Differences Between Men and Women Aged 65 and Older in the Relationship Between Self-Reported Sleep and Cognitive Impairment: A Nationwide Survey in Taiwan

Sex-specific in the association between depressive symptoms and risk of cognitive impairment in Chinese older adults

BACKGROUND

Many studies have focused on the relationship between depressive symptoms and cognitive impairment, but gender differences in this relationship are unclear, especially among Chinese older adults. Therefore, this study explores whether there are gender differences between depressive symptoms and risk of cognitive impairment based on a survey of a Chinese older adult population.

STUDY DESIGN

This is a cross-sectional study.

METHOD

We screened 9678 older adults aged 65 to 105 from the 2018 CLHLS database. The 10-item Center for Epidemiological Studies Depression Scale (CESD-10) and Mini-Mental State Examination (MMSE) were utilized for measuring depressive symptoms and cognitive performance, respectively. Logistic regressions and restricted cubic spline were applied to investigate the relationship between depressive symptoms and cognitive impairment.

RESULTS

Of the 9678 participants, 4719 (48.8 %) were men. The association between severe depressive symptoms and cognitive impairment was more pronounced in older men (male × severe depressive symptoms: OR = 2.71, 95%CI = 1.07-6.92, p = 0.037). Compared with no depressive symptoms, severe depressive symptoms were associated with an almost five times greater risk of cognitive impairment in men (OR = 4.84, 95 % CI = 2.26-10.40, p < 0.001, compared to OR = 2.25, 95 % CI = 1.27-3.96, p = 0.005 in women). Gender differences were demonstrated in the association of individual ten depressive symptoms with cognitive impairment: men who felt lonely were more likely to have cognitive impairment (OR = 1.24, 95 % CI = 1.06-1.47, p = 0.010), while women who slept poorly were more likely to have cognitive impairment (OR = 1.42, 95 % CI = 1.16-1.74, p = 0.001).

CONCLUSION

Results indicate a stronger association between severe depressive symptoms and cognitive impairment among older Chinese males. Our study suggests that reducing loneliness can help prevent cognitive impairment in older men, and improving sleep quality can help improve cognitive function in older women.

Worldwide prevalence of sleep problems in community-dwelling older adults: A systematic review and meta-analysis

The understanding of the prevalence of sleep problems in older adults can provide a broad and reliable perspective into the occurrence of such issues among older adults. This systematic review and meta-analysis aimed to estimate the worldwide prevalence of sleep problems in community-dwelling older adults. Studies that provide information on the prevalence of sleep problems in community-dwelling older adults (≥60 years) were screened between December 2022 and March 2023. A total of 20,379 studies were identified in database searches, from which 252 were included in this review. These studies covered the last 35 years (from 1988 to 2023) and pooled a sample of 995,544 participants from 36 countries. The most frequent sleep problem worldwide was obstructive sleep apnea (46.0%), followed by poor sleep quality (40.0%), other sleep problems (37.0%), insomnia (29.0%), and excessive daytime sleepiness (19.0%). No significant difference in the prevalence estimates of all sleep problems was observed between the sexes. This systematic review and meta-analysis showed a high prevalence of some sleep problems, mainly obstructive sleep apnea, poor sleep quality, and other sleep problems. Our estimates can be useful for managers and policymakers in planning healthcare strategies for sleep problems aimed at the older population.

Long Objective Sleep Duration is a Marker of Cognitive Impairment in Older Adults: Findings from the Cretan Aging Cohort

 We examined associations between objective sleep duration and cognitive status in older adults initially categorized as cognitively non-impaired (CNI, n = 57) or diagnosed with mild cognitive impairment (MCI, n = 53). On follow-up, 8 years later, all participants underwent neuropsychiatric/neuropsychological evaluation and 7-day 24-h actigraphy. On re-assessment 62.7% of participants were cognitively declined. Patients who developed dementia had significantly longer night total sleep time (TST) than persons with MCI who, in turn, had longer night TST than CNI participants. Objective long sleep duration is a marker of worse cognitive status in elderly with MCI/dementia and this association is very strong in older adults.

Sequential link in depression, sleep and cognition: Longitudinal evidence from a serial multiple mediation analysis of older adults in China

BACKGROUND

A growing body of literature examines the link between depression, sleep and cognition, but little is known regarding the extent to which this relationship holds among older adults over time.

OBJECTIVE

This study examines how sleep duration mediates the relationship between depressive symptoms and cognitive performance, by utilizing partial least squares structural equation modelling (PLS-SEM) estimation.

METHODS

This study utilizes the 2013-18 China Health and Retirement Longitudinal Study (CHARLS) dataset, of which 3557 participants over the age of 50 satisfied inclusion criteria. Depressive symptoms and cognitive performance are measured by the Center for Epidemiological Studies Depression Scale (CESD) and the Mini-Mental State Examination (MMSE); sleep duration is assessed using the adapted Pittsburgh Sleep Quality Index (PSQI). A serial multiple mediation model was built to assess how depressive symptoms in 2013 and in 2018 are related, in addition to assessing their links with sleep duration and cognitive performance.

FINDINGS

Results indicate that early depression positively predicts depression progression (std.β = 0.564, 95 % Confidence Interval: 0.534, 0.594), but negatively predicts sleep duration (std.β = -0.081, 95 % CI: -0.128, -0.034) and cognitive performance (std.β = -0.118, 95 % CI: -0.165, -0.072). The sequential indirect effect of early depression operating via depression progression and sleep duration is evaluated to be -0.083 (95 % CI: -0.110, -0.056), representing as much as 41.29 % of the total effect.

CONCLUSIONS

Early depressive symptoms are directly associated with increased depressive symptoms and shortened sleep, which are identified as key channels through which early depression is linked with worsened cognition.

CLINICAL IMPLICATIONS

Many older adults may underestimate the adverse costs of early depression, since its net effects on cognition could be channeled indirectly and discretely via depression progression and sleep, which is worth highlighting in health guidelines and clinical recommendations.

Sex as a moderator of the sleep and cognition relationship in middle-aged and older adults: A preliminary investigation

OBJECTIVES

Despite known sex differences in the prevalence of sleep disturbance and cognitive impairment, research investigating sex differences in sleep/cognition associations is limited. We examined sex as a moderator of associations between self-reported sleep and objective cognition in middle-aged/older adults.

METHODS

Adults aged 50+ (32 men/31 women, Mage = 63.6 ± 7.7) completed the Pittsburgh Sleep Quality Index (PSQI) and cognitive tasks: Stroop (processing speed, inhibition), Posner (spatial attentional orienting) and Sternberg (working memory). Multiple regressions examined whether PSQI metrics (global score, sleep quality ratings, sleep duration, sleep efficiency) were independently or interactively (with sex) associated with cognition, controlling for age and education.

RESULTS

Sex interacted with sleep quality ratings in its association with endogenous spatial attentional orienting (∆R2 = .10, p = .01). Worse ratings of sleep quality were associated with worse orienting in women (B = 22.73, SE = 9.53, p = .02), not men (p = .24). Sex interacted with sleep efficiency in its associations with processing speed (∆R2 = .06, p = .04). Lower sleep efficiency was associated with slower Stroop control trial performance in women (B = -15.91, SE = 7.57, p = .04), not men (p = .48).

CONCLUSIONS

Preliminary findings suggest middle-aged/older women are more vulnerable to associations between poor sleep quality and low sleep efficiency on spatial attentional orienting and processing speed, respectively. Future studies in larger samples investigating sex-specific prospective sleep and cognition associations are warranted.

Association between napping and cognitive impairment: A systematic review and meta-analysis

STUDY OBJECTIVES

Increasing evidence suggests that napping is associated with cognitive impairment and dementia, but the conclusions are inconsistent. Moreover, the extent of the risk is uncertain. We therefore conducted a systematic review and meta-analysis to quantify the connection between napping and cognitive impairment.

METHODS

We performed a systematic search of PubMed, EMBASE, Web of Science, and Cochrane Library for studies that were published up to June 2023, and assessed associations between napping and cognitive impairment. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated as the effect sizes for all studies. Heterogeneity and potential publication biases were assessed.

RESULTS

A total of 4535 papers were retrieved, with 20 reports assessing the relationships between napping and cognitive impairment. Pooled analysis indicated that napping was associated with dementia (OR = 1.14; 95% CI: 1.07-1.21). Importantly, we found that those napping longer than 30, 45, and 60 min/day were 35%, 41%, and 40%, respectively, more likely to have an increased risk of cognitive impairment (30 min: OR = 1.35; 95% CI: 1.24-1.48; 45 min: OR = 1.41; 95% CI: 1.27-1.58; 60 min: OR = 1.40; 95% CI: 1.26-1.56). North America and Europe showed that associations existed between napping and cognitive impairment (North America: OR = 1.15; 95% CI: 1.04-1.27; Europe: OR = 1.13; 95% CI: 1.08-1.18).

CONCLUSIONS

This meta-analysis indicated associations between long napping durations and cognitive impairment or dementia, suggesting that longer napping might be a potential risk factor of adverse cognitive outcomes.

The association of previous night's sleep duration with cognitive function among older adults: a pooled analysis of three Finnish cohorts

STUDY OBJECTIVES

Sleep duration has been shown to associate with cognitive function, but little is known about the short-term effect of sleep duration on the previous night. This study examines how usual sleep duration and previous night's sleep duration are associated with cognitive function in older adults.

METHODS

The study population consisted of 2949 adults aged 59-92 years (mean 72.6, SD 5.7) derived from three Finnish cohorts. Participants' self-reported usual sleep duration was categorized into short (< 7 h, 19%), mid-range (7- < 9 h, 64%), and long (≥ 9 h, 17%). Self-reported sleep duration on the night prior to cognitive testing was categorized into shorter (59%), same (35%), and longer (5.9%) than usual sleep duration. Computerized Cambridge Neuropsychological Test Automated Battery (CANTAB®) was used to assess: (1) learning and memory, (2) working memory, (3) information processing, and (4) reaction time.

RESULTS

Participants with self-reported long, but not short, usual sleep duration had poorer learning and memory (p = .004), information processing (p = .003), and reaction time (p = .006) when compared to those with mid-range sleep duration. Those who slept more than usually the night prior to cognitive testing had poorer information processing (p = .019) than those sleeping the same as usually, while sleeping less than usually was not associated with cognitive function.

CONCLUSIONS

This study suggests that while long sleep duration was associated with worse cognitive function, sleeping more than usually the night prior to cognitive testing was only associated with information processing, and sleeping less than usually is not associated with cognitive function.

Do the relationships of physical activity and total sleep time with cognitive function vary by age and biological sex? A cross-sectional analysis of the Canadian Longitudinal Study on Aging

OBJECTIVES

Physical activity (PA) and total sleep time (TST) are each associated with cognition; however, whether these relationships vary by age and biological sex is unclear. We examined the relationships of PA or TST with cognition, and whether age and sex moderated these relationships, using baseline data from the Canadian Longitudinal Study on Aging (CLSA; 2010-2015).

STUDY DESIGN

A cross-sectional analysis of participants from the Comprehensive cohort of the CLSA with complete PA and sleep data (n = 20,307; age range 45-86 years).

MAIN OUTCOME MEASURES

PA and TST were measured using the Physical Activity Scale for the Elderly (PASE) and self-reported TST over the past month. Cognition was indexed using a three-factor structural equation model (i.e., memory, executive function, and verbal fluency).

RESULTS

Non-linear restricted cubic spline models indicated that PA and TST explained statistically significant (p < 0.01) but modest variance of each cognitive domain (<1 % of 23-24 % variance). Age and sex did not moderate associations of PA with any cognitive domain. However, age and sex moderated relationships of TST with cognition, whereby: 1) associations of TST with memory decreased with age for males and females; and 2) males and females had different age-associated relationships of TST with executive function and verbal fluency.

CONCLUSIONS

PA and TST modestly contribute to multiple domains of cognition across middle and older adulthood. Importantly, the association of PA with cognition does not appear to vary across middle or older adulthood, nor does it vary by biological sex; however, TST appears to have a complex relationship with multiple domains of cognition which is both age- and sex-dependent.

Relationships of Physical Activity, Depression, and Sleep with Cognitive Function in Community-Dwelling Older Adults

This cross-sectional, observational study aimed to integrate the analyses of relationships of physical activity, depression, and sleep with cognitive function in community-dwelling older adults using a single model. To this end, physical activity, sleep, depression, and cognitive function in 864 community-dwelling older adults from the Suwon Geriatric Mental Health Center were assessed using the International Physical Activity Questionnaire, Montgomery-Asberg Depression Rating Scale, Pittsburgh Sleep Quality Index, and Mini-Mental State Examination for Dementia Screening, respectively. Their sociodemographic characteristics were also recorded. After adjusting for confounders, multiple linear regression analysis was performed to investigate the effects of physical activity, sleep, and depression on cognitive function. Models 4, 5, 7, and 14 of PROCESS were applied to verify the mediating and moderating effects of all variables. Physical activity had a direct effect on cognitive function (effect = 0.97, p < 0.01) and indirect effect (effect = 0.36; confidence interval: 0.18, 0.57) through depression. Moreover, mediated moderation effects of sleep were confirmed in the pathways where physical activity affects cognitive function through depression (F-coeff = 13.37, p < 0.001). Furthermore, these relationships differed with age. Thus, the associations among physical activity, depression, and sleep are important in interventions for the cognitive function of community-dwelling older adults. Such interventions should focus on different factors depending on age.

Gender-specific association between obstructive sleep apnea and cognitive impairment among adults

OBJECTIVES

This study aims to explore the gender-specific association between obstructive sleep apnea (OSA) and cognitive impairment.

METHODS

Participants from UK biobank who have completed at least one of the five baseline cognitive tests (visuospatial memory, prospective memory, fluid intelligence, short numeric memory and reaction time) were included, which were initially divided into two groups based on gender and were further categorized into three subgroups: (1) OSA, (2) self-reported snoring but without OSA, and (3) healthy controls (without OSA or snoring). Multivariable regression analysis was performed to examine the associations among snoring, OSA and performance of each of the five cognitive domains.

RESULTS

A total of 267,889 participants (47% male, mean age: 57 years old) were included in our study. In the multivariable regression analysis, female participants in the OSA group had a higher risk of having poor prospective memory (OR: 1.24, 95% CI: 1.02～1.50, p = 0.03). Meanwhile, among female participants, OSA were inversely associated with the performances of fluid intelligence (β: 0.29, 95% CI: 0.46～-0.13, p &lt; 0.001) and short-numeric memory (β: 0.14, 95% CI: 0.35～0.08, p = 0.02). Besides, age-related subgroup analyses showed that these associations were largely reserved in younger (＜65 years old) female participants rather than older (≥65 years old) female participants. In contrast, among male participants, no significant association was observed between OSA and impairment of the five cognitive domains.

CONCLUSIONS

OSA was significantly associated with cognitive impairment at certain dimensions in female participants rather than in male participants, indicating that more special attention and timely interventions should be given to younger female OSA patients to prevent further cognitive impairment.

Napping and cognitive decline: a systematic review and meta-analysis of observational studies

BACKGROUND

No clear evidence is available for the influence of napping on cognitive function in older adults. This systematic review and meta-analysis aimed to elucidate the cross-sectional and longitudinal relationships between napping and cognitive function (global cognition and memory) and to explore whether some individual characteristics and sleep characteristics can modify this relationship.

METHODS

We systematically searched Medline (via PubMed), Web of Science, and Scopus. DerSimonian and Lair and Hartung-Knapp-Sidik-Jonkman random effects methods were used to compute pooled estimates of odds ratios (ORs) and their respective 95% confidence intervals (95% CIs) for the association of global cognition and memory with napping. The mean age, the night sleep time (hours), and the percentage of women, no nappers, and people in the less night-time sleep duration category were used for meta-regressions.

RESULTS

Twenty-five studies were included in this systematic review and meta-analysis, 18 cross-sectional and seven longitudinal studies, including 95,719 participants older than 60 years. The pooled ORs from the cross-sectional analyses were 1.03 (95% CI: 1.01 to 1.06) for global cognition and 1.06 (95%: 0.90 to 1.26) for memory. The pooled ORs from the longitudinal analyses were 1.00 (95% 0.85 to 1.18) for global cognition and 1.08 (95% 0.98 to 1.19) for memory. These associations were not modified by individual or sleep characteristics.

CONCLUSION

Our data confirm the absence of association between napping and global cognition and memory regardless of the characteristics of the population. This information might be considered when providing lifestyle recommendations to adults with and without cognitive complaints.

Sleep habits are associated with cognition decline in physically robust, but not in frail participants: a longitudinal observational study

Frail older adults are vulnerable to stressors; thus, sleep related cognition impairment might more greatly affect frail than healthy older adults. In the present study, we investigated whether the association between sleep problems and cognition varies with physical frailty status (modified from Fried et al.). Participants 55 years and older who completed a baseline and follow-up questionnaire (median follow-up: 5.5 years), were included in the analysis. Sleep parameters were evaluated in an interview at the baseline. Cognitive decline was defined as a loss of 3 or more points on the Mini-Mental State Examination (MMSE) at follow-up. Associations between sleep problems and cognitive decline were examined using logistic regression and were stratified by baseline physical frailty status, adjusted for potential confounders. A short total sleep duration (< 5 vs. 7-9 h, odds ratio (OR) = 1.88, 95% confidence interval (CI) 1.18-3.00), excessive daytime sleepiness (OR = 1.49, 95% CI 1.04-2.13), low sleep efficiency (< 65% vs. ≥ 85%, OR = 1.62, 95% CI 1.07-2.46), and insomnia complaints (OR = 2.34, 95% CI 1.23-4.43) were associated with MMSE decline in physically robust. The association was stronger for the sleep summary score, which summarized abnormal sleep duration, excessive daytime sleepiness, and insomnia complaints ([Formula: see text] 2 vs. 0, OR = 3.79, 95% CI 2.10-6.85, p < 0.0001). Due to the low prevalence of frailty in this community-dwelling population, the statistical power to detect an association was low. More evidence is needed to clarify the role of sleep in the progression of cognitive decline in frail individuals.

Cross-sectional and prospective associations between self-reported sleep characteristics and cognitive function in men and women: The Midlife in the United States study

Sleep behaviour is an important contributing factor in healthy human ageing and cognitive function. Previous studies have linked sleep deficiency with cognitive decline in older adults. However, there is need for more prospective investigations that focus on specific domains of cognitive function. The present study analysed cross-sectional and prospective associations between self-reported sleep and cognitive function in the Midlife in the United States (MIDUS) study. Weekday and weekend sleep duration and habitual sleep quality were obtained via questionnaire data. Brief Test of Adult Cognition by Telephone was conducted to assess overall cognitive function, as well as episodic memory and executive function. We found significant trend for both long weekday and weekend sleep (>8 hr) and lower episodic memory scores in the overall sample. Sex-specific cross-sectional analysis demonstrated men with longer weekend sleep duration have lower overall cognitive function scores, and a negative association between weekend sleep and episodic memory scores. Women demonstrated a positive association between weekend sleep duration and executive function scores. There was no prospective significance for overall or sex-specific analysis. Our present results suggest that sleep duration may contribute to cognitive function, and future studies should include objective sleep measurements and focus on the potential cognitive benefits of improving sleep to further elucidate this association.

Comparative efficacy of digital cognitive behavioral therapy for insomnia: A systematic review and network meta-analysis

The comparative efficacy of various approaches of digital cognitive behavioral therapy for insomnia (CBTi) is still unclear. This network meta-analysis explored the comparative efficacy of digital CBTi approaches in adults with insomnia. Four electronic databases were searched from inception to June 27, 2020. Primary outcomes were self-reported total sleep time (TST), sleep onset latency (SOL), wake after sleep onset (WASO), sleep efficiency (SE), and insomnia symptoms; these were measured using sleep diaries or valid questionnaires. A random-effects network meta-analysis in a frequentist framework was used. Fifty-four randomized controlled trials comprising 11,815 participants were included. Compared with usual care, web-based CBTi with a therapist demonstrated significantly longer TST (mean difference [MD]: 23.19 min, 95% confidence interval [CI]: 18.98-27.39 min), shorter SOL (MD: -18.76 min, 95% CI -24.20 to -13.31 min), lower WASO (MD: -31.40 min, 95% CI: -36.26 to -26.55 min), and greater SE (MD: 10.37%, 95% CI: 8.08%-12.65%). The surface under the cumulative ranking curve indicates that web-based CBTi with therapists is most likely to be ranked the highest among all treatments, and thus, this network meta-analysis suggests that such a treatment is the optimal intervention for improving sleep duration and SE as well as the reductions in SOL and WASO. PROSPERO REGISTRATION NUMBER: CRD42020171134.

Obstructive Sleep Apnea and Cognitive Decline: A Review of Potential Vulnerability and Protective Factors

Around 40% of dementia risk is attributable to modifiable risk factors such as physical inactivity, hypertension, diabetes and obesity. Recently, sleep disorders, including obstructive sleep apnea (OSA), have also been considered among these factors. However, despite several epidemiological studies investigating the link between OSA and cognitive decline, there is still no consensus on whether OSA increases the risk of dementia or not. Part of the heterogeneity observed in previous studies might be related to some individual characteristics that modulate the association between OSA and cognitive decline. In this narrative review, we present these individual characteristics, namely, age, sex, menopause, obesity, diabetes mellitus, hypertension, cardiovascular diseases, smoking, excessive alcohol consumption, depression, air pollution, Apolipoprotein E ε4 allele, physical activity, and cognitive reserve. To date, large cohort studies of OSA and cognitive decline tended to statistically control for the effects of these variables, but whether they interact with OSA to predict cognitive decline remains to be elucidated. Being able to better predict who is at risk of cognitive decline when they have OSA would improve clinical management and treatment decisions, particularly when patients present relatively mild OSA.

Comparative efficacy and safety of hypnotics for insomnia in older adults: a systematic review and network meta-analysis

STUDY OBJECTIVES

To compare the efficacy and safety of various hypnotics for identifying the best treatments for insomnia in older adults.

METHODS

We searched the EMBASE, PubMed, ClinicalTrials.gov, and ProQuest Dissertations and Theses A&I databases from the inception to September 12, 2020. Only randomized controlled trials comparing hypnotics with either another hypnotic or placebo for insomnia treatment in elderly people were included. Sleep outcomes, including total sleep time, sleep onset latency, wake after sleep onset, sleep efficiency, were derived from polysomnography, valid questionnaires, or sleep diaries.

RESULTS

We identified 24 articles with 5917 older adults. Eszopiclone and low-dose doxepin were ranked the optimal therapy for prolonging objective and subjective total sleep time (26.69 and 28.19 min), respectively, compared to placebo. Zaleplon was the most effective therapy in reducing objective and subjective sleep onset latency (-21.63 and -15.86 min) compared with control. Temazepam was the best treatment for objective and subjective wake after sleep onset (-25.29 and -22.25 min) compared with control. Low-dose doxepin appeared to be the effective treatment for increasing objective sleep efficiency (6.08%) Triazolam showed the higher risk of overall adverse events (odds ratio, 1.96, 95% confidence interval 1.03-3.74) when compared to zaleplon.

CONCLUSIONS

Considering study quality and the potential adverse effects of benzodiazepines and nonbenzodiazepines, low-dose doxepin seems to be the optimal pharmacotherapy for the improvements in total sleep time and sleep efficiency. Future RCTs investigating the treatment effects of hypnotics, particularly low-dose doxepin, on insomnia in older adults are warranted. PROSPERO Registration number: CRD42016046301.

Sleep symptomatology is associated with greater subjective cognitive concerns: Findings from the community-based Healthy Brain Project

STUDY OBJECTIVES

To examine if sleep symptomatology was associated with subjective cognitive concerns or objective cognitive performance in a dementia-free community-based sample.

METHODS

A total of 1421 middle-aged participants (mean±standard deviation = 57±7; 77% female) from the Healthy Brain Project completed the Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index (ISI), and Epworth Sleepiness Scale (ESS) to measure sleep quality, insomnia symptom severity, and daytime sleepiness, respectively. Participants were classified as having no sleep symptomatology (normal scores on each sleep measure), moderate sleep symptomatology (abnormal scores on one sleep measure), or high sleep symptomatology (abnormal scores on at least two sleep measures), using established cut-off values. Analysis of covariance was used to compare objective cognitive function (Cogstate Brief Battery) and subjective cognitive concerns (Modified Cognitive Function Instrument) across groups.

RESULTS

Following adjustments for age, sex, education, mood, and vascular risk factors, persons classified as having high sleep symptomatology, versus none, displayed more subjective cognitive concerns (d=0.24) but no differences in objective cognitive performance (d=0.00-0.18). Subjective cognitive concerns modified the association between sleep symptomatology and psychomotor function. The strength of the relationship between high sleep symptomatology (versus none) and psychomotor function was significantly greater in persons with high as compared with low cognitive concerns (β±SE =-0.37±0.16; p=0.02).

CONCLUSIONS

More severe sleep symptomatology was associated with greater subjective cognitive concerns. Persons reporting high levels of sleep symptomatology may be more likely to display poorer objective cognitive function in the presence of subjective cognitive concerns.

Subjective Sleep Quality in Amnestic Mild Cognitive Impairment Elderly and Its Possible Relationship With Plasma Amyloid-β

Study objectives

To investigate the extent to which sleep quality associated with plasma Aβ levels in amnestic mild cognitive impairment (aMCI) elderly.

Methods

A total of 172 cognitively normal (NC) elderly and 133 aMCI elderly were included in this study. For the evaluation of sleep quality, the Pittsburgh Sleep Quality Index (PSQI) was used. Levels of plasma Aβ were determined by the sandwich enzyme-linked immunosorbent assay technique. Multivariable linear regression analysis was applied to evaluate associations between sleep quality and plasma Aβ levels after adjusting potential confounders.

Results

Compared to NC subjects, participants with aMCI had a higher global PSQI score (8.72 ± 3.87 vs. 7.10 ± 3.07, p < 0.001). The global PSQI score was positively associated with plasma Aβ₄₂ level in the aMCI group (β = 0.063, 95% CI 0.001–0.125, and p = 0.049) but not in the NC group (p > 0.05). Additionally, a higher global PSQI score was associated with a higher plasma Aβ₄₂/Aβ₄₀ ratio in both NC (β = 0.010, 95% CI 0.003–0.016, and p = 0.003) and aMCI groups (β = 0.012, 95% CI 0.005–0.018, and p < 0.001). The association between global PSQI score and plasma Aβ₄₂/Aβ₄₀ ratio was stronger in individuals with aMCI relative to the NC subjects (β = 0.076 vs. 0.030, p for interaction = 0.023).

Conclusion

Poor sleep quality was associated with plasma Aβ₄₂ and Aβ₄₂/Aβ₄₀ ratio, with a stronger effect among individuals with aMCI. A better understanding of the role of sleep in plasma Aβ levels in aMCI patients could lead to effective sleep-based intervention against the risk of Alzheimer’s disease.

Age- and Sex-Specific Prevalence and Modifiable Risk Factors of Mild Cognitive Impairment Among Older Adults in China: A Population-Based Observational Study

Background

Minimal data are available on the prevalence of mild cognitive impairment (MCI) in older Chinese adults. Moreover, the current information on MCI shows important geographical variations.

Objective

We aimed to assess the prevalence and risk factors for MCI by age and sex among older adults in a North Chinese population.

Methods

In this population-based cross-sectional study, we enrolled a random sample of 4,943 adults aged ≥ 60 years between March 2018 and June 2019 in Tianjin, China. Of these, 312 individuals were excluded due to a lack of data (e.g., fasting blood test). As a result, 4,631 subjects were assessed. Individuals with MCI were identified using neuropsychological assessments, including the Mini-Mental State Examination and Activities of Daily Living scale, based on a modified version of the Petersen’s criteria.

Results

The mean (SD) age of the 4,631 participants was 67.6 (4.89) years, and 2,579 (55.7%) were female. The overall age- and sex-standardized prevalence of MCI in our study population was 10.7%. There were significant associations of MCI with age [65–69 vs. 60–64 years, OR = 0.74; 95% confidence interval (CI): 0.58, 0.96], physical activity (≥23.0 vs. <23.0 MET-hours/week, OR = 0.79; 95% CI: 0.64, 0.96), body mass index (BMI) (OR = 0.92; 95% CI: 0.89, 0.95), grip strength (OR = 0.50; 95% CI: 0.38, 0.67), hypertension (yes vs. no, OR = 1.44; 95% CI: 1.18, 1.77), higher levels of sleepiness (OR = 1.80; 95% CI: 1.36, 2.37), and longer sleep duration (OR = 1.40; 95% CI: 1.14, 1.72). The inverse association between BMI and MCI was stronger in older age groups (P for heterogeneity = 0.003). Moreover, the magnitude of association between triglycerides and MCI was different between the sexes (P for heterogeneity = 0.029).

Conclusion

The age- and sex-standardized prevalence of MCI was 10.7% in the study sample. Physical activity, BMI, grip strength, sleepiness, sleep duration, and hypertension were associated with the prevalence of MCI. Additionally, triglycerides and BMI might be differently associated with the presence of MCI for different sexes and age stages, respectively.

Sleep Mediates the Relationship Between Depression and Cognitive Impairment in Older Men

Sleep and depression are strongly associated with cognitive impairment. The role of sleep disturbances in the adverse effect of depression on cognitive dysfunction in older adults remains unclear. This study explored the mediating effect of self-reported sleep disturbances on the relationship between depression and cognitive impairment in older adults according to sex differences. This study derived data from the 2009 Taiwan National Health Interview Survey and included 2,175 community-dwelling adults aged 65 years and older (men = 991; women = 1,184). Sleep disturbances were measured using self-reported survey questions. The Center for Epidemiological Studies Depression scale was used to assess depression. The Mini-Mental State Examination was used to evaluate cognitive impairment. A higher proportion of female older persons had cognitive impairment and depression than male older persons (cognition: 24.4% vs. 11.5%; depression: 17.0% vs. 10.8%). The meditating effect of sleep was detected in only men. Difficulty in initiating sleep was a complete mediator of the adverse effect of depression on cognitive impairment (Sobel test: p = .03). In summary, difficultly in initiating sleep may be a crucial, treatable mediator of the adverse effect of depression on cognitive impairment in older men.

Sex differences in sleep and sleep loss-induced cognitive deficits: The influence of gonadal hormones

Males and females can respond differentially to the same environmental stimuli and experimental conditions. Chronic sleep loss is a frequent and growing problem in many modern societies and has a broad variety of negative outcomes for health and well-being. While much has been done to explore the deleterious effects of sleep deprivation (SD) on cognition in both human and animal studies over the last few decades, very little attention has been paid to the part played by sex differences and gonadal steroids in respect of changes in cognitive functions caused by sleep loss. The effects of gonadal hormones on sleep regulation and cognitive performances are well established. Reduced gonadal function in menopausal women and elderly men is associated with sleep disturbances and cognitive decline as well as dementia, which suggests that sex steroids play a key role in modulating these conditions. Finding out whether there are sex differences in respect of the effect of insufficient sleep on cognition, and how neuroendocrine mediators influence cognitive impairment induced by SD could provide valuable insights into the best therapies for each sex. In this review, we aim to highlight the involvement of sex differences and gonadal hormone status on the severity of cognitive deficits induced by sleep deficiency in both human and animal studies.

Sleep and Mental Health in the General Population of Elderly Women

Sleep and mental health complaints are prevalent in the elderly and share common risk factors. We assessed the relationship between sleep and mental health in three representative samples of elderly women while controlling for multiple risk factors common to both. We performed this cross sectional secondary data analysis in 2015 using 2013 data from the Behavioral Risk Factor Surveillance System (BRFSS) for females ages 65 years and older from California (N = 1912), Florida (N = 9120), and Pennsylvania (N = 2429). We conducted multiple logistic regression analysis to assess the relationship between sleep duration group (short, moderate/reference, or long) and mental health issues in the past 30 days (yes or no) in elderly females, while controlling for multiple covariates. About 25% of the elderly females reported mental health issues and 20% reported short or long sleep durations. In adjusted analysis, compared to the elderly females in the moderate sleep duration group (averaging 6-8 h of sleep per day), those in the short and long sleep duration groups had increased prevalence of mental health issues by 66% and 26%, respectively. Mental health was also related to physical health issues including general health status, activity limitations, and chronic health conditions. Overall, sleep was related to mental health in representative samples of elderly females even after controlling for risk factors common to both. Even though we could not determine the direction of influence, the findings indicate a need for clinicians to screen their elderly female patients for both sleep and mental health issues, especially in those with physical health comorbidities.

The bidirectional relationship between sleep duration and depression in community-dwelling middle-aged and elderly individuals: evidence from a longitudinal study

BACKGROUND

There are several studies that have focused on the relationship between sleep duration and depression, however, only a few prospective studies have centered on the bidirectional relationship between them. This four-year longitudinal study aimed to identify the association between sleep duration and depression in community-dwelling mid-age and elderly individuals.

METHODS

10,704 participants from the China Health and Retirement Longitudinal Study (CHARLS) were included for baseline and four-year follow up. Of these individuals, 7866 and 2956 were used to identify the effects of sleep duration on onset and recurrent depression respectively. 4504 individuals with normal sleep duration at baseline were included to examine the effects of depression on changes of sleep time. The 10-item version of the Centre for Epidemiological Studies Depression scale (CESD-10) was used to access depressive symptoms, as well sleep duration was self-reported.

RESULTS

Participants with short sleep duration (<5 and 5-6 h) had a higher risk of depression onset (OR 1.69 [1.36-2.11], 1.48 [1.19-1.84]) and recurrent depression (OR 1.44 [1.12-1.86], 1.32 [1.00-1.74]) compared to participants with normal sleep durations (7-8 h). Long sleep durations (>9 h) had no significant risks for depression. Males and the elderly (over 60 years-old) were more sensitive to short sleep durations and experienced a higher incidence of depression. Individuals with depression were more likely to have short sleep durations instead of long ones (RRR 1.20 [1.02-1.43]).

CONCLUSIONS

The present study identified the bidirectional relationship between sleep duration and depression. Short sleep durations were a risk factor for the onset and recurrent depression. Conversely, depression induced short sleep durations rather than excessive sleep durations. Future studies need to focus on identifying the mechanism between sleep duration and depression, and develop additional evidence-based cost-effective interventions to prevent depression and sleep problems.

Ovarian hormones, sleep and cognition across the adult female lifespan: An integrated perspective

Loss of ovarian function in women is associated with sleep disturbances and cognitive decline, which suggest a key role for estrogens and/or progestins in modulating these symptoms. The effects of ovarian hormones on sleep and cognitive processes have been studied in separate research fields that seldom intersect. However, sleep has a considerable impact on cognitive function. Given the tight connections between sleep and cognition, ovarian hormones may influence selective aspects of cognition indirectly, via the modulation of sleep. In support of this hypothesis, a growing body of evidence indicates that the development of sleep disorders following menopause contributes to accelerated cognitive decline and dementia in older women. This paper draws from both the animal and human literature to present an integrated view of the effects of ovarian hormones on sleep and cognition across the adult female lifespan.