Linking cognition and frailty in middle and old age: metabolic syndrome matters

Association of metabolic syndrome severity with frailty progression among Chinese middle and old-aged adults: a longitudinal study

BACKGROUND

The binary diagnosis of Metabolic Syndrome(MetS) fails to accurately evaluate its severity, and the association between MetS severity and frailty progression remains inadequately elucidated. This study aims to clarify the relationship between the severity of MetS and the progression of frailty among the middle-aged and elderly population in China.

METHOD

Participants from the 2011-2018 China Health and Retirement Longitudinal Study(CHARLS) were included for a longitudinal analysis. The study employs a frailty index(FI) based on 32 health deficits to diagnose frailty and to assess FI trajectories. An age-sex-ethnicity-specific MetS scoring model (MetS score) was used to assess metabolic syndrome severity in Chinese adults. The Cumulative MetS score from 2012 to 2015 was calculated using the formula: (MetS score in wave 1 + MetS score in wave 3) / 2 × time(2015 - 2012). The association between MetS score, Cumulative MetS score, and the risk and trajectory of frailty were evaluated using Cox regression/logistic regression, and linear mixed models. Restricted Cubic Splines(RCS) models were utilized to detect potential non-linear associations.

RESULTS

A higher MetS score was significantly associated with an increased risk of frailty(HR per 1 SD increase = 1.205; 95%CI: 1.14 to 1.273) and an accelerated FI trajectory(β per 1 SD increase = 0.113 per year; 95%CI: 0.075 to 0.15 per year). Evaluating changes in MetS score using a Cumulative MetS score indicated that each 1 SD increase in the Cumulative MetS score increased the risk of frailty by 22.2%(OR = 1.222; 95%CI: 1.133 to 1.319) and accelerated the rate of increase in FI(β = 0.098 per year; 95%CI: 0.058 to 0.138 per year). RCS model results demonstrated a dose-response curve relationship between MetS score and Cumulative MetS score with frailty risk. Stratified analysis showed consistency across subgroups. The interaction results indicate that in males and individuals under aged 60, MetS score may accelerate the increase in FI, a finding consistent across both models.

CONCLUSIONS

Our findings underscore the positive correlation between the severity of MetS and frailty progression in the middle-aged and elderly, highlighting the urgent need for early identification of MetS and targeted interventions to reduce the risk of frailty.

The intersection of frailty and metabolism

On average, aging is associated with unfavorable changes in cellular metabolism, which are the processes involved in the storage and expenditure of energy. However, metabolic dysregulation may not occur to the same extent in all older individuals as people age at different rates. Those who are aging rapidly are at increased risk of adverse health outcomes and are said to be "frail." Here, we explore the links between frailty and metabolism, including metabolic contributors and consequences of frailty. We examine how metabolic diseases may modify the degree of frailty in old age and suggest that frailty may predispose toward metabolic disease. Metabolic interventions that can mitigate the degree of frailty in people are reviewed. New treatment strategies developed in animal models that are poised for translation to humans are also considered. We suggest that maintaining a youthful metabolism into older age may be protective against frailty.

Translational research into frailty from bench to bedside: Salivary biomarkers for inflammaging

Frailty is a complex physiological syndrome associated with adverse ageing and decreased physiological reserves. Frailty leads to cognitive and physical disability and is a significant cause of morbidity, mortality and economic costs. The underlying cause of frailty is multifaceted, including immunosenescence and inflammaging, changes in microbiota and metabolic dysfunction. Currently, salivary biomarkers are used as early predictors for some clinical diseases, contributing to the effective prevention and treatment of diseases, including frailty. Sample collection for salivary analysis is non-invasive and simple, which are paramount factors for testing in the vulnerable frail population. The aim of this review is to describe the current knowledge on the association between frailty and the inflammatory process and discuss methods to identify putative biomarkers in salivary fluids to predict this syndrome. This study describes the relationship between i.-inflammatory process and frailty; ii.-infectious, chronic, skeletal, metabolic and cognitive diseases with inflammation and frailty; iii.-inflammatory biomarkers and salivary fluids. There is a limited number of previous studies focusing on the analysis of inflammatory salivary biomarkers and frailty syndrome; hence, the study of salivary fluids as a source for biomarkers is an open area of research with the potential to address the increasing demands for frailty-associated biomarkers.

The association between metabolic syndrome and presence of frailty: a systematic review and meta-analysis

BACKGROUND

Frailty represents a progressive deterioration in multi-system of the body and could increase vulnerability to stressors. Recently, several studies found that metabolic syndrome was significantly associated with frailty and emphasized its role in assessing and preventing frailty. However, these conclusions are controversial. We conducted this systematic review and meta-analysis to evaluate the association between metabolic syndrome and frailty.

METHODS

Databases including Pubmed, Embase, Web of Science, CINAHL Complete, China National Knowledge Infrastructure (CNKI) and Wanfang Data Knowledge Service Platform were searched for studies on the association between metabolic syndrome and frailty, from inception to 17th June 2022. Two researchers independently screened the literature, extracted the data and evaluated the quality. Stata/SE 15.0 software was used to perform the statistical analysis.

RESULTS

Eleven studies were included in this review and eight studies were included in the meta-analysis, involving one prospective cohort studies and ten cross-sectional studies with 12,640 participants. The pooled results indicated that metabolic syndrome was significantly associated with frailty (OR = 1.82, 95% CI = 1.46-2.27) with a low heterogeneity (I² = 32.1%), and there were significant associations between MetS and weakness (OR = 1.35, 95% CI = 1.15-1.58, I² = 0.0%), slow gait speed (OR = 1.80, 95% CI = 1.51-2.14, I² = 93.4%), weight loss (OR = 1.77, 95% CI = 1.36-2.29, I² = 0.0%) and decreased physical activity (OR = 1.87, 95% CI = 1.49-2.35, I² = 39.7%).

CONCLUSIONS

The findings of this systematic review and meta-analysis suggested that metabolic syndrome could be significantly associated with the presence of frailly. Future studies need to further consider the effects of measurement tools, age and specific disease status in this association. Furthermore, the casual relationship between them is to be determined.

Expressive suppression and rumination mediate the relationship between frailty and depression among older medical inpatients

OBJECTIVE

Frailty is common among older medical inpatients and has been found to be an independent risk factor for depression. However, few studies have explored the underlying mechanisms of the frailty-depression relationship. The present study was aimed to examine emotional regulation strategies as mediators in the frailty-depression relationship based on the process model of emotional regulation.

METHODS

Older medical inpatients (N=684) completed questionnaires and tests on frailty, emotional regulation strategies, and depressive symptoms.

RESULTS

Structural equation models showed that expressive suppression and rumination, but not cognitive reappraisal, mediated the relationship between frailty and depressive symptoms (RMSEA = 0.059, CFI = 0.963, TLI = 0.957).

CONCLUSIONS

Frail older medical inpatients habitually use expressive suppression and rumination in their daily lives, which may lead to more psychological disturbance. Interventions targeting expressive suppression and rumination might be effective in reducing the detrimental effect of frailty on psychological well-being among older medical inpatients.

Telomere Length and Oxidative Stress and Its Relation with Metabolic Syndrome Components in the Aging

A great amount of scientific evidence supports that Oxidative Stress (OxS) can contribute to telomeric attrition and also plays an important role in the development of certain age-related diseases, among them the metabolic syndrome (MetS), which is characterised by clinical and biochemical alterations such as obesity, dyslipidaemia, arterial hypertension, hyperglycaemia, and insulin resistance, all of which are considered as risk factors for type 2 diabetes mellitus (T2DM) and cardiovascular diseases, which are associated in turn with an increase of OxS. In this sense, we review scientific evidence that supports the association between OxS with telomere length (TL) dynamics and the relationship with MetS components in aging. It was analysed whether each MetS component affects the telomere length separately or if they all affect it together. Likewise, this review provides a summary of the structure and function of telomeres and telomerase, the mechanisms of telomeric DNA repair, how telomere length may influence the fate of cells or be linked to inflammation and the development of age-related diseases, and finally, how the lifestyles can affect telomere length.

Physical activity and exercise: Strategies to manage frailty

Frailty, a consequence of the interaction of the aging process and certain chronic diseases, compromises functional outcomes in the elderly and substantially increases their risk for developing disabilities and other adverse outcomes. Frailty follows from the combination of several impaired physiological mechanisms affecting multiple organs and systems. And, though frailty and sarcopenia are related, they are two different conditions. Thus, strategies to preserve or improve functional status should consider systemic function in addition to muscle conditioning. Physical activity/exercise is considered one of the main strategies to counteract frailty-related physical impairment in the elderly. Exercise reduces age-related oxidative damage and chronic inflammation, increases autophagy, and improves mitochondrial function, myokine profile, insulin-like growth factor-1 (IGF-1) signaling pathway, and insulin sensitivity. Exercise interventions target resistance (strength and power), aerobic, balance, and flexibility work. Each type improves different aspects of physical functioning, though they could be combined according to need and prescribed as a multicomponent intervention. Therefore, exercise intervention programs should be prescribed based on an individual's physical functioning and adapted to the ensuing response.

Effectiveness of interventions to prevent pre-frailty and frailty progression in older adults: a systematic review

OBJECTIVE

To summarize the best available evidence regarding the effectiveness of interventions for preventing frailty progression in older adults.

INTRODUCTION

Frailty is an age-related state of decreased physiological reserves characterized by an increased risk of poor clinical outcomes. Evidence supporting the malleability of frailty, its prevention and treatment, has been presented.

INCLUSION CRITERIA

The review considered studies on older adults aged 65 and over, explicitly identified as pre-frail or frail, who had been undergoing interventions focusing on the prevention of frailty progression. Participants selected on the basis of specific illness or with a terminal diagnosis were excluded. The comparator was usual care, alternative therapeutic interventions or no intervention. The primary outcome was frailty. Secondary outcomes included: (i) cognition, quality of life, activities of daily living, caregiver burden, functional capacity, depression and other mental health-related outcomes, self-perceived health and social engagement; (ii) drugs and prescriptions, analytical parameters, adverse outcomes and comorbidities; (iii) costs, and/or costs relative to benefits and/or savings associated with implementing the interventions for frailty. Experimental study designs, cost effectiveness, cost benefit, cost minimization and cost utility studies were considered for inclusion.

METHODS

Databases for published and unpublished studies, available in English, Portuguese, Spanish, Italian and Dutch, from January 2001 to November 2015, were searched. Critical appraisal was conducted using standardized instruments from the Joanna Briggs Institute. Data was extracted using the standardized tools designed for quantitative and economic studies. Data was presented in a narrative form due to the heterogeneity of included studies.

RESULTS

Twenty-one studies, all randomized controlled trials, with a total of 5275 older adults and describing 33 interventions, met the criteria for inclusion. Economic analyses were conducted in two studies. Physical exercise programs were shown to be generally effective for reducing or postponing frailty but only when conducted in groups. Favorable effects on frailty indicators were also observed after the interventions, based on physical exercise with supplementation, supplementation alone, cognitive training and combined treatment. Group meetings and home visits were not found to be universally effective. Lack of efficacy was evidenced for physical exercise performed individually or delivered one-to-one, hormone supplementation and problem solving therapy. Individually tailored management programs for clinical conditions had inconsistent effects on frailty prevalence. Economic studies demonstrated that this type of intervention, as compared to usual care, provided better value for money, particularly for very frail community-dwelling participants, and had favorable effects in some of the frailty-related outcomes in inpatient and outpatient management, without increasing costs.

CONCLUSIONS

This review found mixed results regarding the effectiveness of frailty interventions. However, there is clear evidence on the usefulness of such interventions in carefully chosen evidence-based circumstances, both for frailty itself and for secondary outcomes, supporting clinical investment of resources in frailty intervention. Further research is required to reinforce current evidence and examine the impact of the initial level of frailty on the benefits of different interventions. There is also a need for economic evaluation of frailty interventions.

Frailty and the endocrine system

Frailty is a condition characterised by loss of biological reserves, failure of homoeostatic mechanisms, and vulnerability to adverse outcomes. The endocrine system is considered particularly important in frailty, because of its complex inter-relationships with the brain, immune system, and skeletal muscle. This Review summarises evidence indicating a key role for the hypothalamic-pituitary axis in the pathogenesis of frailty through aberrant regulation of glucocorticoid secretion, insulin-like growth factor signalling, and androgen production. Evidence also indicates a potential role for vitamin D and insulin resistance in the pathogenesis of frailty. The role of thyroid hormones in the pathogenesis of frailty remains uncertain. Key convergent pathological effects of frailty include loss of muscle mass and strength, with consequent impact on mobility and activities of daily living. Future translational research should focus on the understanding of endocrine mechanisms, to identify potential biomarkers of the condition, modifiable targets for treatment, and novel pharmacological drugs targeted at the endocrine components of frailty.

The unity and diversity of executive functions: A systematic review and re-analysis of latent variable studies

Confirmatory factor analysis (CFA) has been frequently applied to executive function measurement since first used to identify a three-factor model of inhibition, updating, and shifting; however, subsequent CFAs have supported inconsistent models across the life span, ranging from unidimensional to nested-factor models (i.e., bifactor without inhibition). This systematic review summarized CFAs on performance-based tests of executive functions and reanalyzed summary data to identify best-fitting models. Eligible CFAs involved 46 samples (N = 9,756). The most frequently accepted models varied by age (i.e., preschool = one/two-factor; school-age = three-factor; adolescent/adult = three/nested-factor; older adult = two/three-factor), and most often included updating/working memory, inhibition, and shifting factors. A bootstrap reanalysis simulated 5,000 samples from 21 correlation matrices (11 child/adolescent; 10 adult) from studies including the three most common factors, fitting seven competing models. Model results were summarized as the mean percent accepted (i.e., average rate at which models converged and met fit thresholds: CFI ≥ .90/RMSEA ≤ .08) and mean percent selected (i.e., average rate at which a model showed superior fit to other models: ΔCFI ≥ .005/.010/ΔRMSEA ≤ -.010/-.015). No model consistently converged and met fit criteria in all samples. Among adult samples, the nested-factor was accepted (41-42%) and selected (8-30%) most often. Among child/adolescent samples, the unidimensional model was accepted (32-36%) and selected (21-53%) most often, with some support for two-factor models without a differentiated shifting factor. Results show some evidence for greater unidimensionality of executive function among child/adolescent samples and both unity and diversity among adult samples. However, low rates of model acceptance/selection suggest possible bias toward the publication of well-fitting but potentially nonreplicable models with underpowered samples. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Hypoglycemic and antioxidant effect of Tai chi exercise training in older adults with metabolic syndrome

Introduction

The antioxidant and anti-inflammatory effects of Tai chi (TC) exercise training in healthy older adults has been demonstrated. However, there are no studies on this effect in older adults with metabolic syndrome (MetS).

Purpose

The aim of this study was to determine the effect of TC exercise on oxidative stress and inflammatory markers in older adults with MetS.

Methods

A quasi-experimental study was carried out with a sample of 110 older sedentary volunteers with clinical diagnoses of MetS: (i) a control group, n = 50, of individuals who do not participate in physical exercise, of which 37 fulfilled the entire study protocol, and (ii) an experimental group, n = 60, of subjects enrolled in a TC exercise training program (eight-form easy), 5 days a week for 6 months, in sessions of 50 min, under the supervision of a qualified instructor, of which 48 fulfilled the entire study protocol. We measured in both groups (pre- and post-intervention) the following cardiovascular parameters: resting heart rate (RHR), diastolic and systolic blood pressure (DBP and SBP), mean arterial pressure (MAP), RHR-SBP product, RHR-MAP product; glycosylated hemoglobin (HbA1c); oxidative stress markers (superoxide dismutase, total antioxidant status, thiobarbituric acid reacting substances, and oxidative stress score); and inflammation markers (TNF-α, IL-6, IL-8, and IL-10).

Results

A statistically significant decrease in HbA1c concentration was observed in the TC group compared with the control group (p < 0.05). This group also showed a statistically significant increase in TAS and a decrease in the oxidative stress score (p < 0.05). We did not observe changes in the cardiovascular parameters (RHR, DBP, SBP, MAP, RHR-SBP product, and RHR-MAP product) in the TC experimental group compared to the control group.

Conclusion

Our findings suggest that the practice of TC exercise has an antioxidative and hypoglycemic effect in the elderly with MetS.

Injury patterns and outcomes in late middle age (55-65): The intersecting comorbidity with high-risk activity - A retrospective cohort study

BACKGROUND

Late middle age (LMA), is a watershed between youth and old age, with unique physical and social changes and declines in vitality, but a desire to remain active despite increasing comorbidity. While post-injury outcomes in the elderly are well studied, little is known regarding LMA patients. We analyzed the injured LMA population admitted to a rural, regional Level 1 Trauma Center relative to outcomes for both younger and older patients.

MATERIALS AND METHODS

Our registry was queried retrospectively for patients admitted 7/2008- 12/2015; they were divided into three cohorts: 18-54, 55-65, and >65 years. Demographics, injury details, comorbidities, and outcomes were compiled and compared using ANOVA and Chi-square; p < 0.05 was significant.

RESULTS

During the study period, 10,543 were admitted; 1419 (14%) were LMA who experienced overall injury mechanisms, severities and patterns that mirrored the younger cohort. However comorbidity rates were high (56.4%) and comparable to the elderly. LMA patients had the highest rates of alcohol abuse, morbid obesity, and psychiatric illness (p < 0.0001) and suffered the poorest outcomes: highest complications and hospital charges, and longest ICU and hospital LOS. LMA mortality (4.1%) was 41% higher than younger patients (2.9%; p < 0.02) and similar to the older cohort (4.7%; p = 0.32).

CONCLUSIONS

The LMA population has similar mechanisms and injury patterns to younger patients, while exhibiting comorbidity rates similar to the elderly. High-energy injuries exact a greater toll in LMA with poorer outcomes and greater resource utilization. Targeted outreach for injury prevention, and future studies, are needed to address high-risk behavior, substance abuse, and societal contributors.

The association between frailty, the metabolic syndrome, and mortality over the lifespan

Frailty and the metabolic syndrome are each associated with poor outcomes, but in very old people (90+ years) only frailty was associated with an increased mortality risk. We investigated the relationship between frailty, metabolic syndrome, and mortality risk, in younger (20-65 years) and older (65+ years) people. This is a secondary analysis of the US National Health and Nutrition Examination Survey (NHANES) datasets for 2003-2004 and 2005-2006, linked with mortality data up to 2011. The metabolic syndrome was defined using the International Diabetes Federation criteria. Frailty was operationalized using a 41-item frailty index (FI). Compared to the younger group (n = 6403), older adults (n = 2152) had both a higher FI (0.10 ± 0.00 vs. 0.22 ± 0.00, p < 0.001) and a greater prevalence of the metabolic syndrome (24.1 vs. 45.5%, p < 0.001). The metabolic syndrome and FI were correlated in younger people (r = 0.25, p < 0.001) but not in older people (r = 0.08, p < 0.1). In bivariate analyses, the FI predicted mortality risk in both age groups whereas the metabolic syndrome did so only in the younger group. In Cox models, adjusted for age, sex, race, education, and each other, the FI was associated with increased mortality risk at both ages (younger HR 1.05 (1.04-1.06); older HR 1.04 (1.03-1.04) whereas the metabolic syndrome did not contribute to mortality risk. The FI better predicted mortality than did the metabolic syndrome, regardless of age.

The metabolic syndrome and 10-year cognitive and functional decline in very old men. A population-based study

OBJECTIVES

To describe longitudinal relationships of metabolic syndrome (MetS) to cognitive decline and functional disability in a sample of older non-institutionalized men.

METHODS

data from 1991 to 2000 of the Italian cohorts of the Finland, Italy, the Netherlands, Elderly (FINE) study, were used. Global cognitive function and functional disability, defined as limitations in mobility, basic (ADLs) and instrumental activities of daily living (IADLs) were screened in 1991 and 2000. MetS was defined according to the NCEP ATP-III criteria.

RESULTS

The study sample consisted of 195 men, baseline age 76.1±3.1years. Baseline MetS was prospectively associated with greater 10-year cognitive and functional decline in ADLs and IADLs. After multiple adjustment including age, education, marital status, ApoE ε4 allele, cerebrovascular disease and initial cognitive and depressive status, MetS predicted cognitive decline (B=-1.684, 95%CI=-2.202 to -1.167, p<0.001) and risk of IADLs (OR=1.09, 95% CI=1.01-1.20, p=0.048) and ADLs disability (OR=1.35, 95%CI=1.12-1.62, p<0.001). Interestingly, such associations were not attributable to individual altered components of MetS nor to their sum. Incident disability in ADLs and IADLs were not explained by parallel decline in cognitive function.

CONCLUSIONS

MetS as an entity was associated with accelerated cognitive and functional decline in a population-based sample of very old men.

Physical frailty in late-life depression is associated with deficits in speed-dependent executive functions

OBJECTIVE

The aim of this study was to examine the association between physical frailty and neurocognitive performance in late-life depression (LLD).

METHODS

Cross-sectional design using baseline data from a treatment study of late-life depression was used in this study. Individuals aged 60 years and older were diagnosed with major depressive disorder at time of assessment (N = 173). All participants received clinical assessment of depression and completed neuropsychological testing during a depressive episode. Physical frailty was assessed using an adaptation of the FRAIL scale. Neuropsychological domains were derived from a factor analysis that yielded three factors: (i) speeded executive and fluency, (ii) episodic memory, and (iii) working memory. Associations were examined with bivariate tests and multivariate models.

RESULTS

Depressed individuals with a FRAIL score >1 had worse performance than nonfrail depressed across all three factors; however, speeded executive and fluency was the only factor that remained significant after controlling for depression symptom severity and demographic characteristics.

CONCLUSIONS

Although physical frailty is associated with broad neurocognitive deficits in LLD, it is most robustly associated with deficits in speeded executive functions and verbal fluency. Causal inferences are limited by the cross-sectional design, and future research would benefit from a comparison group of nondepressed older adults with similar levels of frailty. Research is needed to understand the mechanisms underlying associations among depression symptoms, physical frailty, and executive dysfunction and how they are related to the cognitive and symptomatic course of LLD.

Examining the Association Between Quadriceps Strength and Cognitive Performance in the Elderly

Emerging evidences showed impaired muscle strength was prevalent in older adults with mild cognition impairment or dementia. However, little was known about the role of quadriceps strength in the cognition decline among older population. The objective of our study was to investigate the relation between quadriceps strength and cognitive performance. Using data from the National Health and Nutrition Examination Survey (1999-2002), a total of 1799 participants aged ≥60 years were enrolled in the study. Every subject completed a household interview, digit symbol substitution test (DSST), physical performances, and a questionnaire regarding personal health. Estimation of relationship between quadriceps strength and cognition was using multiple linear regression and quartile-based analysis with an extended-model approach for covariates adjustment. In a model adjusted for demographics, chronic diseases, health behaviors, and levels of folate and vitamin B12, the level of quadriceps strength was significantly associated with the scores of DSST. The β coefficient interpreted as change of DSST scores for each Newton increment in quadriceps strength comparing participants in the highest quartile of quadriceps strength to those in the lowest quartile was 5.003 (95% confidence interval, 2.725-7.281, P < 0.001). The trends of incremental DSST score across increasing quartiles of quadriceps strength were statistically significant (all P for trend <0.001). Higher quadriceps strength was associated with better cognitive performance.