Biopsychosocial frailty and mild cognitive impairment subtypes: Findings from the Italian project on the epidemiology of Alzheimer's disease (IPREA)

Social isolation in relation to the incidence and dynamic progression of frailty in the oldest old: a trajectory analysis of a nationwide cohort

BACKGROUND

There is still a lack of evidence examining the association of behavioral and social factors with frailty transitions and mortality. We investigated whether social isolation is associated with different progressions and outcomes of frailty among community-dwelling older adults.

METHODS

This community-based cohort study assessed the frailty index and objective social isolation of 31,168 participants (58.3% female; average age: 88.1 ± 11.1 years) from the Chinese Longitudinal Healthy Longevity Survey (CLHLS) from 1998 to 2018. Four Markov state-transition models were constructed to examine the associations between social isolation and the seven transitions of the frailty trajectory.

RESULTS

According to the Markov state-transition model, for every one-point increase in the social isolation score of non-frail participants, the risk of developing prefrailty increased by 4.2% [hazard ratio (HR) = 1.042, 95% confidence interval (CI): 1.007-1.079], whereas for prefrail participants, the risk of developing frailty and death increased by 3.9% (HR = 1.039, 95% CI: 1.007-1.073) and 16.1% (HR = 1.161, 95% CI: 1.099-1.226), respectively. For each increase in the social isolation score in the frail population, the risk of death increased by 2.9% (HR = 1.029, 95% CI: 1.004-1.054). Socially isolated persons had a greater cumulative transition probability to prefrailty and frailty. Socially isolated women were more likely to experience prefrailty and frailty than socially isolated men, whereas the latter were more likely to die from prefrailty and frailty than the former.

CONCLUSIONS

This study indicates that social isolation may contribute to an increased risk of both the incidence and progression of frailty, elevating deterioration risks in initially non-frail and prefrail populations, while primarily exacerbating mortality risks in those already experiencing prefrailty or frailty.

Physical and biopsychosocial frailty, cognitive phenotypes, and plasma biomarkers for Alzheimer's disease in Chinese older adults: A population-based study

INTRODUCTION

We sought to examine the associations of physical frailty (PF) and biopsychological frailty (BF) with dementia and mild cognitive impairment (MCI) among Chinese older adults and further to explore neuropathological mechanisms underlying the associations.

METHODS

This population-based cross-sectional study included 5149 participants in the MIND-China baseline examination (2018); of these, we measured plasma amyloid-β (Aβ), neurofilament light chain (NfL), and total tau in 1371 persons and phosphorylated tau 217 (p-tau217) and glial fibrillary acidic protein (GFAP) in 3387 persons.

RESULTS

PF and BF were significantly associated with increased likelihoods of dementia, Alzheimer's disease (AD), vascular dementia (VaD), and MCI. PF was significantly correlated with increased plasma p-tau217, GFAP, and NfL, and reduced Aβ42/Aβ40 ratio; BF was related to higher plasma total tau and NfL and lower Aβ42/Aβ40 ratio. PF in combination with demographics performed excellent in differentiating dementia from non-dementia (area under the curve [AUC] = 0.83).

DISCUSSION

PF and BF are potential clinical biomarkers for dementia and MCI in older adults. Alzheimer's pathology, neuroinflammation, and neurodegeneration may underlie their associations.

HIGHLIGHTS

Physical (PF) and biopsychosocial frailty (BF) were strongly associated with dementia and mild cognitive impairment (MCI) in rural Chinese older adults. Frailty, especially PF, was associated with increased plasma phosphorylated tau 217 (p-tau217), glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL) and a reduced plasma amyloid-β (Aβ)42/Aβ40 ratio. Alzheimer's pathology, neuroinflammation, and neurodegeneration may underlie the associations of frailty with dementia. PF, in combination with demographic factors, performed excellent (area under the curve [AUC] = 0.83) in differentiating dementia from non-dementia in rural older adults.

Association of Social Relationships and Genetic Risk With Frailty

OBJECTIVES

To investigate the association between social relationships and their changes with frailty among older adults, and whether genetic risk modifies these associations.

METHODS

This study included 11,559 older adults (mean age 80.1 years) from the Chinese Longitudinal Healthy Longevity Survey. Social relationships were categorized into three dimensions: social activities, social networks, and social support, each classified as favorable or unfavorable groups. Changes in social relationships were assessed at two time points. The polygenic risk score (PRS) was constructed using 59 single-nucleotide polymorphisms associated with frailty. Cox proportional hazards models were used to assess the effects of social relationships and their changes, and PRS on frailty. Two-sample Mendelian randomization identified causal associations.

RESULTS

During a median follow-up of 5.4 years, 4773 participants developed frailty. Unfavorable social relationships, particularly in social activities and social networks, were associated with increased frailty risk, with stronger effects in those with high genetic risk. Mendelian randomization revealed their harmful effects on frailty. An additive interaction between social relationships and genetic risk on frailty was observed. Combined unfavorable social relationships and high genetic risk increased frailty risk by 39% (HR: 1.39, 95% CI: 1.23-1.57). Persistent unfavorable relationships further increased frailty risk by 58% in those with high genetic risk (HR: 1.58, 95% CI: 1.27-1.97).

CONCLUSION

Unfavorable social relationships increase frailty risk, particularly for individuals with high genetic susceptibility. Persistent unfavorable relationships further increase this risk over time, with the highest frailty risk observed in those with both persistent unfavorable social relationships and high genetic risk.

Association of Loneliness with Functional and Cognitive Status in Minor and Major Neurocognitive Disorders

BACKGROUND

Neurocognitive disorders (NCDs) have a variable decline in cognitive function, while loneliness was associated with cognitive impairment and increased dementia risk. In the present study, we examined the associations of loneliness with functional and cognitive status in patients with minor (mild cognitive impairment) and major NCDs (dementia).

METHODS

We diagnosed mild NCD (n = 42) and major NCD (n = 164) through DSM-5 criteria on 206 participants aged > 65 years using the UCLA 3-Item Loneliness Scale (UCLA-3) to evaluate loneliness, the activities of daily living (ADL) and the instrumental activities of daily living (IADL) scales to measure functional status, and Mini-Mental State Examination (MMSE) to assess cognitive functions.

RESULTS

In a multivariate regression model, the effect of loneliness on cognitive functions was negative in major (β = -1.05, p < 0.0001) and minor NCD (β = -0.06, p < 0.01). In the fully adjusted multivariate regression model (sex-age-education-multimorbidity-depressive symptoms-antidementia drug treatment), the effect of loneliness remained negative for major NCD and became positive for minor NCD (β = 0.09, p < 0.001). The effect of loneliness on IADL (β = -0.26, p < 0.0001) and ADL (β = -0.24, p < 0.001) showed a negative effect for major NCD across the different models, while for minor NCD, the effect was positive (IADL: β = 0.26, p < 0.0001; ADL: β = 0.05, p = 0.01). Minor NCD displayed different levels of MMSE (β = 6.68, p < 0.001) but not ADL or IADL, compared to major NCD for the same levels of loneliness. MANOVA pill test suggested a statistically significant and different interactive effect of loneliness on functional and cognitive variables between minor and major NCDs.

CONCLUSIONS

We confirmed the relationships between loneliness and cognitive and functional status in major NCD, observing a novel trend in minor NCD.

Definition and assessment of psychological frailty in older adults: A scoping review

OBJECTIVES

The confusion surrounding psychological frailty and its components prompts the need for a standardized conceptual definition. To address this, we aimed to (1) identify the psychological variables included in multicomponent frailty assessment instruments used with older adults and examine their operationalization; and (2) formulate a thorough conceptualization of psychological frailty based on the variables identified.

METHODS

This study followed the most recent recommendations for conducting scoping reviews and is reported in accordance with PRISMA-ScR guidelines. We systematically searched the CINAHL, MEDLINE, PsycInfo, Scopus, and Web of Science databases, with additional searches in Google Scholar and reference lists.

RESULTS

Sixteen instruments were identified. The results suggested that: (1) In multicomponent frailty assessment instruments, psychological variables are poorly represented; (2) A wide variety of psychological variables are included in the instruments, the most frequent being cognitive functioning and affective functioning (e.g., depressive symptoms, emotional loneliness, anxiety symptoms, poor coping, and suicidal ideation); and (3) The way in which variables are referred to and operationalized varies across instruments.

CONCLUSIONS

Including both cognitive and affective variables in psychological frailty assessments may lead to inaccuracies. We suggest distinguishing between two separate dimensions within psychological frailty: cognitive frailty and affective frailty. A conceptual definition for each dimension is provided. This proposal aims to advance the debate regarding the conceptualization and assessment of psychological frailty, with further research and discussion needed to ensure its practical applicability.

Midlife cumulative deficit frailty predicts Alzheimer's disease-related plasma biomarkers in older adults

BACKGROUND

The study explores whether frailty at midlife predicts mortality and levels of biomarkers associated with Alzheimer's disease and related dementias (ADRD) and neurodegeneration by early old age. We also examine the heritability of frailty across this age period.

METHODS

Participants were 1,286 community-dwelling men from the Vietnam Era Twin Study of Aging at average ages 56, 62 and 68, all without ADRD at baseline. The cumulative deficit frailty index (FI) comprised 37 items assessing multiple physiological systems. Plasma biomarkers at age 68 included beta-amyloid (Aβ40, Aβ42), total tau (t-tau) and neurofilament light chain (NfL).

RESULTS

Being frail doubled the risk of all-cause mortality by age 68 (OR = 2.44). Age 56 FI significantly predicted age 68 NfL (P = 0.014), Aβ40 (P = 0.001) and Aβ42 (P = 0.023), but not t-tau. Age 62 FI predicted all biomarkers at age 68: NfL (P = 0.023), Aβ40 (P = 0.002), Aβ42 (P = 0.001) and t-tau (P = 0.001). Age 68 FI scores were associated with age 68 levels of NfL (P = 0.027), Aβ40 (P < 0.001), Aβ42 (P = 0.001) and t-tau (P = 0.003). Genetic influences accounted for 45-48% of the variance in frailty and significantly contributed to its stability across 11 years.

CONCLUSIONS

Frailty during one's 50s doubled the risk of mortality by age 68. A mechanism linking frailty and ADRD may be through its associations with biomarkers related to neurodegeneration. Cumulative deficit frailty increases with age but remains moderately heritable across the age range studied. With environmental factors accounting for about half of its variance, early interventions aimed at reducing frailty may help to reduce risk for ADRD.

Knowledge mapping of trends and hotspots in the field of exercise and cognition research over the past decade

Exercise elicits a wide range of physiological responses in mammalian tissues that enhance a broad range of functions, particularly in improving cognitive performance. However, the field lacks a comprehensive bibliometric analysis that clarifies its knowledge structure and research hotspots. This study aims to address this gap and map the research landscape regarding the role of exercise in cognitive function enhancement. Firstly, the frequencies and co-occurrence of keywords were analysed to identify six main clusters: aging, cognitive impairment, rehabilitation, obesity, fatigue, and hippocampus. Secondly, reference timeline co-citation analysis revealed that hippocampus and aging were the major bursts with high intensity and long attention span while children had recently emerged as a topical subject. Finally, the evolution of themes from 2012 to 2022 was analysed, and found that older adults had been the leading research theme for exercise affecting cognition. Childhood obesity was an emerging theme that attracted increasing research attention in recent years while the hippocampus research theme expanded rapidly during the decade but remained a niche topic with less relevance to others. This research identified and summarised research priorities and evolutionary trends in exercise to improve cognition by constructing knowledge networks through visual analysis. It provides researchers with a comprehensive insight into the current state of the field to facilitate further research.

Social Dysfunction and Apathy: Transdiagnostic Domains in Late-Life Cognitive Disorders

Social dysfunction is a maladaptive process of coping, problem solving, and achieving one's goals. A new definition of apathy was cross-linked to social dysfunction, with a reduced goal-directed behavior and social interaction as a separate dimension. We hypothesized that these two neuropsychiatric symptoms may be included in the mild behavioral impairment diagnostic framework, operationalizing and standardizing late-life neuropsychiatric symptom assessment, to improve risk determination of dementia. Social dysfunction and apathy were transdiagnostic and prodromic for late-life cognitive disorders. A transdiagnostic approach could provide a useful mean for a better understanding of apathy and related conditions such as social behavior.

Depressive and Biopsychosocial Frailty Phenotypes: Impact on Late-life Cognitive Disorders

 In older age, frailty is a detrimental transitional status of the aging process featuring an increased susceptibility to stressors defined by a clinical reduction of homoeostatic reserves. Multidimensional frailty phenotypes have been associated with all-cause dementia, mild cognitive impairment (MCI), Alzheimer's disease (AD), AD neuropathology, vascular dementia, and non-AD dementias. In the present article, we reviewed current evidence on the existing links among depressive and biopsychosocial frailty phenotypes and late-life cognitive disorders, also examining common pathways and mechanisms underlying these links. The depressive frailty phenotype suggested by the construct of late-life depression (LLD) plus physical frailty is poorly operationalized. The biopsychosocial frailty phenotype, with its coexistent biological/physical and psychosocial dimensions, defines a biological aging status and includes motivational, emotional, and socioeconomic domains. Shared biological pathways/substrates among depressive and biopsychosocial frailty phenotypes and late-life cognitive disorders are hypothesized to be inflammatory and cardiometabolic processes, together with multimorbidity, loneliness, mitochondrial dysfunction, dopaminergic neurotransmission, specific personality traits, lack of subjective/objective social support, and neuroendocrine dysregulation. The cognitive frailty phenotype, combining frailty and cognitive impairment, may be a risk factor for LLD and vice versa, and a construct of depressive frailty linking physical frailty and LLD may be a good dementia predictor. Frailty assessment may enable clinicians to better target the pharmacological and psychological treatment of LLD. Given the epidemiological links of biopsychosocial frailty with dementia and MCI, multidomain interventions might contribute to delay the onset of late-life cognitive disorders and other adverse health-related outcomes, such as institutionalization, more frequent hospitalization, disability, and mortality.