Association of Short and Long Sleep Duration With Amyloid-β Burden and Cognition in Aging

Association between biological aging and cardiovascular health: Combined evidence based on cross-sectional and prospective study

PURPOSE

To examine the relationship between biological aging metrics and cardiovascular health, as well as the mediating effect of sleep duration.

METHOD

We applied the recommended sampling weights to adjust for the complex survey design of NHANES. Using NHANES data, we first employed restricted cubic spline (RCS) and logistic regression models to explore the cross-sectional associations between biological aging metrics, defined by the Klemera-Doubal method biological age (KDM-BA), phenotypic age (PA), homeostatic dysregulation (HD), and allostatic load (AL), and the prevalence of cardiovascular diseases (CVD) and its subtypes. We then used Cox regression, Kaplan-Meier curves, and RCS models to assess the prospective associations between biological aging metrics and all-cause as well as CVD mortality. Further, ROC and DCA models were used to assess the predicting ability of 4 biological aging metrics to cardiovascular health.

RESULT

This study included 7,704 participants. We found that biological aging metrics were strongly linked to the prevalence of CVD and its subtypes, as well as to all-cause and CVD mortality. Sleep duration appeared to moderate these associations. Among the four biological aging metrics, PA was the most effective predictor of CVD prevalence and its subtypes, though none of the metrics accurately predicted mortality.

CONCLUSION

Biological aging metrics were significantly associated with cardiovascular health, while sleep duration may attenuate this relationship. Clinically, PA can be a potential predictor of cardiovascular health.

Sleep characteristics and brain structure: A systematic review with meta-analysis

BACKGROUND

As the global population ages, the prevalence of associated conditions, including neurodegeneration and dementia, will increase. Thus, reducing risk factors is crucial to prevention. Sleep contributes to brain homeostasis and repair, which, if impaired, could lead to neurodegeneration. However, the relationship between sleep characteristics, disorders, and brain morphology is poorly understood in healthy adults. Therefore, we aimed to systematically analyse the literature and clarify how sleep characteristics are associated with brain structures.

METHODS

We systematically searched PUBMED, MEDLINE, ProQuest, Web of Science, and Scopus for empirical studies of healthy adults examining the associations between sleep characteristics or disorders and brain structure, adjusting for age, gender, and head size. We conducted a meta-analysis with random effects models for volumetric studies and a seed-based spatial analysis for voxel-based morphometry (VBM) studies.

RESULTS

One hundred and five articles (60 volumetric, 45 VBM) with 106 studies reporting 108,364 participants were included. Most studies (73.1%) found sleep characteristics and disorders to be associated with predominantly lower brain volumes (cross-sectional: 51.9% of all cross-sectional; longitudinal: 45.5% of longitudinal). In VBM studies, REM sleep behaviour disorder was linked to lower grey matter volume in the right frontal gyrus (z-score = -3.617, 68 voxels, p-value = <0 0.001).

CONCLUSION

Sleep characteristics - poor quality, short or long sleep - and sleep disorders are predominantly associated with lower brain volumes, suggesting that inadequate sleep (short, long or poor quality) might contribute to neurodegeneration. This insight highlights the importance of monitoring, managing, and enforcing sleep health to prevent or mitigate potential neurodegenerative processes.

Interactions between daily sleep-wake rhythms, γ-secretase, and amyloid-β peptide pathology point to complex underlying relationships

Disrupted or insufficient sleep is a well-documented risk factor for Alzheimer's disease (AD) and related dementias. Previous studies in our lab and others have shown that chronic fragmentation of the daily sleep-wake rhythm in mice can accelerate the development of AD-related neuropathology in the brain, including increases in the levels of amyloid-β (Aβ). Although sleep is known to increase clearance of Aβ via the glymphatic system, little is known about the effect of sleep on Aβ production and the role this might play in amyloid deposition. To examine the relationship of Aβ production and its interaction with sleep and sleep dysfunction, we treated mice from an APP × PS1 mutant knock-in line (APPΔNLh/ΔNLh × PS1P264L/P264L) with an inhibitor of γ-secretase (LY-450,139; Semagacestat®) during a protocol of mild sleep fragmentation (SF). Compared to the male mice, the female mice slept less, and had more Aβ pathology. Semagacestat treatment reduced Aβ, but only in the most soluble extractable fraction. Although the female mice showed an increase in the amount of Aβ following SF, this effect was blocked by Semagacestat, an effect that was not seen in the male mice. SF also led to a significant, sex-dependent changes in the relative amounts of C-terminal fragments of the amyloid precursor protein, the immediate substrate of the γ-secretase enzyme. These findings indicate that the relationship between disruption of the daily sleep-wake rhythm and the development of AD-related pathology is complex, and may involve unappreciated interactions with biological sex. Consideration of these factors is necessary for a better understanding of AD risk, especially the elevated risk in women.

Circadian rhythms and the light-dark cycle interact to regulate amyloid plaque accumulation and tau phosphorylation in 5xFAD mice

Background

Circadian disruption has long been appreciated as a downstream consequence of Alzheimer's Disease in humans. However, an upstream role for behavioral circadian disruption in regulating AD pathology remains an open question.

Methods

To determine the role of the central circadian clock in the suprachiasmatic nucleus (SCN) in regulating amyloid pathology, we crossed the 5xFAD amyloid mouse model with mice harboring deletion of the critical clock gene Bmal1 in GABAergic neurons using VGAT-iCre, which is expressed in >95% of SCN cells. To examine the role the light-dark cycle in this process, we aged these mice in either regular 12:12 light-dark (LD) or constant darkness (DD) conditions. Transcriptional, behavioral, and physiological rhythms were examined in VGAT-iCre; 5xFAD; Bmal1 fl/fl (VGAT-BMAL1KO;5xFAD) mice under varying light conditions. Amyloid plaque deposition, peri-plaque tau phosphorylation, and other pathology was examined by immunohistochemistry, and transcriptomic changes were examined by high-throughput qPCR.

Results

VGAT-BMAL1KO;5xFAD mice showed loss of SCN BMAL1 expression and severe disruption of behavioral rhythms in both LD and DD, with loss of day-night rhythms in consolidated sleep and blunting of rhythmic clock gene expression in the brain. Surprisingly, VGAT-BMAL1KO;5xFAD mice kept under LD showed reduced total plaque accumulation and peri-plaque tau phosphorylation, compared to Cre-negative controls. These changes were gated by the light-dark cycle, as they were absent in VGAT-BMAL1KO;5xFAD mice kept in DD conditions. Total plaque accumulation was also reduced in control 5xFAD mice kept in DD as compared to LD, suggesting a general effect of light-dark cycle on amyloid aggregation. Expression of murine presenilin 1 (Psen1) -- which catalyzes the processing of sAPPβ into Aβ -- as well as APP cleavage to C-terminal fragments, were suppressed in VGAT-BMAL1KO;5xFAD under LD conditions.

Conclusions

These studies elucidated an interaction between the circadian clock in GABAergic neurons and the light-dark cycle in regulating amyloid pathology and suggest that decoupling the central clock form the light-dark cycle may reduce APP cleavage and plaque formation. These results call into question the proposed simple positive feedback loop between circadian rhythm disruption and Alzheimer's Disease pathology.

The association between measures of sleepiness and subjective cognitive decline symptoms in a diverse population of cognitively normal older adults

Subjective cognitive decline (SCD) is associated with preclinical Alzheimer's disease (AD). Suboptimal sleep is also a risk factor for cognitive decline, but with unclear relationship to SCD. We conducted a retrospective cross-sectional study in a biracial research cohort of 148 cognitively normal older adults who underwent quantification of SCD (Cognitive Change Index; CCI), sleepiness (Epworth Sleepiness Scale; ESS), depression (Geriatric Depression Scale; GDS), and amyloid/tau PET. ESS score was associated with total, amnestic, and non-amnestic CCI scores, after adjustment for GDS, amyloid/tau burden, and race. This supports future longitudinal work on how sleepiness impacts SCD outcomes.

Review on pathogenesis and treatment of Alzheimer's disease

The rising incidence of Alzheimer's disease (AD) and the associated economic impacts has prompted a global focus in the field. In recent years, there has been a growing understanding of the pathogenic mechanisms of AD, including the aggregation of β-amyloid, hyperphosphorylated tau, and neuroinflammation. These processes collectively lead to neurodegeneration and cognitive decline, which ultimately results in the loss of autonomy in patients. Currently, there are three main types of AD treatments: clinical tools, pharmacological treatment, and material interventions. This review provides a comprehensive analysis of the underlying etiology and pathogenesis of AD, as well as an overview of the current prevalence of AD treatments. We believe this article can help deepen our understanding of the AD mechanism, and facilitate the clinical translation of scientific research or therapies, to address this global problem of AD.

Regulation of lipid dysmetabolism and neuroinflammation linked with Alzheimer's disease through modulation of Dgat2

Alzheimer's disease (AD) is a progressive neurodegenerative disorder marked by amyloid-β (Aβ) plaque accumulation, cognitive decline, lipid dysregulation, and neuroinflammation. While mutations in the Amyloid Precursor Protein (APP) and Aβ42 accumulation contribute to AD, the mechanisms linking Aβ to lipid metabolism and neuroinflammation remain unclear. Using Drosophila models, we show that App NLG and Aβ42 expression causes locomotor deficits, disrupted sleep, memory impairments, lipid accumulation, synaptic loss, and neuroinflammation. Similar lipid and inflammatory changes are observed in the App NLG-F knock-in mouse model, reinforcing their role in AD pathogenesis. We identify diacylglycerol O-acyltransferase 2 (Dgat2), a key lipid metabolism enzyme, as a modulator of AD phenotypes. In Drosophila and mouse AD models, Dgat2 levels and its transcription factors are altered. Dgat2 knockdown in Drosophila reduced lipid accumulation, restored synaptic integrity, improved locomotor and cognitive function, and mitigated neuroinflammation. Additionally, Dgat2 modulation improved sleep and circadian rhythms. In App NLG-F mice, Dgat2 inhibition decreased neuroinflammation and reduced AD risk gene expression. These findings highlight the intricate link between amyloid pathology, lipid dysregulation, and neuroinflammation, suggesting that targeting Dgat2 may offer a novel therapeutic approach for AD. Conserved lipid homeostasis mechanisms across species provide valuable translational insights.

Associations among sleep quality, sleep duration, and Alzheimer's disease biomarkers: A systematic review and meta-analysis

INTRODUCTION

Although sleep disturbances are widely recognized as risk factors for cognitive decline and Alzheimer's disease (AD), their influence on AD biomarkers remains unclear. This study aimed to clarify whether sleep quality or sleep duration affect amyloid beta (Aβ) and tau levels in plasma, cerebrospinal fluid (CSF), and positron emission tomography (PET) in non-demented populations.

METHODS

PubMed, Web of Science, and Embase were systematically searched up to February 2025.

RESULTS

In total, 30 studies were included comprising 14,997 subjects. Individuals with poor sleep quality exhibited greater PET Aβ burden and higher Aβ42 levels in plasma than those with good sleep quality. Shorter sleep duration was associated with higher Aβ burden on PET. However, no association between either sleep quality or sleep duration and tau levels was found.

DISCUSSION

Sleep may be a modifiable marker of early AD management by modulating Aβ levels.

HIGHLIGHTS

lPoor sleep quality and shorter sleep duration were significantly associated with higher amyloid beta (Aβ) burden detected by positron emission tomography (PET) in non-demented populations. Poor sleep quality was also associated with elevated Aβ42 levels in plasma. lNo significant associations were found between sleep quality or sleep duration and tau levels in plasma, cerebrospinal fluid, or PET. lInterventions targeting sleep could serve as a viable and low-cost prevention strategy for early management of Alzheimer's disease.

Relationship between development trajectories of leisure activity and sleep time on incident cognitive impairment: A study based on the Chinese Longitudinal Healthy Longevity Survey (CLHLS)

BackgroundLeisure activity and sleep time are key factors in cognitive impairment, but the impact of their long-term trajectories on incident cognitive impairment remains unclear.ObjectiveTo examine the association of leisure activity trajectories, sleep time trajectories and their combined effects with incident cognitive impairment in older adults.MethodsData from the Chinese Longitudinal Healthy Longevity Survey (2008-2018) were analyzed, including adults aged ≥65 who participated in at least three surveys. Group-based trajectory modeling explored leisure activity and sleep time patterns. Cox proportional-hazards regression model assessed the association of leisure activity trajectories and sleep time trajectories and their combined effects with incident cognitive impairment.ResultsWe included 3094 participants with a median follow-up of 6.07 years. The optimal trajectory groups for leisure activity and sleep time were four and three, respectively. The low-level leisure activity group were associated with an increased risk of cognitive impairment (HR, 95%CI: 2.07, 1.37-3.13), whereas the high-level leisure activity group were associated with a reduced risk of cognitive impairment (HR, 95%CI: 0.60, 0.36-0.99). Short sleep time group was associated with a reduced risk of cognitive impairment (HR, 95%CI: 0.62, 0.41-0.92). In the combined effect, leisure activity belonging to the low-level group and sleep time belonging to the moderate sleep time group or the long sleep time group were associated with an increased risk of cognitive impairment.ConclusionsLong-term high-level leisure activity and short sleep time are associated with a reduced risk of cognitive impairment in older adults.

Brain Health in Sleep Disorders

Sleep is a critical determinant of brain health, influencing cognitive, emotional, and physiologic functions. The complex bidirectional relationship between sleep and brain health underscores the importance of sleep in maintaining cognitive function, regulating brain homeostasis, and facilitating the clearance of metabolic waste through the glymphatic system. Chronic sleep deprivation and sleep disorders such as insomnia and obstructive sleep apnea have been shown to negatively impact brain structures and functions. This review discusses the impact of sleep disorders on brain health. It also explores the implications of impaired sleep on cardiovascular health, immune function, and neuroplasticity.

Longitudinal patterns of cognitive function and depression: insights from the China Health and Retirement Longitudinal Study

Background

With the acceleration of population aging, cognitive impairment and depression have become serious public health challenges in countries around the world. The influencing factors of cognitive trajectory, depression trajectory, and dual trajectories in middle-aged and elderly adults have not been fully studied.

Methods

This study used data from the China Health and Retirement Longitudinal Study database spanning from 2011-2018. Group-based trajectory modelling and group-based dual trajectory modelling were employed to examine different trajectories. Restricted cubic spline and multivariate logistic regression analysis were used to elucidate the relationship between sleep duration and grip strength with these different trajectories. Mediation analysis was conducted to explore the mediating roles of sleep duration and grip strength in the activities of daily living (ADLs) and their impact on these trajectories.

Results

Trajectory analysis identified two longitudinal patterns of cognitive function and depression scores: low and high cognitive group, low and high depression group, respectively, and two states of the dual trajectories of cognition and depression: the stable state group and the state decline group. Sleep duration and grip strength were associated with the cognitive trajectory, depression trajectory and dual trajectories. Sleep duration has an inverted U-shaped relationship with cognitive trajectory. Grip strength was nonlinearly associated with the above trajectories. The mediation effects of sleep duration in the association between ADLs and cognitive, depression and dual trajectories were 3.14, 6.14, and 2.70%. While the mediation effects of grip strength were 7.21, 1.67 and 6.24%, respectively (P < 0.05).

Conclusions

Sleep duration and grip strength were not only associated with cognitive, depression, and dual trajectories, but also partially mediate the relationship between ADLs and these trajectories. This study will provide a basis for how to intervene in the cognitive and mental health of middle-aged and elderly adults.

Dose-response associations of device-measured sleep regularity and duration with incident dementia in 82391 UK adults

BACKGROUND

Sleep is a crucial lifestyle factor with impacts on mental and cognitive health. The associations between objectively measured sleep and risk of incident dementia are not yet fully understood. To evaluate the associations of device-measured sleep duration and regularity with incident dementia and explore whether sleep regularity moderates the association of sleep duration with dementia.

METHODS

Population-based prospective cohort study of 82,391 adults aged 43 to 79 years from the UK Biobank accelerometry subsample, collected between 2013 and 2015, followed up to 2022. Device-based sleep duration (h/day) and sleep regularity index (SRI), a metric ranging from 0-100 that quantifies a person's sleep regularity (with a greater value indicating higher consistency), were calculated from wrist-worn accelerometry data recorded over the course of one week. Incident all-cause dementia cases were obtained from national hospital admission, primary care and mortality data followed up to 30 November 2022. We used Cox proportional hazard models to estimate the hazard ratios (HRs) for incident dementia after adjustment for common demographic and clinical covariates.

RESULTS

Over a mean follow-up of 7.9 years, 694 incident dementia cases occurred. We observed a U-shaped association between sleep duration and incident dementia, with only short sleep (< 7 h) being significantly associated with a higher risk of dementia. The median sleep duration for short sleepers (< 7 h) of 6.5 h, compared to the reference point of 7.9 h was associated with HR of 1.19 (95%CI 1.01,1.40) for incident dementia. Sleep regularity was negatively associated with dementia risk in a near-linear fashion (linear p = 0.01, non-linear p = 0.57). When we dichotomized sleep regularity, those in the higher sleep regularity group (SRI ≥ 70) had an HR of 0.74 (95%CI 0.63, 0.87) compared to those with lower sleep regularity (SRI < 70). The beneficial associations between sleep regularity and incident dementia were present only among participants with short (< 7 h) and long (≥ 8 h) sleep duration.

CONCLUSIONS

Assuming that the associations we observed are causal, maintaining a regular sleep pattern may help offset the deleterious association of inadequate sleep duration with dementia. Interventions aimed at improving sleep regularity may be a viable option for people not able to achieve the recommended hours of sleep.

The role of sleep in Alzheimer's disease: a mini review

Sleep is a stereotyped and well-preserved series of neurophysiological states that are essential for overall health and brain functioning. Emerging research suggests that sleep disturbances are not only associated with but also causally contribute to neurodegenerative disease onset and progression. This mini-review examines some of the current knowledge and evidence for relationships between sleep abnormalities and Alzheimer's disease within context of possible uses and limitations of sleep biomarkers for evaluation of Alzheimer's disease. Understanding these relationships could lead to readily accessible and easily quantifiable biomarkers of Alzheimer's dementia.

Association between weekend catch-up sleep and hypertension of the United States population from 2017 to 2020: a cross-sectional study

Background

Hypertension is a prevalent cardiovascular risk factor that significantly contributes to morbidity and mortality worldwide. Previous studies have highlighted the role of inadequate sleep during weekdays in the development of hypertension. However, the potential mitigative effects of weekend catch-up sleep (WCS) on hypertension have been less explored.

Methods

This cross-sectional study analyzed data from the National Health and Nutrition Examination Survey (NHANES) 2017-2020, focusing on American adults. We assessed the association between WCS (defined as the difference in sleep duration between weekend and weekday) and the presence of hypertension. Participants were classified into two groups based on their WCS duration: none (below 1 hours), yes (over 1 hours). Multivariable logistic regression models adjusted for potential confounders such as age, gender, Body mass index (BMI), and lifestyle factors were utilized to explore this association. A Generalized Additive Model (GAM) was employed to generate smooth curves for a nuanced analysis of the nonlinear relationship.

Results

The findings indicated that moderate WCS (less than 4 hours) was significantly associated with a reduced risk of hypertension, while excessive WCS (greater than 4 hours) showed no significant protective benefits.

Conclusion

Moderate weekend catch-up sleep could serve as an effective intervention to mitigate hypertension risk, especially in populations with restricted weekday sleep. These results suggest the potential for integrating sleep management strategies into public health recommendations to address hypertension. Future longitudinal studies are needed to confirm these findings and clarify the mechanisms underlying the relationship between WCS and hypertension risk.

Association of rapid eye movement sleep latency with multimodal biomarkers of Alzheimer's disease

INTRODUCTION

Sleep disturbances are associated with Alzheimer's disease (AD) and Alzheimer's disease and related dementias (ADRD), but the relationship between sleep architecture, particularly rapid eye movement (REM) sleep, and AD/ADRD biomarkers remains unclear.

METHODS

We enrolled 128 adults (64 with Alzheimer's disease, 41 with mild cognitive impairment [MCI], and 23 with normal cognition [NC]), mean age 70.8 ± 9.6 years, 56.9% female, from a tertiary hospital in China. Participants underwent overnight polysomnography (PSG), amyloid β (Aβ) positron emission tomography (PET), and plasma biomarker analysis: phosphorylated tau at threonine 181 (p-tau181), neurofilament light (NfL), and brain-derived neurotrophic factor (BDNF).

RESULTS

After adjusting for demographics, apolipoprotein E (APOE) ε4 status, cognition, and comorbidities, the highest tertile of REM latency was associated with higher Aβ burden (β = 0.08, 95% confidence interval [CI]: 0.03 to 0.13, p = 0.002), elevated p-tau181 (β = 0.19, 95% CI: 0.02 to 0.13, p = 0.002), and reduced BDNF levels (β = -0.47, 95% CI: -0.68 to -0.13, p = 0.013), compared to the lowest tertile.

DISCUSSION

Prolonged REM latency may serve as a novel marker or risk factor for AD/ADRD pathogenesis.

HIGHLIGHTS

Rapid eye movement latency (REML) may be a potential marker for Alzheimer's disease and Alzheimer's disease and related dementias (AD/ADRD) pathogenesis. Prolonged REML was associated with higher amyloid beta (Aβ) burden, phosphorylated tau-181 (p-tau181), and lower brain-derived neurotrophic factor (BDNF) levels. Intervention trial is needed to determine if targeting REML can modify AD/ADRD risk. Slow-wave sleep was not associated with AD/ADRD biomarkers.

Automated remote sleep monitoring needs uncertainty quantification

Wearable electroencephalography devices emerge as a cost-effective and ergonomic alternative to gold-standard polysomnography, paving the way for better health monitoring and sleep disorder screening. Machine learning allows to automate sleep stage classification, but trust and reliability issues have hampered its adoption in clinical applications. Estimating uncertainty is a crucial factor in enhancing reliability by identifying regions of heightened and diminished confidence. In this study, we used an uncertainty-centred machine learning pipeline, U-PASS, to automate sleep staging in a challenging real-world dataset of single-channel electroencephalography and accelerometry collected with a wearable device from an elderly population. We were able to effectively limit the uncertainty of our machine learning model and to reliably inform clinical experts of which predictions were uncertain to improve the machine learning model's reliability. This increased the five-stage sleep-scoring accuracy of a state-of-the-art machine learning model from 63.9% to 71.2% on our dataset. Remarkably, the machine learning approach outperformed the human expert in interpreting these wearable data. Manual review by sleep specialists, without specific training for sleep staging on wearable electroencephalography, proved ineffective. The clinical utility of this automated remote monitoring system was also demonstrated, establishing a strong correlation between the predicted sleep parameters and the reference polysomnography parameters, and reproducing known correlations with the apnea-hypopnea index. In essence, this work presents a promising avenue to revolutionize remote patient care through the power of machine learning by the use of an automated data-processing pipeline enhanced with uncertainty estimation.

Sleep Capital: Linking Brain Health to Wellbeing and Economic Productivity Across the Lifespan

INTRODUCTION AND FRAMEWORK

Sleep capital contributes to individual and societal wellbeing, productivity, and economic outcomes and involves a novel aspect of brain capital. It encompasses the quality and quantity of sleep as integral components that influence cognitive abilities, mental and brain health, and physical health, affecting workplace productivity, learning, decision-making, and overall economic performance. Here, we bring a framework to understand the complex relationship between sleep quality, health, wellbeing, and economic productivity. Then we outline the multilevel impact of sleep on cognitive abilities, mental/brain health, and economic indicators, providing evidence for the substantial returns on investment in sleep health initiatives. Moreover, sleep capital is a key factor when considering brain health across the lifespan, especially for the aging population.

DISCUSSION

We propose specific elements and main variables to develop specific indexes of sleep capital to address its impacts on health, wellbeing and productivity.

CONCLUSION

Finally, we suggest policy recommendations, workplace interventions, and individual strategies to promote sleep health and brain capital. Investing in sleep capital is essential for fostering a healthier, happier, fairer and more productive society.

The combined effects of sleep and extreme heat exposure on cognitive function among older adults

BACKGROUND

Extreme heat is linked to cognitive impairment. Normal sleep duration and good sleep quality can reduce cognitive impairment risks. However, the combined impact of sleep (duration and quality) and extreme heat on cognitive impairment is unclear. This study tests whether normal sleep duration and good sleep quality during a heatwave reduce cognitive impairment compared to poor sleep quality and long sleep duration in older adults.

METHODS

This study used cohort data from 9153 older adults. Extreme heat was defined as periods ≥ 3 days with daily minimum temperatures above the 92.5th percentile during the warm season. Cognitive function was assessed with the Mini-Mental State Examination (MMSE). Sleep duration was categorized as long, normal, or short, and sleep quality as good or poor. Six and four categories were used for combinations of heatwave exposure with sleep duration and quality, respectively. Cox regression models were applied for analysis.

RESULTS

Compared to those with long sleep duration during heatwaves, participants exposed to heatwaves with normal sleep duration had lower cognitive impairment risk (HR: 0.86, 95 %CI: 0.76-0.97). Those exposed to extreme heat with short sleep duration also showed lower cognitive risks (HR: 0.74, 95 %CI: 0.62-0.88). Compared to those with poor sleep quality during heatwave, participants with good sleep quality during heatwaves did not show significantly lower cognitive impairment risk (HR: 1.10, 95 %CI: 0.98-1.23).

CONCLUSION

Older adults with normal or short sleep duration during heatwaves may face lower cognitive impairment risks, highlighting the importance of sleep guidance to protect cognitive health during extreme heat.

Hypothalamic volume is associated with age, sex and cognitive function across lifespan: a comparative analysis of two large population-based cohort studies

BACKGROUND

Emerging findings indicate that the hypothalamus, the body's principal homeostatic centre, plays a crucial role in modulating cognition, but comprehensive population-based studies are lacking.

METHODS

We used cross-sectional data from the Rhineland Study (N = 5812, 55.2 ± 13.6 years, 58% women) and the UK Biobank Imaging Study (UKB) (N = 45,076, 64.2 ± 7.7 years, 53% women), two large-scale population-based cohort studies. Volumes of hypothalamic structures were obtained from 3T structural magnetic resonance images through an automatic parcellation procedure (FastSurfer-HypVINN). The standardised cognitive domain scores were derived from extensive neuropsychological test batteries. We employed multivariable linear regression to assess associations of hypothalamic volumes with age, sex and cognitive performance.

FINDINGS

In older individuals, volumes of total, anterior and posterior hypothalamus, and mammillary bodies were smaller, while those of medial hypothalamus and tuberal region were larger. Larger medial hypothalamus volume was related to higher cortisol levels in older individuals, providing functional validation. Volumes of all hypothalamic structures were larger in men compared to women. In both sexes, larger volumes of total, anterior and posterior hypothalamus, and mammillary bodies were associated with better domain-specific cognitive performance, whereas larger volumes of medial hypothalamus and tuberal region were associated with worse domain-specific cognitive performance.

INTERPRETATION

We found strong age and sex effects on hypothalamic structures, as well as robust associations between these structures and domain-specific cognitive functions. Overall, these findings thus implicate specific hypothalamic subregions as potential therapeutic targets against age-associated cognitive decline.

FUNDING

Institutional funds, Federal Ministry of Education and Research of Germany, Alzheimer's Association.

Excessive sleep is associated with worse cognition, cognitive decline, and dementia in mild cognitive impairment

INTRODUCTION

This study examines the link between daytime and nighttime excessive sleep and cognition, cognitive decline, and dementia in individuals with existing mild cognitive impairment (MCI).

METHODS

Using data from the Swedish longitudinal study Good Aging in Skåne, participants aged 60-102 years were retrospectively classified as MCI based on cognitive testing. The average follow-up time was 6.59 years. Mixed linear models assessed cross-sectional and longitudinal associations between excessive sleep patterns (napping ≥2 h or nighttime sleep ≥9 h) and multiple cognitive domains. Cox regressions estimated dementia risk for excessive sleep.

RESULTS

Of 4930 participants, 2052 (41%) had MCI. Excessive daytime napping and nighttime sleep were associated with worse cognition and cognitive decline. Excessive napping and nighttime sleep were also linked to higher dementia risk (hazard ratios: 1.75 and 1.86, respectively).

DISCUSSION

These findings suggest that excessive sleep in MCI is associated with further cognitive decline and dementia.

Highlights

Excessive daytime napping and nighttime sleep are linked cognitive decline for those with MCI.Excessive sleep during the day or at night heighten dementia risk.Worse test scores across multiple cognitive domains were observed for excessive daytime nappers.Excessive sleep in MCI may be a warning sign for further cognitive decline.

Alzheimer's disease: a comprehensive review of epidemiology, risk factors, symptoms diagnosis, management, caregiving, advanced treatments and associated challenges

Background

Alzheimer's disease (AD) is a chronic, progressive neurodegenerative disorder characterized by cognitive decline, memory loss, and impaired reasoning. It is the leading cause of dementia in older adults, marked by the pathological accumulation of amyloid-beta plaques and neurofibrillary tangles. These pathological changes lead to widespread neuronal damage, significantly impacting daily functioning and quality of life.

Objective

This comprehensive review aims to explore various aspects of Alzheimer's disease, including its epidemiology, risk factors, clinical presentation, diagnostic advancements, management strategies, caregiving challenges, and emerging therapeutic interventions.

Methods

A systematic literature review was conducted across multiple electronic databases, including PubMed, MEDLINE, Cochrane Library, and Scopus, from their inception to May 2024. The search strategy incorporated a combination of keywords and Medical Subject Headings (MeSH) terms such as "Alzheimer's disease," "epidemiology," "risk factors," "symptoms," "diagnosis," "management," "caregiving," "treatment," and "novel therapies." Boolean operators (AND, OR) were used to refine the search, ensuring a comprehensive analysis of the existing literature on Alzheimer's disease.

Results

AD is significantly influenced by genetic predispositions, such as the apolipoprotein E (APOE) ε4 allele, along with modifiable environmental factors like diet, physical activity, and cognitive engagement. Diagnostic approaches have evolved with advances in neuroimaging techniques (MRI, PET), and biomarker analysis, allowing for earlier detection and intervention. The National Institute on Aging and the Alzheimer's Association have updated diagnostic criteria to include biomarker data, enhancing early diagnosis.

Conclusion

The management of AD includes pharmacological treatments, such as cholinesterase inhibitors and NMDA receptor antagonists, which provide symptomatic relief but do not slow disease progression. Emerging therapies, including amyloid-beta and tau-targeting treatments, gene therapy, and immunotherapy, offer potential for disease modification. The critical role of caregivers is underscored, as they face considerable emotional, physical, and financial burdens. Support programs, communication strategies, and educational interventions are essential for improving caregiving outcomes. While significant advancements have been made in understanding and managing AD, ongoing research is necessary to identify new therapeutic targets and enhance diagnostic and treatment strategies. A holistic approach, integrating clinical, genetic, and environmental factors, is essential for addressing the multifaceted challenges of Alzheimer's disease and improving outcomes for both patients and caregivers.

The Effects of Experimental Sleep Extension in Middle-to-Older-Aged Healthy Sleepers

Objectives  To determine the feasibility for middle-aged and older adults to extend their time in bed by 2 h per night for 3 consecutive weeks. Other aims were to examine the effects of sleep extension on mood, cognitive performance, and cardiovascular health. Methods  Ten healthy middle-aged to older adults (9 women; M  = 65.20 ± 4.78 years) who reported regularly sleeping 6 to 8 h per night participated in a randomized controlled cross-over study: 3 weeks of both habitual sleep and extended sleep (1-week recovery between treatments). Participants were asked to spend 2 additional hours in bed per night during sleep extension. Cognitive (e.g., errors, response time), psychological (e.g., depression, anxiety, mood), and physiological measures (e.g., inflammation, glucose, triglycerides, blood pressure) were assessed. Results  Compared with habitual sleep, time in bed increased 81.63 ± 33.11 min and total sleep time increased 66.33 ± 28.64 min during sleep extension; these variables did not significantly change during baseline or the habitual sleep treatment. No significant treatment differences were found in the cognitive, psychological, or physiological measures. Discussion  Neither significant positive nor negative effects of sleep extension were found for any of the variables. In terms of feasibility, it was difficult for the participants to extend their time in bed and, subsequently, attain more sleep by the targeted amount. Sleep extension by a greater degree or longer period of times might be more likely to elicit positive or negative effects.

Associations between sleep duration, depression status, and cognitive function among Chinese elderly: A community-based study

BACKGROUND

The associations of sleep duration and depressive status on cognitive function among the elderly remain controversial. This study aimed to investigate the associative effects and mediating mechanisms between sleep duration and depressive status on cognitive function in elderly adults.

METHODS

Participants were recruited from cross-sectional and cohort surveys of the Chinese Longitudinal Healthy Longevity Survey (CLHLS). We identified thresholds for sleep duration and depression and used logistic regression to explore their independent and joint effects on cognitive impairment. Further, we analyze the mediating effects of depressive status on the association between sleep duration and cognitive function.

RESULTS

Of 13840 elderly (median age: 84 years, female: 54.6 %), 2835 (20.5 %) had cognitive impairment. Compared with those who slept 6-8 h, the ORs (95%CIs) for those who slept < 6 h and > 8 h were 0.98 (0.85, 1.12) and 1.48 (1.32, 1.66). Compared with non-depressed, the OR (95%CI) for the depressed participants was 1.74 (1.53, 1.98). Compared with those with sleep 6-8 h and none-depression, those with sleep > 8 h and depression had the highest odds of cognitive impairment (OR = 2.40, 95%CI: 1.88-3.07). Additionally, Compared with those who slept 6-8 h, the associations between depression-mediated short and long sleep and cognitive impairment were 51.1 % and 6.5 %, respectively.

LIMITATIONS

Cross-sectional studies require caution in the interpretation of causal associations.

CONCLUSIONS

Long sleep and depression were independently and jointly associated with higher odds of cognitive impairment among the Chinese elderly, and short sleep increased the risk of cognitive impairment by promoting the prevalence of depression.

The effects of sleep duration on the risk of dementia incidence in short and long follow-up studies: A systematic review and meta-analysis

Sleep duration's association with future dementia could be a cause or consequence, or both. We searched electronic databases on 14th April 2023 for primary peer-reviewed, longitudinal studies examining the relationship between sleep duration and dementia with any follow-up duration. We meta-analysed studies examining brief (≤6 h/night) and extended sleep duration (≥9 h/night) separately and divided the studies into those with follow-up periods of less or more than 10 years. The quality of evidence was assessed using the Newcastle-Ottawa scale. 31 studies fulfilled the inclusion criteria. For brief sleep duration, a meta-analysis of short follow-up studies (≤10 years) found a 46 % increased risk of future dementia (relative risk [RR] - 1·46; 95 % Confidence Intervals [CIs] 1·48-1·77; I2 = 88·92 %, 6 studies). Studies with long follow-ups (>10 years) did not show a significantly increased risk (RR - 1·12; 0·95-1·29; I2 = 65·91 %; 5 studies). For extended sleep duration, a meta-analysis of short and long follow-up studies reported an increased risk of dementia (respectively RR - 2·20; 1·11-3·3; I2 = 94·17 %; 4 studies and RR - 1·74; 1·30-2·18; I2 = 86·56 %; 4 studies). Our findings suggest that brief sleep duration might be a prodromal symptom but not a risk factor of dementia. Extended sleep duration may be a risk factor. However, our results had high heterogeneity limiting external validity and generalisability.

Sleep disturbance impaired memory consolidation via lateralized disruption of metabolite in the thalamus and hippocampus: A cross-sectional proton magnetic resonance spectroscopy study

BACKGROUND

Memory consolidation in sleep-dependent individuals involves the circuitry connections of cortex, thalamus and hippocampus, regulating via neural metabolites. However, the disruption of metabolic pattern in thalamus and hippocampus remains unclear.

OBJECTIVE

We aim to explore the disruptive effects of insomnia on the metabolites during memory consolidation, particularly the underlying neurometabolic mechanisms in comorbidity of failed memory consolidation.

METHODS

This study integrates clinical research with animal experiment. In clinical research, 49 participants were divided into four groups: healthy controls (HC, n = 11), insomnia with normal cognition (IS, n = 14), mild cognitive impairment without insomnia (MCI, n = 10), and insomnia with mild cognitive impairment (IS-MCI, n = 14). Magnetic resonance spectroscopy (MRS) was used to evaluate the neural γ-aminobutyric acid (GABA) and glutamate-glutamine (Glx) in bilateral thalamus. In experimental studies, the rat model of sleep deprivation combined with amyloid-β (Aβ) injection was established, after behavior testing, the levels of Glx, choline (Cho) and N-acetyl aspartate (NAA) in the bilateral hippocampus were evaluated with MRS.

RESULTS

The patients in the IS-MCI group exhibited significantly lower GABA level than IS, MCI and HC groups. Results from rat studies showed that sleep deprivation exacerbated asymmetric alterations in Aβ-induced bilateral hippocampal metabolite abnormalities, which correlated with cognition. These neuro-metabolite disruption accompanied with synaptic loss and activation of astrocytes.

CONCLUSIONS

The lateralized decrease in GABA levels of thalamus and NAA, Cho, and Glx levels of hippocampus under conditions of sleep disturbance with cognitive decline may provide evidence for the neural metabolic mechanisms underlying the disruption of memory consolidation.

Associations among healthy lifestyle characteristics, neuroinflammation, and cerebrospinal fluid core biomarkers of Alzheimer's disease in cognitively intact adults: The CABLE study

BACKGROUND

The occurrence of Alzheimer's disease (AD) can be partially prevented through healthy lifestyles, but the mechanisms associated with AD pathology are unclear.

OBJECTIVE

To explore associations among healthy lifestyle characteristics (HLCs), cerebrospinal fluid (CSF) soluble TREM2 (sTREM2), and AD biomarkers.

METHODS

From the Chinese Alzheimer's Biomarker and LifestylE (CABLE) study, 924 cognitively normal participants were enrolled in this cross-sectional analysis. We defined the following 11 HLCs: appropriate frequencies of coffee and tea consumption, sufficient frequencies of fish and fruit intake, non-social isolation, adequate sleep, regular physical activity, no depression, never smoking, non-hazardous drinking, and well-maintained blood pressure. We categorized participants according to the number of HLCs reported by participants into favorable, intermediate, and unfavorable lifestyle groups. Multiple linear regression was used to investigate the relationship among HLCs, CSF sTREM2, and AD biomarkers. Mediation effects were tested using a causal mediation analysis having 10,000 bootstrap iterations.

RESULTS

Included subjects were with a mean age of 61.8 ± 10.2 years, of which 41.8% were female. Sufficient fish intake (β = -0.164, p = 0.017) and well-maintained blood pressure (β = -0.232, p = 0.006) were significantly correlated with lower CSF sTREM2 levels. A larger number of HLCs were associated with lower CSF T-tau (p = 0.001), P-tau (p = 0.012), and sTREM2 (p = 0.040) levels. CSF sTREM2 partially mediated the association between the number of HLCs and CSF tau pathology (mediating proportion T-tau: 22.4%; P-tau: 25.0%).

CONCLUSIONS

HLCs might impact the pathological processes of AD by regulating neuroinflammation.

Exploring the relationship of sleep duration on cognitive function among the elderly: a combined NHANES 2011-2014 and mendelian randomization analysis

BACKGROUND

As one of the key features of sleep, sleep duration (SD) has been confirmed to be associated with multiple health outcomes. However, the link between SD and cognitive function (CF) is still not well understood.

METHODS

We employed a combined approach utilizing data from the National Health and Nutrition Examination Survey (NHANES 2011-2014) and Mendelian Randomization (MR) methods to investigate the relationship between SD and CF. In the NHANES cross-sectional analysis, the association between these variables was primarily examined through multivariate linear regression to explore direct correlations and utilized smoothing curve fitting to assess potential nonlinear relationships. To ensure the robustness of our findings, subgroup analyses were also conducted. MR analysis was used to assess the causal relationship between SD and sleeplessness on CF. After excluding confounding factors, univariate and multivariate MR were performed using inverse variance weighting (IVW) as the main analysis method, and sensitivity analysis was performed.

RESULTS

The results of our cross-sectional study indicate a notable negative association between SD and CF, forming an inverted U-shaped curve with the inflection point occurring at SD = 6 h. This relationship remains consistent and robust across subgroup analyses differentiated by variables such as age, levels of physical activity, and frequency of alcohol intake. In MR analysis, IVW analysis showed no causal relationship between SD and sleeplessness on CF (Both P > 0.05).

CONCLUSION

Cross-sectional studies suggest the existence of an inverted U-shaped correlation between SD and CF among the elderly. However, MR analysis did not reveal a causal relationship between SD and CF, which the lack of nonlinear MR analysis may limit. These findings provide evidence from a sleep perspective for optimizing cognitive strategies in older adults.

Short Sleep Duration and Hypertension: A Double Hit for the Brain

BACKGROUND

Short sleep duration has been associated with an increased risk of cognitive impairment and dementia. Short sleep is associated with elevated blood pressure, yet the combined insult of short sleep and hypertension on brain health remains unclear. We assessed whether the association of sleep duration with cognition and vascular brain injury was moderated by hypertensive status.

METHODS AND RESULTS

A total of 682 dementia-free participants (mean age, 62±9 years; 53% women) from the Framingham Heart Study completed assessments of cognition, office blood pressure, and self-reported habitual and polysomnography-derived sleep duration; 637 underwent brain magnetic resonance imaging. Linear regressions were performed to assess effect modification by hypertensive status on total sleep time (coded in hours) and cognitive and magnetic resonance imaging outcomes. There was a significant interaction between sleep duration and hypertensive status when predicting executive function/processing speed (Trail Making B-A) and white matter hyperintensities. When results were stratified by hypertensive status, longer sleep duration was associated with better executive functioning/processing speed scores in the hypertensive group (meaning that shorter sleep duration was associated with poorer executive function/processing speed scores) (self-report sleep: β=0.041 [95% CI, 0.012-0.069], P=0.005; polysomnography sleep: β=0.045 [95% CI, 0.002-0.087], P=0.038), but no association was observed for the normotensive group. Similarly, shorter subjective sleep duration was associated with higher white matter hyperintensity burden in the hypertensive group (β=-0.115 [95% CI, -0.227 to -0.004], P=0.042), but not in the normotensive group.

CONCLUSIONS

In individuals with hypertension, shorter sleep duration was associated with worse cognitive performance and greater brain injury.

The association between sleep duration trajectories and successful aging: a population-based cohort study

BACKGROUND

Insufficient or excessive sleep duration are associated with increased risk of individual adverse outcomes. However, it remains largely unknown whether sleep duration trajectories are associated with overall health among older adults. This study aimed to examine the association between sleep duration trajectories and successful aging.

METHODS

In the China Health and Retirement Longitudinal Study (CHARLS), 3,306 participants without major chronic diseases at baseline and survived to aged 60 years and older at the end of follow-up were potentially eligible participants. Total sleep duration was assessed in 2011, 2013, and 2015, and successful aging was evaluated in 2020 and was defined as being free of major chronic diseases, no physical impairment, high cognitive function, good mental health, and active engagement with life. Latent class mixed model (LCMM) was used to identify sleep duration trajectories and logistic regression was performed to explore the association between these trajectories and successful aging.

RESULTS

During the 9-year follow-up, 455 individuals (13.8%) met the criteria for successful aging. Five sleep duration trajectories were identified: normal stable, long stable, decreasing, increasing, and short stable. Compared with the normal stable trajectory, the adjusted ORs (95% CI) for achieving successful aging for participants with long stable, decreasing, increasing, and short stable trajectories were 1.00 (0.77, 1.30), 0.64 (0.40, 1.03), 0.64 (0.45, 0.92), and 0.48 (0.35, 0.66), respectively. The stratified and sensitivity analyses were generally consistent with the main results.

CONCLUSIONS

Increasing and short stable trajectories of sleep duration are associated with lower odds of successful aging relative to participants in the normal stable trajectory. The findings underscore the critical importance of monitoring dynamic changes in sleep duration in middle-aged and older Chinese adults.

Total dietary antioxidant capacity and food groups and their relationship with the sleep time of Brazilian graduates (CUME Study)

To investigate the association between the Dietary Total Antioxidant Capacity (dTAC) and the Total Antioxidant Capacity of food groups (fgTAC) with the sleep time of Brazilian graduates participating in the Cohort of Universities of Minas Gerais (CUME Study). This cross-sectional study analyzed 6,387 graduates (2,052 men, 4,335 women, 35.3 ± 9.3 years old) from the CUME Study. Data was collected online, and dTAC was obtained by the Ferric Reduction Antioxidant Power (FRAP) method. Daily sleep time was classified as short sleep, normal sleep, and long sleep (≤6, 7-8, and ≥9 h, respectively). Multinomial logistic regression models were used to estimate the Odds Ratio (OR) and its 95% Confidence Interval (95% CI) between short sleep and long sleep with quartiles of dTAC and the fgTAC. Lower odds of short sleep was observed for the third quartile of dTAC and for fourth quartile of fgTAC of fruits, beans, and lentils, and for the third quartile of fgTAC of vegetables and oils and fats. Higher odds of short sleep for the fourth quartile of fgTAC of teas and coffees. For long sleep, inverse associations were observed for the fourth quartile of fgTAC of oilseeds and the third quartile of fgTAC of teas and coffees. Higher odds of long sleep were observed for the third quartile of artificial juices and sodas. We cannot independently assert an association between higher dTAC and sleep time. In turn, the associations between sleep time and fgTAC show the importance of the food matrix that antioxidants are inserted, requiring longitudinal studies to observe the direction of associations.

Louis EK, McCarter SJ, Bukartyk J, Przybelski SA, Kamykowski MG, Spychalla AJ, Machulda MM, Boeve BF, Petersen RC, Jack CR, Lowe VJ, Graff-Radford J, Worrell GA, Somers VK, Varga AW, Vemuri P. Non-rapid eye movement sleep slow-wave activity features are associated with amyloid accumulation in older adults with obstructive sleep apnoea

Obstructive sleep apnoea (OSA) is associated with an increased risk for cognitive impairment and dementia, which likely involves Alzheimer's disease pathology. Non-rapid eye movement slow-wave activity (SWA) has been implicated in amyloid clearance, but it has not been studied in the context of longitudinal amyloid accumulation in OSA. This longitudinal retrospective study aims to investigate the relationship between polysomnographic and electrophysiological SWA features and amyloid accumulation. From the Mayo Clinic Study of Aging cohort, we identified 71 participants ≥60 years old with OSA (mean baseline age = 72.9 ± 7.5 years, 60.6% male, 93% cognitively unimpaired) who had at least 2 consecutive Amyloid Pittsburgh Compound B (PiB)-PET scans and a polysomnographic study within 5 years of the baseline scan and before the second scan. Annualized PiB-PET accumulation [global ΔPiB(log)/year] was estimated by the difference between the second and first log-transformed global PiB-PET uptake estimations divided by the interval between scans (years). Sixty-four participants were included in SWA analysis. SWA was characterized by the mean relative spectral power density (%) in slow oscillation (SO: 0.5-0.9 Hz) and delta (1-3.9 Hz) frequency bands and by their downslopes (SO-slope and delta-slope, respectively) during the diagnostic portion of polysomnography. We fit linear regression models to test for associations among global ΔPiB(log)/year, SWA features (mean SO% and delta% or mean SO-slope and delta-slope), and OSA severity markers, after adjusting for age at baseline PiB-PET, APOE ɛ4 and baseline amyloid positivity. For 1 SD increase in SO% and SO-slope, global ΔPiB(log)/year increased by 0.0033 (95% CI: 0.0001; 0.0064, P = 0.042) and 0.0069 (95% CI: 0.0009; 0.0129, P = 0.026), which were comparable to 32% and 59% of the effect size associated with baseline amyloid positivity, respectively. Delta-slope was associated with a reduction in global ΔPiB(log)/year by -0.0082 (95% CI: -0.0143; -0.0021, P = 0.009). Sleep apnoea severity was not associated with amyloid accumulation. Regional associations were stronger in the pre-frontal region. Both slow-wave slopes had more significant and widespread regional associations. Annualized PiB-PET accumulation was positively associated with SO and SO-slope, which may reflect altered sleep homeostasis due to increased homeostatic pressure in the setting of unmet sleep needs, increased synaptic strength, and/or hyper-excitability in OSA. Delta-slope was inversely associated with PiB-PET accumulation, suggesting it may represent residual physiological activity. Further investigation of SWA dynamics in the presence of sleep disorders before and after treatment is necessary for understanding the relationship between amyloid accumulation and SWA physiology.

Alzheimer's disease and sleep disorders: A bidirectional relationship

Alzheimer's disease (AD) is the most prevalent dementia, pathologically featuring abnormal accumulation of amyloid-β (Aβ) and hyperphosphorylated tau, while sleep, divided into rapid eye movement sleep (REM) and nonrapid eye movement sleep (NREM), plays a key role in consolidating social and spatial memory. Emerging evidence has revealed that sleep disorders such as circadian disturbances and disruption of neuronal rhythm activity are considered as both candidate risks and consequence of AD, suggesting a bidirectional relationship between sleep and AD. This review will firstly grasp basic knowledge of AD pathogenesis, then highlight macrostructural and microstructural alteration of sleep along with AD progression, explain the interaction between accumulation of Aβ and hyperphosphorylated tau, which are two critical neuropathological processes of AD, as well as neuroinflammation and sleep, and finally introduce several methods of sleep enhancement as strategies to reduce AD-associated neuropathology. Although theories about the bidirectional relationship and relevant therapeutic methods in mice have been well developed in recent years, the knowledge in human is still limited. More studies on how to effectively ameliorate AD pathology in patients by sleep enhancement and what specific roles of sleep play in AD are needed.

Sleep Duration, Insomnia, and Associated Factors Among Ukrainians 1 Year After Russia's Full-Scale Invasion

OBJECTIVE

We aimed to investigate the prevalence of sleep disturbances and associated factors among Ukrainians 1 year after Russia's full-scale invasion.

METHODS

Quota sampling was used to collect online survey data from 2364 adults living in Ukraine aged 18 to 79 years from April 5, 2023, to May 15, 2023. Short sleep duration was defined as sleep duration ≤6 hours and long sleep duration as ≥9 hours. Insomnia was assessed by the Insomnia Symptom Questionnaire.

RESULTS

The prevalences of short sleep duration, long sleep duration, and insomnia were 39.4%, 6.9%, and 38.5%, respectively. Short sleep duration and insomnia were both more likely in females (short sleep duration: adjusted odds ratio [aOR] = 1.44; insomnia: aOR = 2.17), individuals with depression (short sleep duration: aOR = 1.61; insomnia: aOR = 7.76), affected by the 2014 Russian invasion (short sleep duration: aOR = 1.37; insomnia: aOR = 1.78), and with more trauma events (short sleep duration: quartile 3 [Q3] versus Q1: aOR = 1.88; Q4 versus Q1: aOR = 1.83; insomnia: Q3 versus Q1: aOR = 2.14; Q4 versus Q1: aOR = 2.32). Insomnia was more likely in Ukrainians with posttraumatic stress disorder (aOR = 2.95), anxiety (aOR = 4.57), and loneliness (aOR = 1.67). Essential public service was associated with short sleep duration (aOR = 1.64). Short sleep duration and insomnia were associated with lower quality of life in physical, psychological, and environmental domains. Insomnia was associated with the social relationships domain.

CONCLUSIONS

Sleep health among Ukrainian adults 1 year into the war is concerning, with more than one-third reporting inadequate sleep or insomnia. More studies are needed on impacts and interventions for sleep health during and after the war.

A Compensatory Role of Physical Activity in the Association Between Sleep and Cognition

We synthesize evidence investigating the hypothesis that greater engagement in physical activity (PA) may compensate for some of the negative cognitive consequences associated with poor sleep in older adults. Potential mechanistic pathways include glymphatic clearance, influences on depression, and other comorbidities. The evidence base is largely cross-sectional and observational, and further experimental studies are required.

Validating the CogSleep Screener in older adults at a memory and cognition clinic

While sleep disturbances are prevalent in older people and are linked with poor health and cognitive outcomes, screening for the range of sleep disturbances is inefficient and therefore not ideal nor routine in memory and cognition clinic settings. We aimed to develop and validate a new brief self-report questionnaire for easy use within memory and cognition clinics. The design for this study was cross-sectional. Older adults (aged ≥50 in Sydney, Australia) were recruited from a memory and cognition research clinic. Participants (N = 402, mean age 67.3 years, range 50-86, 63.6% female) completed a comprehensive medical, neuropsychological, and mental health assessment, alongside self-report instruments, including existing sleep questionnaires and a new 10-item sleep questionnaire, the CogSleep Screener. We examined the factor structure, convergent validity, internal consistency, and discriminant validity of this novel questionnaire. Using exploratory principal component analysis, a 3-factor solution was generated highlighting the factors of Insomnia, Rapid Eye Movement (REM) Symptoms and Daytime Sleepiness. Each factor was significantly correlated with currently used sleep questionnaires for each subdomain (all Spearman rho >0.3, all p < 0.001), suggesting good convergent validity. Internal consistency was also good (Cronbach's α = 0.73). Receiver operating characteristic curves showed good discriminative ability between participants with and without sleep disturbances (all area under curve >0.7, all p < 0.01). The CogSleep Screener has good psychometric properties in older to elderly adults attending a memory and cognition clinic. The instrument has the potential to be used in memory clinics and other clinical settings to provide quick and accurate screening of sleep disturbances.

Associations of Advanced Glycation End Products with Sleep Disorders in Chinese Adults

BACKGROUND

Advanced glycation end products (AGEs), a group of food processing byproducts, have been implicated in the development of various diseases. However, the relationship between circulating AGEs and sleep disorders remains uncertain.

METHODS

This cross-sectional study elucidated the association of plasma AGEs with sleep disorders among 1732 Chinese adults who participated in the initial visit (2019-2020) of the Tongji-Shenzhen Cohort (TJSZC). Sleep behavior was assessed using self-reported questionnaires and precise accelerometers. Plasma levels of AGEs, including Nε-(Carboxymethyl)lysine (CML), Nε-(Carboxyethyl)lysine (CEL), and Nδ-(5-hydro-5-methyl-4-imidazolone-2-yl)-ornithine (MG-H1), were quantified by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

RESULTS

In logistic regression, per IQR increment in individual AGEs was associated with an increased odds ratio of short sleep duration (CML: 1.11 [1.00, 1.23]; CEL: 1.16, [1.04, 1.30]), poor sleep quality (CML: 1.33 [1.10, 1.60]; CEL: 1.53, [1.17, 2.00]; MG-H1: 1.61 [1.25, 2.07]), excessive daytime sleepiness (CML: 1.33 [1.11, 1.60]; MG-H1: 1.39 [1.09, 1.77]), and insomnia (CML: 1.29 [1.05, 1.59]). Furthermore, in weighted quantile sum regression and Bayesian kernel machine regression analyses, elevated overall exposure levels of plasma AGEs were associated with an increased risk of sleep disorders, including short sleep duration, poor sleep quality, excessive daytime sleepiness, and insomnia, with CML being identified as the leading contributor. Insufficient vegetable intake and higher dietary fat intake was associated with an increase in plasma CEL.

CONCLUSIONS

These findings support a significant association between plasma AGEs and sleep disorders, indicating that AGEs may adversely influence sleep health and reducing the intake of AGEs may facilitate preventing and ameliorating sleep disorders.

Sex differences in the role of sleep on cognition in older adults

Study Objectives

The study aimed to investigate sex differences in the relationship between sleep quality (self-report and objective) and cognitive function across three domains (executive function, verbal memory, and attention) in older adults.

Methods

We analyzed cross-sectional data from 207 participants with normal cognition (NC) or mild cognitive impairment (89 males and 118 females) aged over 60 years. The relationship between sleep quality and cognitive performance was estimated using generalized additive models. Objective sleep was measured with the GT9X Link ActiGraph, and self-reported sleep was measured with the Pittsburgh Sleep Quality Index.

Results

We found that females exhibited lower executive function with increased objective total sleep time, with a steeper decline in performance after 400 minutes (p = .015). Additionally, longer objective sleep correlated with lower verbal memory linearly (p = .046). In males, a positive linear relationship emerged between objective sleep efficiency and executive function (p = .036). Self-reported sleep was not associated with cognitive performance in females and males with NC. However, in males with cognitive impairment, there was a nonlinear positive relationship between self-reported sleep and executive function (p < .001).

Conclusions

Our findings suggest that the association between sleep parameters on cognition varies between older males and females, with executive function being most strongly associated with objective sleep for both sexes top of form. Interventions targeting sleep quality to mitigate cognitive decline in older adults may need to be tailored according to sex, with distinct approaches for males and females.

Risk factors associated with the Motoric Cognitive Risk syndrome: A meta-analysis of data from a cross-national study

BACKGROUND

Identifying risk factors associated with the Motoric Cognitive Risk (MCR) syndrome (a pre-dementia syndrome) can assist in developing risk reduction strategies and interventions to delay progression to dementia. Tailored interventions require comparisons of high- and middle-income countries to determine if the same or different risk factors should be targeted. We examined risk factors associated with MCR in seven Health and Retirement Studies with harmonized measures.

METHODS

Data from adults aged ≥65 years (n = 20,036, mean age 71.2(SD 6.2)-80.1(SD 4.1)) from the U.S. Health and Retirement Study, English Longitudinal Study of Aging, Survey of Health, Aging and Retirement in Europe, China Health and Retirement Longitudinal Study, Harmonized Diagnostic Assessment of Dementia for Longitudinal Aging Study in India, Mexican Health and Aging Study, and Brazilian Longitudinal Study of Aging was included. MCR was defined as the presence of cognitive complaints and slow gait (no mobility disability and dementia). Associations of demographic [education], medical [hypertension, diabetes, heart disease, obesity, stroke, Parkinson's, falls], psychological [depressive symptoms, psychiatric problems], sensorimotor [grip strength, hearing], and behavioral factors [smoking, sedentariness, sleep], with prevalent MCR were examined using age- and sex-adjusted logistic regression models. A meta-analysis was performed to compare risk factors for MCR in high- versus middle-income countries.

RESULTS

Except for depressive symptoms and weak grip strength, different risk factor clusters were associated with individual studies. Poor sleep, hearing, weak grip, and multiple falls emerged as novel associations with MCR. When grouped by income, some risk factors (i.e., education) were associated with MCR in high- and middle-income countries. Others (i.e., obesity) were specific to high-income countries.

CONCLUSIONS

This cross-sectional, cross-national study identified new, shared, and specific risk factors associated with MCR in high- and middle-income countries, providing insights to develop public health approaches and interventions to forestall the onset of dementia in those with MCR.

Associations between sleep duration trajectories and cognitive decline: A longitudinal cohort study in China

OBJECT

The relationship between sleep duration trajectories and cognitive decline remains uncertain. This study aims to examine the connections between various patterns of sleep duration and cognitive function.

METHODS

Group-based trajectory modeling (GBTM) was employed to identify longitudinal trajectories of sleep duration over four-year follow-up period, while considering age, sex and nap duration as adjustments. Logistic regression was utilized to analyze the association between sleep trajectories and cognition, with odds ratios (OR) and 95 % confidence intervals (CI) reported. Subgroup analyses based on various demographic characteristics were conducted to explore potential differences in sleep trajectories and cognitive decline across different population subgroups.

RESULTS

A total of 5061 participants were followed for four years, and three sleep duration trajectories were identified: high increasing (n = 2101, 41.6 %), stable increasing (n = 2087, 40.7 %), and low decreasing (n = 873, 17.7 %). After adjustment for basic demographic information, health status, and baseline cognition, the high increasing trajectory was found to be associated with cognitive decline in terms of global cognition (OR:1.52,95 %CI:1.18-1.96), mental intactness (OR:1.36,95 %CI:1.07-1.73) and episodic memory (OR:1.33, 95 %CI:1.05-1.67), as compared to stable increasing trajectory. These associations were particularly prominent among the non-elderly population (≤65 years) and those without depressive symptoms.

CONCLUSION

This study suggests that both high increasing and low decreasing sleep duration trajectories are linked to cognitive decline, as compared to the stable increasing trajectory. Long-term attention to changes in sleep duration facilitates early prevention of cognitive decline.

Sleep, 24-Hour Activity Rhythms, and Subsequent Amyloid-β Pathology

Importance

Sleep disturbances are common among older adults and have been associated with the development of Alzheimer disease (AD), such as amyloid-β (Aβ) pathology. For effective AD prevention, it is essential to pinpoint the specific disturbances in sleep and the underlying 24-hour activity rhythms that confer the highest risk of Aβ deposition.

Objective

To determine the associations of 24-hour activity rhythms and sleep with Aβ deposition in adults without dementia, to evaluate whether disrupted 24-hour activity and sleep may precede Aβ deposition, and to assess the role of the apolipoprotein E ε4 (APOE4) genotype.

Design, Setting, and Participants

This was an observational cohort study using data from the Rotterdam Study. Of 639 participants without dementia who underwent Aβ positron emission tomography (PET) from September 2018 to November 2021, 319 were included in the current study. Exclusion criteria were no APOE genotyping and no valid actigraphy data at the baseline visits from 2004 to 2006 or from 2012 to 2014. The mean (SD) follow-up was 7.8 (2.4) years. Data were analyzed from March 2023 to April 2024.

Exposures

Actigraphy (7 days and nights, objective sleep, and 24-hour activity rhythms), sleep diaries (self-reported sleep), Aβ42/40, phosphorylated tau (p-tau)181 and p-tau217 plasma assays, 18F-florbetaben PET (mean standard uptake value ratio [SUVR] in a large cortical region of interest), and APOE4 genotype.

Main Outcomes and Measures

Association of objective and self-reported sleep and 24-hour activity rhythms at baseline with brain Aβ PET burden at follow-up.

Results

The mean (range) age in the study population was 61.5 (48-80) years at baseline and 69.2 (60-88) years at follow-up; 150 (47%) were women. Higher intradaily variability at baseline, an indicator of fragmented 24-hour activity rhythms, was associated with higher Aβ PET burden at follow-up (β, 0.15; bootstrapped 95% CI, 0.04 to 0.26; bootstrapped P = .02, false discovery rate [FDR] P = .048). APOE genotype modified this association, which was stronger in APOE4 carriers (β, 0.38; bootstrapped 95% CI, 0.05 to 0.64; bootstrapped P = .03) compared to noncarriers (β, 0.07; bootstrapped 95% CI, -0.04 to 0.18; bootstrapped P = .19). The findings remained largely similar after excluding participants with AD pathology at baseline, suggesting that a fragmented 24-hour activity rhythm may have preceded Aβ deposition. No other objective or self-reported measure of sleep was associated with Aβ.

Conclusions and Relevance

Among community-dwelling adults included in this study, higher fragmentation of the 24-hour activity rhythms was associated with greater subsequent Aβ burden, especially in APOE4 carriers. These results suggest that rest-activity fragmentation could represent a modifiable risk factor for AD.

Memory performance mediates subjective sleep quality associations with cerebrospinal fluid Alzheimer's disease biomarker levels and hippocampal volume among individuals with mild cognitive symptoms

Sleep disturbances are prevalent in Alzheimer's disease (AD), affecting individuals during its early stages. We investigated associations between subjective sleep measures and cerebrospinal fluid (CSF) biomarkers of AD in adults with mild cognitive symptoms from the European Prevention of Alzheimer's Dementia Longitudinal Cohort Study, considering the influence of memory performance. A total of 442 participants aged >50 years with a Clinical Dementia Rating (CDR) score of 0.5 completed the Pittsburgh Sleep Quality Index questionnaire and underwent neuropsychological assessment, magnetic resonance imaging acquisition, and CSF sampling. We analysed the relationship of sleep quality with CSF AD biomarkers and cognitive performance in separated multivariate linear regression models, adjusting for covariates. Poorer cross-sectional sleep quality was associated with lower CSF levels of phosphorylated tau and total tau alongside better immediate and delayed memory performance. After adjustment for delayed memory scores, associations between CSF biomarkers and sleep quality became non-significant, and further analysis revealed that memory performance mediated this relationship. In post hoc analyses, poorer subjective sleep quality was associated with lesser hippocampal atrophy, with memory performance also mediating this association. In conclusion, worse subjective sleep quality is associated with less altered AD biomarkers in adults with mild cognitive symptoms (CDR score 0.5). These results could be explained by a systematic recall bias affecting subjective sleep assessment in individuals with incipient memory impairment. Caution should therefore be exercised when interpreting subjective sleep quality measures in memory-impaired populations, emphasising the importance of complementing subjective measures with objective assessments.

Associations Between Sleep Duration and Cardiometabolic Diseases Among Residents in Southwest China

Introduction

The burden of cardiometabolic diseases (CMDs), defined as stroke, coronary artery disease, and diabetes mellitus, continues to pose a global challenge. Sleep duration has been linked to cardiovascular health. However, there is a lack of focused investigations on CMDs in underdeveloped areas of China.

Purpose

This study aimed to examine the relationship between sleep duration and CMDs among residents from southwest China.

Patients and Methods

This large cross-sectional study screened data from the National Key Research and Development Program (2018YFC1311400). Based on sleep duration reported through a standardized questionnaire, encompassing the sleep patterns of the past five years, participants were classified into three groups: <6, 6-8, >8 hours. Baseline characteristics were compared, and Poisson regression models were used to assess the relationship between sleep duration and CMDs. Subgroup analysis was conducted based on age and gender.

Results

This study included 28,908 participants with an average age of 65.6 ± 10.0 years, of whom 57.6% were female. The overall prevalence of CMDs was 22.6%. After multivariate adjustments, the prevalence ratios (PR) (95% CI) for CMDs across the three groups (6-8h, <6h and >8h) were: reference, 1.140 (1.068-1.218), 1.060 (0.961-1.169) (P for trend =0.003), respectively. The subgroup analysis revealed that among older females, a longer sleep duration (>8h) was also associated with an increased prevalence risk of CMDs, with PR 1.169 (1.001-1.365) (p=0.049).

Conclusion

A shorter sleep duration (<6 hours) was associated with an increased risk of CMDs in the general population, while a longer sleep duration (>8 hours) also raised the prevalence risk among older females.

Brain metabolites are associated with sleep architecture and cognitive functioning in older adults

Sleep deficits are a possible risk factor for development of cognitive decline and dementia in older age. Research suggests that neuroinflammation may be a link between the two. This observational, cross-sectional study evaluated relationships between sleep architecture, neuroinflammation and cognitive functioning in healthy older adults. Twenty-two adults aged ≥60 years underwent whole-brain magnetic resonance spectroscopic imaging (in vivo method of visualizing increased brain temperatures as a proxy for neuroinflammation), supervised laboratory-based polysomnography, and comprehensive neurocognitive testing. Multiple regressions were used to assess relationships between magnetic resonance spectroscopic imaging-derived brain temperature and metabolites related to inflammation (choline; myo-inositol; N-acetylaspartate), sleep efficiency, time and % N3 sleep and cognitive performance. Choline, myo-inositol and N-acetylaspartate were associated with sleep efficiency and cognitive performance. Higher choline and myo-inositol in the bilateral frontal lobes were associated with slower processing speed and lower sleep efficiency. Higher choline and myo-inositol in bilateral frontoparietal regions were associated with better cognitive performance. Higher N-acetylaspartate around the temporoparietal junction and adjacent white matter was associated with better visuospatial function. Brain temperature was not related to cognitive or sleep outcomes. Our findings are consistent with the limited literature regarding neuroinflammation and its relationships with sleep and cognition in older age, which has implicated ageing microglia and astrocytes in circadian dysregulation, impaired glymphatic clearance and increased blood-brain barrier integrity, with downstream effects of neurodegeneration and cognitive decline. Inflammatory processes remain difficult to measure in the clinical setting, but magnetic resonance spectroscopic imaging may serve as a marker of the relationship between neuroinflammation, sleep and cognitive decline in older adults.

Relationship Between Sleep Duration and Cognitive Function in Older Adults: Analysis of NHANES and UK Biobank GWAS Data

OBJECTIVES

To explore the relationship between sleep duration and cognitive functions in older adults using NHANES, a national US population study dataset, and to explore the causal association with Mendelian randomization (MR) using the UK Biobank.

METHODS

First, an observational study was conducted with the NHANES database with participants ≥60 years. Sleep duration was measured with accelerometers for 7 consecutive days. Participants were divided into habitual short sleep (<7 h) and long sleep (>9 h) groups. Cognitive functions were measured with the CERAD Word Learning sub-set, Animal Fluency, and Digit Symbol Substitution test (DSST). Multivariate regression models were used to explore relationships between sleep duration and cognitive functions. Second, bidirectional MR was conducted with data for self-reported sleep duration, which came from a genome-wide association study (GWAS) comprising 446,118 adults from the UK Biobank, and general cognitive performance, which was obtained from a recent GWAS study (N = 257,841). Inverse-variance weighted (IVW) was used as the primary estimation of the outcome.

RESULTS

In the observational study, 2687 participants were included. Sleep duration was associated with cognitive functions in a non-linear way. Habitual long sleep (>9°h) was associated with lower scores on DSST (OR = 0.01, p = .003) in the fully-adjusted model. The association between habitual short sleep and cognitive functions was insignificant. For the MR, genetically predicted lower general cognitive performance was causally associated with a higher prevalence of habitual short sleep (OR = 0.97, p = 5.1 × 10-7) and long sleep (OR = 0.97, p = 8.87 × 10-16).

DISCUSSION

Short and long sleep duration might be both causally associated with worse outcomes of cognitive functions in older adults, highlighting the importance of maintaining sleep health.

U-shaped association between sleep duration and biological aging: Evidence from the UK Biobank study

Previous research on sleep and aging largely has failed to illustrate the optimal dose-response curve of this relationship. We aimed to analyze the associations between sleep duration and measures of predicted age. In total, 241,713 participants from the UK Biobank were included. Habitual sleep duration was collected from the baseline questionnaire. Four indicators, homeostatic dysregulation (HD), phenoAge (PA), Klemera-Doubal method (KDM), and allostatic load (AL), were chosen to assess predicted age. Multivariate linear regression models were utilized. The association of sleep duration and predicted age followed a U-shape (All p for nonlinear <0.05). Compared with individuals who sleep for 7 h/day, the multivariable-adjusted beta of ≤5 and ≥9 h/day were 0.05 (95% CI 0.03, 0.07) and 0.03 (95% CI 0.02, 0.05) for HD, 0.08 (95% CI 0.01, 0.14) and 0.36 (95% CI 0.31, 0.41) for PA, and 0.21 (95% CI 0.12, 0.30) and 0.30 (95% CI 0.23, 0.37) for KDM. Significant independent and joint effects of sleep and cystatin C (CysC) and gamma glutamyltransferase (GGT) on predicted age metrics were future found. Similar results were observed when conducting stratification analyses. Short and long sleep duration were associated with accelerated predicted age metrics mediated by CysC and GGT.

Subjective sleep more predictive of global cognitive function than objective sleep in older adults: A specification curve analysis

OBJECTIVES

Sleep is associated with cognitive function in older adults. In the current study, we examined this relationship from subjective and objective perspectives, and determined the robustness and dimensional specificity of the associations using a comprehensive modelling approach.

METHODS

Multiple dimensions of subjective (sleep quality and daytime sleepiness) and objective sleep (sleep stages, sleep parameters, sleep spindles, and slow oscillations), as well as subjectively reported and objectively measured cognitive function were collected from 55 older adults. Specification curve analysis was used to examine the robustness of correlations for the effects of sleep on cognitive function.

RESULTS

Robust associations were found between sleep and objectively measured cognitive function, but not with subjective cognitive complaints. In addition, subjective sleep showed robust and consistent associations with global cognitive function, whereas objective sleep showed a more domain-specific association with episodic memory. Specifically, subjective sleep quality and daytime sleepiness correlated with global cognitive function, and objective sleep parameters correlated with episodic memory.

CONCLUSIONS

Overall, associations between sleep and cognitive function in older adults depend on how they are measured and which specific dimensions of sleep and domains of cognitive function are considered. It highlights the importance of focusing on specific associations to ameliorate the detrimental effects of sleep disturbance on cognitive function in later life.

Association of past and current sleep duration with structural brain differences: A large population-based study from the UK Biobank

OBJECTIVE

This study aimed to examine the association between past/current sleep duration and macro-/micro-structural brain outcomes and explore whether hypertension or social activity plays a role in such association.

METHODS

Within the UK Biobank, 40 436 dementia-free participants (age 40-70 years) underwent a baseline assessment followed by a brain magnetic resonance imaging (MRI) scan 9 years later. Past (baseline) and current (MRI scans) sleep duration (hours/day) were recorded and classified as short (≤5), intermediate (6-8), and long (≥9). Brain structural volumes and diffusion markers were assessed by MRI scans.

RESULTS

Compared with past intermediate sleep, past short sleep was related to smaller cortex volumes (standardized β [95 % CI]: -0.04 [-0.07, -0.02]) and lower regional fractional anisotropy (FA) (-0.08 [-0.13, -0.03]), while past long sleep was related to smaller regional subcortical volumes (standardized β: -0.04 to -0.07 for thalamus, accumbens, and hippocampus). Compared to current intermediate sleep, current short sleep was associated with smaller cortex volumes (-0.03 [-0.05, -0.01]), greater white matter hyperintensities (WMH) volumes (0.04 [0.01, 0.08]), and lower regional FA (-0.07 [-0.11, -0.02]). However, current long sleep was related to smaller total brain (-0.03 [-0.05, -0.02]), grey matter (-0.05 [-0.07, -0.03]), cortex (-0.05 [-0.07, -0.03]), regional subcortical volumes [standardized β: -0.05 to -0.09 for putamen, thalamus, hippocampus, and accumbens]), greater WMH volumes (0.06 [0.03, 0.09]), as well as lower regional FA (-0.05 [-0.09, -0.02]). The association between current long sleep duration and poor brain health was stronger among people with hypertension or low frequency of social activity (all Pinteraction <0.05).

CONCLUSIONS

Both past and current short/long sleep are associated with smaller brain volume and poorer white matter health in the brain, especially in individuals with hypertension and low frequency of social activity. Our findings highlight the need to maintain 6-8 h' sleep duration for healthy brain aging.

Association between Subjective Cognitive Complaints and Sleep Disturbance among Community-Dwelling Elderly Individuals in Japan

Subjective cognitive complaints (SCCs) are a crucial modifiable risk factor for dementia. There is increasing interest in the association between SCC and sleep disturbance; however, the effects of sleep disturbance on SCC development among community-dwelling elderly individuals in Japan remain unclear. We aimed to cross-sectionally investigate the association between SCC and sleep disturbance, with adjustment for multiple factors related to cognitive decline, among 241 community-dwelling elderly persons without cognitive impairment. The measures were SCCs (Kihon Checklist-Cognitive Function, KCL-CF), sleep disturbance (Japanese version of the Athens Insomnia Scale, AIS-J), general cognitive function (Mini-Mental State Examination), and depressive symptoms (five-item version of the Geriatric Depression Scale [GDS-5]). The following data were collected: sex, age, educational history, whether the participants had visited a medical institution for diseases (hypertension, diabetes, hyperlipidemia, heart disease), and the presence/absence of established risk factors (hearing loss, history of head injury, drinking habits, smoking habits, social isolation, and physical inactivity and activity). Based on the KCL-CF, 96 and 145 participants were considered to have and lack SCCs, respectively. On logistic regression analysis, the AIS-J score and smoking history were significantly associated with SCCs. Our findings suggest that sleep disturbance is associated with SCC development among community-dwelling elderly people in Japan. Evaluating and managing sleep disturbances can be important in preventing SCCs and dementia.

Correlations among serum alpha-(1,6)-fucosyltransferase and early symptoms associated with Parkinson's disease: A cross-sectional retrospective study

Alpha-(1,6)-fucosyltransferase (FUT8) has been found to play a role in modulating the central immune system and inflammatory responses. Limited studies have assessed the correlations between serum FUT8 levels and various non-motor symptoms associated with early Parkinson's disease (PD). Therefore, our research aims to investigate the associations between serum FUT8 levels and symptoms such as smell dysfunction, sleep duration, sleep problems, and MMSE scores in PD patients. FUT8 and neurofilament light chain (NfL) levels were measured using enzyme-linked immunosorbent assays (ELISA). We analyzed the correlations between serum FUT8 levels, NfL, and early symptoms of PD using Spearman's correlation, multiple linear regression, and logistic regression models. The expression of FUT8 in CSF samples from PD patients was significantly upregulated, with its protein levels in CSF being positively associated with serum levels. Furthermore, there were significant positive associations between serum FUT8 levels with NfL levels, smell dysfunction, short sleep duration, and long sleep duration. However, a significant inverse relationship was observed between FUT8 levels and MMSE scores. Additionally, we explored gender and age differences in the correlations of FUT8 levels and early symptoms in patients. This study reveals that increased FUT8 levels are positively correlated with a higher risk of early PD-associated symptoms. These findings suggest that serum FUT8 could serve as a promising biomarker for the early detection of PD.

The associations of daytime napping and motoric cognitive risk syndrome: Findings from the China Health and Retirement Longitudinal Study

INTRODUCTION

Motoric cognitive risk syndrome (MCR), characterized by subjective cognitive complaints and slow gait in older populations, is associated with sleep duration. However, the association between MCR and daytime nap duration has not been thoroughly explored.

METHODS

Baseline data from the China Health and Retirement Longitudinal Study (CHARLS) were used in this study. MCR was defined as the coexistence of subjective cognitive complaints and objective slow gait speed without a history of dementia or mobility disability. Daytime nap duration was categorized into four groups: no napping, short napping (<30 min), moderate napping (30-89 min) and extended napping (≥90 min). Multivariable logistic regression models were used to explore the association of daytime napping duration and MCR.

RESULTS

A total of 4230 individuals aged ≥60 were included in the current analysis, of which 463 were diagnosed with MCR. Moderate napping of 30-89 min per day was found to be significantly associated with lower odds of MCR compared with the reference group of no napping. In subgroup analysis, individuals with sleep durations of <7 h per night had lower odds of MCR in the model that adjusted for all potential confounders with ≥30 min daytime nap duration compared with no napping. Interestingly, for people with a night sleep duration of 7-8 h, only those with a moderate nap of 30-89 min had lower odds of MCR than non-nappers after adjustment for potential confounders.

CONCLUSION

A moderate nap of 30-89 min could lower the odds of MCR, especially for older adults with a night sleep duration of ≤8 h.