assessment tools used.

Methods

Systematic literature searches will be conducted in PubMed, PsycINFO, CINAHL, Scopus, and Web of Science.

Results

Results will be synthesized using meta-analysis and, where meta-analysis is not feasible, narrative synthesis.

Conclusion

Despite the preponderance of motor subtyping research in PD, our study will be the first to systematically review evidence regarding the association between motor subtypes and cognitive impairment. Understanding the nature of the motor-cognitive relationship in PD may lead to important insights regarding shared underlying disease pathology, which would have significant implications for early diagnosis, prognosis, and treatment of cognitive impairment in PD.

Associations of body habitus and its changes with incident dementia in older adults

BACKGROUND

This study examined the associations of body mass index (BMI) and waist circumference (WC), as well as their short- and long-term changes over time, with incident dementia in older individuals.

METHODS

Data came from 18,837 community-dwelling individuals aged 65+ years from Australia and the United States, who were relatively healthy without major cognitive impairment at enrolment. Anthropometric measures were prospectively assessed at baseline, as well as change and variability from baseline to year two (three time-points). In a subgroup (n = 11,176), self-reported weight at age 18 and 70+ years was investigated. Dementia cases satisfied DSM-IV criteria. Cox regression was used to examine the associations between anthropometric measures and incident risk of dementia.

RESULTS

Compared to normal weight, an overweight (HR: 0.67, 95%CI: 0.57-0.79, p < 0.001) or obese BMI (HR: 0.73, 95%CI: 0.60-0.89, p = 0.002), or a larger WC (elevated, HR: 0.71, 95%CI: 0.58-0.86, p < 0.001; highly elevated, HR: 0.65, 95%CI: 0.55-0.78, p < 0.001; relative to low) at baseline was associated with lower dementia risk. In contrast, substantial increases in BMI (>5%) over 2 years after baseline were associated with higher dementia risk (HR: 1.49, 95% CI: 1.17-1.91, p = 0.001). Increased dementia risk was also seen with an underweight BMI at baseline and a 2-year BMI decrease (>5%), but these associations appeared only in the first 4 years of follow-up. Compared to normal weight at both age 18 and 70+ years, being obese at both times was associated with increased dementia risk (HR: 2.27, 95%CI: 1.22-4.24, p = 0.01), while obesity only at age 70+ years was associated with decreased risk (HR: 0.70, 95%CI: 0.51-0.95, p = 0.02).

CONCLUSIONS

Our findings suggest that long-term obesity and weight gain in later life may be risk factors for dementia. Being underweight or having substantial weight loss in old age may be early markers of pre-clinical dementia.

Sex differences in biological aging and the association with clinical measures in older adults

Females live longer than males, and there are sex disparities in physical health and disease incidence. However, sex differences in biological aging have not been consistently reported and may differ depending on the measure used. This study aimed to determine the correlations between epigenetic age acceleration (AA), and other markers of biological aging, separately in males and females. We additionally explored the extent to which these AA measures differed according to socioeconomic characteristics, clinical markers, and diseases. Epigenetic clocks (HorvathAge, HannumAge, PhenoAge, GrimAge, GrimAge2, and DunedinPACE) were estimated in blood from 560 relatively healthy Australians aged ≥ 70 years (females, 50.7%) enrolled in the ASPREE study. A system-wide deficit accumulation frailty index (FI) composed of 67 health-related measures was generated. Brain age and subsequently brain-predicted age difference (brain-PAD) were estimated from neuroimaging. Females had significantly reduced AA than males, but higher FI, and there was no difference in brain-PAD. FI had the strongest correlation with DunedinPACE (range r: 0.21 to 0.24 in both sexes). Brain-PAD was not correlated with any biological aging measures. Significant correlations between AA and sociodemographic characteristics and health markers were more commonly found in females (e.g., for DunedinPACE and systolic blood pressure r = 0.2, p < 0.001) than in males. GrimAA and Grim2AA were significantly associated with obesity and depression in females, while in males, hypertension, diabetes, and chronic kidney disease were associated with these clocks, as well as DunedinPACE. Our findings highlight the importance of considering sex differences when investigating the link between biological age and clinical measures.

Long-term blood pressure variability and frailty risk in older adults

INTRODUCTION

In healthy older adults, the relationship between long-term, visit-to-visit variability in blood pressure (BP) and frailty is uncertain.

METHODS

Secondary analysis of blood pressure variability (BPV) and incident frailty in >13 000 participants ≥65-70 years enrolled in the ASPirin in Reducing Events in the Elderly (ASPREE) trial and its observational follow-up (ASPREE-XT). Participants were without dementia, physical disability, or cardiovascular disease at baseline. BPV was estimated using standard deviation of mean BP from three annual visits (baseline through the second annual follow-up). Frailty was defined using Fried phenotype and a frailty deficit accumulation index (FDAI). Participants with frailty during the BPV estimation period were excluded from the main analysis. Adjusted Cox proportional hazards regression evaluated the association between BPV and incident frailty, and linear mixed models for change in frailty scores, through a maximum of 9 years of follow-up.

RESULTS

Participants in the highest systolic BPV tertile were at higher risk of frailty compared to those in the lowest (referent) tertile of systolic BPV [Fried hazard ratio (HR) 1.17, 95% confidence interval (CI) 1.04-1.31; FDAI HR 1.18, 95% CI 1.07-1.30]. Findings were consistent when adjusted for multiple covariates and when stratified by antihypertensive use. Linear mixed models showed that higher systolic BPV was associated with increasing frailty score over time. Diastolic BPV was not consistently associated.

CONCLUSIONS

High systolic BPV, independent of mean BP, is associated with increased risk of frailty in healthy older adults. Variability of BP across visits, even in healthy older adults, can convey important risk information beyond mean BP.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01038583 and ISRCTN83772183.

Current evidence on the association of tongue strength with cognitive decline in older adults and the known risk factors of frailty, sarcopenia and nutritional health: a scoping review protocol

INTRODUCTION

Evidence suggests that the pathology underlying cognitive decline leading to dementia begins 15-20 years before cognitive symptoms emerge. Thus, identifying biomarkers in this preclinical phase is critically important. Age-related decrease in muscle mass and strength, a known risk factor for sarcopenia, frailty and cognitive decline, also affects the tongue. This paper describes an a priori protocol by a multidisciplinary team to address the following questions relating to adults ≥50 years of age: (1) What is the current evidence on the association of tongue strength with cognitive decline? (2) How does tongue strength associate with frailty and sarcopenia? (3) What is the association of tongue strength with nutritional health?

METHODS AND ANALYSIS

Search terms will be identified then multiple electronic databases (PubMed, PsycINFO (Ovid), Scopus, Embase (Ovid), CINAHL and Web of Science) searched systematically for peer-reviewed articles published in English that address the following inclusion criteria: (1) human studies, (2) participants ≥50 years of age and (3) studies with tongue pressure values measured in relation to at least one of the following: frailty, sarcopenia, nutritional health, cognitive function and dementia (Alzheimer's, vascular, frontotemporal and Lewy body). Grey literature also will be searched to identify additional studies, clinical trials and policy papers appropriate for inclusion. The search will be from database inception. After removing duplicates, two research team members will independently screen abstracts and identify articles for full-text review. The team will use a data charting tool for data extraction. Data will be analysed quantitatively and qualitatively.

ETHICS AND DISSEMINATION

The scoping review does not require ethics approval as data will be from publicly available sources. Results will be disseminated in workshops and conferences and a peer-reviewed journal paper.