Apolipoprotein ε4 allele is associated with frailty syndrome: results from the hellenic longitudinal investigation of ageing and diet study

Cognitive function is mediated by deficit accumulation in older, long-term breast cancer survivors

PURPOSE

This study aims to examine whether cognitive function in older, long-term breast cancer survivors is both a direct effect of cancer and cancer treatments and an indirect effect mediated by deficit accumulation.

PATIENTS AND METHODS

Female breast cancer survivors who had been diagnosed and treated at age 60 or older and were 5-15-year survivors (N = 220) and age- and education-matched non-cancer controls (N = 123) were assessed at enrollment and at 8-, 16-, and 24-month follow-ups with standard neuropsychological tests and the comprehensive geriatric assessment which was used to calculate the deficit accumulation frailty index (DAFI). Blood or saliva samples for APOE genotyping were collected at enrollment. Participants were purposely recruited so that approximately 50% had a history of treatment with chemotherapy or and 50% were not exposed to chemotherapy.

RESULTS

Latent variable mediation analysis revealed that cognitive performance was mediated by deficit accumulation for all three domains. The direct effect of cancer diagnosis and treatment history was significant for the Language domain (p = 0.04), a trend for the learning and memory domain (p = 0.054), and non-significant for the attention, processing speed, executive function (APE) domain. Carrying the APOE ε4 allele had a significant negative direct effect on the APE domain (p = 0.05) but no indirect effect through deficit accumulation.

CONCLUSION

Cognitive function in older, long-term breast cancer survivors appears to be primarily mediated through deficit accumulation.

IMPLICATIONS FOR CANCER SURVIVORS

These findings have important clinical implications suggesting that the most effective intervention to prevent or slow cognitive aging in older cancer survivors may be through prevention or management of comorbidities and interventions that maintain functional capacity (exercise, physical therapy) and social and mental health.

Utilizing multimodal approach to identify candidate pathways and biomarkers and predicting frailty syndrome in individuals from UK Biobank

Frailty, a prevalent clinical syndrome in aging adults, is characterized by poor health outcomes, represented via a standardized frailty-phenotype (FP), and Frailty Index (FI). While the relevance of the syndrome is gaining awareness, much remains unclear about its underlying biology. Further elucidation of the genetic determinants and possible underlying mechanisms may help improve patients' outcomes allowing healthy aging.Genotype, clinical and demographic data of subjects (aged 60-73 years) from UK Biobank were utilized. FP was defined on Fried's criteria. FI was calculated using electronic-health-records. Genome-wide-association-studies (GWAS) were conducted and polygenic-risk-scores (PRS) were calculated for both FP and FI. Functional analysis provided interpretations of underlying biology. Finally, machine-learning (ML) models were trained using clinical, demographic and PRS towards identifying frail from non-frail individuals.Thirty-one loci were significantly associated with FI accounting for 12% heritability. Seventeen of those were known associations for body-mass-index, coronary diseases, cholesterol-levels, and longevity, while the rest were novel. Significant genes CDKN2B and APOE, previously implicated in aging, were reported to be enriched in lipoprotein-particle-remodeling. Linkage-disequilibrium-regression identified specific regulation in limbic-system, associated with long-term memory and cognitive-function. XGboost was established as the best performing ML model with area-under-curve as 85%, sensitivity and specificity as 0.75 and 0.8, respectively.This study provides novel insights into increased vulnerability and risk stratification of frailty syndrome via a multi-modal approach. The findings suggest frailty as a highly polygenic-trait, enriched in cholesterol-remodeling and metabolism and to be genetically associated with cognitive abilities. ML models utilizing FP and FI + PRS were established that identified frailty-syndrome patients with high accuracy.

Navigating and diagnosing cognitive frailty in research and clinical domains

While physical frailty has been recognized as a clinical entity for some time, the concept of cognitive frailty (CF) is now gaining increasing attention in the geriatrics research community. CF refers to the co-occurrence of physical frailty and cognitive impairment in older adults, which has been suggested as a potential precursor to both dementia and adverse physical outcomes. However, this condition represents a challenge for researchers and clinicians, as there remains a lack of consensus regarding the definition and diagnostic criteria for CF, which has limited its utility. Here, using insights from both the physical frailty literature and cognitive science research, we describe emerging research on CF. We highlight areas of agreement as well as areas of confusion and remaining knowledge gaps, and provide our perspective on fine-tuning the current construct, aiming to stimulate further discussion in this developing field.

Nutrition in Alzheimer's disease: a review of an underappreciated pathophysiological mechanism

Alzheimer's disease (AD) is the leading cause of dementia in older individuals and is an escalating challenge to global public health. Pharmacy therapy of AD is one of the well-funded areas; however, little progress has been made due to the complex pathogenesis. Recent evidence has demonstrated that modifying risk factors and lifestyle may prevent or delay the incidence of AD by 40%, which suggests that the management should pivot from single pharmacotherapy toward a multipronged approach because AD is a complex and multifaceted disease. Recently, the gut-microbiota-brain axis has gained tremendous traction in the pathogenesis of AD through bidirectional communication with multiple neural, immune, and metabolic pathways, providing new insights into novel therapeutic strategies. Dietary nutrition is an important and profound environmental factor that influences the composition and function of the microbiota. The Nutrition for Dementia Prevention Working Group recently found that dietary nutrition can affect cognition in AD-related dementia directly or indirectly through complex interactions of behavioral, genetic, systemic, and brain factors. Thus, considering the multiple etiologies of AD, nutrition represents a multidimensional factor that has a profound effect on AD onset and development. However, mechanistically, the effect of nutrition on AD is uncertain; therefore, optimal strategies or the timing of nutritional intervention to prevent or treat AD has not been established.Thus, this review summarizes the current state of knowledge concerning nutritional disorders, AD patient and caregiver burden, and the roles of nutrition in the pathophysiology of AD. We aim to emphasize knowledge gaps to provide direction for future research and to establish optimal nutrition-based intervention strategies for AD.

Risk Factors of Progression to Cognitive Frailty: Singapore Longitudinal Ageing Study 2

INTRODUCTION

Cognitive frailty is associated with higher risk of dementia and adverse health outcomes. However, multidimensional factors that influence cognitive frailty transitions are not known. We aimed to investigate risk factors of incident cognitive frailty.

METHODS

Prospective cohort study participants were community-dwelling adults without dementia and other degenerative disorders and baseline and follow-up, including N = 1,054 participants aged ≥55 free of cognitive frailty at baseline, with complete baseline (March 6, 2009, to June 11, 2013) and follow-up data at 3-5 years later (January 16, 2013, to August 24, 2018). Incident cognitive frailty was defined by one or more criteria of the physical frailty phenotype and <26 of Mini-Mental State Examination (MMSE) score. Potential risk factors assessed at baseline included demographic, socioeconomic, medical, psychological and social factors, and biochemical markers. Data were analyzed using least absolute shrinkage selection operator (LASSO) multivariable logistic regression models.

RESULTS

A total of 51 (4.8%) participants, including 21 (3.5%) of the cognitively normal and physically robust participants, 20 (4.7%) of the prefrail/frail only, and 10 (45.4%) of cognitively impaired only, transited to cognitive frailty at follow-up. Risk factors for transition to cognitive frailty were having eye problem (OR = 2.6, 95% CI 1.24-5.43) and low HDL cholesterol (OR = 4.1, 95% CI 2.03-8.40), while protective factors for cognitive frailty transition were higher levels of education (OR = 0.3, 95% CI 0.10-0.74) and participation in cognitive stimulating activities (OR = 0.4, 95% CI 0.17-0.82).

CONCLUSION

Multi-domain modifiable factors especially related to leisure activities predict cognitive frailty transition and may be targeted for prevention of dementia and associated adverse health outcomes.

Biological Features of the Outcome-Based Intrinsic Capacity Composite Scores From a Population-Based Cohort Study: Pas de Deux of Biological and Functional Aging

Introduction

This study aims to develop and validate an integrative intrinsic capacity (IC) scoring system, to investigate its associations with a wide spectrum of biomarkers and to explore the predictive value of the integrative IC score on 4-year mortality among community dwelling people aged 50 years and older.

Methods

We included 839 adults aged ≥50 years from the Social Environment and Biomarkers of Aging Study (SEBAS) and randomly divided them into derivation and validation cohorts to develop the IC scoring system. The multivariate logistic regression model was used to weight each subdomain (locomotion, sensory, vitality, psychological, and cognition) of IC according to its association with impairments in instrumental activities of daily living (IADL) and to construct the integrative IC score. Age-related biomarkers and genetic markers were compared between IC groups by ordinal logistic regression. A Cox proportional hazard model was used to examine the association between IC and mortality, and subgroup analysis was used to assess the robustness of the results among participants aged 60 years and older.

Results

A 12-score IC scoring system (AUROC = 0.83; Hosmer–Lemeshow goodness-of-fit test p = 0.17) was developed, and higher scores indicated better intrinsic capacity. High interleukin (IL)-6, high E-selectin, low serum albumin and low folate were significantly associated with low IC in the whole sample. However, high IL-6, low serum albumin, low folate, high allostatic load, and APOE ε4 genotype were significantly associated with low IC in those aged 60 years old and older. Compared to the high IC group, the low IC group was significantly associated with all-cause mortality (HR: 2.50, 95% CI: 1.22–5.11, p = 0.01 for all participants; HR 2.19, 95% CI 1.03–4.64, p = 0.04 for participants aged 60 years and older).

Conclusions

The conceptually proposed IC can be easily transformed into a scoring system considering different weights of individual subdomains, which not only predicts mortality but also suggests different pathophysiologies across the life course of aging (inflammation, nutrition, stress, and ApoE4 genotype). An intervention study is needed using the composite IC score to promote healthy aging and determine the underlying pathophysiology.

Biological and Neuroimaging Markers as Predictors of 5-Year Incident Frailty in Older Adults: A Secondary Analysis of the MAPT Study

BACKGROUND

This study aims to investigate the predictive value of biological and neuroimaging markers to determine incident frailty among older people for a period of 5 years.

METHODS

We included 1394 adults aged 70 years and older from the Multidomain Alzheimer Preventive Trial, who were not frail at baseline (according to Fried's criteria) and who had at least 1 post-baseline measurement of frailty. Participants who progressed to frailty during the 5-year follow-up were categorized as "incident frailty" and those who remained non-frail were categorized as "without frailty." The differences of baseline biochemical factors (25-hydroxyvitamin D, homocysteine, omega-3 index, C-reactive protein), other biological markers (Apolipoprotein E genotypes, amyloid-β deposits), and neuroimaging data (gray matter volume, hippocampal volume, white matter hyperintensities) were compared between groups. Cox proportional hazard model was used to evaluate the associations between biomarkers and incident frailty.

RESULTS

A total of 195 participants (14.0%) became frail over 5 years. Although 25-hydroxyvitamin D deficiency, homocysteine levels, low-grade inflammation (persistently increased C-reactive protein 3-10 mg/L), gray matter, and hippocampal volume were significantly associated with incident frailty in unadjusted models, these associations disappeared after adjustment for age, sex, and other confounders. Omega-3 index was the sole marker that presented a trend of association with incident frailty (hazard ratio: 0.92; 95% confidence interval: 0.83-1.01; p = .082).

CONCLUSIONS

This study failed to identify biomarkers able to predict frailty incidence in community-dwelling older adults for a period of 5 years. Further longitudinal research with multiple measurements of biomarkers and frailty is needed to evaluate the long-term relationships between changes in biomarkers levels and frailty evolution.

Apolipoprotein E Polymorphism and Frailty: Apolipoprotein ε4 Allele Is Associated with Fatigue but Not Frailty Syndrome in a Community-Dwelling Older Population Cohort

OBJECTIVE

Frailty is known to be influenced by genetics, however, little evidence on the association of Apolipoprotein E (ApoE) genotype and frailty exists which we aim to investigate.

DESIGN

This study is a cross-sectional analysis from a prospective longitudinal study cohort.

SETTING AND PARTICIPANTS

Community-dwelling individuals aged 55 years and older from Beijing region in China.

MEASUREMENTS

A total of 3,569 older adults with a mean age of 75.06(±6.79) years were included. We investigated the association between ApoE polymorphism and frailty syndrome using the frailty index (FI) and frailty phenotype (including association with individual components of the frailty phenotype). Logistic regressions were performed to investigate the relation between ApoE variants and frailty.

RESULTS

There was no significant association between ApoE variants and frailty as assessed by the FI. In the age and sex-adjusted model, compared to the ApoE e3/e3 carriers ApoE e4 carriers had almost 1.5 times higher odds of being frail as assessed by the frailty phenotype. However, the significance was lost on the model with adjustment for cognitive impairment. Compared to the ApoE e3/e3 carriers ApoE e4 carriers had almost two times higher odds of fatigue. ApoE e4 heterozygotes had higher odds of fatigue compared to ApoE e4 non-carriers. No significant association was found between ApoE variants and other components of frailty phenotype.

CONCLUSIONS

Our findings do not support an association between ApoE genotype and frailty irrespective of the frailty assessment tools. Fatigue in older adults is the only component of frailty phenotype influenced by ApoE genotype.

Apolipoprotein E and Health in Older Men: The Concord Health and Ageing in Men Project

APOE genotype has been associated with various age-related outcomes including Alzheimer's disease, frailty, and mortality. In this study, the relationship between health, particularly cognitive function, and APOE was investigated in older men from the Concord Health and Ageing in Men Project (n = 1,616; age 76.9 ± 5.5 years [range 70-97 years]; Australia). Baseline characteristics and survival up to 12 years were determined. Frailty was measured using Cardiovascular Health study (CHS) criteria and Rockwood frailty index, and cognition using Mini-Mental State Examination (MMSE) and Addenbrookes Cognitive Examination. APOE ε4 was less common in the oldest men and those born in Mediterranean countries. APOE ε2 was beneficially associated with cholesterol, creatinine, gamma-glutamyl transaminase, glucose, and HDL cholesterol while APOE ε4 was adversely associated with cholesterol and albumin. APOE ε4 was associated with a clinical diagnosis of Alzheimer's disease when adjusted for age and region of birth (ε4 homozygotes Odds ratio (OR) 7.0; ε4 heterozygotes OR 2.4, p < .05), and APOE ε2 had a small positive association with cognition. On multivariate regression, overall cognitive function in the entire cohort was associated with age, country of birth, education, and frailty (all p < .001). APOE was not associated with frailty or survival. In conclusion, age and region of birth influenced distribution of APOE genotype in older men. Although APOE ε4 was associated with Alzheimer's disease, overall cognitive function in the cohort was associated more strongly with frailty than APOE genotype.

Omics biomarkers for frailty in older adults

Frailty is a clinical state characterized by an age-related unsteady state of the body, a decline in physiological function, and an increased vulnerability to adverse outcomes. Early diagnosis of frailty is important for improving the quality of life in older adults and promoting healthy aging. The biological mechanisms underlying frailty have been extensively studied in recent years. Combining assessment tools and biomarkers can facilitate the early diagnosis of frailty. However, there is a lack of stable and reliable frailty-related biomarkers for use in clinical practice. Advances in the multi-omics platforms have provided new information on the molecular mechanisms underlying frailty. Thus, identifying biomarkers using omics-based approaches helps explore the physiological mechanisms underlying frailty, and aids the evaluation of the risk of frailty development and progression. This article reviews the current status of frailty biomarkers from the genomics, transcriptomics, proteomics, and metabolomics perspectives.

Genetics of frailty: A longevity perspective

Frailty is a complex late life phenotype characterized by cumulative declines in multiple physiological systems that increases the risk for disability and mortality. The biological changes associated with aging are risk factors for frailty as well as for complex diseases; whereas longevity is assumed to be an outcome of protective biological mechanisms. Understanding the interplay between biological alterations associated with aging and protective mechanisms associated with longevity in the context of frailty may help guide development of interventions to increase healthspan and promote successful aging. The complexity of these phenotypes and relatively low heritability in studies are the main roadblocks in deciphering genetic mechanisms of these age associated conditions. We review genetic research related to frailty, and discuss the possible intertwined biology of frailty and longevity.