Sleep disturbances and cognitive decline in the Northern Manhattan Study

The association between nutritional status and sleep quality of Chinese community-dwelling older adults

BACKGROUND

Sleep disorders are a common syndrome and could affect the life quality of the older adults.

AIMS

This study aimed to investigate the association between nutritional status and sleep quality in the Chinese community-dwelling older adults.

METHODS

A total of 2,878 participants ≥ 65 years old from the Yiwu Elderly Cohort were included in the study. Nutritional status was assessed using the Mini Nutritional Assessment Short Form (MNA-SF). Participants were categorized as subjects with malnutrition, at risk of malnutrition or well-nourished based on their MNA-SF score. Pittsburgh Sleep Quality Index (PSQI) was used to identify sleep disorders. PSQI score ≥ 6 was categorized as poor sleep quality.

RESULTS

Among the 2,878 participants (mean age 72.71 ± 5.79 years, 50.3% men), 31.5% (n = 906) were classified as having sleep disorders, and 25.5% were identified as malnutrition or at risk of malnutrition. We found a significantly relationship between nutritional status and sleep quality in older adults, and the results showed well-nourished decreased the risk of sleep disorders (OR = 0.32, 95% CI = 0.13, 0.75). And well-nourished status was significantly associated with less daytime dysfunction, adequate sleep duration, and good subjective sleep quality (all P < 0.05).

CONCLUSION

There was a close association of nutritional status and sleep quality in older adults. We should pay more attention to the nutritional status of older people with sleep problems, as well as the sleep quality of older adults with malnutrition.

A high propensity for excessive daytime sleepiness independent of lifestyle is associated with cognitive performance in community-dwelling older adults

Objective

The relationship between excessive daytime sleepiness (EDS) and cognitive performance of older adults remains unclear, especially when a healthy lifestyle is considered. The study aimed to explore the association between EDS in passive and active situations and general cognitive function among community-dwelling older adults.

Methods

Two hundred and seventy-one older adults aged 60 and above were recruited from the community cohort in Shangrao. All study participants were free of depression and dementia. The Chinese version of the Epworth Sleepiness Scale (CESS) was used to evaluate EDS. Using the item scores of CESS, the presence of EDS among all study participants were grouped as non-EDS, passive situation-related EDS (PSR-EDS), active situation-related EDS (ASR-EDS), and high sleep propensity (HSP). The Hong Kong Brief Cognitive Test (HKBC) was used to assess cognitive function. Chinese healthy lifestyle metrics were scored based on AHA Life Simple-7. The multivariate logistic regression model was used to estimate the association between the presence of EDS and cognitive function.

Results

The PSR-EDS (n = 29, 20.8 ± 5.3) and the HSP groups (n = 21, 19.8 ± 4.8) scored lower with HKBC than in the non-EDS group (n = 213, 23.2 ± 4.9). The subdomain performance of language in the HSP group was poorer than in the non-EDS group (ps < 0.05). Relative to non-EDS, HSP (OR = 3.848, 95% CI = 1.398-10.591) was associated with an increased risk of poor cognitive performance after adjusting age, sex, education, and healthy lifestyle metrics.

Conclusion

High propensity for excessive daytime sleepiness, irrespective of lifestyle, is associated with poorer cognitive performance among community-dwelling older adults. The findings may provide empirical evidence to support sleepiness intervention for reducing the risk of cognitive decline.

Sleep Quality and Cognitive Decline Across the Adult Age Range: Findings from the Maastricht Aging Study (MAAS)

BACKGROUND

Sleep disturbances have been linked with cognitive decline and a higher risk of dementia. However, there is a lack of studies with sufficient follow-up duration, a detailed neuropsychological assessment and adequate control of main confounders.

OBJECTIVE

To investigate the relation between self-reported sleep quality and cognitive decline over 12 years in cognitively healthy individuals from the general population.

METHODS

We used data from the Maastricht Aging Study (MAAS), a Dutch population-based prospective cohort study of 1,823 community-dwelling adults aged 24 to 82 years at baseline. Cognitive performance was measured at baseline, 6 and 12 years on verbal memory, executive functions, and information processing speed. Sleep quality was assessed at baseline using the sleep subscale score of the 90-item Symptom Checklist (SCL-90). Additional modifiable dementia risk factors were summarized in the LIfestyle for BRAin health (LIBRA) risk score. Weighted linear mixed models tested the association between continuous scores and tertiles of subjective sleep quality and change in cognitive performances over time. Models were adjusted for age, gender, educational level, LIBRA, and use of hypnotic (sleep) medication.

RESULTS

Worse sleep quality was associated with faster decline in processing speed. At older age (≥65 years), it was also associated with faster decline in verbal memory. Association were independent of other modifiable dementia risk factors and use of hypnotic medication. Directionally similar but non-significant associations were found between worse sleep quality and executive functions.

CONCLUSIONS

In this population-based study across the adult age range, poor self-reported sleep was associated with accelerated cognitive decline.

Relationship between Resting State Heart Rate Variability and Sleep Quality in Older Adults with Mild Cognitive Impairment

Sleep problems can be caused by psychological stress but are also related to cardiovascular and neurodegenerative diseases. Improving lifestyle behaviors, such as good sleep hygiene, can help to counteract the negative effects of neurodegenerative diseases and to improve quality of life. The purpose of this cross-sectional study was to investigate the relationship between subjectively reported measures of sleep quality (via Pittsburgh Sleep Quality Index (PSQI)) and objective measures of cardiac autonomic control (via resting state heart rate variability (HRV)) among individuals with mild cognitive impairment (MCI). The PSQI and resting state HRV data of 42 MCI participants (69.0 ± 5.5; 56-80 years) were analyzed. Nineteen of the participants reported poor sleep quality (PSQI score > 5). Good sleepers showed higher resting heart rate than bad sleepers (p = 0.037; ES = 0.670). Correlation analysis showed a significant correlation between the parameter HF nu and sleep efficiency, contrasting the expected positive association between reduced HRV and poor sleep quality in healthy and individuals with specific diseases. Otherwise, there were no significances, indicating that measures of subjective sleep quality and resting HRV were not related in the present sample of MCI participants. Further research is needed to better understand the complex relationship between HRV and lifestyle factors (e.g., sleep) in MCI.

Associations between sleep duration patterns and cognitive decline trajectories in older Chinese adults

BACKGROUND

Abnormal sleep duration has been identified as a risk factor for cognitive decline. However, most studies have measured sleep duration and cognitive function at a single time point, while both tend to decrease with age.

AIMS

This study aimed to investigate the association between changes in sleep duration patterns and cognitive trajectories in older adults.

METHODS

Using longitudinal data (2005-2014) from the Chinese Longitudinal Healthy Longevity Survey, a total of 4347 subjects were included in this study. Cognitive function was measured with the Chinese version of the Mini-Mental State Examination. Group-based trajectory models were used to identify the trajectories of sleep duration and cognitive decline within the study sample as the participants aged. Furthermore, the association between sleep duration patterns and cognitive trajectories was examined by multinomial logistic regression analysis.

RESULTS

Using the medium-stable sleep duration pattern as a reference, the trajectory with a long and increased sleep duration pattern was more likely to be associated with the slight cognitive decline trajectory (OR = 1.80; 95% CI 1.31-2.44). Persistent short sleep was associated with a decreased likelihood of having a rapid cognitive decline trajectory (OR = 0.32; 95% CI 0.12-0.75).

DISCUSSION

Changes in sleep duration over time were independently associated with cognitive decline and may be a marker of cognitive decline.

CONCLUSIONS

Tracking of sleep duration over time in older adults may provide a useful insight for prevention of cognitive decline, and the increased sleep duration should be noticed with greater vigilance.

Modifying pathways by age and sex for the association between combined sleep disordered breathing and long sleep duration with neurocognitive decline in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL)

INTRODUCTION

We aimed to determine whether obesity or metabolic syndrome (MetS) modify associations between sleep-disordered breathing (SDB), self-reported sleep duration (SD), and phenotypes of combined SDB/SD with 7-year neurocognitive decline (ND) in a community based-cohort of U.S. Hispanic/Latinos (N = 5500) in different age and sex groups.

METHODS

The exposures were baseline SDB (respiratory event index ≥ 15), sleepiness (Epworth Sleepiness Scale ≥ 10), SD (< 6 hours, 6-9 hours, ≥ 9 hours). The outcome was 7-year ND.

RESULTS

Mean age was 56.0 years, 54.8% were females. Obesity modified the association between SDB/SD and ND in memory (F = 21.49, P < 0.001) and global cognition (F = 9.14, P < 0.001) in the oldest age group. Women without MetS with combined long sleep/SDB exhibited most pronounced decline in global cognition (F = 3.07, P = 0.010).

DISCUSSION

The association between combined SDB/long sleep and declines in memory and global cognition was most pronounced in obese older adults. Among women, MetS status modified the association between long sleep/SDB and decline in global cognition.

Association between self-reported night sleep duration and cognitive function among older adults with intact global cognition

OBJECTIVES

The purpose of this study was to clarify the association between self-reported night sleep duration and cognitive functions such as word memory, story memory, attention, executive function, and processing speed of older adults with normal global cognitive function.

METHODS

A total of 241 functionally independent older adults (mean age, 75.5 ± 6.4 years) participated in this study. No participants had a history of dementia diagnosis, and each had a Mini-Mental State Examination (MMSE) score ≥ 24. Participants were evaluated for self-reported sleep duration and cognitive function using the National Center for Geriatrics and Gerontology-Functional Assessment Tool (NCGG-FAT).

RESULTS

The longest sleep duration group (≥9 h) had lower MMSE scores (p = 0.010), Z-score of word list memory II (delayed recall; p = 0.001), and Z-score of story memory II (delayed recognition; p = 0.002) than the medium sleep duration group (7-8 h). Longest and long sleep duration (8-9 h) was significantly associated with impairment of story memory II (longest sleep duration: adjusted odds ratio [OR] = 3.58, 95% confidence interval [CI] = 1.13-11.37, long sleep duration: adjusted OR = 4.30, 95% CI = 1.34-13.82) with reference to medium sleep duration, but no impairment of MMSE according to multiple logistic regression analysis. Furthermore, short sleep duration (<7 h) was not associated with cognitive impairment.

CONCLUSIONS

This study suggests that long sleep duration is associated with cognitive impairment, especially of story memory (delayed recognition) in older adults with normal global cognitive function.

Central Obesity, Cardiometabolic Risk, and Cognitive Change in the Study of Latinos - Investigation of Neurocognitive Aging

BACKGROUND

The relationships between obesity and cognitive decline in aging are mixed and understudied among Hispanics/Latinos.

OBJECTIVE

To understand associations between central obesity, cognitive aging, and the role of concomitant cardiometabolic abnormalities among Hispanics/Latinos.

METHODS

Participants included 6,377 diverse Hispanics/Latinos enrolled in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) and SOL-Investigation for Neurocognitive Aging (SOL-INCA). Participants were 45 years and older at the first cognitive testing session (Visit 1). Cognitive outcomes (z-score units) included global composite and domain specific (learning, memory, executive functioning, processing speed) measures at a second visit (SOL-INCA, on average, 7 years later), and 7-year change. We used survey linear regression to examine associations between central obesity (waist circumference≥88 cm and≥102 cm for women and men, respectively) and cognition. We also tested whether the relationships between obesity and cognition differed by cardiometabolic status (indication of/treatment for 2 + of the following: high triglycerides, hypertension, hyperglycemia, low high-density lipoprotein cholesterol).

RESULTS

Central obesity was largely unassociated with cognitive outcomes, adjusting for covariates. However, among individuals with central obesity, cardiometabolic abnormality was linked to poorer cognitive function at SOL-INCA (ΔGlobalCognition =-0.165, p < 0.001) and to more pronounced cognitive declines over the average 7 years (ΔGlobalCognition = -0.109, p < 0.05); this was consistent across cognitive domains.

CONCLUSION

Central obesity alone was not associated with cognitive function. However, presence of both central obesity and cardiometabolic abnormalities was robustly predictive of cognition and 7-year cognitive declines, suggesting that in combination these factors may alter the cognitive trajectories of middle-aged and older Hispanics/Latinos.

The association of sleep quality and sleep duration with nutritional status in older adults: Findings from the WCHAT study

OBJECTIVE

To identify the associations between sleep quality, sleep duration and nutritional status in older adults.

METHODS

Data from a total of 6792 community-dwellings adults aged 50 and over from the baseline of the West China Health and Aging Trend (WCHAT) study were analyzed. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI). PSQI scores >5 were categorized as poor sleep quality. Duration of sleep was classified as <6 h, 6-7 h, 7-8 h, 8-9 h and ≥9 h. The Mini Nutritional Assessment Short Form (MNA-SF) was used to assess nutritional status and a score <12 was identified as indicating a risk of malnutrition. Logistic regression models were used to explore the associations.

RESULTS

Of 6792 participants (mean age 62.4 ± 8.3 years, 62.5 % women), 1831 (27.0 %) were at risk of malnutrition. The prevalence of poor sleep quality was 47.1 %. In the logistic regression model adjusted for potential confounders, poor sleep quality was significantly associated with a risk of malnutrition (OR = 1.62, 95 %CI = 1.44, 1.82). Sleep durations of less than 6 h and of more than 9 h were shown to increase the odds of malnutrition risk (OR = 1.42, 95 %CI = 1.16, 1.73 and OR = 1.24, 95 %CI = 1.05, 1.47, respectively).

CONCLUSIONS

Sleep disorders were significantly associated with malnutrition risk among older adults. Our results highlight the importance of good sleep quality and enough sleep in order to maintain good nutritional status in older adults.

Circadian Rhythms, Sleep, and Aging

Abstract. Circadian mechanisms and the sleep-wakefulness rhythms guarantee survival, adaptation, efficient action in everyday life or in emergencies and well-being. Disordered circadian processes at central and/or cellular levels, sleep disorders, and unhealthy wakefulness/sleep rhythms can impair the physiological circadian organization and result in subjective, professional, or behavioral changes ranging from functional inadequacy to higher risks at work or on the road to medical relevance. Circadian rhythms and the sleep organization change ontogenetically; major changes result from normal aging and from the multiple diseases that are often associated. There are circular functional interactions involving sleep/sleep disorders, the autonomic and immune systems, and the functional changes in the circadian system due to aging that deserve attention but have been overlooked thus far.

Sleep Disturbances After General Anesthesia: Current Perspectives

The purpose of this article is to review (1) sleep mechanism under general anesthesia, harmful effects of postoperative sleep disturbances; (2) risk factors associated with postoperative sleep disturbances; (3) measures to prevent and improve postoperative sleep disturbances. General anesthesia changes the postoperative sleep structure especially in elderly patients after major surgery and results in a high incidence rate of sleep disturbances. Sleep disturbances produce harmful effects on postoperative patients and lead to a higher risk of delirium, more cardiovascular events, and poorer recovery. Some researchers do propose non-pharmacological treatments such as attention to environmental and psychological factors, application of electroacupuncture (EA) technology and pharmacological treatments are helpful, but larger high-quality clinical trials with longer following-up are needed to further investigate the efficacy and safety.

Behavioral and Psychological Symptoms that Predict Cognitive Decline or Impairment in Cognitively Normal Middle-Aged or Older Adults: a Meta-Analysis

Epidemiological studies have revealed that behavioral and psychological (or non-cognitive) symptoms are risk factors for cognitive decline in older adults. This study aimed to systematically review the literature and determine which behavioral and psychological symptoms are most predictive of future cognitive decline among individuals with no pre-existing cognitive impairments. The selected studies included middle-aged or older adults without cognitive impairments. The predictors were assessed using behavioral and psychological questionnaires, or diagnostic interviews, to identify non-cognitive symptoms or psychiatric clinical conditions. The follow-up period was at least one year, and the design of the selected studies was either retrospective or prospective. This study compared individuals with and without non-cognitive manifestations and resulted in one of three outcomes: (a) a score change on a cognitive measure, (b) a diagnosis of mild cognitive impairment, or (c) a diagnosis of Alzheimer's disease or dementia. Four online databases were searched for eligible studies from the database inception to January 17, 2017: MEDLINE (PubMed), Embase (OVID), PsycINFO, and Web of Science. Pooled effect sizes were estimated using a random-effect model. Higgins I², the Q statistic, and tau-squared were used to quantify the observed heterogeneity between the studies. Results indicate that depression and sleep duration (long and short) were the most consistent associations between behavioral or psychological symptoms and cognitive decline. This meta-analysis supports the need to assess behavioral and psychological symptoms in cognitively intact older adults to identify those who are at risk for cognitive decline.

Associations between self-reported sleep characteristics and incident mild cognitive impairment: The Heinz Nixdorf Recall Cohort Study

Associations of sleep characteristics with mild cognitive impairment (MCI) have been examined in cross-sectional, but rarely in longitudinal studies. Incident MCI and sleep characteristics were assessed in 1,890 participants of the first and second follow-up of the Heinz Nixdorf Recall study, a population-based cohort study in Germany (age at first follow-up 50-80 years, mean follow-up 5.2 years). MCI was assessed with extensive cognitive tests. Sleep questionnaires including PSQI (Pittsburgh Sleep Quality Index) were used to assess sleep quality, sleep disturbances, time asleep, and time in bed. Relative risks (RR) of developing MCI when exposed to sleep characteristics were assessed in regression models adjusted for sociodemographic and cardiovascular risk factors. Poor sleep quality (PSQI > 5) (RR = 1.43, 95% CI: 1.12-1.82, fully adjusted, reference: PSQI ≤ 5) and difficulties initiating sleep (almost nightly versus never) (RR = 1.40, 0.94-2.08) were associated with incident MCI. For time in bed, the risk of MCI was increased for ≤ 5 hours (RR = 2.86, 1.24─6.60, reference:7 to <8 hours). In this longitudinal study with older participants, MCI risk was increased in persons with poor sleep quality, difficulties initiating sleep, and short time in bed.

Sleep and neurocognitive decline in the Hispanic Community Health Study/Study of Latinos

INTRODUCTION

To determine if sleep-disordered breathing (SDB), daytime sleepiness, insomnia, and sleep duration predict seven-year neurocognitive decline in US Hispanics/Latinos (N = 5247).

METHODS

The exposures were baseline SDB, daytime sleepiness, insomnia, and sleep duration. The outcomes were change in episodic learning and memory (B-SEVLT-Sum and SEVLT-Recall), language (word fluency [WF]), processing speed (Digit Symbol Substitution), and a cognitive impairment screener (Six-item Screener [SIS]).

RESULTS

Mean age was 63 ± 8 years, with 55% of the population being female with 7.0% Central American, 24.5% Cuban, 9.3% Dominican, 35.9% Mexican, 14.4% Puerto Rican, and 5.1% South American background. Long sleep (>9 hours), but not short sleep (<6 hours), was associated with decline (standard deviation units) in episodic learning and memory (β_SEVLT-Sum ⁼ -0.22 [se = 0.06]; P < .001; β_SEVLT-Recall = -0.13 [se = 0.06]; P < .05), WF (Pwf = -0.20 [se 5 0.06]; P < .01), and SIS (β_SIS = -0.16 [se = 0.06]; P < .01), but not processing speed, after adjusting for covariates. SDB, sleepiness, and insomnia were not associated with neurocognitive decline.

CONCLUSION

Long sleep duration predicted seven-year cognitive decline.

Dietary Patterns, Physical Activity, Sleep, and Risk for Dementia and Cognitive Decline

PURPOSE OF REVIEW

Diet, physical activity, and sleep are three major modifiable lifestyle factors. This selective review examines the evidence for strong and reliable associations between these three lifestyle factors and risk of dementia and cognitive decline, in an effort to assist clinicians with providing more informed answers to the common questions they face from patients.

RECENT FINDINGS

Certain aspects of nutrition can decrease risk for dementia. Physical activity has also been associated with delayed or slower age-related cognitive decline. In addition, emerging evidence links sleep dysfunction and dementia, with amyloid deposition being a possible mediator. Data from further clinical trials are needed before more definitive conclusions can be drawn regarding the efficacy of these lifestyle interventions for lowering the risk of incident dementia and cognitive decline. Nevertheless, it is reasonable to make recommendations to our patients to adopt certain dietary changes and to engage in regular physical activity to improve cardiovascular risk factors for dementia. It is also reasonable to include questions on sleep during cognitive evaluations of the elderly, given the common co-occurrence of sleep dysfunction and cognitive impairment in the elderly population.

Association of health related quality of life domains with daytime sleepiness among elderly recipients of long-term services and supports

Excessive daytime sleepiness (EDS) is prevalent in older adults; however, data are lacking that examine EDS across living environments. The aims of this secondary data analysis were to identify the prevalence and predictors of EDS among older adults receiving long-term services and supports (LTSS) in assisted living communities (ALCs), nursing homes (NHs), and the community. Participants (n = 470) completed multiple measures including daytime sleepiness. Logistic regression modeling was used to identify EDS predictors. Participants were primarily female and white with a mean age of 81 ± 9 years. The overall prevalence of EDS was 19.4%; the prevalence differed across living environment. Older adults in ALCs and NHs had higher odds of EDS than those living in the community. Also, depressive symptoms and number of bothersome symptoms predicted EDS. Upon admission for LTSS, evaluating older adults, especially those in ALCs and NHs, for depression and bothersome symptoms may reveal modifiable factors of EDS.

Association Between Daily Sleep Duration and Risk of Dementia and Mortality in a Japanese Community

OBJECTIVES

To investigate the association between daily sleep duration and risk of dementia and death in a Japanese elderly population.

DESIGN

Prospective cohort study.

SETTING

The Hisayama Study, Japan.

PARTICIPANTS

Community-dwelling Japanese individuals aged 60 and older without dementia.

MEASUREMENTS

Self-reported daily sleep duration was grouped into 5 categories (<5.0, 5.0-6.9, 7.0-7.9, 8.0-9.9, ≥10.0 hours). The association between daily sleep duration and risk of dementia and death was determined using a Cox proportional hazards models.

RESULTS

During follow-up, 294 participants developed dementia, and 282 died. Age- and sex-adjusted incidence rates of dementia and all-cause mortality were significantly greater in subjects with daily sleep duration of less than 5.0 hours and 10.0 hours and more than in those with daily sleep duration of 5.0 to 6.9 hours. These associations remained unchanged after adjustment for potential confounding factors (<5.0 hours: hazard ratio (HR)=2.64, 95% confidence interval (CI)=1.38-5.05 for dementia; HR=2.29, 95% CI=1.15-4.56 for death; ≥10.0 hours: HR=2.23, 95% CI=1.42-3.49 for dementia; HR=1.67, 95% CI=1.07-2.60 for death). Similar U-shaped associations were observed for Alzheimer's disease and vascular dementia. With regard to the influence of hypnotic use on risk of dementia and death, subjects who used hypnotics and had any sleep duration had a risk of dementia that was 1.66 times as great and a risk of death that was 1.83 times as great as those who did not use hypnotics and had a daily sleep duration of 5.0 to 6.9 hours.

CONCLUSION

Short and long daily sleep duration and hypnotic use are risk factors for dementia and death in Japanese elderly adults.

Short sleep is associated with more depressive symptoms in a multi-ethnic cohort of older adults

OBJECTIVES

To evaluate cross-sectional and prospective associations between short and long sleep duration and depressive symptoms in older adults (aged >65 years).

METHODS

The data from a subsample of the racially/ethnically diverse Northern Manhattan Study were analyzed. Depressive symptoms were assessed twice with the Center for Epidemiologic Studies Depression Scale (CES-D), approximately 5 years apart. The presence of depressive symptoms was defined as a CES-D score ≥16 or use of antidepressants. Self-reports of short (<6 h), intermediate (6-8 h) and long (≥9 h) sleep were assessed prior to the initial CES-D. Logistic regression was used to evaluate the cross-sectional associations between short and long sleep durations with depressive symptoms, using intermediate sleep as the reference. The prospective association between sleep duration and depression in a sample of participants without depressive symptoms at first CES-D was also analyzed. All models were adjusted for demographic, behavioral, and vascular risk factors.

RESULTS

The initial sample consisted of 1110 participants: 62% women, 69% Hispanic, 17% black, 14% white. Short sleep was reported by 25%, intermediate sleep by 65%, and long sleep by 9%. Depressive symptoms were described in 25% of the initial sample. Short sleep, but not long sleep, was associated with depressive symptoms at baseline (adjusted OR 1.8, 95% CI 1.3-2.6), and at follow-up (adjusted OR 1.9, 95% CI 1.1-3.5; median follow-up = 5.1 years).

CONCLUSION

Short sleep duration had a cross-sectional and prospective association with depressive symptoms in an urban multi-ethnic cohort of older adults.

Excessive Sleepiness and Longer Nighttime in Bed Increase the Risk of Cognitive Decline in Frail Elderly Subjects: The MAPT-Sleep Study

Objective: To identify self-reported sleep-wake disturbances that increase the risk of cognitive decline over 1-year follow-up in frail participants.

Background: Risk factors for cognitive impairment need to be better identified especially at earliest stages of the pathogenesis. Sleep-wake disturbances may be critical factors to consider and were thus being assessed in this at-risk population for cognitive decline.

Methods: Frail elderly participants aged ≥70 years were selected from a subsample of the Multi-domain Alzheimer Preventive Trial (MAPT) for a sleep assessment (MAPT-sleep study) at 18-month follow-up (M18). Sleep-wake disturbances were evaluated using a clinical interview (duration of daytime and nighttime sleep, time in bed, number of naps, and presence of clinically-defined sleep disorders) and numerous validated questionnaires [Epworth Sleepiness Scale for excessive daytime sleepiness (EDS), Insomnia Severity Scale and Berlin Questionnaire]. Cognitive decline was defined as a difference between the MMSE and cognitive composite scores at M24 and M36 that was ranked in the lowest decile. Multivariate logistic regression models adjusted for several potential confounding factors were performed.

Results: Among the 479 frail participants, 63 developed MMSE-cognitive decline and 50 cognitive composite score decrease between M24 and M36. Subjects with EDS had an increased risk of MMSE decline (OR = 2.46; 95% CI [1.28; 4.71], p = 0.007). A longer time spent in bed during night was associated with cognitive composite score decline (OR = 1.32 [1.03; 1.71], p = 0.03). These associations persisted when controlling for potential confounders. Patients with MMSE score decline and EDS had more naps, clinically-defined REM-sleep Behavior Disorder, fatigue and insomnia symptoms, while patients with cognitive composite score decline with longer time in bed had increased 24-h total sleep time duration but with higher wake time after onset.

Conclusions: The risk of cognitive decline is higher in frailty subjects with EDS and longer nighttime in bed. Early detection of sleep-wake disturbances might help identifying frail subjects at risk of cognitive decline to further propose sleep health strategies to prevent cognitive impairment.

http://www.clinicaltrials.gov NCT00672685; Date of registration May, 2nd 2008.

The enigma of sleep

Sleep has a critical role in promoting and maintaining neurological health and organismal homeostasis. Research over the past 135 years has brought significant understanding on various aspects of sleep biology; however, many questions still remain around the role and function of sleep. Sleep clearly has a powerful influence on infectious disease, cardiovascular health and neurological disorders. During the modern age, the majority of investigation into sleep has focused on identifying the biological factors underlying the effect of sleep on various pathological conditions. Disorders of sleep have the power to affect neuroimmunity, cognition and the development of neurological disorders such as Alzheimer's and autism. This present short review will highlight these factors affecting sleep.