Sex Differences in Cognitive Decline Among US Adults

The COVID-19 pandemic's effects on cognition and 24-hour movement behaviours: Findings from the CLSA

BACKGROUND

The COVID-19 pandemic may have negatively impacted cognition due to pandemic-associated changes in 24-h movement behaviours (i.e., physical activity, sedentary behaviour, and sleep). Whether the pandemic's effects vary by age and sex is unclear.

METHODS

We examined those participants (aged 45-85 years) of the Canadian Longitudinal Study on Aging (CLSA) with complete neuropsychological measures at baseline (2011-2015), no dementia/memory disorder, and partial or complete assessments at baseline, 3-year (FU1; 2015-2018), and 6-year follow-up (FU2; 2018-2021). Participants were categorized into pre-pandemic (N = 6174) or intra-pandemic (N = 5181) cohorts by FU2 assessment timing (before/after March 11th, 2020) and stratified by baseline age/sex. Cognition was measured with reliable change indices using: the Rey Auditory-Verbal Learning Test, Mental Alternation Test (MAT), and animal fluency. We indexed physical activity and sedentary behaviour using the Physical Activity Scale for the Elderly (PASE), and self-reported restless sleep.

FINDINGS

Compared with their pre-pandemic peers, intra-pandemic men aged 65-85 years had lower animal fluency (-0.40 points, 99 % CI: [-0.72, -0.07]), lower PASE (-16.48 points, 99 % CI: [-24.60, -8.36]) and 14 % higher probability of ≥4 h/day sedentary behaviour (99 % CI: [0.03, 0.26]) at FU2. Intra-pandemic women aged 65-85 years had lower MAT (-0.43 points, 99 % CI: [-0.86, -0.01]) and 12 % higher probability of ≥4 h/day sedentary behaviour (99 % CI: [0.01, 0.23]). There were no between-cohort differences for those aged 45-64 years. Pandemic-related changes in 24-h movement behaviours (FU1 to FU2) were not associated with cognitive changes, regardless of age or sex.

INTERPRETATION

The pandemic's effects on cognition and 24-h movement behaviours varied by age and sex; these effects are unrelated.

Moderated mediation of physical activity through depression on the relationship between loneliness and cognitive function in older adults

OBJECTIVES

This study examined the mediating effects of depression on the relationship between loneliness and cognitive function. It also aimed to test whether this mediating effect varied with the level of physical activity.

METHOD

Data were obtained from the English Longitudinal Study of Aging (ELSA) and responses of 3,537 adults aged 65 years or older were analyzed.

RESULTS

Analysis using the PROCESS Macro 7 model showed that loneliness had a negative effect on cognitive function. Also, the mediating effect of depression on the association between loneliness and cognitive function and the moderated mediating effect of physical activity were significant. That is to say, loneliness influenced cognitive function decline mediating depression, and the mediating effect of depression varied according to the level of physical activity.

CONCLUSION

This study revealed the psychological mechanism by which loneliness influences cognitive decline in older adults, and suggests that physical activity can be a preventive and therapeutic intervention for cognitive decline.

Alzheimer disease seen through the lens of sex and gender

Alzheimer disease (AD) is a life-limiting neurodegenerative disorder that disproportionately affects women. Indeed, sex and gender are emerging as crucial modifiers of diagnostic and therapeutic pathways in AD. This Review provides an overview of the interactions of sex and gender with important developments in AD and offers insights into priorities for future research to facilitate the development and implementation of personalized approaches in the shifting paradigm of AD care. In particular, this Review focuses on the influence of sex and gender on important advances in the treatment and diagnosis of AD, including disease-modifying therapies, fluid-based biomarkers, cognitive assessment tools and multidomain lifestyle interventional studies.

Association of adiposity evaluated by anthropometric and bioelectrical impedance analysis measures with cognitive performance in the ELSA-Brasil study

BACKGROUND

While midlife obesity is linked to cognitive decline, this association is inconsistent in older adults, possibly due to the limitations of body mass index (BMI) in accurately assessing adiposity at older ages. Most studies focused on White or Asian populations, did not include other adiposity measures besides BMI, adjusted the analyses for mediators, and did not investigate potential subgroup-specific associations. We compared the associations of adiposity measured by anthropometrical and bioelectrical impedance analysis (BIA) with cognitive performance in a diverse population, examining modifications by age, sex, and race, and investigating the mediating effects of obesity-related comorbidities.

METHODS

Cross-sectional analysis of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) cohort (n = 12,636). Adiposity was evaluated using BMI, waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), and body fat percentage (BFP). A composite global cognition score was derived from immediate, delayed recall, and word recognition word list, phonemic and semantic verbal fluency, and trail-making tests. Adjusted linear regression models were used to investigate associations. We included an interaction term in the regression models to verify if age, sex, and race were modifiers of these associations and used causal mediation methods to assess the mediating role of obesity-related comorbidities.

RESULTS

Among 10,725 participants [mean age (SD): 58.9 (8.6) years; 55.8% women, 54.4% White], larger WHR and WHtR were associated with worse global cognitive performance. These associations were not modified by age, sex, or race. An association of BFP with cognition was observed only in younger adults. Mediation analysis identified only indirect effects of these adiposity measures on cognitive performance and no direct effects.

CONCLUSION

WHR and WHtR were more consistently associated with cognitive performance than BMI. BIA measures of adiposity were associated with cognition only in younger adults. Obesity-related comorbidities fully mediated the associations of adiposity with cognition.

Cognitive strategy in verbal fluency: sex differences, menstrual cycle, and menopause effects

Cognitive sex differences are shaped by hormone effects on brain development, organisation, structure, function, and ageing. In human speech and language, sex differences and hormone effects are typically studied in the form of performance-based differences (via measures of central tendency) with little attention given to underlying cognitive strategy. This study presents data from 126 healthy adults, aged 20-79 years, from three studies of letter based verbal fluency. Comparisons were conducted based on sex, menstrual cycle phase, and menopause stage to examine total words produced, plus switching and clustering strategy use. The investigation probed differences in performance, underlying cognitive strategies, and correlations between performance and strategy. For performance, there were no statistically significant sex or menopause group differences in total words, number of switches and cluster size. Menstrual cycle differences were significant for switches and cluster size, but not total words. However, there were large effect sizes for correlations between total word performance and strategy measures in some groups; these correlations formed patterns which differed as a function of sex, menstrual cycle phase, and menopausal stage. Words produced were highly correlated with switching in younger women at higher hormone menstrual cycle phases. Correlations between total words and both strategies were moderate and equivalent in older premenopausal and perimenopausal women. Postmenopausal women showed a pattern of higher correlation between total words and cluster size which was observed in younger women at the lower hormone cycle phase, and men. This study illustrates the impact of hormones and sex differences on strategy use in verbal fluency-underscoring the value of comparisons in strategy use between women at different reproductive life stages.

Sex differences in the executive and behavioral reserve of autosomal dominant frontotemporal dementia

INTRODUCTION

Self-reported sex influences brain resilience, but its role in genetic frontotemporal dementia (FTD) remains unclear.

METHODS

We analyzed 394 genetic-FTD patients and 279 controls from the ALLFTD consortium, assessing annual neuropsychological performance and MRI-based cortical thickness. Clinical characteristics and cortical thickness were compared between sexes. We used the residuals of linear regression models, which predict each participant's cognitive and behavioral performance levels relative to cortical thickness, as a proxy for reserve. We then modeled sex differences in longitudinal trajectories with linear mixed-effects models.

RESULTS

Symptomatic females with genetic FTD had lower frontal cortical thickness than males, and the C9orf72 subgroup showed lower-than-expected frontal cortical thickness for a given level of executive functioning. Differences in cognitive reserve between sexes peaked near symptom onset but diminished thereafter.

DISCUSSION

Females with genetic FTD showed higher cognitive reserve than males, suggesting that self-reported sex modulates resilience to frontotemporal neurodegeneration.

HIGHLIGHTS

Females with genetic FTD showed higher cognitive reserve than males. Those differences were particularly pronounced in the C9orf72 and GRN subgroups. The higher cognitive reserve in females declined as the disease progressed.

Slow but Steady: Similarities and Differences in Executive Functioning Between Autistic and Non-Autistic Adults

Prior research has established differences between autistic and non-autistic individuals across the domains of executive function (EF). While some early theories portrayed these differences as universal to the autism spectrum, recent findings have been quite mixed. Factors like small samples, the components of EF being measured, and the age and intelligence quotient (IQ) of those being compared may contribute to this diversity in results. Moreover, research suggests performance over time might fluctuate in different patterns for autistic and non-autistic individuals. To test EF differences and the possible influence of these factors upon them, we recruited a sample of over 900 autistic and non-autistic participants (with generally average/above average IQ levels) from 18 to 77 years of age. They completed a battery of tasks measuring inhibition, cognitive flexibility, working memory, and attentional orienting to social and nonsocial cues. We found that performance was similar between groups in our primary measures of EF, although autistic participants were consistently slower, more susceptible to the effects of spatial cueing, and more prone to certain errors in the working memory task. Differences between groups were generally not influenced by participants' age, gender, or IQ. Performance over time varied only in the working memory task. While autistic adults may still face related challenges in real life, these findings suggest that being autistic does not necessarily imply executive dysfunction on a basic cognitive level, contradicting theories assuming universal impairments therein. Moreover, the lack of influence of included demographic factors suggests that explanations for discrepancies in the literature lie elsewhere.

Leveraging research into sex differences and steroid hormones to improve brain health

Sex differences, driven in part by steroid hormones, shape the structure and function of the brain throughout the lifespan and manifest across brain health and disease. The influence of steroid hormones on neuroplasticity, particularly in the adult hippocampus, differs between the sexes, which has important implications for disorders and diseases that compromise hippocampus integrity, such as depression and Alzheimer disease. This Review outlines the intricate relationship between steroid hormones and hippocampal neuroplasticity across the adult lifespan and explores how the unique physiology of male and female individuals can affect health and disease. Despite calls to include sex and gender in research, only 5% of neuroscience studies published in 2019 directly investigated the influence of sex. Drawing on insights from depression, Alzheimer disease and relevant hippocampal plasticity, this Review underscores the importance of considering sex and steroid hormones to achieve a comprehensive understanding of disease susceptibility and mechanisms. Such consideration will enable the discovery of personalized treatments, ultimately leading to improved health outcomes for all.

Cognitive reserve moderates the effect of COVID-19 on cognition: A systematic review and meta-analysis of individual participant data

Elucidating the factors that mitigate the effects of COVID-19 on cognitive function offers important insights for public health policy and intervention. This systematic review and individual participant data (IPD) meta-analysis assesses cognitive reserve (CR) as a potential moderator of post-COVID-19 cognitive dysfunction (PCCD). Under PRISMA-IPD guidelines, data searches were conducted via PubMed, PsycINFO, Scopus, and Embase, up to January 2023. Eligible studies included at least one cognitive assessment, CR proxy, and disease severity indicator. Of 5604 studies, 87 were eligible (10,950 COVID-19 cases; 78,305 controls), and IPD was obtained for 29 datasets (3919 COVID-19 cases; 8267 controls). Three-level random-effects meta-analyses indicated that CR had a moderate positive association (rsp =.29), and COVID-19 severity had a small negative association (rsp = -.07) with cognitive outcomes. These effects were moderated by a significant within-study interaction. Cognitive deficits following COVID-19 were 33 % smaller among high CR individuals, and 33 % greater among low CR individuals, relative to those with average CR. Population-based initiatives promoting reserve-building behaviors may alleviate the PCCD-related public health burden. REVIEW REGISTRATION: PROSPERO registration number: CRD42022360670.

COVID-19 Pandemic-Related Exposures and Cognitive Function in Middle-Aged Women

Importance

The COVID-19 pandemic has been associated with risk factors for cognitive decline, such as bereavement and SARS-CoV-2 infection.

Objective

To examine whether the COVID-19 pandemic and pandemic-related exposures are associated with cognitive function among middle-aged women.

Design, Setting, and Participants

This cohort study analyzed data from the Nurses' Health Study II, an ongoing study of registered nurses in the US. The present study focused on women aged 51 to 76 years who completed 2 to 8 objective cognitive assessments both prior to (October 1, 2014, to February 29, 2020) and during the COVID-19 pandemic (March 1, 2020, to September 30, 2022). Statistical analyses were performed from January 2023 to January 2025.

Exposure

COVID-19 pandemic.

Main Outcomes and Measures

Two standardized (ie, z-scored) composite cognitive scores (psychomotor speed and attention, learning and working memory) and a global score constituted the primary outcomes. Higher scores indicated better cognitive function. Cognitive function was assessed using the Cogstate Brief Battery, a computer-administered cognitive test battery. Participants completed cognitive assessments every 6 to 12 months.

Results

A total of 5191 women (mean [SD] age at first cognitive assessment, 63.0 [4.8] years) completed both prepandemic and during-pandemic measures, contributing 23 678 cognitive assessments. After adjustment for age at cognitive assessment, educational level for both participants and their parents, cognitive test practice effects, and comorbidities (eg, diabetes, hypertension), no difference in cognitive function was observed between assessments taken during vs before the pandemic (psychomotor speed and attention: β = -0.01 SD [95% CI, -0.05 to 0.02 SD]; learning and working memory: β = 0.00 SD [95% CI, -0.03 to 0.03 SD]; global score: β = 0.00 SD [95% CI, -0.03 to 0.02 SD]). Among 4456 participants who responded to the COVID-19 substudy (ie, surveys about pandemic-related events), those with a history of SARS-CoV-2 infection (164 [3.7%]) or post-COVID-19 conditions (PCC; 62 [1.4%]), at a median (IQR) 20.0 (18.5-22.1) months after initial infection, had reduced cognitive function compared with women without infection or PCC; however, these differences did not reach statistical significance, and the wide CIs suggested considerable uncertainty.

Conclusions and Relevance

This cohort study of middle-aged women found that the COVID-19 pandemic and pandemic-related events were not associated with cognitive decline up to 2.5 years after the onset of the pandemic. Future studies are needed to examine the long-term implications of SARS-CoV-2 infection and PCC for cognitive function.

Rest-activity rhythm characteristics associated with lower cognitive performance and Alzheimer's disease biomarkers in midlife women

INTRODUCTION

Disrupted rest-activity rhythms (RARs) have been linked to poorer cognitive function and Alzheimer's disease (AD) biomarkers. Here we extend this work to midlife women, who commonly experience menopause-related sleep and cognitive problems.

METHODS

One hundred ninety-four postmenopausal participants underwent a neuropsychological evaluation, 72 h of wrist actigraphy generating RAR variables, and a blood draw to measure AD biomarkers: phosphorylated tau (p-tau181, p-tau231) and amyloid beta (Aβ40, Aβ42).

RESULTS

Lower interdaily stability (IS) and relative amplitude (RA) and higher interdaily variability (IV) and least active 5 h (L5) were associated with worse processing speed, independent of sleep. Adjustment for sleep significantly attenuated the associations of RA with memory. Lower RA was associated with higher p-tau231 level, independent of sleep. Further adjustment for menopause-related factors modestly accounted for the associations between RAR, cognitive measures, and AD biomarkers.

DISCUSSION

Weaker RAR, particularly RA, was associated with worse cognitive functions, and higher AD biomarkers levels, possibly linking RAR with AD pathology in women.

Highlights

Lower rhythm stability and robustness and higher fragmentation were associated with worse processing speed.Lower robustness was associated with higher levels of phosphorylated tau-231.Menopause factors did not attenuate the association between rest-activity rhythms and cognitive function.

Midlife financial stress and cognitive and physical impairments in older age: The role of potentially modifying factors

BACKGROUND

Financial stress is an important source of chronic stress and has been associated with cognitive and physical impairments. The goal of this study was to investigate whether financial stress is associated with cognitive and physical impairment and their combination, the role of potential modifiable factors and potential sex differences.

METHODS

The Cardiovascular Risk Factors, Aging, and Dementia population-based cohort study from Finland was used (n = 1497) (baseline data collected 1972-1987, mean age 50 years). Two late-life re-examinations (mean total follow-up 21 years). Midlife financial stress was measured using two questions on financial situation. Cognitive functioning was based on six cognitive domains. Physical impairment was self-reported, including activities of daily living and mobility. Potential mediation factors investigated were smoking, alcohol, physical activity, cohabitant status, non-manual work, and sleep disturbances. Sex differences were investigated. We used path analyses with full information maximum likelihood estimation.

RESULTS

Midlife financial stress was associated with worse cognitive functioning, physical impairment and their combination. Smoking and sleep disturbances mediated the associations between financial stress, physical impairment, and combined impairments. For men: Among smokers financial stress was associated with worse cognitive functioning; alcohol interacted with financial stress on combined impairments; cohabitation and non-manual work mediated associations to worse cognitive functioning. Among women, sleep disturbances moderated the association to worse cognitive functioning.

CONCLUSIONS

Midlife financial stress is associated with late-life impairments, and lifestyle/sociodemographic factors may modify these associations. Sex differences were observed. Interventions promoting healthier lifestyle and psychosocial factors may buffer against the deleterious role of financial stress.

Nesplora Ice Cream test: a normative study of a virtual reality-based executive function assessment in adults

This study aims to establish normative data for participants aged 17 to 80 who completed the Nesplora Ice Cream test, a virtual reality tool designed to assess executive functions. The objective is to provide a comprehensive reference for evaluating executive function performance in healthy adults across different age groups. A total of 419 participants (51% female) were recruited from nine locations in Spain. Trained evaluators administered the Nesplora Ice Cream test. The study utilized empirical analysis to identify key factors related to executive function, focusing on planning, learning, and flexibility. Cluster analysis was employed to define age groups for each factor: 17-40, 41-61, and 62-80 for planning; 17-44, 45-61, and 62-80 for learning; and 17-20, 21-36, and 37-80 for flexibility. The analysis revealed three main factors-planning, learning, and flexibility-that characterize executive function performance. No significant gender differences were found. Descriptive normative data were provided based on age and gender. Confirmatory factor analysis supported the three-factor structure of the test. Additionally, data on the validity, reliability, and internal consistency of the test were included. These normative data are valuable for assessing executive functions in an ecologically valid way. The findings provide a robust reference point for studying the early identification of executive dysfunction in adults and the impact of neurodegenerative conditions in clinical settings. Further research is needed to evaluate the test's sensitivity and specificity in clinical populations. These norms enable the development of timely, personalized interventions for individuals showing executive function impairments.

Network Analysis of Key Instrumental Activities of Daily Living and Cognitive Domains for Targeted Intervention in US Older Adults Without Dementia: Cross-Sectional Study

Background

Cognitive impairment in older adults reduces independence and raises health care costs but can be mitigated through stimulating activities. Based on network theory, intricate relationships within and between clusters of instrumental activities of daily living (IADLs) and cognitive domains suggest the existence of central IADLs and cognitive domains, as well as bridge IADLs. Modifying these can significantly enhance daily living activities and cognitive functions holistically.

Objective

This study aims to identify central IADLs (key activities within the IADL network), central cognitive domains (key domains within the cognitive network), and bridge IADLs (linking IADL and cognitive networks). These insights will inform targeted interventions to effectively improve IADL and cognitive well-being in older adults.

Methods

A cross-sectional analysis of adults aged 65 years and older in the United States focused on 5 IADLs and 6 cognitive domains from the National Health and Aging Trends Study (NHATS). Network analysis identified central and bridge variables. Nonparametric and case-dropping bootstrap methods checked network stability. Network comparison tests assessed sex differences with Benjamini-Hochberg adjustments.

Results

Of the 2239 participants, 56.4% were female (n=976). We computed and tested 3 networks: IADL, cognition, and bridge-with correlation stability coefficients of 0.67, 0.75, and 0.44, respectively (all>0.25). Meal preparation was identified as the central IADL, with a centrality index of 3.87, which was significantly higher than that of other IADLs (all P<.05). Visual attention emerged as the central cognition domain, with a centrality index of 0.86, which was significantly higher than that of other cognition domains (all P<.05). Shopping was determined to be the bridge IADL, with a centrality index of 0.41, which was significantly higher than that of other IADLs (all P<.05). Notably, gender differences emerged in the IADL network, with stronger associations between laundry and meal preparation in females (1.69 vs males: 0.74; P=.001) and higher centrality in meal preparation among females (difference=1.99; P=.007).

Conclusions

While broad enhancements in all IADL and cognitive domains are beneficial, targeting meal preparation, visual attention, and shopping may leverage their within-network influence to yield a more pronounced improvement in holistic IADL, holistic cognition, and holistic cognition function through IADL interventions among older adults. Notably, meal preparation interventions may be less effective in males, requiring tailored approaches.

Aging activates escape of the silent X chromosome in the female mouse hippocampus

Women live longer than men and exhibit less cognitive aging. The X chromosome contributes to sex differences, as females harbor an inactive X (Xi) and active X (Xa), in contrast to males with only an Xa. Thus, reactivation of silent Xi genes may contribute to sex differences. We use allele-specific, single-nucleus RNA sequencing to show that aging remodels transcription of the Xi and Xa across hippocampal cell types. Aging preferentially changed gene expression on the X's relative to autosomes. Select genes on the Xi underwent activation, with new escape across cells including in the dentate gyrus, critical to learning and memory. Expression of the Xi escapee Plp1, a myelin component, was increased in the aging hippocampus of female mice and parahippocampus of women. AAV-mediated Plp1 elevation in the dentate gyrus of aging male and female mice improved cognition. Understanding how the Xi may confer female advantage could lead to novel targets that counter brain aging and disease in both sexes.

Strategies for studying sex differences in brain aging

Studying sex effects and their underlying mechanisms is of major relevance to understanding brain health. Despite growing interests, experimentally studying sex differences, particularly in the context of aging, remains challenging. Since sex chromosomal content influences gonadal development, separating the effects of gonadal hormones and chromosomal factors requires specific model systems. Here, we highlight rodent and tractable models for examining sex dimorphism in brain and cognitive aging. In addition, we discuss multi-omic and bioinformatic approaches that yield biological insights from animal and human studies. This review provides a comprehensive overview of the diverse toolkit now available to advance our understanding of sex differences in brain aging.

Sex differences in the association between hypertension, cerebral small vessel disease and cognitive decline: a narrative review

The objective of this study was to review how cerebral small vessel disease (CSVD) is associated with hypertension and cognitive decline, specifically regarding sex differences in this association. Strong evidence supports the associations between hypertension and cognitive decline, hypertension and CSVD, as well as CSVD and cognitive decline in both women and men. Sex-stratified analyses show that compared to men, hypertension leads to worse cognitive decline in women likely due to its stronger association with CSVD in women. Indeed, compared to men, prevalence of CSVD and CSVD lesion progression is also higher in women and later in life, the incidence of hypertension is higher in women. Moreover, the association between hypertension and CSVD was found to be stronger in women, as was the association between hypertension and cognitive decline. Therefore, focus on hypertension and CSVD as an important pathophysiological mechanism for cognitive decline may uncover novel sex-specific therapeutic avenues.

Sex-stratified genome-wide meta-analysis identifies novel loci for cognitive decline in older adults

INTRODUCTION

Many complex traits and diseases show sex-specific biases in clinical presentation and prevalence.

METHODS

To understand sex-specific genetic architecture of cognitive decline across five cognitive domains (attention, memory, executive function, language, and visuospatial function) and global cognitive function, we performed sex-stratified genome-wide meta-analysis in 3021 older adults aged ≥ 65 years (female = 1545, male = 1476) from three prospective cohorts. Gene-based and gene-set enrichment analyses were conducted for each cognitive trait.

RESULTS

We identified a novel genome-wide significant (GWS) intergenic locus for decline of memory in males near RPS23P3 on chromosome 4 (rs6851574: minor allele frequency [MAF] = 0.39, Pmale = 4.10E-08, βmale = 0.19; Pinteraction = 3.76E-04). We also identified a subthreshold GWS locus for decline of executive function on chromosome 12 in females near the NDUFA12 gene, involved in oxidative phosphorylation (rs11107823: MAF = 0.12, Pfemale  = 9.35E-08, βfemale = 0.28; Pinteraction = 7.42E-06).

DISCUSSION

Sex-aware genetic studies can help in the identification of novel genetic loci and enhance sex-specific understanding of cognitive decline.

HIGHLIGHTS

Our genome-wide meta-analysis of single variants identified two new genetic associations, one in males and one in females. The novel male association was observed with the decline of memory in the intergenic region near the RPS23P3 gene on chromosome 4. This intergenic region has previously been implicated in several brain and cognition related traits, including anatomical brain aging, brain shape, and educational attainment. The novel female-specific association was observed with decline in executive function on chromosome 12 near the NDUFA12 gene, which is involved in oxidative phosphorylation. Sex-stratified analyses offer sex-specific understanding of biological pathways involved in cognitive aging.

Trajectory of Cognitive Function After Incident Heart Failure

BACKGROUND

The magnitude of cognitive changes after incident heart failure (HF) is unclear. We assessed whether incident HF is associated with changes in cognition after accounting for pre-HF cognitive trajectories and known determinants of cognition.

METHODS

This pooled cohort study included adults without HF, stroke, or dementia from 6 US population-based studies from 1971 to 2019. Linear mixed-effects models estimated cognitive change with incident HF diagnosis and the rate of cognitive change over the years after HF, controlling for pre-HF cognitive trajectories and participant factors. Outcomes included change in global cognition (primary outcome), executive function, and memory (secondary outcomes). Cognitive outcomes were standardized to a t score metric (mean [SD], 50 [10]); a 1-point difference represented a 0.1-SD difference in cognition.

RESULTS

We included 29 614 adults (mean [SD] age was 61 [10] years, 55% female, 70% White). During a median follow-up of 6.6 (Q1-Q3, 5.0-19.8) years, 1407 (5%) adults received an incident diagnosis of HF. Incident HF diagnosis was associated with initial decreases in global cognition (-1.1 points [95% CI, -1.4 to -0.8]) and executive function (-0.6 points [95% CI, -1.0 to -0.3]). Larger decreases in global cognition after HF were seen with older age, female sex, and White race. Participants with incident HF diagnosis demonstrated faster and long-term declines in global cognition (-0.1 points per year [95% CI, -0.2 to -0.1]) and executive function (-0.2 points per year [95% CI, -0.2 to -0.1]). The change in memory with incident HF diagnosis was not statistically significant but showed a similar trend with an initial decline of -0.5 points (95% CI, -1.4 to +0.3) and a slope of -0.1 points per year (95% CI, -0.3 to 0.0).

CONCLUSIONS

In this pooled cohort study, incident HF diagnosis was associated with initial decreases in global cognition and executive function and faster, persistent declines in these domains at follow-up.

Age- and Sex-Specific Patterns in Adult Brain Network Segregation

The human brain is organized into several segregated associative and sensory functional networks, each responsible for various aspects of cognitive and sensory processing. These functional networks become less segregated over the adult lifespan, possibly contributing to cognitive decline that is observed during advanced age. To date, a comprehensive understanding of decreasing network segregation with age has been hampered by (1) small sample sizes, (2) lack of investigation at different spatial scales, (3) the limited age range of participants, and more importantly (4) an inadequate consideration of sex (biological females and males) differences. This study aimed to address these shortcomings. Resting-state functional magnetic resonance imaging data were collected from 357 cognitively intact participants (18.2-91.8 years; 49.9 ± 17.1 years; 27.70 ± 1.72 MoCA score, 203 [56.8%] females), and the segregation index (defined as one minus the ratio of between-network connectivity to within-network connectivity) was calculated at three spatial scales of brain networks: whole-brain network, intermediate sensory and associative networks, as well as core visual (VIS), sensorimotor (SMN), frontoparietal (FPN), ventral attention (VAN), dorsal attention (DAN), and default mode networks (DMN). Where applicable, secondary within-, between-, and pairwise connectivity analyses were also conducted to investigate the origin of any observed age and sex effects on network segregation. For any given functional metric, linear and quadratic age effects, sex effects, and respective age by sex interaction effects were assessed using backwards iterative linear regression modeling. Replicating previous work, brain networks were found to become less segregated across adulthood. Specifically, negative quadratic decreases in whole-brain network, intermediate associative network, VAN, and DMN segregation index were observed. Intermediate sensory networks, VIS, and SMN exhibited negative linear decreases in segregation index. Secondary analysis revealed that this process of age-related functional reorganization was preferential as functional connectivity was observed to increase either between anatomically adjacent associative networks (DMN-DAN, FPN-DAN) or between anterior associative and posterior sensory networks (VIS-DAN, VIS-DMN, VIS-FPN, SMN-DMN, and SMN-FPN). Inherent sex differences in network segregation index were also observed. Specifically, whole-brain, associative, DMN, VAN, and FPN segregation index was greater in females compared to males, irrespective of age. Secondary analysis found that females have reduced functional connectivity between associative networks (DAN-VAN, VAN-FPN) compared to males and independent of age. A notable linear age-related decrease in FPN SI was also only observed for females and not males. The observed findings support the notion that functional networks reorganize across the adult lifespan, becoming less segregated. This decline may reflect underlying neurocognitive aging mechanisms like neural dedifferentiation, inefficiency, and compensation. The aging trajectories and rates of decreasing network segregation, however, vary across associative and sensory networks. This study also provides preliminary evidence of inherent sex differences in network organization, where associative networks are more segregated in females than males. These inherent sex differences suggest that female functional networks may be more efficient and functionally specialized compared to males across adulthood. Given these findings, future studies should take a more focused approach to examining sex differences across the lifespan, incorporating multimodal methodologies.

Alterations in iron levels in the locus coeruleus of a transgenic Alzheimer's disease rat model

Iron is essential for brain function, acting as a cofactor for enzymes involved in neurotransmitter synthesis and metabolism. However, dysregulated iron homeostasis is increasingly linked to neurodegenerative diseases, including Alzheimer's disease (AD). The locus coeruleus (LC), a norepinephrine-producing brainstem nucleus, is among the earliest regions affected in AD, yet its iron dynamics remain poorly understood. This study presents the first comprehensive analysis of iron content in the LC by combining a transgenic AD rat model, precise anatomical isolation, and Inductively Coupled Plasma Mass Spectrometry for high-sensitivity metal quantification. This approach enabled the profiling of iron and zinc concentrations in the LC, uncovering novel insights into iron dysregulation in AD. We observed a significant genotype-specific increase in LC iron levels in TgF344-AD rats compared to wild-type controls. Notably, our findings reveal distinct iron alterations in TgF344-AD rats, suggesting a previously unrecognized role for iron homeostasis in LC dysfunction. These results provide new perspectives on iron dysregulation in AD pathology and its potential as a therapeutic target.

Sex differences in the association of Alzheimer's disease biomarkers and cognition in a multicenter memory clinic study

BACKGROUND

This study investigated sex differences in the associations between Alzheimer's disease (AD) biomarkers, cognitive performance, and decline in memory clinic settings.

METHODS

249 participants (females/males:123/126), who underwent tau-PET, amyloid-PET, structural MRI, and plasma glial fibrillary acidic protein (GFAP) measurement were included from Geneva and Lausanne Memory Clinics. Mann-Whitney U tests investigated sex differences in clinical and biomarker data. Linear regression models estimated the moderating effect of sex on the relationship between biomarkers and cognitive performance and decline. Sex differences in cognitive decline were further evaluated using longitudinal linear mixed-effect models with three-way interaction effects.

RESULTS

Women and men present similar clinical features, amyloid, and neurodegeneration. Women had higher tau load and plasma levels of GFAP than men (p < 0.05). Tau associations with amyloid (standardized β = 0.54,p < 0.001), neurodegeneration (standardized β=-0.44,p < 0.001), and cognition (standardized β=-0.48,p < 0.001) were moderated by a significant interaction with sex. Specifically, the association between amyloid and tau was stronger among women than men (standardized β=-0.19,p = 0.047), whereas the associations between tau and cognition and between tau and neurodegeneration were stronger among men than in women (standardized β=-0.76,p = 0.001 and standardized β=-0.56,p = 0.044). Women exhibited faster cognitive decline than men in the presence of severe cortical thinning (p < 0.001).

CONCLUSION

Women showed higher tau load and stronger association between amyloid and tau than men. In individuals with high tau burden, men exhibited greater neurodegeneration and cognitive impairment than women. These findings support that sex differences may impact tau deposition through an upstream interplay with amyloid, leading to downstream effects on neurodegeneration and cognitive outcomes.

Greater BMI across the lifespan is associated with better midlife cognition: The Bogalusa Heart Study

Studies of adiposity and cognition's relationship have been highly mixed, depending on points in the lifespan when adiposity and cognition were measured, primarily with low Black American representation. Therefore, we examined the association between adiposity (from early to mid-life) and mid-life cognition in an Black American (BA) and White American longitudinal cohort to address these literature gaps. The Bogalusa Heart Study has followed participants from childhood to adulthood since 1973. Adiposity was measured via body mass index (BMI) at roughly biannual visits from 1973-2016 and cognition was measured in 1295 participants between 2013- 2016. Cognition included Logical Memory I, II and II Recognition, Digit Spans Forward and Backward, Trail Making Tests A and B, and a global composite. BMI was averaged within age epochs (childhood/adolescence; early adulthood (EA); midlife (M)) with childhood/adolescence BMI as percentiles. Separate linear regression models were run for each cognitive measure (outcome), BMI within one epoch, and sex, race, and education (predictors). All analyses included the 1292 individuals who provided complete data across all epochs. Greater BMI within EA and M was associated with better global cognition (EA: Est. 0.139 S.D./BMI p = 0.000; M: Est. 0.094 S.D./BMI p = 0.022), and Logical Memory I (EA: Est. 0.036 S.D./BMI p = 0.000; M: Est. 0.022 S.D./BMI p = 0.000), II (EA: Est. 0.036 S.D./BMI p = 0.000; M: Est. 0.020 S.D./BMI p = 0.022) and II Recognition (EA: Est. 0.029 S.D./BMI p = 0.000; M: Est. 0.022 S.D./BMI p = 0.000) among men. Among BA, greater BMI within EA and M was associated with better Logical Memory I (EA: Est. 0.022 S.D./BMI p = 0.000; M: Est. 0.019 S.D./BMI p = 0.000) and II (EA: Est. 0.018 S.D./BMI p = 0.042; M: Est. 0.017 S.D./BMI p = 0.000). Greater adiposity from early adulthood to midlife was associated with better memory performance in midlife (associations strongest among men and Black Americans). More anatomically precise measurements of adiposity (e.g., subcutaneous vs. visceral fat) could help clarify the complex adiposity cognition relationship across the lifespan.

Role of cognitive impairment in predicting the long-term risk of all-cause mortality: a 20-year prospective cohort study in China

BACKGROUND

There is limited evidence of the relationship between cognitive changes and all-cause mortality. And it has no report of population-attributable fraction (PAF) of mortality due to cognitive impairment in Chinese elderly. In light of this, we comprehensively examined the relationship between cognitive impairment and all-cause mortality after 20-year follow-up among the elderly Chinese.

METHODS

This is an epidemiological survey with a 20-year prospective cohort study design. A total of 9093 participants came from the Chinese Longitudinal Healthy Longevity Survey 1998-2018 waves. Cox proportional hazards regressions were performed to analyze the relationship between baseline cognitive impairment status, the rate of change in the MMSE scores over two years and subsequent all-cause mortality.

RESULTS

We observed a dose-response relationship between cognition and mortality. Compared to those with no impairment, elderly with mild (AHR = 1.11, 95% CI 1.05-1.18), moderate (AHR = 1.22, 95% CI 1.13-1.33) and severe (AHR = 1.30, 95% CI 1.19-1.42) cognitive impairment showed increased mortality risk. Elderly with rapid cognitive decline had 24% higher mortality risk than those with stable cognitive (AHR = 1.24, 95%CI 1.10-1.39). The PAF of mortality due to severe cognitive impairment was 3.69% (95%CI:2.36-5.25%). Impairment in the subdomain of naming foods (AHR = 1.12, 95% CI 1.04-1.21), registration (AHR = 1.18, 95% CI 1.11-1.26), attention and calculation (AHR = 1.13, 95% CI 1.07-1.21), copy figure (AHR = 1.13, 95% CI 1.06-1.20), delayed recall (AHR = 1.14, 95% CI 1.07-1.20) and language (AHR = 1.14, 95% CI 1.05-1.24) were independently associated with increased mortality risk among participants.

CONCLUSION

Baseline cognitive impairment was inversely associated with longevity among the elderly Chinese. The rapid cognitive decline increased all-cause mortality, and this risk would continue for 20 years. These findings underscore the crucial role of early detection and management of cognitive impairment in the elderly.

Identification of circulating risk biomarkers for cognitive decline in a large community-based population in Chongqing China

INTRODUCTION

This study aims to investigate the relationship between blood-based pathologies and established risk factors for cognitive decline in the community-based population of Chongqing, a region with significant aging.

METHODS

A total of 26,554 residents aged 50 years and older were recruited. Multinomial logistic regression models were applied to assess the risk factors of cognition levels. Propensity score matching and linear mixed effects models were used to evaluate the relationship between key risk factors and the circulating biomarkers.

RESULTS

Shared and distinct risk factors for MCI and dementia were identified. Age, lower education, medical history of stroke, hypertension, and epilepsy influenced mild cognitive impairment (MCI) progression to dementia. Correlations between key risk factors and circulating neurofilament light chain (NfL), glial fibrillary acidic protein (GFAP), amyloid β protein (Aβ)40, and Aβ42/Aβ40 ratio suggest underlying mechanisms contributing to cognitive impairment.

DISCUSSION

The common and distinct risk factors across cognitive decline stages emphasize the need for tailored interventions. The correlations with blood biomarkers provide insights into potential management targets.

HIGHLIGHTS

From a large community-based cohort study on the residents in Chongqing, we have identified that mild cognitive impairment (MCI) and dementia share several common risk factors, including age, female gender, rural living, lower education levels, and a medical history of stroke. However, each condition also has its own unique risk factors. Several factors contribute to the progression of MCI into dementia including age, education levels, occupation, and a medical history of hypertension and epilepsy. We discover the correlations between the risk factors for dementia and blood biomarkers that indicate the presence of axonal damage, glial activation, and Aβ pathology.

Biological sex, microglial signaling pathways, and radiation exposure shape cortical proteomic profiles and behavior in mice

Patients receiving cranial radiation therapy experience tissue damage and cognitive deficits that severely decrease their quality of life. Experiments in rodent models show that these adverse neurological effects are in part due to functional changes in microglia, the resident immune cells of the central nervous system. Increasing evidence suggests that experimental manipulation of microglial signaling can regulate radiation-induced changes in the brain and behavior. Furthermore, many studies show sex-dependent neurological effects of radiation exposure. Despite this, few studies have used both males and females to explore how sex and microglial function interact to influence radiation effects on the brain. Here, we used a system levels approach to examine how deficiencies in purinergic and fractalkine signaling, two important microglial signaling pathways, impact brain proteomic and behavioral profiles in irradiated and control male and female mice. We performed a comprehensive analysis of the cortical proteomes from irradiated and control C57BL/6J, P2Y12-/-, and CX3CR1-/- mice of both sexes using multiple bioinformatics methods. We identified distinct proteins and biological processes, as well as behavioral profiles, regulated by sex, genotype, radiation exposure, and their interactions. Disrupting microglial signaling, had the greatest impact on proteomic expression, with CX3CR1-/- mice showing the most distinct proteomic profile characterized by upregulation of CX3CL1. Surprisingly, radiation exposure caused relatively smaller proteomic changes in glial and synaptic proteins, including Rgs10, Crybb1, C1qa, and Hexb. While we observed some radiation effects on locomotor behavior, biological sex as well as loss of P2Y12 and CX3CR1 signaling had a stronger influence on locomotor outcomes in our model. Lastly, loss of P2Y12 and CX3CR1 strongly regulated exploratory behaviors. Overall, our findings provide novel insights into the molecular pathways and proteins that are linked to P2Y12 and CX3CR1 signaling, biological sex, radiation exposure, and their interactions.

Tau pathology is associated with postsynaptic metabotropic glutamate receptor 5 (mGluR5) in early Alzheimer's disease in a sex-specific manner

INTRODUCTION

To investigate the associations of metabotropic glutamate receptor 5 (mGluR5) with tau deposition and cognitive ability in patients with early Alzheimer's disease (AD).

METHODS

Twenty-six cognitively impaired (CI) and 14 cognitively unimpaired (CU) individuals underwent mGluR5 positron emission tomography (PET) ([18F]PSS232), amyloid PET ([18F]florbetapir), and tau PET ([18F]MK6240), and neuropsychological assessment. The relationships among mGluR5 availability, tau deposition, and neuropsychological assessment were analyzed using Spearman's correlation and mediation analyses.

RESULTS

CI patients had lower mGluR5 in the hippocampus than CU (standardized uptake value ratio [SUVr]: 2.03 ± 0.25 vs 1.79 ± 0.17, p = 0.003). Hippocampal mGluR5 was negatively associated with hippocampal tau deposition (r = -.46, p = 0.003) and positively associated with cognitive performance, but only in women. Hippocampal tau deposition mediated the effect of mGluR5 on cognitive performance.

DISCUSSION

Reduced hippocampal mGluR5 is negatively related with tau deposition in most cortical regions and positively associated with cognitive performance, making it a promising biomarker for AD diagnosis and therapy.

HIGHLIGHTS

Cognitively impaired (CI) patients exhibited lower metabotropic glutamate receptor 5 (mGluR5) availability in the hippocampus than cognitively unimpaired (CU) subjects. Hippocampal mGluR5 availability was negatively associated with tau deposition in widespread cortex. Hippocampal mGluR5 availability was positively associated with cognitive performance. The close association of mGluR5 with tau and cognition performance exists only in females. Tau pathology mediated the relationship between mGluR5 availability and cognition.

Female sex is linked to a stronger association between sTREM2 and CSF p-tau in Alzheimer's disease

In Alzheimer's disease (AD), Aβ triggers p-tau secretion, which drives tau aggregation. Therefore, it is critical to characterize modulators of Aβ-related p-tau increases which may alter AD trajectories. Here, we assessed whether factors known to alter tau levels in AD modulate the association between fibrillar Aβ and secreted p-tau181 determined in the cerebrospinal fluid (CSF). To assess potentially modulating effects of female sex, younger age, and ApoE4, we included 322 ADNI participants with cross-sectional/longitudinal p-tau181. To determine effects of microglial activation on p-tau181, we included 454 subjects with cross-sectional CSF sTREM2. Running ANCOVAs for nominal and linear regressions for metric variables, we found that women had higher Aβ-related p-tau181 levels. Higher sTREM2 was associated with elevated p-tau181, with stronger associations in women. Similarly, ApoE4 was related to higher p-tau181 levels and faster p-tau181 increases, with stronger effects in female ApoE4 carriers. Our results show that sex alone modulates the Aβ to p-tau axis, where women show higher Aβ-dependent p-tau secretion, potentially driven by elevated sTREM2-related microglial activation and stronger effects of ApoE4 carriership in women.

Determinants of cognitive health in the elderly: a comprehensive analysis of demographics, health status, and lifestyle factors from NHANES

This study analyzes data from the National Health and Nutrition Examination Survey (NHANES) to identify factors influencing cognitive performance among the elderly, as measured by the Digit Symbol Substitution Test (DSST). Employing multivariable linear regression, we evaluated the impact of demographic, lifestyle, and health-related factors on cognitive function in U.S. adults aged 60 and older. Our findings indicate that advanced age, particularly in those aged 70-79 and 80 + years, is associated with lower DSST scores. Male gender is linked with reduced cognitive performance, while higher educational attainment appears protective. Lifestyle factors, including current smoking and higher alcohol consumption, negatively impact cognitive outcomes, and excessive sleep duration (over 9 h) is also detrimental. Among health conditions, diabetes, chronic heart failure, and a history of stroke were associated with cognitive declines. Furthermore, increasing severity of depression correlates with lower cognitive function. These results underline the need for comprehensive public health strategies that integrate lifestyle modifications and chronic disease management to maintain cognitive health in older adults.

Depressive intensity, duration, and their associations with cognitive decline: a population-based study in Korea

Existing epidemiological studies have ignored the effect of depressive duration on cognitive decline despite the presence of biological cues and understudied the depression-cognition association in Asian countries in the context of increasing cognitive burden worldwide. We aimed to comprehensively characterize the effects of depressive duration and intensity on cognitive decline at the population level. A total of 6406 individuals from the Korean Longitudinal Study of Aging (KLoSA) from 2010 to 2018 were included to generate four datasets with durations of 2, 4, 6, and 8 years. Depressive intensity was categorized as no, mild, and major depression according to the Center for Epidemiological Studies Depression scale (CES-D10), and duration was measured by the span of consecutive interviews. Cognitive function was assessed using the Korean Mini-Mental Status Examination (K-MMSE). Multiple linear regressions and meta-regressions were used to estimate the effects of depressive intensity and duration on global cognition and seven cognitive subdomains. Stratified analyses were performed to explore effect differences between subpopulations of different sexes and ages. The potential bias in the effect of depressive intensity on cognitive decline when ignoring duration was also explored. On average, a 1-year longer duration decreased the global cognitive scores by 0.44 (95% CI 0.36, 0.51) across intensities and major depression decreased the scores by an additional 0.82 (95% CI 0.59, 1.04) points than mild depression across durations. Similar trends held for seven cognitive subdomains except for visual construction. Older adults suffered more cognitive decline from major depression than middle-aged adults did. More severe and longer-duration depression lead to greater cognitive decline. Ignoring depressive duration can lead to an overestimated effect of depressive intensity on cognitive decline. The depressive effects and susceptible populations clarified in our study have important implications for the preservation of cognitive health in Asian region.

The Dynamics of Cognitive Decline towards Alzheimer's Disease Progression: Results from ADSP-PHC's Harmonized Cognitive Composites

INTRODUCTION

Accurately assessing temporal order of cognitive decline across multiple domains is critical in Alzheimer's disease (AD). Existing literature presented controversial conclusions likely due to the use of a single cohort and different analytical strategies.

METHODS

Harmonized composite cognitive measures in memory, language and executive functions from 13 cohorts in the ADSP-PHC data are used. A novel double anchoring events-based sigmoidal mixed model was developed using time to the incident of AD diagnosis as the time scale.

RESULTS

Decline in memory occurred before decline in language which was followed by the decline in executive function. Throughout the entire AD continuum, APOE-ε4 non-carriers and non-Hispanic Whites showed better memory performance, respectively, in all three cognitive domains.

DISCUSSION

Using harmonized data across multiple cohorts is the key to accurately characterizing the temporal order of AD biomarkers. Time to incident AD diagnosis should be used as the time scale for reproducibility purposes.

A systematic review and meta-analysis of dual-task outcomes in subjective cognitive decline

Subjective cognitive decline (SCD) may represent a preclinical manifestation of objective cognitive impairment. This review consolidated existing findings to determine if dual-tasks objectively differentiate between individuals with SCD, motoric cognitive risk syndrome (MCR), mild cognitive impairment (MCI), and dementia. MEDLINE, Embase, PsycINFO, CENTRAL, AgeLine, and CINAHL were systematically searched for dual-task studies examining older adults with SCD and analyzed using random-effects meta-analyses. Thirteen studies met the inclusion criteria. Within the SCD group, faster gait speed (SMD, 1.35; 95% CI, 0.57-2.13; p = .0007) and longer step length (SMD, 0.85; 95% CI, 0.44-1.26; p < .0001) favored the single compared to dual-task condition. Faster gait speed was observed in the SCD group compared to MCI (SMD, 0.48; 95% CI, 0.28-0.67; p = .0001). A standardized dual-task approach is needed to track gait parameters longitudinally, beginning with changes occurring at the SCD stage as these may precede future cognitive impairments.

Highlights

Evidence demonstrates that SCD may be a precursor to dementia.Faster dual-task gait speed was observed in the SCD group compared to MCI.Slower dual-task gait speed and shorter step length were observed within the SCD group.Dual-tasks may help differentiate between preclinical and clinical cognitive decline.Dual-tasks should be standardized and changes should be tracked longitudinally.

Biological Sex Disparities in Alzheimer's Disease

Alzheimer's disease is a highly complex and multifactorial neurodegenerative disorder, with age being the most significant risk factor. The incidence of Alzheimer's disease doubles every 5 years after the age of 65. Consequently, one of the major challenges in Alzheimer's disease research is understanding how the brain changes with age. Gaining insights into these changes could help identify individuals who are more prone to developing Alzheimer's disease as they age. Over the past 25 years, studies on brain aging have examined thousands of human brains to explore the neuronal basis of age-related cognitive decline. However, most of these studies have focused on adults over 60, often neglecting the critical menopause transition period. During menopause, women experience a substantial decline in ovarian sex hormone production, with a decrease of about 90% in estrogen levels. Estrogen is known for its neuroprotective effects, and its significant loss during menopause affects various biological systems, including the brain. Importantly, despite known differences in dementia risk between sexes, the impact of biological sex and sex hormones on brain aging and the development of Alzheimer's disease remains underexplored.

Association of serum n-3 and n-6 docosapentaenoic acids with cognitive performance in elderly adults: National Health and Nutrition Examination Survey 2011-2014

Limited information exists on the influence of docosapentaenoic acid (DPA) on cognitive function. We investigated the association between serum n-3 and n-6 DPAs and cognitive performance in an elderly population from the National Health and Nutrition Examination Survey, 2011-2014. Restricted cubic spline and logistic regression analyses were utilized. A total of 1,366 older participants were included. Elevated proportions of DPA(n3) in total serum fatty acids were slightly associated with higher DSST scores (OR 0.61, 95% CI (0.38-0.97)), and higher proportions of DPA(n6) in total serum fatty acids were significantly associated with lower scores on different cognitive tests (CERAD (1.64, 1.02-2.65), AFT (2.31, 1.43- 3.75), DSST (3.21, 1.98-5.22) and global cognition (2.85, 1.74-4.66)). After multivariable adjustment, DPA(n3) exhibited no association with cognitive performance, whereas DPA(n6) remained correlated with AFT (1.98, 1.13-3.48), DSST (2.63, 1.43-4.82) and global cognition (2.15, 1.19-3.90). In stratified analyses, higher levels of DPA(n3) were associated with better performance in CERAD among participants aged ≥70, in DSST among those without diabetes and in global cognition among people with lower incomes. Increased DPA(n6) levels were associated with worse performance in AFT and DSST among those aged 60-70 and in all cognitive tests among those with better incomes. In conclusions, elevated levels of serum DPA(n3) may be beneficial for cognitive performance among elderly adults, especially in those over 70 years, with lower incomes and without diabetes. Serum n-6 DPA might be negatively associated with cognitive function, and this association is more pronounced among those who aged 60-70 with higher incomes.

Longitudinal relationships between Aβ and tau to executive function and memory in cognitively normal older adults

The early accumulation of AD pathology such as Aβ and tau in cognitively normal older people is predictive of cognitive decline, but it has been difficult to dissociate the cognitive effects of these two proteins. Early Aβ and tau target distinct brain regions that have different functional roles. Here, we assessed specific longitudinal pathology-cognition associations in seventy-six cognitively normal older adults from the Berkeley Aging Cohort Study who underwent longitudinal PiB PET, FTP PET, and cognitive assessments. Using linear mixed-effects models to estimate longitudinal changes and residual approach to characterizing cognitive domain-specific associations, we found that Aβ accumulation, especially in frontal/parietal regions, was associated with faster decline in executive function, not memory, whereas tau accumulation, especially in left entorhinal/parahippocampal regions, was associated with faster decline in memory, not executive function, supporting an "Aβ-executive function, tau-memory" double-dissociation in cognitively normal older people. These specific relationships between accumulating pathology and domain-specific cognitive decline may be due to the particular vulnerabilities of the frontal-parietal executive network to Aβ and temporal memory network to tau.

Relationship between hemoglobin and specific cognitive domain among older adults using network analysis

OBJECTIVES

Hemoglobin (Hgb) is associated with cognitive function, with low and high levels of Hgb leading to impaired cerebral oxygenation and perfusion. Yet, current studies focused on understanding the association between Hgb and cognitive function without consideration for each cognitive domain. Thus, this study aims to identify and visualize potentially interactive associations between Hgb and specific cognitive domains among older adults.

METHOD

This is a secondary data analysis using Wave II data from the National Social Life, Health, and Aging Project (NSHAP) and included 1022 older adults aged between 65 and 85 years. The network structure of three different models was estimated to understand the association between specific cognitive domains and Hgb in a mixed graphical model using the R-package 'mgm'. Model 1 did not adjust for any covariates, Model 2 adjusted for age and gender, and Model 3 adjusted for all covariates.

RESULTS

Among all cognitive domains, the visuospatial (edge weight = 0.06-0.10) and memory domains (0.04-0.07) were associated with Hgb in all three models Though not present in Model 3, the attention domain was associated with Hgb in Model 1 and Model 2 (0.08-0.11). In addition, the predictability of Hgb was the highest (8.1%) in Model 3.

CONCLUSION

Findings from this study suggest that cognition should be considered as a multidimensional construct, and its specific cognitive domain should be carefully assessed and managed in relation to Hgb among older adults.

Sex Disparities in Cognitive Impairment Research: A Scoping Review in Informatics Literature

Rationale

A scoping review was conducted to investigate knowledge gaps in the informatics research literature regarding sex differences in cognitive decline, identifying existing studies and areas where further studies are needed.

Materials and Methods

We searched Ovid and other databases for studies on sex differences and cognitive decline, focusing on publications in peer-reviewed informatics journals and conference proceedings from 2000 to 2023. The selected manuscripts were analyzed and summarized through discussion among three reviewers.

Results

A total of 13 articles were selected and examined for metadata and attributes analysis. Most studies are conducted in United States (n=5) and European Union (n=4), about a half are published after 2020 (n=6), and most studies are published in Springer and Elsevier. Our attributes-based analysis highlights the different aspects of reported studies such as task, method, dataset and its size, and sex-specific inferences.

Discussion

Sex-specific disparities in cognitive decline remain a critical issue in healthcare, yet most informatics research has primarily concentrated on identifying basic sex differences, such as tracking the progression of cognitive decline in men and women. While these studies are valuable, they fall short of addressing the more complex underlying causes of these sex-specific disparities in progression of cognitive decline.

Conclusion

There is a significant gap using informatics in understanding how biological, social, and behavioral factors contribute to sex-specific disparities. This limited focus restricts the development of effective intervention strategies for mitigating sex-specific differences in cognitive health outcomes, underscoring the need for more comprehensive research that goes beyond mere identification to find the root cause of these disparities in healthcare.

Computational and digital analyses in the INSPIRE mouse cohort to define sex-specific functional determinants of biological aging

Biological age, which reflects the physiological state of an individual, offers a better predictive value than chronological age for age-related diseases and mortality. Nonetheless, determining accurate functional features of biological age remains challenging due to the multifactorial nature of aging. Here, we established a unique mouse cohort comprising 1576 male and female outbred SWISS mice subjected or not to high-fat, high-sucrose diet to investigate multiorgan/system biological aging throughout adulthood. Comprehensive functional and biological phenotyping at ages of 6, 12, 18, and 24 months revealed notable sex-specific disparities in longitudinal locomotion patterns and multifunctional aging parameters. Topological data analysis enabled the identification of functionally similar mouse clusters irrespective of chronological age. Moreover, our study pinpointed critical functional markers of biological aging such as muscle function, anxiety characteristics, urinary patterns, reticulocyte maturation, cardiac remodeling and function, and metabolic alterations, underscoring muscle function as an early indicator of biological age in male mice.

X-chromosome-wide association study for Alzheimer's disease

Due to methodological reasons, the X-chromosome has not been featured in the major genome-wide association studies on Alzheimer's Disease (AD). To address this and better characterize the genetic landscape of AD, we performed an in-depth X-Chromosome-Wide Association Study (XWAS) in 115,841 AD cases or AD proxy cases, including 52,214 clinically-diagnosed AD cases, and 613,671 controls. We considered three approaches to account for the different X-chromosome inactivation (XCI) states in females, i.e. random XCI, skewed XCI, and escape XCI. We did not detect any genome-wide significant signals (P ≤ 5 × 10-8) but identified seven X-chromosome-wide significant loci (P ≤ 1.6 × 10-6). The index variants were common for the Xp22.32, FRMPD4, DMD and Xq25 loci, and rare for the WNK3, PJA1, and DACH2 loci. Overall, this well-powered XWAS found no genetic risk factors for AD on the non-pseudoautosomal region of the X-chromosome, but it identified suggestive signals warranting further investigations.

Childhood maltreatment, cognitive performance, and cognitive decline in middle-aged and older adults with chronic disease: A prospective study

OBJECTIVES

Childhood maltreatment (CM) may increase the risk for cognitive deficits and dementia later in life. However, most research has been cross-sectional in nature, has typically focused on specific types of CM, and rarely examined individual differences. The objectives are to evaluate 1) if CM predicts poorer cognitive performance and greater cognitive decline over a 5-year follow-up in older men and women with coronary artery disease (CAD) or other non-cardiovascular (non-CVD) chronic disease, and whether 2) sex and CAD status influence these relations.

METHODS

Men and women (N = 1254; 39.6 % women; 65.6 ± 7.0 years old) with CAD or other non-CVD chronic diseases completed the Childhood Trauma Questionnaire Short Form (CTQ-SF). The Montreal Cognitive Assessment (MoCA) was administered twice at 5-year intervals. Main analyses included bivariate correlations, hierarchical analyses and moderation analyses controlling for sociodemographic and health parameters.

RESULTS

CM was experienced by 32 % of the sample, while scores suggestive of cognitive deficits were obtained by 32.7 % and 40.2 % at study onset and follow-up, respectively. CM was associated with significantly lower MoCA scores at study onset (b = -0.013, p = 0.020), but not with change in MoCA over time (b = -0.002, p = 0.796). While MoCA scores did differ as a function of sex and CAD status, the latter did not influence the relations between maltreatment and MoCA.

CONCLUSIONS

CM predicted poorer cognitive functioning among older individuals with chronic diseases but did not play a role in any further cognitive decline over the follow-up period. Further research is needed to help understand the mechanisms implicated.

Latent change-on-change between amyloid accumulation and cognitive decline

INTRODUCTION

While the influence of cross-sectional β-amyloid (Aβ) on longitudinal changes in cognition is well established, longitudinal change-on-change between Aβ and cognition is less explored.

METHODS

A series of bivariate latent change score models (LCSM) examined the relationship between changes in 11C-Pittsburgh Compound-B (PiB) positron emission tomography (PET) and the Preclinical Alzheimer's Cognitive Composite-5 (PACC-5) while adjusting for covariates, including cross-sectional medial temporal lobe (MTL) tau-PET burden. We selected 352 clinically normal older participants with up to 9 years of PiB-PET and PACC-5 data from the Harvard Aging Brain Study (HABS).

RESULTS

Aβ accumulation was associated with subsequent cognitive decline beyond the effects of cross-sectional Aβ burden. Within this model including covariates such as age, sex, and apolipoprotein ε4 (APOEε4) status, we found no evidence supporting previously published associations between cross-sectional tau-PET and cognitive intercept/slope.

DISCUSSION

Short-term Aβ changes are significantly associated with cognitive decline in clinically normal older adults and may eclipse the effect of cross-sectional Aβ and MTL tau.

HIGHLIGHTS

Aβ accumulation is associated with subsequent cognitive decline. High Aβ burden is not the sole metric signaling impending cognitive decline. Contrary to prior work, MTL tau-PET and cognition were not associated in our models. Models of bivariate latent Aβ and cognitive change may eclipse the effects of MTL tau.

Racial Differences in Older Adult's Mental Health and Cognitive Symptomatology: Identifying Subgroups Using Multiple-Group Latent Class Analysis

INTRODUCTION

Little is known on the potential racial differences in latent subgroup membership based on mental health and cognitive symptomatology among older adults.

METHODS

This is a secondary data analysis of Wave 2 data from the National Social Life, Health, and Aging Project (N = 1819). Symptoms were depression, anxiety, loneliness, happiness, and cognition. Multiple-group latent class analysis was conducted to identify latent subgroups based on mental health and cognitive symptoms and to compare these differences between race.

RESULTS

Class 1: "Severe Cognition & Mild-Moderate Mood Impaired," Class 2: "Moderate Cognition & Mood Impaired," and Class 3: "Mild Cognition Impaired & Healthy Mood" were identified. Black older adults were more likely to be in Class 1 while White older adults were more likely to be in Class 2 and Class 3.

DISCUSSION

Clinicians need to provide culturally-sensitive care when assessing and treating symptoms across different racial groups.

Sex-specific age-related differences in cerebrospinal fluid clearance assessed by resting-state functional magnetic resonance imaging

Cerebrospinal fluid (CSF) flow may assist the clearance of brain wastes, such as amyloid-β (Aβ) and tau, and thus play an important role in aging and dementias. However, a lack of non-invasive tools to assess the CSF dynamics-related clearance in humans hindered the understanding of the relevant changes in healthy aging. The global infra-slow (<0.1 Hz) brain activity measured by the global mean resting-state fMRI signal (gBOLD) was recently found to be coupled by large CSF movements. This coupling has been found to correlate with various pathologies of Alzheimer's disease (AD), particularly Aβ pathology, linking it to waste clearance. Using resting-state fMRI data from a group of 719 healthy aging participants, we examined the sex-specific differences of the gBOLD-CSF coupling over a wide age range between 36-100 years of age. We found that this coupling index remains stable before around age 55 and then starts to decline afterward, particularly in females. Menopause may contribute to the accelerated decline in females.

Sex-specific risk factors and clinical dementia outcomes for white matter hyperintensities in a large South Korean cohort

OBJECTIVE

White matter hyperintensities (WMH) on brain MRI images are the most common feature of cerebral small vessel disease (CSVD). Studies have yielded divergent findings on the modifiable risk factors for WMH and WMH's impact on cognitive decline. Mounting evidence suggests sex differences in WMH burden and subsequent effects on cognition. Thus, we aimed to identify sex-specific modifiable risk factors for WMH. We then explored whether there were sex-specific associations of WMH to longitudinal clinical dementia outcomes.

METHODS

Participants aged 49-89 years were recruited at memory clinics and underwent a T2-weighted fluid-attenuated inversion recovery (FLAIR) 3T MRI scan to measure WMH volume. Participants were then recruited for two additional follow-up visits, 1-2 years apart, where clinical dementia rating sum of boxes (CDR-SB) scores were measured. We first explored which known modifiable risk factors for WMH were significant when tested for a sex-interaction effect. We additionally tested which risk factors were significant when stratified by sex. We then tested to see whether WMH is longitudinally associated with clinical dementia that is sex-specific.

RESULTS

The study utilized data from 713 participants (241 males, 472 females) with a mean age of 72.3 years and 72.8 years for males and females, respectively. 57.3% and 59.5% of participants were diagnosed with mild cognitive impairment (MCI) for males and females, respectively. 40.7% and 39.4% were diagnosed with dementia for males and females, respectively. Of the 713 participants, 181 participants had CDR-SB scores available for three longitudinal time points. Compared to males, females showed stronger association of age to WMH volume. Type 2 Diabetes was associated with greater WMH burden in females but not males. Finally, baseline WMH burden was associated with worse clinical dementia outcomes longitudinally in females but not in males.

DISCUSSION

Older females have an accelerated increase in cerebrovascular burden as they age, and subsequently are more vulnerable to clinical dementia decline due to CSVD. Additionally, females are more susceptible to the cerebrovascular consequences of diabetes. These findings emphasize the importance of considering sex when examining the consequences of CSVD. Future research should explore the underlying mechanisms driving these sex differences and personalized prevention and treatment strategies.

CLINICAL TRIAL REGISTRATION

The BICWALZS is registered in the Korean National Clinical Trial Registry (Clinical Research Information Service; identifier, KCT0003391). Registration Date 2018/12/14.

Risk Factors for Rapid Cognitive Decline in Amyloid-Negative Individuals Without Cognitive Impairment or With Early-Stage Cognitive Loss in Screening Tests

PURPOSE

Although rapid cognitive decline (RCD) is an important unfavorable prognostic factor, not much is known about it, especially in amyloid-negative individuals. The purpose of this study was to investigate risk factors for RCD in amyloid-negative individuals.

PATIENTS AND METHODS

We retrospectively enrolled 741 individuals who were either cognitively unimpaired or had early-stage cognitive ability loss and who underwent 18 F-florbetaben (FBB) (n = 402) or 18 F-flutemetamol (FMM) (n = 339) PET/CT. Based on visual and semiquantitative (SUV ratio [SUVR]-based) analysis, the following amyloid-negative groups were established: visual-negative FBB (n = 232), visual-negative FMM (n = 161), SUVR-negative FBB (n = 104), and SUVR-negative FMM (n = 101). Univariable and multivariable logistic regression analyses were performed for RCD using 5 SUVRs, 5 cortical thicknesses, and 5 neuropsychological domains and clinico-demographic factors.

RESULTS

In the amyloid-negative groups, a decline in language function was commonly identified as a significant risk factor for RCD ( P = 0.0044 in the visual-negative FBB group, P = 0.0487 in the visual-negative FMM group, P = 0.0031 in the SUVR-negative FBB group, and P = 0.0030 in the SUVR-negative FMM group). In addition, declines in frontal/executive function, frontal SUVR, and parietal SUVR; a longer duration of education; and mild cognitive decline in the amyloid-negative groups were also significant risk factors for RCD.

CONCLUSIONS

Even in amyloid-negative individuals without cognitive impairment or with early-stage cognitive ability loss, those with decreased language and frontal/executive functions on neuropsychological testing are at risk of progression to RCD.

Intersectionality of gender with social determinants of health and asymptomatic Alzheimer's disease neuropathology

BACKGROUND

Women comprise approximately two-thirds of Alzheimer's disease cases.

OBJECTIVE

This is the first known study to investigate the role of intersectionality between gender and other social determinants of health (SDOH) in the presentation of cognitive symptoms (i.e., being asymptomatic or symptomatic) among those with pathologically confirmed Alzheimer's disease.

METHODS

We studied 3107 individuals with Alzheimer's disease neuropathology (ADNP) confirmed at autopsy. Asymptomatic ADNP was defined as the absence of a clinical diagnosis of mild cognitive impairment (MCI) or dementia before death (versus symptomatic: diagnosis of MCI/dementia). SDOH included gender, education, ethnoracial group, living alone, and primary language. Multivariable logistic regression tested associations between SDOH and asymptomatic ADNP (versus symptomatic); models were also stratified by gender.

RESULTS

Women, Hispanics, those living alone, and more educated individuals were found to have higher odds of asymptomatic ADNP. Non-English speakers had lower odds of asymptomatic ADNP. Both women and men had higher odds of asymptomatic ADNP if Hispanic or living alone. In only women, non-English speakers had lower odds while in only men, more education was associated with higher odds of asymptomatic ADNP.

CONCLUSIONS

Gender, education, ethnicity, primary language, and living alone, and intersectionality of gender with primary language, may differentially influence MCI and dementia diagnosis prior to death among those with underlying ADNP. These findings emphasize the need for future Alzheimer's disease research to prioritize social determinants of brain health including their intersectionality with gender and how to inform targeted interventions.

Norms for neuropsychological tests in cognitively healthy French oldest old adults

OBJECTIVE

Normal aging often leads to cognitive decline, and oldest old people, over 80 years old, have a 15% risk of developing neurodegenerative diseases. Therefore, it is important to have appropriate tools to assess cognitive function in old age. The study aimed to provide new norms for neuropsychological tests used to evaluate the cognitive abilities in people aged 80 years and older in France, focusing on the impact of education and gender differences.

METHOD

107 healthy participants with an average age of 85.2 years, with no neurological history or major cognitive deficits were included. A comprehensive neuropsychological assessment was performed, covering several cognitive functions such as memory, visuospatial abilities, executive functions, attention, processing speed, and praxis.

RESULTS

Individuals with lower levels of education performed poorly on some tests and took longer to complete. Gender differences were observed, with women outperforming men in verbal episodic memory, while men showed better performance in visuoconstructive tasks. The participants showed lower performance in verbal episodic memory compared to norms established in previous French studies. In relation to executive functions, participants were slower to perform complex tasks than participants in previous studies.

CONCLUSION

This study provides cognitive norms specifically adapted to the oldest old population, which differ from established norms for younger aging adults. It highlights the importance of including these norms in future clinical and scientific investigations. The findings underscore the importance of education on cognitive abilities and emphasize the need to consider gender differences when assessing cognitive functions in aging populations.

Association between depressive duration and cognitive decline in middle-aged and older adults: Evidence from the Health and Retirement Study 2010-2018

BACKGROUND

Depression has been found to be associated with cognitive decline, but whether longer depressive durations lead to more severe cognitive declines has not been investigated. We aimed to estimate the association between depressive duration and cognitive decline in middle-aged and older Americans based on a large-scale representative population study.

METHODS

We included 27,886 participants from the Health and Retirement Study (HRS) in 2010-2018. Four datasets with 2-, 4-, 6-, and 8-year consecutive interviews were further derived which involving persistent depressed and persistent depression-free individuals. Multiple linear regressions were constructed to estimate the effects of each depressive duration on the decline in global cognition, memory and mental status. Meta-regressions were performed to test the linear trends and to explore the heterogeneity between sex, age and baseline cognitive function along with subgroup analyses.

RESULTS

Depressive durations of 2, 4, 6, and 8 years were associated with reductions in global cognitive scores of 0.62 points (95% CI: 0.51-0.73), 0.77 points (95% CI: 0.60-0.94), 0.83 points (95% CI: 0.55-1.10), and 1.09 points (95% CI: 0.63-1.55), respectively, indicating a linear trend (P = 0.016). More pronounced associations were observed in middle-aged adults and females. Similar patterns were found in the associations between depressive duration and two subdomains, i.e., memory and mental health.

LIMITATIONS

This study is essentially a cross-sectional study and therefore cannot provide causal associations.

CONCLUSIONS

Longer depressive durations were linearly related to more severe cognitive declines. Timely intervention for depression targeted middle-aged adults can more effectively alleviate cognition-related burdens.

Effects of brain microRNAs in cognitive trajectory and Alzheimer's disease

microRNAs (miRNAs) have a broad influence on gene expression; however, we have limited insights into their contribution to rate of cognitive decline over time or Alzheimer's disease (AD). Given this, we tested associations of 528 miRNAs with cognitive trajectory, AD hallmark pathologies, and AD clinical diagnosis using small RNA sequencing from the dorsolateral prefrontal cortex of 641 community-based donors. We found 311 miRNAs differentially expressed in AD or its endophenotypes after adjusting for technical and sociodemographic variables. Among these, 137 miRNAs remained differentially expressed after additionally adjusting for several co-occurring age-related cerebral pathologies, suggesting that some miRNAs are associated with the traits through co-occurring pathologies while others through mechanisms independent from pathologies. Pathway enrichment analysis of downstream targets of these differentially expressed miRNAs found enrichment in transcription, postsynaptic signalling, cellular senescence, and lipoproteins. In sex-stratified analyses, five miRNAs showed sex-biased differential expression for one or more AD endophenotypes, highlighting the role that sex has in AD. Lastly, we used Mendelian randomization to test whether the identified differentially expressed miRNAs contribute to the cause or are the consequence of the traits. Remarkably, 15 differentially expressed miRNAs had evidence consistent with a causal role, laying the groundwork for future mechanistic studies of miRNAs in AD and its endophenotypes.