The projected effect of risk factor reduction on Alzheimer's disease prevalence

Risk of dementia in patients with age-related medical conditions: a retrospective cohort study

OBJECTIVE

This retrospective cohort study aimed to investigate the impact of age-related medical conditions on the incidence of dementia, considering factors such as hypertension, diabetes mellitus, cerebrovascular disease, cardiovascular disease, chronic kidney disease, osteoarthritis, osteoporosis, chronic obstructive pulmonary disease, and hearing difficulties.

METHODS

Data from 513 640 patients at Keimyung University Dongsan Hospital were analyzed using the Observational Medical Outcomes Partnership Common Data Model. Patients with and without age-related medical conditions were assigned to experimental and control groups, respectively, with propensity score matching. Cox proportional hazards models assessed the association between each condition and dementia incidence.

RESULTS

Hypertension, diabetes mellitus, cerebrovascular disease, cardiovascular disease, chronic kidney disease, osteoarthritis, osteoporosis, and hearing difficulties were associated with increased dementia risk. Chronic obstructive pulmonary disease showed no significant association with increased risk of dementia. Incidence rates ranged from 4.52 to 8.05 per 1000 person-years in the control group and 7.46 to 14.99 per 1000 person-years in the experimental group. Hazard ratios ranged from 1.38 to 2.36.

CONCLUSIONS

The study highlights the importance of managing age-related medical conditions to mitigate dementia risk. Understanding these risk factors can inform preventive strategies and improve cognitive health outcomes. Problems with deidentification data analysis and the need for further multicentred studies are among the limitations of this study.

Myeloproliferative Neoplasms and Dementia Risk: A Population-Based Cohort Study

Objectives

To estimate dementia risk for persons diagnosed with Philadelphia chromosome–negative myeloproliferative neoplasms (MPNs), which serve as a human chronic inflammation model.

Methods

We identified 9895 individuals in Denmark newly diagnosed with MPNs from 1995 to 2017; matched them 10:1 by age and sex with a general population cohort of 95 770 individuals; and followed them until dementia identification, death, emigration, or December 31, 2018. We applied a Cox proportional‐hazards regression model to estimate the cause‐specific hazard ratios (HRs) and 95% confidence intervals (CIs) for dementia. We included control diseases, like chronic lymphocytic leukemia (CLL), which is not characterized by chronic inflammation.

Results

Patients with MPNs showed a 1.15‐fold (95% CI: 1.04–1.27) increased incidence of dementia compared with members of the general population. Associations were stronger for men with MPNs (HR: 1.40, 95% CI: 1.19–1.63) than for women (HR: 1.02, 95% CI: 0.89–1.15). Patients with CLL showed a decreased dementia incidence (HR: 0.81, 95% CI: 0.72–0.90). The findings for CLL could be explained by depletion‐of‐susceptibles bias, suggesting that the findings for MPNs were underestimated by a similar bias.

Conclusions

The findings support MPNs as risk factors for dementia and the role of chronic inflammation in dementia development.

Moving Beyond Depression: Mood Symptoms Across the Spectrum Relate to Tau Pathology in Older Women at Risk for Alzheimer's Disease

We examined how symptoms across the mood spectrum relate to Alzheimer's disease (AD) biomarkers in older women at high risk for AD. Participants included 25 women aged 65+ with mild cognitive deficits and elevated AD genetic risk. The Profile of Mood States Questionnaire measured mood symptoms and a total mood disturbance (TMD) score. Tau burden in the meta-temporal region of interest was measured using MK-6240 Tau positron emission tomography (PET) imaging. A subset (n = 12) also had p-Tau181, and Aß40/42 levels measured in plasma. Higher TMD scores related to higher tau PET standardized uptake value ratio (SUVR). Greater negative mood symptoms correlated with higher tau PET SUVR, while greater vigor correlated with lower SUVR. Similar results were seen with plasma p-Tau181 levels, but not with Aβ40/42 levels. In conclusion, positive and negative mood symptoms related to tau pathology in older women at high risk for AD, highlighting a role of mental well-being in AD risk.

Social patterning of cognitive impairment in Colombia: evidence from the SABE 2015 study

INTRODUCTION

Dementia, an increasingly critical public health concern in low and middle-income countries, is associated with lower socioeconomic status, early cognitive impairment, and elevated dementia-related mortality risk. This study seeks to estimate the prevalence of cognitive impairment, investigate its links with social indicators, and visualize social gradients across different regions in Colombia.

METHODS

Secondary data analysis from the SABE 2015 survey, multinomial regression analyses, and equiplot graphs.

RESULTS

A sample of 23,694 individuals 60 years or older from Colombia. Higher risks were observed among individuals with dark skin color (OR 1.27; 95%CI: 1.10 - 1.47), lower educational levels (OR 3.01; 95%CI:2.04 - 4.42) and reading illiteracy (OR 2.14; 95%CI: 1.87 - 2.46). Inequity patterns were identified by region of residence and income.

DISCUSSION

This study underscores the need for targeted interventions aimed at reducing health inequities. The results highlight the higher prevalence rates of cognitive impairment among socially disadvantaged individuals.

Potential molecular mechanisms of tobacco smoke exposure in Alzheimer's disease

BACKGROUND

Smoking is detrimental to health, with tobacco use being a critical factor in the development of various neurodegenerative diseases, including Alzheimer's disease (AD), which progressively impairs brain function and poses a significant threat to public health. This study aims to examine the potential genetic alterations induced by smoking that are associated with AD and to investigate the underlying regulatory mechanisms. The research will provide theoretical foundations for targeted prevention and treatment strategies for AD.

METHODS

This study analyzed datasets from the Gene Expression Omnibus (GEO) and the Comparative Toxicogenomics Database (CTD) to identify genes affected by tobacco smoke exposure and those altered in patients with AD relative to normal controls. We conducted Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses using OmicShare tools to screen for key pathways. Key genes were identified by constructing protein-protein interaction networks (PPI) in the STRING database with the aid of CytoHubba. Additionally, the binding activity of the proteins encoded by these key genes to nicotine, the main component of tobacco, was analyzed using molecular docking techniques. Finally, the analytical results were verified using Quantitative Real-Time Polymerase Chain Reaction.

RESULTS

The CTD identified 12,164 CE-related genes affected by tobacco smoke exposure. A comparison of these datasets yielded 94 common genes that were both influenced by tobacco and differentially expressed across all brain regions. The GO and KEGG pathway enrichment analyses showed that these common differentially expressed genes (DEGs) were predominantly enriched in the Wnt/β-catenin and PI3K-AKT signaling pathways. The DEGs' PPI network, constructed using the STRING database, highlighted key genes such as HSP90AB1, SOS2, MAGI1, and YWHAZ. Molecular docking studies demonstrated that nicotine binds effectively to the protein structures of these key genes, primarily through amino acid residues such as Ser and Glu. Experimental validation showed that HSP90AB1 and YWHAZ exhibited notable expression discrepancies under varying concentrations of cigarette smoke extract (CSE) treatments, particularly demonstrating a pronounced down-regulation trend at elevated concentrations.

CONCLUSION

The study indicates that tobacco may impact the function of transmembrane transporter proteins and contribute to the development of AD by affecting key genes such as HSP90AB1 and YWHAZ, as well as signaling pathways like PI3K-AKT.

Cardiorespiratory fitness is associated with cognitive function in late adulthood: baseline findings from the IGNITE study

OBJECTIVES

To evaluate the association between cardiorespiratory fitness (CRF) and cognition in a large sample of older adults, and to examine clinical and demographic factors that might moderate these associations.

METHODS

CRF was measured with a graded exercise test performed on a motorised treadmill. A confirmatory factor analysis was conducted using data from a comprehensive neuropsychological battery to obtain latent factors reflecting core cognitive domains. Linear regression models evaluated the association between CRF and each of the cognitive composites, and potential moderators including demographic factors (age, sex, education), apolipoprotein E ε4 (APOE4) carriage, beta-blocker use and components of maximal effort criteria during CRF testing.

RESULTS

The sample consisted of 648 adults (mean (SD) age 69.88 (3.75)), including 461 women (71.1%). The highest oxygen consumption obtained during testing (VO2max) was mean (SD) = 21.68 (5.06) mL/kg/min. We derived a five-factor model composed of episodic memory, processing speed, working memory, executive function/attentional control and visuospatial function. Higher CRF was associated with better performance across all five cognitive domains after controlling for covariates. Age and APOE4 carriage did not moderate observed associations. The relationship between CRF and cognitive performance was greater in women, those with fewer years of education and those taking beta-blockers in the domains of processing speed (sex: β=-0.447; p=0.015; education: β=-0.863; p=0.018) and executive function/attentional control (sex: β=-0.417; p=0.022; education β=-0.759; p=0.034; beta-blocker use: β=0.305; p=0.047).

CONCLUSION

Higher CRF in older adulthood is associated with better cognitive performance across multiple domains susceptible to age-related cognitive decline. Sex, education and use of beta-blockers moderated observed associations within select cognitive domains.

Population attributable fraction of total stroke associated with modifiable risk factors in the United States

Stroke is a leading cause of death in the United States across all race/ethnicity and sex groups, though disparities exist. We investigated the potential for primary prevention of total first stroke for Americans aged 20 years or older, stratified by sex and race/ethnicity. Specifically, we calculated population attributable fractions (PAFs) of first stroke for 7 potentially modifiable risk factors: smoking, physical inactivity, poor diet, obesity, hypertension, diabetes, and atrial fibrillation. Population attributable fractions are a function of (1) the relative risk of first stroke for people with the exposure and (2) the prevalence of the risk factor in the population. Relative risks came from recent meta-analyses, and sex- and race/ethnicity-specific prevalence estimates came from the 2015-2018 National Health and Nutrition Examination Survey or Multi-Ethnic Study of Atherosclerosis (for atrial fibrillation only). Approximately one-third of strokes (35.7% [95% CI, 21.6-49.0] for women; 32.7% [95% CI, 19.2-45.1] for men) were attributable to the 7 risk factors we considered. A 20% proportional reduction in stroke risk factors would result in approximately 37 000 fewer strokes annually in the United States. The estimated PAF was highest for non-Hispanic Black women (39.3%; 95% CI, 24.8-52.3) and lowest for non-Hispanic Asian men (25.5%; 95% CI, 14.6-36.2). For most groups, obesity and hypertension were the largest contributors to stroke rates.

Lifestyle empowerment for Alzheimer's prevention prescribed by physicians: Methods and adaptations to COVID-19

The health care system is insufficiently capitalizing on the benefits of physical exercise in America's aging population. Few tools exist to help clinicians incorporate physical activity into their clinical care, and barriers limit older adults from initiating and maintaining exercise programs. The Lifestyle Empowerment for Alzheimer's Prevention (LEAP! Rx) Program has been designed to support providers and participants in lifestyle change. LEAP! Rx uses two forms of participant enrollment: physician referrals through electronic health records and self-referrals to test the efficacy of delivering a community-based exercise and healthy lifestyle program to older adults. After referral into the program, participants are randomized to receive the LEAP! Rx Program or are placed in a standard-of-care group to receive the program later. The LEAP! Rx program consists of a personalized and structured exercise program, lifestyle education, and mobile health monitoring. This includes a 12-week Empowerment phase with coaching and supervised exercise training, followed by a 40-week Lifestyle phase with intermittent supervised exercise and coaching. Lifestyle education includes monthly, evidence-based classes on optimal aging. The evaluation of LEAP! Rx focuses on 1) the assessment of implementation and scalability of the LEAP!Rx Program for clinicians and patients 2) the effect of the LEAP! Rx Program on cardiorespiratory fitness, 3) the impact of the LEAP! Rx Program on secondary intervention outcome measures of chronic disease risk factors, including insulin resistance, body composition, and lipids. If successful, this study's findings could advance future healthcare practices, providing a new and practical approach to aging and chronic disease prevention.

Cardiovascular risk of dementia is associated with brain-behaviour changes in cognitively healthy, middle-aged individuals

Alzheimer's Disease (AD) neuropathology start decades before clinical manifestations, but whether risk factors are associated with early cognitive and brain changes in midlife remains poorly understood. We examined whether AD risk factors were associated with cognition and functional connectivity (FC) between the Locus Coeruleus (LC) and hippocampus - two key brain structures in AD neuropathology - cross-sectionally and longitudinally in cognitively healthy midlife individuals. Neuropsychological assessments and functional Magnetic Resonance Imaging were obtained at baseline (N=210), and two-years follow-up (N=188). Associations of cognition and FC with apolipoprotein ε4 (APOE ε4) genotype, family history of dementia, and the Cardiovascular Risk Factors, Aging, and Incidence of Dementia (CAIDE) score were investigated. Cross-sectionally, higher CAIDE scores were associated with worse cognition. Menopausal status interacted with the CAIDE risk on cognition. Furthermore, the CAIDE score significantly moderated the relationship between cognition and LC-Hippocampus FC. Longitudinally, the LC-Hippocampus FC decreased significantly over 2 years. These results suggest that cardiovascular risk of dementia is associated with brain-behaviour changes in cognitively healthy, middle-aged individuals.

A Lack of Food for Thought: Midlife Food Insecurity and Its Association With Subsequent Cognitive Ability of Older Americans

OBJECTIVES

The 50-59 age group in the United States experience higher levels of food insecurity (FI) compared to older adults. While previous research has identified an association between FI and cognition outcomes in older populations, limited research has examined midlife as a specific FI exposure window and the association of this hardship with long-run cognition outcomes.

METHODS

Utilizing 14 waves of Health and Retirement Study (HRS) data (1995-2020), I applied mixed-effects models to assess the relationship between midlife FI exposure and later-life cognitive function, controlling for childhood disadvantages and other health-related and sociodemographic characteristics.

RESULTS

Findings indicate that both cumulative FI duration and ever experiencing FI during ages 50-59 are significantly associated with subsequent cognitive decline. Specifically, ever experiencing FI during midlife was linked to a decrease in cognitive function by 0.07 standard units (95% confidence interval [CI], -0.13 to -0.003; p < .05). In addition, each additional year of FI exposure during midlife was associated with a reduction in cognitive function by 0.01 standard units (95% CI: -0.03 to -0.003; p < .05). These associations remained robust even after accounting for a range of potential confounders and covariates.

DISCUSSION

The findings support the cumulative inequality model, suggesting that midlife FI is a significant predictor of lower cognitive function in later life. Both the timing and extent of FI during midlife are crucial factors in shaping cognitive health outcomes. Policy interventions targeting FI in the 50-59 age group could play a pivotal role in promoting healthy aging and mitigating cognitive decline in older adulthood.

Dementia risk scores, apolipoprotein E, and risk of Alzheimer's disease: One size does not fit all

INTRODUCTION

Evaluating the generalizability of dementia risk scores, primarily developed in non-Latinx White (NLW) participants, and interactions with genetic risk factors in diverse populations is crucial for addressing health disparities.

METHODS

We analyzed the association of the Cardiovascular Risk Factors, Aging, and Incidence of Dementia (CAIDE) and modified CAIDE (mCAIDE) scores with dementia risk using logistic regression models stratified by race/ethnicity in National Alzheimer's Coordinating Center (NACC) and Alzheimer's Disease Neuroimaging Initiative (ADNI), and assessed their interaction with apolipoprotein E (APOE).

RESULTS

Higher CAIDE scores were associated with an increased risk of dementia in Asian, Latinx, and NLW participants but not in Black participants. In contrast, higher mCAIDE scores were also associated with an increased risk of dementia in Black participants. Unfavorable mCAIDE risk profiles exacerbated the apolipoprotein E*ε4 (APOE*ε4) risk effect and attenuated the APOE*ε2 protective effect.

DISCUSSION

Our findings underscore the importance of evaluating the validity of dementia risk scores in diverse populations for their use in personalized medicine approaches to promote brain health.

HIGHLIGHTS

Dementia risk scores demonstrate race/ethnic-specific effects on dementia risk. Unfavorable modifiable risk profiles moderate the effect of APOE on dementia risk. Dementia risk scores need to be validated in diverse populations.

Age-dependent sex differences in cofilin1 pathway (LIMK1/SSH1) and its association with AD biomarkers after chronic systemic inflammation in mice

Chronic systemic inflammation (CSI) results in neuroinflammation and neurodegeneration. Cofilin1 is a stress protein that activates microglia and induces neuroinflammation, but its role in CSI at different aging stages remains unidentified. Therefore, the study aims to identify cofilin1 and its upstream regulators LIMK1 and SSH1 after CSI in young-, middle-, and advanced-aged mice. CSI was induced by injecting the male and female mice with a sub-lethal dose of Lipopolysaccharide weekly for six weeks. The results showed that normal male mice did not show cofilin pathway dysregulation, but a significant dysregulation was observed in CSI advanced-aged mice. In females, cofilin1 dysregulation was observed in healthy and CSI advanced-aged mice, while significant cofilin1 dysregulation was observed in middle-aged mice during CSI. Furthermore, cofilin1 pathway dysregulations correlated with Alzheimer's disease (AD) biomarkers in the brain and saliva, astrocyte activation, synaptic degeneration, neurobehavioral impairments, gut-microbiota abnormalities, and circulatory inflammation. These results provide new insights into cofilin1 sex and age-dependent mechanistic differences that might help identify targets for modulating neuroinflammation and early onset of AD.

Association of amyloid and cardiovascular risk with cognition: Findings from KBASE

BACKGROUND

Limited research has explored the effect of cardiovascular risk and amyloid interplay on cognitive decline in East Asians.

METHODS

Vascular burden was quantified using Framingham's General Cardiovascular Risk Score (FRS) in 526 Korean Brain Aging Study (KBASE) participants. Cognitive differences in groups stratified by FRS and amyloid positivity were assessed at baseline and longitudinally.

RESULTS

Baseline analyses revealed that amyloid-negative (Aβ-) cognitively normal (CN) individuals with high FRS had lower cognition compared to Aβ- CN individuals with low FRS (p < 0.0001). Longitudinally, amyloid pathology predominantly drove cognitive decline, while FRS alone had negligible effects on cognition in CN and mild cognitive impairment (MCI) groups.

CONCLUSION

Our findings indicate that managing vascular risk may be crucial in preserving cognition in Aβ- individuals early on and before the clinical manifestation of dementia. Within the CN and MCI groups, irrespective of FRS status, amyloid-positive individuals had worse cognitive performance than Aβ- individuals.

HIGHLIGHTS

Vascular risk significantly affects cognition in amyloid-negative older Koreans. Amyloid-negative CN older adults with high vascular risk had lower baseline cognition. Amyloid pathology drives cognitive decline in CN and MCI, regardless of vascular risk. The study underscores the impact of vascular health on the AD disease spectrum.

APOE4 and Chronic Health Risk Factors are Associated with Sex-Specific Preclinical Alzheimer's Disease Neuroimaging Biomarkers

Introduction

Two thirds of Alzheimer's disease (AD) patients are female. Genetic and chronic health risk factors for AD affect females more negatively compared to males.

Objective

This exploratory multimodal neuroimaging study aimed to examine sex differences in cognitively unimpaired older adults on: (1) amyloid-β via 18F-AV-45 Florbetapir PET imaging, (2) neurodegeneration via T1 weighted MRI volumetrics, (3) cerebral blood flow via ASL-MRI. We identified AD risk factors including genetic (APOE genotype status) and health markers (fasting glucose, mean arterial pressure, waist-to-hip ratio, and android and gynoid body fat) associated with neuroimaging outcomes for which we observed sex differences.

Methods

Participants were sedentary, amyloid-β positive older adults (N = 112, ages 65-87 years) without evidence of cognitive impairment (CDR = 0).

Results

Multivariate analysis of covariance models adjusted for intracranial volume, age, and years of education demonstrated lower volume (F (7, 102) = 2.67, p = 0.014) and higher blood flow F (6, 102) = 4.25, p =<0.001) among females compared to males in regions of interest connected to AD pathology and the estrogen receptor network. We did not observe sex differences in amyloid-β levels. Higher than optimal waist to hip ratio was most strongly associated with lower volume, while higher android fat percentage and APOE ε4 carrier status were most strongly associated with higher blood flow among female participants.

Discussion

Findings suggest genetic and chronic health risk factors are associated with sex-specific AD neuroimaging biomarkers. Underlying sex-specific biological pathways may explain these findings. Our results highlight the importance of considering sex differences in neuroimaging studies and when developing effective interventions for AD prevention and risk reduction.

A Mindfulness-Based Lifestyle Intervention for Dementia Risk Reduction: Protocol for the My Healthy Brain Feasibility Randomized Controlled Trial

BACKGROUND

Lifestyle behavior change and mindfulness have direct and synergistic effects on cognitive functioning and may prevent Alzheimer disease and Alzheimer disease-related dementias (AD/ADRD). We are iteratively developing and testing My Healthy Brain (MHB), the first mindfulness-based lifestyle group program targeting AD/ADRD risk factors in older adults with subjective cognitive decline. Our pilot studies (National Institutes of Health [NIH] stage 1A) have shown that MHB is feasible, acceptable, and associated with improvement in lifestyle behavior and cognitive outcomes.

OBJECTIVE

We will compare the feasibility of MHB versus an education control (health enhancement program [HEP]) in 50 older adults (aged ≥60 y) with subjective cognitive decline and AD/ADRD risk factors. In an NIH stage 1B randomized controlled trial (RCT), we will evaluate feasibility benchmarks, improvements in cognitive and lifestyle outcomes, and engagement of hypothesized mechanisms.

METHODS

We are recruiting through clinics, flyers, web-based research platforms, and community partnerships. Participants are randomized to MHB or the HEP, both delivered in telehealth groups over 8 weeks. MHB participants learn behavior modification and mindfulness skills to achieve individualized lifestyle goals. HEP participants receive lifestyle education and group support. Assessments are repeated after the intervention and at a 6-month follow-up. Our primary outcomes are feasibility, acceptability, appropriateness, credibility, satisfaction, and fidelity benchmarks. The secondary outcomes are cognitive function and lifestyle (physical activity, sleep, nutrition, alcohol and tobacco use, and mental and social activity) behaviors. Data analyses will include the proportion of MHB and HEP participants who meet each benchmark (primary outcome) and paired samples 2-tailed t tests, Cohen d effect sizes, and the minimal clinically important difference for each measure (secondary outcomes).

RESULTS

Recruitment began in January 2024. We received 225 inquiries. Of these 225 individuals, 40 (17.8%) were eligible. Of the 40 eligible participants, 21 (52.5%) were enrolled in 2 group cohorts, 17 (42.5%) were on hold for future group cohorts, and 2 (5%) withdrew before enrollment. All participants have completed before the intervention assessments. All cohort 1 participants (9/21, 43%) have completed either MHB or the HEP (≥6 of 8 sessions) and after the intervention assessments. The intervention for cohort 2 (12/21, 57%) is ongoing. Adherence rates for the Garmin Vivosmart 5 (128/147, 87.1% weeks) and daily surveys (105/122, 86.1% weeks) are high. No enrolled participants have dropped out. Enrollment is projected to be completed by December 2024.

CONCLUSIONS

The RCT will inform the development of a larger efficacy RCT (NIH stage 2) of MHB versus the HEP in a more diverse sample of older adults, testing mechanisms of improvements through theoretically driven mediators and moderators. The integration of mindfulness with lifestyle behavior change in MHB has the potential to be an effective and sustainable approach for increasing the uptake of AD/ADRD risk reduction strategies among older adults.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05934136; https://www.clinicaltrials.gov/study/NCT05934136.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/64149.

The Combined Impact of Physical Activity and Sedentary Behavior on Executive Functions in Older Adults: A Cross-Sectional Study

Background

The interplay between physical activity (PA) and sedentary behavior (SB) significantly influences cognitive health in older adults, with executive functions (EFs) being particularly vulnerable to lifestyle factors. However, previous research on older adults focused mainly on PA and is limited due to the lack of comprehensive consideration of other factors that influence EFs. Current guidelines suggest an association between sedentary behavior (SB) and EFs, yet few studies have examined the combined effects of PA and SB on EFs.

Objective

This cross-sectional study aimed to explore the relationship between PA, SB, and EFs in older adults.

Methods

A total of 116 healthy older adults aged ≥65 years were recruited and categorized into four groups based on activity lifestyles: higher PA and higher SB (PHSH); higher PA and lower SB (PHSL); lower PA and higher SB (PLSH); and lower PA and lower SB (PLSL). EFs were assessed using the Tower of London (TOL) task and the Stroop test, which measure high-order EFs (planning and problem-solving) and core EFs (inhibitory control), respectively.

Results

The PHSL group performed better on the TOL task, with lower total move scores and shorter total problem-solving times, compared to the PLSH group. The total move score of the PLSL group was better, and the total problem-solving time of the PHSH group was shorter than those of the PLSH group. However, the Stroop test scores did not differ between the four groups.

Conclusion

These findings suggest that increasing PA or reducing SB selectively enhances executive functions, particularly in planning and problem-solving, while less impacting inhibitory control in older adults. This highlights the importance of considering the nuanced effects of PA and SB on different aspects of executing functioning in older adults.

Poststroke seizures and epilepsy increase the risk of dementia among stroke survivors: A population-based study

OBJECTIVE

With global aging, the occurrence of stroke and associated outcomes like dementia are on the rise. Seizures and epilepsy are common poststroke complications and have a strong connection to subsequent dementia. This study examines the relationship between poststroke seizures (PSS) or poststroke epilepsy (PSE) and dementia using a national health care database.

METHODS

We conducted a retrospective study using data from the Taiwan National Health Insurance Research Database from 2009 to 2020. We identified acute stroke patients from 2010 to 2015, excluding those with pre-existing neurological conditions. Based on age, sex, stroke severity level, and the year of index stroke, patients with PSS or PSE were matched to those without. The main outcome was incident dementia.

RESULTS

This study included 62 968 patients with an average age of 63 years, with males accounting for 62.9%. Of them, 60.3% had ischemic strokes, and 39.7% had hemorrhagic strokes. After an average follow-up period of 5.2 years, dementia developed in 15.9% of patients who had PSS or PSE, as opposed to 8.4% of those without these conditions. A time-dependent Fine and Gray competing risk analysis showed that PSS and PSE were significantly associated with dementia across all stroke types. Subgroup analyses revealed significantly increased risk of dementia across all age groups (<50, 50-64, and ≥65 years), sexes, and various stroke severity levels. The link between PSS or PSE and dementia was particularly pronounced in men, with a less distinct correlation in women.

SIGNIFICANCE

The risk of incident dementia was higher in patients with PSS or PSE. The potential for therapeutic interventions for seizures and epilepsy to reduce poststroke dementia underscores the importance of seizure screening and treatment in stroke survivors.

The early diagnosis of Alzheimer's disease: Blood-based panel biomarker discovery by proteomics and metabolomics

Diagnosis and prediction of Alzheimer's disease (AD) are increasingly pressing in the early stage of the disease because the biomarker-targeted therapies may be most effective. Diagnosis of AD largely depends on the clinical symptoms of AD. Currently, cerebrospinal fluid biomarkers and neuroimaging techniques are considered for clinical detection and diagnosis. However, these clinical diagnosis results could provide indications of the middle and/or late stages of AD rather than the early stage, and another limitation is the complexity attached to limited access, cost, and perceived invasiveness. Therefore, the prediction of AD still poses immense challenges, and the development of novel biomarkers is needed for early diagnosis and urgent intervention before the onset of obvious phenotypes of AD. Blood-based biomarkers may enable earlier diagnose and aid detection and prognosis for AD because various substances in the blood are vulnerable to AD pathophysiology. The application of a systematic biological paradigm based on high-throughput techniques has demonstrated accurate alterations of molecular levels during AD onset processes, such as protein levels and metabolite levels, which may facilitate the identification of AD at an early stage. Notably, proteomics and metabolomics have been used to identify candidate biomarkers in blood for AD diagnosis. This review summarizes data on potential blood-based biomarkers identified by proteomics and metabolomics that are closest to clinical implementation and discusses the current challenges and the future work of blood-based candidates to achieve the aim of early screening for AD. We also provide an overview of early diagnosis, drug target discovery and even promising therapeutic approaches for AD.

Effects of exercise on brain-derived neurotrophic factor in Alzheimer's disease models: A systematic review and meta-analysis

A growing body of research examining effects of exercise on brain-derived neurotrophic factor (BDNF) in Alzheimer's disease (AD) models, while due to differences in gender, age, disease severity, brain regions examined, and type of exercise intervention, findings of available studies were conflicting. In this study, we aimed to evaluate current evidence regarding effects of exercise on BDNF in AD models. Searches were performed in PubMed, Web of Science, Cochrane, and EBSCO electronic databases, through July 20, 2023. We included studies that satisfied the following criteria: eligible studies should (1) report evidence on experimental work with AD models; (2) include an exercise group and a control group (sedentary); (3) use BDNF as the outcome indicator; and (4) be randomized controlled trials (RCTs). From 1196 search records initially identified, 36 studies met the inclusion criteria. There was a significant effect of exercise on increasing BDNF levels in AD models [standardized mean differences (SMD) = 0.98, P < 0.00001]. Subgroup analysis showed that treadmill exercise (SMD = 0.92, P< 0.0001), swimming (SMD = 1.79, P< 0.0001), and voluntary wheel running (SMD = 0.51, P= 0.04) were all effective in increasing BDNF levels in AD models. In addition, exercise significantly increased BDNF levels in the hippocampus (SMD = 0.92, P< 0.00001) and cortex (SMD = 1.56, P= 0.02) of AD models. Exercise, especially treadmill exercise, swimming, and voluntary wheel running, significantly increased BDNF levels in hippocampus and cortex of AD models, with swimming being the most effective intervention type.

Boosting Brain Health: Interventions for the Prevention and Treatment of Mild Cognitive Impairment and Early Neurodegenerative Disease

Mild Cognitive Impairment (MCI) and dementia are becoming more common with an aging population, and the numbers are expected to rise. These conditions can have a significant impact on patients, family, and health care systems. Lifestyle changes including physical activity, nutrition, quality sleep, socialization, cognitive activity and mental stimulation, routine medical care, and mental health care have the potential to prevent cognitive and functional decline and optimize daily living in all individuals, including those with MCI and early neurodegenerative disease. Brain Boosters is an important group intervention used to provide psychoeducation on lifestyle factors and strategies that can improve brain health, cognition, and functioning.

Racial differences in links between perceived discrimination, depressive symptoms, and ambulatory working memory

OBJECTIVES

Perceived discrimination is associated with racial cognitive health disparities. Links between discrimination and cognitive performance, like working memory, in everyday settings (i.e. ambulatory performance) require investigation. Depressive symptoms may be a mechanism through which discrimination relates to ambulatory working memory.

METHOD

Discrimination, retrospective and momentary depressive symptoms/mood, and aggregated and momentary working memory performance among older Black and White adults were examined within the Einstein Aging Study.

RESULTS

Racially stratified analyses revealed that discrimination did not relate to Black or White adults' ambulatory working memory. Among Black adults, however, more frequent discrimination was associated with greater retrospectively reported depressive symptoms, which related to more working memory errors across two weeks (indirect effect p < 0.05). This path was not significant among White adults. Links between discrimination and momentary working memory were not explained by momentary reports of depressed mood for Black or White adults.

CONCLUSION

Depressive symptoms may play an important role in the link between discrimination and ambulatory working memory among Black adults across extended measurements, but not at the momentary level. Future research should address ambulatory cognition and momentary reports of discrimination and depression to better understand how to minimize cognitive health disparities associated with discrimination.

Relationships of Physical Activity and Type 2 Diabetes With Cognition in Mexican Americans and Non-Hispanic Whites

Problem, Research Strategy, and Findings: Low physical activity (PA) and Type 2 diabetes are associated with cognitive aging and Alzheimer's disease, but the evidence is inconsistent and particularly limited by ethnicity. The purpose of this study was to examine the relationships of PA and Type 2 diabetes with cognition in Mexican Americans and non-Hispanic Whites. The study was a cross-sectional analysis of the Health and Aging Brain Study-Health Disparities (n = 1,982-2,000 after removing outliers). Predictors included Rapid Assessment of Physical Activity and hemoglobin A1c (HbA1c). Episodic memory was assessed by Weschler Memory Scale-Third Edition Logical Memory and Spanish-English Verbal Learning Test, executive function by Weschler Memory Scale-Third Edition Digit Span and Digit Symbol Substitution Test, verbal fluency by FAS and animal naming, and global cognition by the Mini-Mental State Examination. Results show that aerobic PA and HbA1c were not associated with domain-specific, or global cognition, but strength/flexibility PA was associated with FAS (b = 0.404, 95% CI [0.023, 0.761]). Higher aerobic PA was associated with greater verbal fluency for Mexican Americans (b = 0.294, 95% CI [0.96, 0.497]) only. HbA1c was negatively associated with Mini-Mental State Examination (b = 0.838, 95% CI [0.008, 1.656]). For low HbA1c, the association between aerobic PA and Digit Symbol Substitution Test was significant for non-Hispanic Whites (b = 0.838, 95% CI [0.008, 1.656]) in comparison to Mexican Americans. Takeaway for Practice: The relationships between PA, Type 2 diabetes, and cognition vary by cognitive domains and ethnicity. Increasing aerobic activities may be particularly important for Mexican Americans who have elevated HbA1c to potentially improve fluency or executive function.

Population attributable fractions for risk factors for dementia in seven Latin American countries: an analysis using cross-sectional survey data

BACKGROUND

Approximately 40% of dementia cases worldwide are attributable to 12 potentially modifiable risk factors. However, the proportion attributable to these risks in Latin America remains unknown. We aimed to determine the population attributable fraction (PAF) of 12 modifiable risk factors for dementia in seven countries in Latin America.

METHODS

We used data from seven cross-sectional, nationally representative surveys with measurements of 12 modifiable risk factors for dementia (less education, hearing loss, hypertension, obesity, smoking, depression, social isolation, physical inactivity, diabetes, excessive alcohol intake, air pollution, and traumatic brain injury) done in Argentina, Brazil, Bolivia, Chile, Honduras, Mexico, and Peru. Data were collected between 2015 and 2021. Sample sizes ranged from 5995 to 107 907 participants (aged ≥18 years). We calculated risk factor prevalence and communalities in each country and used relative risks from previous meta-analyses to derive weighted PAFs. Pooled PAFs for Latin America were obtained using random effect meta-analyses.

FINDINGS

The overall proportion of dementia cases attributed to 12 modifiable risk factors varied across Latin American countries: weighted PAF 61·8% (95% CI 37·9-79·5) in Chile, 59·6% (35·8-77·3) in Argentina, 55·8% (35·7-71·5) in Mexico, 55·5% (35·9-70·4) in Bolivia, 53·6% (33·0-69·3) in Honduras, 48·2% (28·1-63·9) in Brazil, and 44·9% (25·8-61·2) in Peru. The overall PAF for dementia was 54·0% (48·8-59·6) for Latin America. The highest weighted PAFs in Latin American countries overall were for obesity (7%), physical inactivity (6%), and depression (5%).

INTERPRETATION

The estimated PAFs for Latin American countries were higher than previous global estimates. Obesity, physical inactivity, and depression were the main risk factors for dementia across seven Latin American countries. These findings have implications for public health and individually targeted dementia prevention strategies in Latin America. Although these results provide new information about Latin American countries, demographics and representativeness variations across surveys should be considered when interpreting these findings.

FUNDING

None.

Current Health Status of Gulf War Deployed and Gulf War Era Veterans Who Use Veterans Affairs Health Care

Background: Although some recent studies have examined the health of female Gulf War (GW) deployed and non-deployed GW era veterans, these all relied on self-report, which can be inaccurate and subject to recall bias. This study investigated the current health of GW deployed and non-deployed GW era female and male veterans using Veterans Health Administration (VHA) electronic health records (EHR). Methods: We performed a cohort study of deployed GW and non-deployed GW era veterans, identified from a list from the Defense Manpower Data Center (DMDC). We used the VA-Frailty Index (VA-FI), calculated with VHA administrative claims and EHR, as a proxy measure of current health. Results: We identified 402,869 veterans (351,496 GW deployed; 51,3373 non-deployed GW era; 38,555 female) in VHA databases. Deployed female veterans had the highest VA-FI (i.e., were frailest) despite being younger than deployed and non-deployed male veterans and non-deployed female veterans. Compared with deployed male veterans, deployed females were more likely to be pre-frail, mildly, and moderately frail. Health differences between deployed and non-deployed female veterans were more prominent among older (60+ years) than younger (<60 years) veterans. Conclusions: Mirroring reports from recent, smaller survey studies of users and non-users of VA health care, findings from this cohort study indicate that deployed female GW veterans who use VA health care are frailer and have more health deficits than non-deployed female GW era and deployed male GW veterans. Because deployed female GW veterans appear to have additional health care needs, this may warrant increased outreach from women's clinics at VA hospitals.

Association between idiopathic normal pressure hydrocephalus and Alzheimer's disease: a bidirectional Mendelian randomization study

Observational studies have suggested a bidirectional relationship between idiopathic normal pressure hydrocephalus (iNPH) and Alzheimer's disease (AD). However, the causal association between these two neurodegenerative disorders remains unclear. This study aimed to explore the causal relationship between iNPH and AD using a two-sample bidirectional Mendelian randomization (MR) method. Large-scale genome-wide association studies of iNPH (Ncase = 767, Ncontrol = 375,610) and AD (Ncase/proxy = 111,326, Ncontrol = 677,663) in European individuals were used to screen genetic instruments for MR analysis. Inverse variance-weighted (IVW) method was used as the main analysis, other MR methods and a series of sensitivity analyses were performed to ensure the reliability. In the forward MR analysis, genetic predisposition to iNPH had no effects on the risk of AD development. Likewise, in the reverse MR analysis, AD did not demonstrate a significant causal effect on iNPH. Sensitivity analyses bolstered the reliability of the MR results. Our MR study indicated no genetic evidence supporting a suggestive association between AD and iNPH in either direction, and provided evidence on the dichotomy between true iNPH and neurodegenerative NPH.

Lifestyle approaches to hypertension for prevention of stroke and vascular cognitive impairment: a realist review protocol

INTRODUCTION

Stroke and vascular cognitive impairment (VCI) are major global public health pandemics. The increased incidence of stroke and VCI is in part due to modifiable risk factors (MRFs), with hypertension (HTN) being the strongest single MRF. Even though the underlying causes of HTN are multifactorial, lifestyle choices (eg, poor diet, physical inactivity, alcohol consumption) are chief contributors. Lifestyle medicine (LSM) is a medical and evidence-based discipline that is a promising approach for preventing stroke and cognitive impairment, including VCI. The empirical evidence from systematic reviews, meta-analyses and large population-based studies has reported on the effectiveness of LSM interventions. However, the evaluation of such complex, social and behavioural interventions warrants more information to allow its successful implementation into innovative clinical care models. More importantly, we need to understand how such interventions work, who it works for and under what circumstances to successfully manage HTN and other MRFs (eg, hyperlipidaemia, smoking, alcohol use and diet).

METHODS AND ANALYSIS

This realist review will follow the Realist and Meta-narrative Evidence Synthesis: Evolving Standards. The review will comprise four stages: (1) clarify the scope, (2) search for the evidence, (3) critically appraise primary studies and extract data focusing on the context, mechanism and outcome configuration and (4) synthesise evidence and draw conclusions.

ETHICS AND DISSEMINATION

Research ethics board approval is not required for this review. The primary output of this review will be an evidence-based programme theory for LSM interventions for the management of HTN and other MRFs to reduce the risk of stroke and VCI. Findings from this review will be disseminated at three levels: micro (eg, patients, caregivers, clinicians, non-research partners), meso (eg, public, national not-for-profit organisations, professional associations and centres) and macro (eg, policymakers and government partners).

PROSPERO REGISTRATION NUMBER

CRD42024511566.

Graded Intensity Aerobic Exercise to Improve Cerebrovascular Function and Performance in Older Veterans: Protocol for a Randomized Controlled Trial

BACKGROUND

Growing health care challenges resulting from a rapidly expanding aging population necessitate examining effective rehabilitation techniques that mitigate age-related comorbidity and improve quality of life. To date, exercise is one of a few proven interventions known to attenuate age-related declines in cognitive and sensorimotor functions critical to sustained independence.

OBJECTIVE

This work aims to implement a multimodal imaging approach to better understand the mechanistic underpinnings of the beneficial exercise-induced adaptations to sedentary older adults' brains and behaviors. Due to the complex cerebral and vascular dynamics that encompass neuroplastic change with aging and exercise, we propose an imaging protocol that will model exercise-induced changes to cerebral perfusion, cerebral vascular reactivity (CVR), and cognitive and sensorimotor task-dependent functional magnetic resonance imaging (fMRI) after prescribed exercise.

METHODS

Sedentary older adults (aged 65-80 years) were randomly assigned to either a 12-week aerobic-based interval-based cycling intervention or a 12-week balance and stretching intervention. Assessments of cardiovascular fitness used the YMCA submaximal VO2 test, basal cerebral perfusion using arterial spin labeling (ASL), CVR using hypercapnic fMRI, and cortical activation using fMRI during verbal fluency and motor tapping tasks. A battery of cognitive-executive and motor function tasks outside the scanning environment will be performed before and after the interventions.

RESULTS

Our studies and others show that improved cardiovascular fitness in older adults results in improved outcomes related to physical and cognitive health as well as quality of life. A consistent but unexplained finding in many of these studies is a change in cortical activation patterns during task-based fMRI, which corresponds with improved task performance (cognitive-executive and motor). We hypothesize that the 12-week aerobic exercise intervention will increase basal perfusion and improve CVR through a greater magnitude of reactivity in brain areas susceptible to neural and vascular decline (inferior frontal and motor cortices) in previously sedentary older adults. To differentiate between neural and vascular adaptations in these regions, we will map changes in basal perfusion and CVR over the inferior frontal and the motor cortices-regions we have previously shown to be beneficially altered during fMRI BOLD (blood oxygen level dependent), such as verbal fluency and motor tapping, through improved cardiovascular fitness.

CONCLUSIONS

Exercise is one of the most impactful interventions for improving physical and cognitive health in aging. This study aims to better understand the mechanistic underpinnings of improved health and function of the cerebrovascular system. If our hypothesis of improved perfusion and cerebrovascular reactivity following a 12-week aerobic exercise intervention is supported, it would add critically important insights into the potential of exercise to improve brain health in aging and could inform exercise prescription for older adults at risk for neurodegenerative disease brought on by cerebrovascular dysfunction.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05932069; https://clinicaltrials.gov/study/NCT05932069.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/58316.

Treadmill Exercise Facilitates Synaptic Plasticity in APP/PS1 Mice by Regulating Hippocampal AMPAR Activity

Accumulating evidence underscores exercise as a straightforward and cost-effective lifestyle intervention capable of mitigating the risk and slowing the emergence and progression of Alzheimer's disease (AD). However, the intricate cellular and molecular mechanisms mediating these exercise-induced benefits in AD remain elusive. The present study delved into the impact of treadmill exercise on memory retrieval performance, hippocampal synaptic plasticity, synaptic morphology, and the expression and activity of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic receptors (AMPARs) in 6-month-old APP/PS1 mice. APP/PS1 mice (4-month-old males) were randomly assigned to either a treadmill exercise group or a sedentary group, with C57BL/6J mice (4-month-old males) as the control group (both exercise and sedentary). The exercise regimen spanned 8 weeks. Our findings revealed that 8-week treadmill exercise reversed memory retrieval impairment in step-down fear conditioning in 6-month-old APP/PS1 mice. Additionally, treadmill exercise enhanced basic synaptic strength, short-term potentiation (STP), and long-term potentiation (LTP) of the hippocampus in these mice. Moreover, treadmill exercise correlated with an augmentation in synapse numbers, refinement of synaptic structures, and heightened expression and activity of AMPARs. Our findings suggest that treadmill exercise improves behavioral performance and facilitates synaptic transmission by increasing structural synaptic plasticity and the activity of AMPARs in the hippocampus of 6-month-old APP/PS1 mice, which is involved in pre- and postsynaptic processes.

Multi-ancestry population attributable risk assessment of common genetic variation in Alzheimer's and Parkinson's diseases

Multiple scientific studies, mostly performed within European populations, have unraveled many of the genetic factors associated with Alzheimer's disease (AD) and Parkinson's disease (PD) etiologies, improving our understanding of the molecular pathways implicated in the pathogenesis of these conditions. However, there is increasing evidence that the genetic architecture of these diseases differs across ancestral populations. This raises concerns about the efficacy of therapeutic interventions crafted around genetic targets prevalent only in European ancestry populations. Such interventions neglect potentially distinctive etiological profiles, including Latino, Black/African American, and East Asian populations. In the current study, we explore Population Attributable Risk (PAR) in AD and PD etiologies and assess the proportion of disease attributed to specific genetic factors across diverse populations. Leveraging data from genome-wide association studies across four ancestries, we explore distinct and universal therapeutic targets across diverse populations. Multi-ancestral genetics research is critical to the development of successful therapeutics and treatments for neurodegenerative diseases. By offering insights into genetic disparities, we aim to inform more inclusive and effective therapeutic strategies, advancing personalized healthcare.

Cerebrovascular disease is associated with Alzheimer's plasma biomarker concentrations in adults with Down syndrome

By age 40 years, over 90% of adults with Down syndrome have Alzheimer's disease pathology and most progress to dementia. Despite having few systemic vascular risk factors, individuals with Down syndrome have elevated cerebrovascular disease markers that track with the clinical progression of Alzheimer's disease, suggesting a role of cerebrovascular disease that is hypothesized to be mediated by inflammatory factors. This study examined the pathways through which small vessel cerebrovascular disease contributes to Alzheimer's disease-related pathophysiology and neurodegeneration in adults with Down syndrome. One hundred eighty-five participants from the Alzheimer's Biomarkers Consortium-Down Syndrome [mean (SD) age = 45.2 (9.3) years] with available MRI and plasma biomarker data were included in this study. White matter hyperintensity (WMH) volumes were derived from T2-weighted fluid-attenuated inversion recovery MRI scans, and plasma biomarker concentrations of amyloid beta 42/40, phosphorylated tau 217, astrocytosis (glial fibrillary acidic protein) and neurodegeneration (neurofilament light chain) were measured with ultrasensitive immunoassays. We examined the bivariate relationships of WMH, amyloid beta 42/40, phosphorylated tau 217 and glial fibrillary acidic protein with age-residualized neurofilament light chain across Alzheimer's disease diagnostic groups. A series of mediation and path analyses examined statistical pathways linking WMH and Alzheimer's disease pathophysiology to promote neurodegeneration in the total sample and groups stratified by clinical diagnosis. There was a direct and indirect bidirectional effect through the glial fibrillary acidic protein of WMH on phosphorylated tau 217 concentration, which was associated with neurofilament light chain concentration in the entire sample. Amongst cognitively stable participants, WMH was directly and indirectly, through glial fibrillary acidic protein, associated with phosphorylated tau 217 concentration, and in those with mild cognitive impairment, there was a direct effect of WMH on phosphorylated tau 217 and neurofilament light chain concentrations. There were no associations of WMH with biomarker concentrations among those diagnosed with dementia. The findings from this cross-sectional study suggest that among individuals with Down syndrome, cerebrovascular disease promotes neurodegeneration by increasing astrocytosis and tau pathophysiology in the presymptomatic phases of Alzheimer's disease, but future studies will need to confirm these associations with longitudinal data. This work joins an emerging literature that implicates cerebrovascular disease and its interface with neuroinflammation as a core pathological feature of Alzheimer's disease in adults with Down syndrome.

Proteogenomic signature of risk of Alzheimer's disease and related dementia risk in individuals with a history of major depression disorder

The mechanisms linking a history of major depressive disorder (MDD) to an increased risk of Alzheimer's disease and related dementia (ADRD) are not fully understood. Using the UK Biobank available proteomic and genomic data, we evaluated the biological mechanisms linking both conditions. In participants with a history of MDD at baseline (n=3,615), we found that plasma levels of NfL, GFAP, PSG1 were associated with higher risk (HR=1.38; 1.37; 1.34, respectively; all adjusted p-values<0.05), while VGF, GET3, and HPGDS were associated with lower risk of incident ADRD (n=150) (HR=0.73; 0.71; 0.66, respectively; all adjusted p-values<0.05) during a mean follow-up of 13.7 years (SD=2.2). Two-sample Mendelian randomization analysis using cis-pQTLs genetic instruments revealed that a lower protein expression of apolipoprotein E and higher IL-10 receptor subunit B were causally linked to incident ADRD. Finally, we developed a Proteomic Risk Score (PrRSMDD-ADRD), which showed strong discriminative power (C-statistic = 0.84) to identify participants with MDD that developed ADRD upon follow-up. In addition to demonstrating an association between plasma proteins associated with inflammation and future ADRD risk in individuals with MDD, our findings include an element of causality using Mendelian Randomization (MR) and PrRSMDD-ADRD can be useful to identify individuals with the highest risk to develop ADRD in a highly vulnerable population.

A critique and examination of the polysocial risk score approach: predicting cognition in the Health and Retirement Study

Polysocial risk scores were recently proposed as a strategy for improving the clinical relevance of knowledge about social determinants of health. Our objective in this study was to assess whether the polysocial risk score model improves prediction of cognition and all-cause mortality in middle-aged and older adults beyond simpler models including a smaller set of key social determinants of health. We used a sample of 13 773 individuals aged ≥50 years at baseline from the 2006-2018 waves of the Health and Retirement Study, a US population-based longitudinal cohort study. Four linear mixed models were compared: 2 simple models including a priori-selected covariates and 2 polysocial risk score models which used least absolute shrinkage and selection operator (LASSO) regularization to select covariates among 9 or 21 candidate social predictors. All models included age. Predictive accuracy was assessed via R2 and root mean-squared prediction error (RMSPE) using training/test split validation and cross-validation. For predicting cognition, the simple model including age, race, sex, and education had an R2 value of 0.31 and an RMSPE of 0.880. Compared with this, the most complex polysocial risk score selected 12 predictors (R2 = 0.35 and RMSPE = 0.858; 2.2% improvement). For all-cause mortality, the simple model including age, race, sex, and education had an area under the receiver operating characteristic curve (AUROC) of 0.747, while the most complex polysocial risk score did not demonstrate improved performance (AUROC = 0.745). Models built on a smaller set of key social determinants performed comparably to models built on a more complex set of social "risk factors."

Circadian rhythm disruption and retinal dysfunction: a bidirectional link in Alzheimer's disease?

Dysfunction in circadian rhythms is a common occurrence in patients with Alzheimer's disease. A predominant function of the retina is circadian synchronization, carrying information to the brain through the retinohypothalamic tract, which projects to the suprachiasmatic nucleus. Notably, Alzheimer's disease hallmarks, including amyloid-β, are present in the retinas of Alzheimer's disease patients, followed/associated by structural and functional disturbances. However, the mechanistic link between circadian dysfunction and the pathological changes affecting the retina in Alzheimer's disease is not fully understood, although some studies point to the possibility that retinal dysfunction could be considered an early pathological process that directly modulates the circadian rhythm.

Infection burden, periodontal pathogens, and their interactive association with incident all-cause and Alzheimer's disease dementia in a large national survey

INTRODUCTION

Relationships and interplay of an infection burden (IB) and periodontal pathogens or periodontal disease (Pd) markers with Alzheimer's disease (AD) and all-cause dementia among US adults were examined.

METHODS

Less than or equal to 2997 participants from the National Health and Nutrition Survey III were linked to CMS-Medicare [≥45 years (1988-1994); ≤30 years follow-up].

RESULTS

Hepatitis C (hazard ratio = 3.33, p = 0.004) and herpes simplex virus 2 were strongly associated with greater all-cause dementia risk. Porphyromonas gingivalis and Streptococcus oralis were associated with greater AD risk at higher IB. The red-green periodontal pathogen cluster coupled with higher IB count increased the risk of all-cause dementia among minority racial groups. Pocket probing depth associated with dementia risk at lower IB in the overall sample.

DISCUSSION

Select viruses and bacteria were associated with all-cause and AD dementia, while the IB interacted with Pd markers in relation to these outcomes.

HIGHLIGHTS

Interplay of infection burden (IB) and periodontal disease with dementia was tested. ≤2997 participants from NHANES III were linked to Medicare. Hepatitis C and herpes simplex virus 2 strongly associated with dementia risk. Tetanus sero-positivity increased Alzheimer's disease (AD) risk. Porphyromonas gingivalis and Streptococcus oralis associated with AD at higher IB. Red-green periodontal cluster at high IB, increased dementia in racial minorities. Pocket probing depth associated with dementia risk at lower IB.

Factors related to cognitive performance among black caregivers of persons living with a chronic illness: An exploratory study

This study investigated factors associated with cognitive performance among Black caregivers of persons living with two chronic conditions: dementia or cancer. Fifty-six Black caregivers of people living with dementia or cancer were recruited from clinic and community sources. Variables measured included: depression, anxiety, stress, sleep, fatigue, and caregiver burden. Cognitive performance was assessed using the Montreal Cognitive Assessment (MoCA). Descriptive statistics and non-parametric analyses were conducted to identify factors related to MoCA scores. Caregivers were 58.3 years of age and predominantly female. The average MoCA score was 25.23. Gender and education, along with positive appraisal of caregiving were significantly associated with cognitive performance. Several other factors approached significance including cohabitation with the care recipient, fatigue, and stress due to perceived individual and institutional racism. Our findings suggest several factors that warrant further investigation for understanding the relationship between caregiving and cognitive performance in Black caregivers of people living with cancer or dementia.

Population-attributable fraction of psychiatric and physical disorders for suicide among older adults in Taiwan

BACKGROUND

This study aimed to estimate the population-attributable fraction (PAF) of psychiatric and physical disorders for suicide among older adults, focusing on sex- and age-specific factors.

METHODS

Data from Taiwan's National Health Insurance Research Data and National Death Registry included 9136 cases of suicide in individuals aged 65+, with 89,439 matched controls. Physical and psychiatric disorders were identified through diagnostic records. Conditional logistic regression assessed risk factors, and PAF was calculated using disorder prevalence and adjusted odds ratios.

RESULTS

Major suicide risk factors among older adults were depressive disorders, anxiety disorders, and sleep disorders. Physical disorders like hypertension, peptic ulcers, and cancer also showed significant PAF values. The combined PAF of physical disorders equaled that of psychiatric disorders. Psychiatric disorders had a greater impact on women and the youngest-old adults, while physical disorders had a higher contribution among men, middle-old adults, and oldest-old adults.

LIMITATIONS

Relying solely on claim data to identify psychiatric and physical disorders may underestimate their prevalence and associations with suicide due to unrecorded cases of individuals not seeking help and the absence of key risk factors like social isolation and family support.

CONCLUSIONS

This study identifies preventable or treatable risk factors for older adult suicide, emphasizing the need to target specific psychiatric and physical disorders in suicide prevention efforts while taking into account sex- and age-specific considerations. It also underscores the importance of establishing social welfare support systems to address the unique challenges older adults face.

Morphological and Biophysical Study of S100A9 Protein Fibrils by Atomic Force Microscopy Imaging and Nanomechanical Analysis

Atomic force microscopy (AFM) imaging enables the visualization of protein molecules with high resolution, providing insights into their shape, size, and surface topography. Here, we use AFM to study the aggregation process of protein S100A9 in physiological conditions, in the presence of calcium at a molar ratio 4Ca2+:S100A9. We find that S100A9 readily assembles into a worm-like fibril, with a period dimension along the fibril axis of 11.5 nm. The fibril's chain length extends up to 136 periods after an incubation time of 144 h. At room temperature, the fibril's bending stiffness was found to be 2.95×10-28 Nm2, indicating that the fibrils are relatively flexible. Additionally, the values obtained for the Young's modulus (Ex=6.96×105 Pa and Ey=3.37×105 Pa) are four orders of magnitude lower than those typically reported for canonical amyloid fibrils. Our findings suggest that, under the investigated conditions, a distinct aggregation mechanism may be in place in the presence of calcium. Therefore, the findings reported here could have implications for the field of biomedicine, particularly with regard to Alzheimer's disease.

An 11-Fold Higher Risk of Incident Mild Cognitive Impairment With Hispanic Ethnicity and Baseline Neuropsychiatric Symptoms

OBJECTIVE

Neuropsychiatric symptoms (NPSs) have been linked to cognitive decline. This study explored ethnic differences and the effects of baseline NPSs on incident mild cognitive impairment (MCI) among 386 Hispanic and non-Hispanic participants from the Texas Harris Alzheimer's Research Study.

METHODS

Data on NPSs from the Neuropsychiatric Inventory Questionnaire were available for all participants. Cox proportional hazards regression models were used to estimate the effect of ≥1 NPS at baseline and Hispanic ethnicity on incident MCI over a 7-year follow-up period.

RESULTS

NPSs at baseline were associated with incident MCI for Hispanic participants but not non-Hispanic participants. Being Hispanic with at least one NPS at baseline had an 11-times higher risk of incident MCI.

CONCLUSIONS

The Hispanic participants converted to MCI to a greater extent than the non-Hispanic participants. Only depressive symptoms increased the risk of MCI among non-Hispanics. Being of Hispanic ethnicity and having NPSs appeared to jointly increase the risk of progressing to MCI. To better understand the Alzheimer's disease continuum, further studies should explore other cultural, genetic, and medical risk factors influencing disease progression. Our findings strongly suggest the need to incorporate NPSs as outcomes of disease progression in future clinical trials involving Hispanic participants.

Estrogen Receptors: A New Frontier in Alzheimer's Disease Therapy

Alzheimer's disease (AD) is a long-term neurodegenerative condition that leads to the deterioration of neurons and synapses in the cerebral cortex, resulting in severe dementia. AD is significantly more prevalent in postmenopausal women, suggesting a neuroprotective role for estrogen. Estrogen is now known to regulate a wide array of physiological functions in the body by interacting with three known estrogen receptors (ERs) and with the β-amyloid precursor protein, a key factor in AD pathogenesis. Recent experimental evidence indicates that new selective ER modulators and phytoestrogens may be promising treatments for AD for their neuroprotective and anti-apoptotic properties. These alternatives may offer fewer side effects compared to traditional hormone therapies, which are associated with risks such as cardiovascular diseases, cancer, and metabolic dysfunctions. This review sheds light on estrogen-based treatments that may help to partially prevent or control the neurodegenerative processes characteristic of AD, paving the way for further investigation in the development of estrogen-based treatments.

Dementia Risk Scores, APOE, and risk of Alzheimer disease: one size does not fit all

Introduction

Evaluating the generalizability of dementia risk scores, primarily developed in non-Latinx White (NLW) participants, and interactions with genetic risk factors in diverse populations is crucial for addressing health disparities.

Methods

We analyzed the association of the Cardiovascular Risk Factors, Aging, and Incidence of Dementia (CAIDE) and modified CAIDE (mCAIDE) scores with dementia risk using logistic regression models stratified by race/ethnicity in NACC and ADNI, and assessed their interaction with APOE.

Results

Higher CAIDE scores were associated with an increased risk of dementia in Asian, Latinx, and NLW participants but not in Black participants. In contrast, higher mCAIDE scores were also associated with an increased risk of dementia in Black participants. Unfavorable mCAIDE risk profiles exacerbated the APOE*ε4 risk effect and attenuated the APOE*ε2 protective effect.

Discussion

Our findings underscore the importance of evaluating the validity of dementia risk scores in diverse populations for their use in personalized medicine approaches to promote brain health.

Tobacco cigarette smoking induces cerebrovascular dysfunction followed by oxidative neuronal injury with the onset of cognitive impairment

While chronic smoking triggers cardiovascular disease, controversy remains regarding its effects on the brain and cognition. We investigated the effects of long-term cigarette smoke (CS) exposure (CSE) on cerebrovascular function, neuronal injury, and cognition in a novel mouse exposure model. Longitudinal studies were performed in CS or air-exposed mice, 2 hours/day, for up to 60 weeks. Hypertension and carotid vascular endothelial dysfunction (VED) occurred by 16 weeks of CSE, followed by reduced carotid artery blood flow, with oxidative stress detected in the carotid artery, and subsequently in the brain of CS-exposed mice with generation of reactive oxygen species (ROS) and secondary protein and DNA oxidation, microglial activation and astrocytosis. Brain small vessels exhibited decreased levels of endothelial NO synthase (eNOS), enlarged perivascular spaces with blood brain barrier (BBB) leak and decreased levels of tight-junction proteins. In the brain, amyloid-β deposition and phosphorylated-tau were detected with increases out to 60 weeks, at which time mice exhibited impaired spatial learning and memory. Thus, long-term CSE initiates a cascade of ROS generation and oxidative damage, eNOS dysfunction with cerebral hypoperfusion, as well as cerebrovascular and BBB damage with intracerebral inflammation, and neuronal degeneration, followed by the onset of impaired cognition and memory.

Age and Gender Differences in the Relationship Between Chronic Pain and Dementia Among Older Australians

OBJECTIVES

Chronic pain is a highly debilitating condition that affects older adults and has the potential to increase their odds of experiencing cognitive impairment. The primary objective of this study was to examine the correlation between chronic pain and dementia. Additionally, this research endeavors to ascertain whether the association between chronic pain and dementia differs by age and gender.

METHODS

Cross-sectional data were derived from the Survey of Disability, Ageing, and Carers. A total of 20 671 and 20 081 participants aged 65 years and older in 2015 and 2018, respectively, were included in this study. The pooled association between chronic pain and dementia was assessed using a multivariable logistic regression model. Furthermore, the study also examined the multiplicative interaction effects between chronic pain and age, as well as chronic pain and gender, with dementia.

RESULTS

The pooled analysis demonstrated that chronic pain was associated with a heightened odds of dementia (adjusted odds ratio 1.95; 95% CI 1.85-2.05) among older Australians compared with their counterparts without chronic pain. The interaction effect indicated that individuals with chronic pain across all age groups exhibited increased odds of living with dementia. Additionally, women with chronic pain had higher odds of dementia compared with their counterparts without chronic pain and being male.

CONCLUSIONS

A continuous, coordinated, and tailored healthcare strategy is necessary to determine the pain management goals and explore early treatment options for chronic pain in older adults, particularly in groups with the greatest need.

The association between Weight-adjusted-Waist Index (WWI) and cognitive function in older adults: a cross-sectional NHANES 2011-2014 study

BACKGROUND

The impact of obesity on cognitive function has engendered considerable interest. Weight-adjusted waist index (WWI) has emerged as a novel and innovative marker of obesity that reflects weight-independent abdominal obesity. However, the association between WWI and cognitive function remains unclear. To address this gap, the present study aims to explore the relationship between weight-adjusted waist index (WWI) and cognitive performance in older adults.

METHODS

We conducted a cross-sectional investigation using datasets from the National Health and Nutrition Examination Survey (NHANES) 2011-2014. The study included 3,472 participants (48.59% male, 51.41% female) of various races (Mexican American, Other Hispanic, Non-Hispanic White, Non-Hispanic Black, and Other), with a mean age of 69.95 years (SD = 6.94). Multivariate regression and smoothing curve fitting were used to investigate the linear and nonlinear relationship between WWI and cognitive performance in the following domains: learning and memory, verbal fluency, and processing speed, as measured by Consortium to Establish a Registry for Alzheimer's Disease Word Learning subtest (CERAD-WL), Animal Fluency Test (AFT), and Digit Symbol Substitution Test (DSST), respectively. Subgroup analysis and interaction tests were conducted to examine the stability of this relationship across groups. Machine learning models based on random forests were used to analyze the predictive performance of WWI for cognitive function.

RESULTS

A total of 3,472 participants were included in the analysis. The results revealed significant negative associations between WWI and low scores on the CERAD-WL [-0.96 (-1.30, -0.62)], AFT [-0.77 (-1.05, -0.49)], and DSST [-3.67 (-4.55, -2.79)]. This relationship remained stable after converting WWI to a categorical variable. In addition, this significant negative association was more pronounced in men than women and diminished with advancing age. Non-linear threshold effects were observed, with correlations intensifying between WWI and CERAD-WL when WWI surpassed 12.25, AFT when WWI surpassed 11.54, and DSST when WWI surpassed 11.66.

CONCLUSIONS

A higher WWI, indicating increased abdominal obesity, was associated with deficits in learning, memory, verbal fluency, and processing speed among older adults. These findings suggest that abdominal obesity may play a crucial role in cognitive decline in this population. The stronger relationship observed between WWI and cognition in men highlights the need for gender-specific considerations in interventions targeting abdominal obesity. The results demonstrate the importance of interventions targeting abdominal obesity to preserve cognitive performance in older adults.

Perceptions of Dementia among Nursing Students in South Korea: A Phenomenological Study

This study aimed to determine nursing students' perceptions of dementia and patients with dementia. Specifically, this study sought to illuminate the essential meaning of dementia among nursing students to uncover insights useful for developing patient-centered care rooted in empathy for patients with dementia. This study used a descriptive phenomenological research method. Between August and September 2023, semi-structured interviews were conducted with 15 nursing students. Colaizzi's method was used for the manual analysis. After analyzing the interview data on nursing students' awareness of dementia, four categories, nine theme clusters, and 28 formulated meanings were derived. The four categories were "View of dementia", "Feelings about dementia", "Efforts made regarding dementia", and "Dementia as a nursing student". Although nursing students' perceptions of dementia resulted in negative perspectives and emotions, by looking into coping methods and wishes for dementia, this study also confirmed that nursing students had an awareness of caring for patients with dementia.

Interplay between microglia and environmental risk factors in Alzheimer's disease

Alzheimer's disease, among the most common neurodegenerative disorders, is characterized by progressive cognitive impairment. At present, the Alzheimer's disease main risk remains genetic risks, but major environmental factors are increasingly shown to impact Alzheimer's disease development and progression. Microglia, the most important brain immune cells, play a central role in Alzheimer's disease pathogenesis and are considered environmental and lifestyle "sensors." Factors like environmental pollution and modern lifestyles (e.g., chronic stress, poor dietary habits, sleep, and circadian rhythm disorders) can cause neuroinflammatory responses that lead to cognitive impairment via microglial functioning and phenotypic regulation. However, the specific mechanisms underlying interactions among these factors and microglia in Alzheimer's disease are unclear. Herein, we: discuss the biological effects of air pollution, chronic stress, gut microbiota, sleep patterns, physical exercise, cigarette smoking, and caffeine consumption on microglia; consider how unhealthy lifestyle factors influence individual susceptibility to Alzheimer's disease; and present the neuroprotective effects of a healthy lifestyle. Toward intervening and controlling these environmental risk factors at an early Alzheimer's disease stage, understanding the role of microglia in Alzheimer's disease development, and targeting strategies to target microglia, could be essential to future Alzheimer's disease treatments.

Shedding light on subiculum's role in human brain disorders

Subiculum is a pivotal output component of the hippocampal formation, a structure often overlooked in neuroscientific research. Here, this review aims to explore the role of the subiculum in various brain disorders, shedding light on its significance within the functional-neuroanatomical perspective on neurological diseases. The subiculum's involvement in multiple brain disorders was thoroughly examined. In Alzheimer's disease, subiculum alterations precede cognitive decline, while in epilepsy, the subiculum plays a critical role in seizure initiation. Stress involves the subiculum's impact on the hypothalamic-pituitary-adrenocortical axis. Moreover, the subiculum exhibits structural and functional changes in anxiety, schizophrenia, and Parkinson's disease, contributing to cognitive deficits. Bipolar disorder is linked to subiculum structural abnormalities, while autism spectrum disorder reveals an alteration of inward deformation in the subiculum. Lastly, frontotemporal dementia shows volumetric differences in the subiculum, emphasizing its contribution to the disorder's complexity. Taken together, this review consolidates existing knowledge on the subiculum's role in brain disorders, and may facilitate future research, diagnostic strategies, and therapeutic interventions for various neurological conditions.

Lifestyle Empowerment for Alzheimer's Prevention Prescribed by Physicians: Methods and Adaptations to COVID-19

The health care system is insufficiently capitalizing on the benefits of physical exercise in America's aging population. Few tools exist to help clinicians incorporate physical activity into their clinical care, while barriers limit older adults from initiating and maintaining exercise programs. The Lifestyle Empowerment for Alzheimer's Prevention (LEAP! Rx) Program has been designed to support providers and participants in lifestyle change. LEAP! Rx uses two forms of participant enrollment: physician referrals through electronic health records and self-referrals to test the efficacy of delivering a community-based exercise and healthy lifestyle program to older adults. After referral into the program, participants are randomized to receive the LEAP! Rx Program or are placed in a standard-of-care group to receive the program later. The LEAP! Rx program consists of a personalized and structured exercise program, lifestyle education, and mobile health monitoring. This includes a 12-week Empowerment phase with coaching and supervised exercise training, followed by a 40-week Lifestyle phase with intermittent supervised exercise and coaching. Lifestyle education includes monthly, evidence-based classes on optimal aging. The evaluation of LEAP! Rx focuses on 1) the assessment of implementation and scalability of the LEAP!Rx Program for clinicians and patients 2) the effect of the LEAP! Rx Program on cardiorespiratory fitness, 3) the impact of the LEAP! Rx Program on secondary intervention outcome measures of chronic disease risk factors, including insulin resistance, body composition, and lipids. If successful, this study's findings could advance future healthcare practices, providing a new and practical approach to aging and chronic disease prevention.

Association of modified dementia risk score with cerebrospinal fluid biomarkers and cognition in adults without dementia

Introduction

This study aimed to investigate the cognitive profile and prospective cognitive changes in non-demented adults with elevated Modified Dementia Risk Scores (MDRS), while also exploring the potential relationship between these associations and cerebrospinal fluid (CSF) biomarkers of Alzheimer's disease (AD) pathology and neuroinflammation.

Methods

Within the Chinese Alzheimer's Biomarker and LifestylE (CABLE) database, 994 participants without dementia were assessed on MDRS, CSF biomarkers and cognition. We examined the associations of the MDRS with CSF biomarkers and cognitive scores using linear regressions. Causal mediation analyses were conducted to analyze the associations among MDRS, brain pathologies, and cognition. The Alzheimer's Disease Neuroimaging Initiative (ADNI) study was used to validate the mediation effects and to investigate the longitudinal association between MDRS and cognitive decline.

Results

The results revealed that higher MDRS were linked to poorer cognitive performance (Model 1: PFDR  < 0.001; Model 2: PFDR  < 0.001) and increases in CSF levels of phosphorylated tau (P-tau, Model 1: PFDR  < 0.001; Model 2: PFDR  < 0.001), total tau (T-tau, Model 1: PFDR  < 0.001; Model 2: PFDR  < 0.001), P-tau/Aβ42 ratio (Model 1: PFDR  = 0.023; Model 2: PFDR  = 0.028), T-tau/Aβ42 ratio (Model 1: PFDR  < 0.001; Model 2: PFDR  < 0.001) and soluble triggering receptor expressed on myeloid cells 2 (sTrem2, Model 1: PFDR  < 0.001; Model 2: PFDR  < 0.001) in the CABLE study. The impact of MDRS on cognition was partially mediated by neuroinflammation and tau pathology. These mediation effects were replicated in the ADNI study. Baseline MDRS were significantly associated with future cognitive decline, as indicated by lower scores on the Mini-Mental State Examination (MMSE, Model 1: PFDR  = 0.045; Model 2: PFDR  < 0.001), ADNI composite memory score (ADNI-MEM, Model 1: PFDR  = 0.005; Model 2: PFDR  < 0.001), ADNI composite executive function score (ADNI-EF, Model 1: PFDR  = 0.045; Model 2: PFDR  < 0.001), and higher score on the Alzheimer's Disease Assessment Scale (ADAS13, Model 1: PFDR  = 0.045; Model 2: PFDR  < 0.001).

Discussion

The findings of this study revealed significant associations between MDRS and cognitive decline, suggesting a potential role of tau pathology and neuroinflammation in the link between MDRS and poorer cognitive performance in individuals without dementia. Consequently, the MDRS holds promise as a tool for targeted preventive interventions in individuals at high risk of cognitive impairment.

Charting Alzheimer's Disease and Dementia: Epidemiological Insights, Risk Factors and Prevention Pathways

Alzheimer's disease (AD), the most common cause of dementia, is a complex and multifactorial condition without cure at present. The latest treatments, based on anti-amyloid monoclonal antibodies, have only a modest effect in reducing the progression of cognitive decline in AD, whereas the possibility of preventing AD has become a crucial area of research. In fact, recent studies have observed a decrease in dementia incidence in developed regions such as the US and Europe. However, these trends have not been mirrored in non-Western countries (Japan or China), and the contributing factors of this reduction remain unclear. The Lancet Commission has delineated a constrained classification of 12 risk factors across different life stages. Nevertheless, the scientific literature has pointed to over 200 factors-including sociodemographic, medical, psychological, and sociocultural conditions-related to the development of dementia/AD. This narrative review aims to synthesize the risk/protective factors of dementia/AD. Essentially, we found that risk/protective factors vary between individuals and populations, complicating the creation of a unified prevention strategy. Moreover, dementia/AD explanatory mechanisms involve a diverse array of genetic and environmental factors that interact from the early stages of life. In the future, studies across different population-based cohorts are essential to validate risk/protective factors of dementia. This evidence would help develop public health policies to decrease the incidence of dementia.

Implementation and evaluation of a community-based mindful walking randomized controlled trial to sustain cognitive health in older African Americans at risk for dementia

BACKGROUND

With an increasing proportion of older adults and the associated risk of Alzheimer's Disease and Related Dementias (ADRD) around the globe, there is an urgent need to engage in ADRD risk reduction efforts. African American (AA) older adults in the U.S. are disproportionally impacted by ADRD compared to other races and ethnicities. Mindful walking integrates two potentially protective factors of ADRD by elevating mindfulness and physical activity (i.e., walking), resulting in a synergistic behavioral strategy that is feasible and safe for older adults. However, the efficacy of applying this intervention for cognitive health outcomes has not been evaluated using experimental designs.

METHODS

This paper documents the goal and protocol of a community-based, mindful walking randomized controlled trial to examine the short- and longer-term efficacy on cognitive and other health-related outcomes in ADRD at-risk AA older adults. The study outcomes include various brain health determinants, including cognitive function, quality of life, psychological well-being, physical activity, mindfulness, sleep, and overall health status. In addition, the estimated costs of program implementation are also collected throughout the study period. This study will recruit 114 older adults (ages 60+ years) with elevated ADRD risk from the Midlands region of South Carolina. Older adults are randomly assigned to participate in 24 sessions of outdoor mindful walking over three months or a delayed mindful walking group (n=57 in each group). Participants in both groups follow identical measurement protocols at baseline, after 12 weeks, after 18 weeks, and after 24 weeks from baseline. The outcome measures are administered in the lab and in everyday settings. Costs per participant are calculated using micro-costing methods. The eliciting participant costs for mindful walking engagement with expected results are reported using the payer and the societal perspectives.

DISCUSSION

This study will generate evidence regarding the efficacy of mindful walking on sustaining cognitive health in vulnerable older adults. The results can inform future large-scale effectiveness trials to support our study findings. If successful, this mindful walking program can be scaled up as a low-cost and viable lifestyle strategy to promote healthy cognitive aging in diverse older adult populations, including those at greatest risk.

TRIAL REGISTRATION

ClinicalTrials.gov number NCT06085196 (retrospectively registered on 10/08/2023).