Sleep duration, sleep efficiency, and amyloid ß among cognitively healthy later-life adults: a systematic review and meta-analysis.

BACKGROUND: Abnormal amyloid ß (Aß) deposits in the brain are a hallmark of Alzheimer's disease (AD). Insufficient sleep duration and poor sleep quality are risk factors for developing AD. Sleep may play a role in Aß regulation, but the magnitude of the relationship between sleep and Aß deposition remains unclear. This systematic review examines the relationship between sleep (i.e., duration and efficiency) with Aß deposition in later-life adults. METHODS: A search of PubMed, CINAHL, Embase, and PsycINFO generated 5,005 published articles. Fifteen studies met the inclusion criteria for qualitative syntheses; thirteen studies for quantitative syntheses related to sleep duration and Aß; and nine studies for quantitative syntheses related to sleep efficiency and Aß. RESULTS: Mean ages of the samples ranged from 63 to 76 years. Studies measured Aß using cerebrospinal fluid, serum, and positron emission tomography scans with two tracers: Carbone 11-labeled Pittsburgh compound B or fluorine 18-labeled. Sleep duration was measured subjectively using interviews or questionnaires, or objectively using polysomnography or actigraphy. Study analyses accounted for demographic and lifestyle factors. Based on 13 eligible articles, our synthesis demonstrated that the average association between sleep duration and Aß was not statistically significant (Fisher's Z = -0.055, 95% CI = -0.117 ~ 0.008). We found that longer self-report sleep duration is associated with lower Aß (Fisher's Z = -0.062, 95% CI = -0.119 ~ -0.005), whereas the objectively measured sleep duration was not associated with Aß (Fisher's Z = 0.002, 95% CI = -0.108 ~ 0.113). Based on 9 eligible articles for sleep efficiency, our synthesis also demonstrated that the average association between sleep efficiency and Aß was not statistically significant (Fisher's Z = 0.048, 95% CI = -0.066 ~ 0.161). CONCLUSION: The findings from this review suggest that shorter self-reported sleep duration is associated with higher Aß levels. Given the heterogeneous nature of the sleep measures and outcomes, it is still difficult to determine the exact relationship between sleep and Aß. Future studies with larger sample sizes should focus on comprehensive sleep characteristics and use longitudinal designs to better understand the relationship between sleep and AD.

Exploring the interplay of psychological and biological components of stress response and telomere length in the transition from middle age to late adulthood: A systematic review.

Ageing and chronic stress have been linked to reduced telomere length (TL) in mixed-age groups. Whether stress response components are linked to TL during the midlife-to-late adulthood transition remains unclear. Our study aimed to synthesise evidence on the relationship between psychological and biological components of stress response on TL in middle-aged and older adults. We conducted a systematic review of studies obtained from six databases (PubMed, CINAHL, EMBASE, PsycINFO, Web of Science, and Scopus) and evaluated by two independent reviewers. Original research measuring psychological and biological components of stress response and TL in human individuals were included. From an initial pool of 614 studies, 15 were included (n = 9446 participants). Synthesis of evidence showed that higher psychological components of the stress response (i.e., global perceived stress or within a specific life domain and cognitive appraisal to social-evaluative stressors) were linked to shorter TL, specifically in women or under major life stressors. For the biological stress response, cortisol, dehydroepiandrosterone sulphate and IGF-1/cortisol imbalance, IL-6, MCP-1, blood pressure, and heart rate presented a significant association with TL, but this relationship depended on major life stressors and the stress context (manipulated vs. non-manipulated conditions). This comprehensive review showed that psychological and biological components of the stress response are linked to shorter TL, but mainly in women or those under a major life stressor and stress-induced conditions. The interaction between stressor attributes and psychological and biological reactions in the transition from middle to late adulthood still needs to be fully understood, and examining it is a critical step to expanding our understanding of stress's impact on ageing trajectories.

Circadian timing, melatonin and hippocampal volume in later-life adults.

Hippocampal atrophy is a prominent neurodegenerative feature of Alzheimer's disease and related dementias. Alterations in circadian rhythms can exacerbate cognitive aging and neurodegeneration. This study aimed to examine how dim light melatonin onset and melatonin levels are associated with hippocampal volume in cognitively healthy individuals. We studied data from 52 later-life adults (mean age ± SD = 70.0 ± 6.3 years). T1-weighted anatomical images from 3.0 T magnetic resonance imaging data were collected and processed using the BRAINSTools toolbox. Dim light melatonin onset was used to assess circadian timing. The area under the curve was calculated to quantify melatonin concentration levels 6 hr before bedtime, and 14-day wrist actigraphy data were used to assess habitual bedtime. Multiple linear regression modelling with hippocampal volume as the dependent variable was used to analyse the data adjusting for age and sex. The average dim light melatonin onset was 19:45 hours (SD = 84 min), and area under the curve of melatonin levels 6 hr before habitual bedtime was 38.4 pg ml-1 × hr (SD = 29.3). We found that later dim light melatonin onset time (b = 0.16, p = 0.005) and greater area under the curve of melatonin levels 6 hr before habitual bedtime (b = 0.05, p = 0.046) were associated with greater adjusted hippocampal volume. The time between dim light melatonin onset and the midpoint of sleep timing was not associated with hippocampal volume. The findings suggest that earlier circadian timing (dim light melatonin onset) and reduced melatonin may be associated with reduced hippocampal volume in older adults. Future research will help researchers utilize circadian rhythm information to delay brain aging.

Sleep Duration and Amyloid ß Among Cognitively Healthy Later-Life Adults: A Systematic Review and Meta-Analysis.

Background: Amyloid ß (Aß) is a hallmark of Alzheimer's disease (AD). Insufficient sleep duration and poor sleep quality have been found to be a risk factor of developing AD because sleep may involve regulating Aß. However, the magnitude of the relationship between sleep duration and Aß is still unclear. This systematic review examines the relationship between sleep duration and Aß in later-life adults. Methods: We screened 5,005 published articles searched from relevant electronic databases (i.e., PubMed, CINAHL, Embase, and PsycINFO) and reviewed 14 articles for the qualitative synthesis and 7 articles for the quantitative synthesis. Results: Mean ages of the samples ranged from 63 to 76. Studies measured Aß using cerebrospinal fluid, serum, and positron emission tomography scans with two tracers: Carbone 11-labeled Pittsburgh compound B or fluorine 18-labeled. Sleep duration was subjectively measured using interviews, questionnaires, or using objective measures such as polysomnography or actigraphy. The studies accounted for demographic and lifestyle factors in their analyses. Five of the 14 studies reported a statistically significant association between sleep duration and Aß. Using seven eligible articles, our quantitative synthesis demonstrated that the average association between sleep duration and Aß was not statistically significant (Fisher's Z = -0.006, 95% CI= -0.065 ~ 0.054). Conclusion: This review suggests that caution should be taken when considering sleep duration as the primary factor for Aß levels. More studies are needed using a longitudinal design, comprehensive sleep metrics, and larger sample sizes to advance our understanding of the optimal sleep duration and AD prevention.

Sleep, circadian rhythm characteristics, and melatonin levels in later life adults with and without coronary artery disease.

STUDY OBJECTIVES: The purpose of this study was to conduct a comprehensive assessment of sleep and circadian rhythms in individuals with and without coronary artery disease (CAD). METHODS: This was a cross-sectional study. Participants were 32 individuals, mean age = 70.9, female 46.9%, 19 with CAD, and 13 without CAD. We assessed sleep quality and 24-hour rest-activity rhythms for 14 days using wrist actigraphy and self-report measures, and circadian rhythm using dim light melatonin onset. RESULTS: Melatonin levels prior to habitual bedtime were significantly lower in individuals with CAD than in those without CAD (median area under the curve = 12.88 vs 26.33 pg/ml × h, P = .049). The median circadian timing measured by dim light melatonin onset was the same for the 2 groups with 20:26 [hours:minutes] for individuals with CAD and 19:53 for the control group (P = .64, r = .14). Compared to the control group, the CAD group had significantly lower amplitude (P = .03, r =-.48), and lower overall rhythmicity (pseudo-F-statistic P = .004, r = -.65) in their 24-hour rest-activity rhythms. CONCLUSIONS: This is one of the first studies to comprehensively assess both sleep and circadian rhythm in individuals with CAD. Compared to non-CAD controls, individuals with CAD had lower levels of melatonin prior to habitual bedtime and a lower 24-hour rest-activity rhythm amplitude and overall rhythmicity. Future studies using larger sample sizes should further investigate the possibility of suppressed circadian rhythmicity in individuals with CAD. CITATION: Moon C, Benson CJ, Albashayreh A, Perkhounkova Y, Burgess HJ. Sleep, circadian rhythm characteristics, and melatonin levels in later life adults with and without coronary artery disease. J Clin Sleep Med. 2023;19(2):283-292.

Association of Sleep With Risk of Alzheimer's Disease Mortality: NIH-AARP Diet and Health Study.

OBJECTIVES: Alzheimer's disease (AD) and related dementias contribute to one in three senior deaths. Lifestyle factors, including sleep, may contribute to AD risk and mortality; however, current evidence on sleep and AD mortality is mixed. METHODS: We used data from the NIH-AARP Diet and Health Study. Sleep duration and napping were self-reported and AD death were ascertained via linkage to the National Death Index. RESULTS: Long sleep and napping were both associated with increased AD mortality. Specifically, 9+ hr of sleep was associated with 50% increase (hazard ratio = 1.50, 95% CI = [1.17, 1.92]) in AD mortality when compared 7 to 8 hr, while napping for 1+ hr was associated with 29% increase (1.29 [1.08, 1.55]) when compared with no napping. Results appeared to be stronger in men and remained after removing AD deaths within first 5 years after baseline. DISCUSSION: Long sleep and napping may predict higher AD mortality in the older population.

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.

Relationships among types of activity engagement and insomnia symptoms among older adults.

BACKGROUND: An increasing awareness exists that lack of activity engagement is associated with insomnia symptoms. However, the majority of studies have focused on the association between a single type of activity engagement and insomnia symptoms. METHODS: This is a cross-sectional study using secondary data from the Health and Retirement Study examining the relationships among different types of activity engagement and insomnia symptoms among older adults. The sample for this study included 3321 older adults who responded to survey modules on activity engagement and insomnia symptoms in 2016. Activity engagement was measured using items for three types of activities (i.e., social, cognitive, and physical) validated in this study. Insomnia symptoms were measured using four items (i.e., difficulty of falling asleep, waking up during the night, waking up too early, and feeling rested). Independent t-tests were conducted to identify the differences in insomnia symptoms according to activity engagement level. Regressions were conducted to examine the associations among three types of activity engagement and insomnia symptoms after adjusting for covariates such as demographics, chronic disease, activities of daily living difficulty, cognitive function, sleep disorder, loneliness, and caregiving. RESULTS: The respondents in the high-level social, cognitive, and physical activity engagement groups were found to show fewer insomnia symptoms. Furthermore, higher social (ß = - 0.04, p = 0.040) and cognitive (ß = - 0.06, p = 0.007) activity engagements were associated with fewer insomnia symptoms even after adjusting for other types of activity engagement and all covariates. CONCLUSIONS: This study suggests that older adults with higher social and cognitive activity engagements may be likely to have fewer insomnia symptoms. Based on these results, future research is needed to develop multi-component intervention programs that can encourage older adults to engage in these activities.

Longitudinal sleep characteristics and hypertension status: results from the Wisconsin Sleep Cohort Study.

AIMS: Sleep characteristics such as short sleep duration or sleep-disordered breathing are established predictors of hypertension. However, few studies have used in-lab polysomnography with a longitudinal design to measure how hypertension is associated with different sleep stages over time. The purpose of this study is to examine whether hypertension is associated with the longitudinal course of sleep quality over time. METHODS: The current study evaluated data from the Wisconsin Sleep Cohort Study, which consists of 1525 adults in a community-based population of middle-aged to older adults followed for approximately 12-25 years. Sleep characteristics were objectively measured using polysomnography and subjectively assessed using a self-report questionnaire on insomnia complaints. We used linear mixed-effects regression models and cumulative logit models to assess whether the interaction of hypertension and time is associated with objective and subjective sleep. RESULTS: We found people with hypertension exhibited a greater decline in total sleep time in rapid eye movement sleep (%) over time than those without hypertension (P < 0.05). Individuals with hypertension had less decline in % N3 sleep over time than those without hypertension (P < 0.05). Among the subjective insomnia complaints, our findings indicate hypertensive individuals have a higher probability of having higher levels of 'difficulties in falling asleep' compared with people without hypertension. CONCLUSION: These findings suggest that hypertension is associated with modified longitudinal changes of objective and subjective sleep characteristics.

Postdoctoral Opportunities for Nursing PhD Graduates: A Resource Guide.

Before completing a nursing PhD program, doctoral students are encouraged to seek out and apply for a position in one of many, often highly competitive postdoctoral programs. These programs include the more traditional National Institutes of Health (NIH) funded experiences, such as the T32, as well as the nontraditional institution funded positions, including the associate faculty role. Graduates often need guidance on which postdoctoral programs are available, the resources each program offers to promote development of the applicant's program of research, the disadvantages of each program, and what each program uses as benchmarks for success. This article summarizes both traditional and nontraditional postdoctoral positions including the T32, F32, F99/K00, T90/R90, research supplements, associate faculty, research associate, and hospital-affiliated postdoctoral positions. This article updates previous papers describing postdoctoral opportunities and offers a starting place to aide PhD students planning their postgraduate activities in seeking and evaluating these positions.

The association of sleep-disordered breathing and white matter hyperintensities in heart failure patients.

Heart failure patients often manifest white matter hyperintensites on brain magnetic resonance imaging (MRI). White matter hyperintnsities have also been linked with cognitive problems in patients with heart failure. Sleep disordered breathing may contribute to structural brain changes in heart failure. The purpose of this study was to test the extent to which the apnea hypopnea index is associated with global and regional white matter hyperintensities, and is a moderating factor in the relationship between age and white matter hyperintensites. A total of 28 HF patients [mean age (SD) = 67.89 (5.8)] underwent T1-weighted and T2FLAIR MRI and a home sleep monitoring study. The apnea hypopnea index cut off of 10 was used to compare between higher and lower risks of sleep disordered breathing. Regression analysis was used to test the association between apnea hypopnea index and both global and regional white matter hyperintensities. The interaction term was entered to identify the moderation effect. Apnea hypopnea index was associated with higher regional white matter hyperintensities but not global white matter hyperintensities. There was a significant interaction between the apnea hypopnea index and age, such that older participants with the apnea hypopnea index ≥10 showed greater regional white matter hyperintensities than those with the apnea hypopnea index <10. The results of this preliminary study indicate that a higher apnea hypopnea index is associated with more white matter hyperintensities. The age-related white matter hyperintensities appear to be exacerbated by apnea hypopnea index in our individuals with heart failure. Future studies are needed to further investigate the underlying mechanisms.

Multiple chronic conditions: Implications for cognition - Findings from the Wisconsin Registry for Alzheimer's Prevention (WRAP).

INTRODUCTION: Several chronic illnesses have demonstrated relationships to cognitive decline in the context of aging. However, researchers have largely ignored the effects of multi-morbidity in the context of Alzheimer's disease and related dementias (ADRD) risk. The purpose of this study is to examine the relationship between multiple chronic conditions (MCC) and cognitive decline. METHODS: Latent class analysis (LCA) was completed to identify different subgroups of the 1285 participants from the Wisconsin Registry for Alzheimer's Prevention who were recognized based on their self-reported chronic illnesses. Differences between variables of interest (i.e., biomarkers and depressive symptom scores) and each of the individual classes were then explored. Chi-square tests were used to examine the association between MCC and cognitive status. RESULTS: LCA revealed a four-class model best fit solution. Participants in the sleep class had the highest incidence of new onset cognitive decline. DISCUSSION: Findings offer evidence of an association between specific MCC groups and the development of cognitive decline. Nurses should monitor and screen for cognitive decline in the presence of MCC in order to better target self-management interventions.

Sleep-disordered breathing, brain volume, and cognition in older individuals with heart failure.

BACKGROUND AND PURPOSE: Sleep-disordered breathing is common in individuals with heart failure and may contribute to changes in the brain and decreased cognition. However, limited research has explored how the apnea-hypopnea index contributes to brain structure and cognition in this population. The aims of this study were to explore how the apnea-hypopnea index is associated with brain volume and cognition in heart failure patients. METHODS: Data of 28 heart failure patients (mean age = 67.93; SD = 5.78) were analyzed for this cross-sectional observational study. We evaluated the apnea-hypopnea index using a portable multichannel sleep-monitoring device. All participants were scanned using 3.0 Tesla magnetic resonance imaging and neuropsychological tests. Brain volume was evaluated using a voxel-based morphometry method with T1-weighted images. We used multiple regressions to analyze how the apnea-hypopnea index is associated with brain volume and cognition. RESULTS: We found an inverse association between apnea-hypopnea index scores and white matter volume (ß = -0.002, p = 0.026), but not in gray matter volume (ß = -0.001, p = 0.237). Higher apnea-hypopnea index was associated with reduced regional gray and white matter volume (p < 0.001, uncorrected). Cognitive scores were not associated with the apnea-hypopnea index (p-values were >0.05). CONCLUSION: Findings from this study provide exploratory evidence that higher apnea-hypopnea index may be associated with greater brain volume reduction in heart failure patients. Future studies are needed to establish the relationship between sleep-disordered breathing, brain volume, and cognition in heart failure samples.

Multimodal brain imaging investigation of self-reported sleep quality and daytime sleepiness in older adults with heart failure.

PURPOSE OF THE STUDY: Individuals with heart failure (HF) have a high frequency of sleep problems. Patients with HF present with structural brain changes different from normal aging including reductions in brain volume, increases in white matter hyperintensity (WMH) and reduced cerebral blood flow. These structural changes in the brain may explain the pathophysiology of sleep and daytime problems. The objective of this study was to determine whether multimodal imaging data are related to self-reported sleep problems and daytime sleepiness in older adults with HF. METHODS: Participants in this study underwent magnetic resonance imaging scans on the General Electric 3.0 T Discovery MR750 to acquire WMH, cerebral blood flow and brain volume. Data on 37 stable HF patients (mean age = 68; SD = 5.75) were included. RESULTS: In this sample, WMH was associated with daytime sleepiness (p = 0.025). However, gray and white matter volume and cerebral blood flow were not associated with daytime sleepiness, sleep quality or insomnia. CONCLUSION: Although further studies are needed to determine the relationship between WMH and sleep and daytime problems, the findings preliminarily support that increases in WMH from ischemic changes could explain increases in daytime sleepiness among people with HF.

Rest-Activity Patterns in Older Adults with Heart Failure and Healthy Older Adults.

The purpose of this investigation is to examine differences in rest-activity patterns and sleep characteristics in older adults with heart failure (HF) and healthy older adults. The sample included older adults with HF (n = 20) and a reference group of healthy older adults (n = 20). Traditional cosinor analysis was used to assess three parameters of rest-activity from wrist actigraphy data: amplitude (range of activity), mesor (mean activity), and acrophase (time of peak activity). Traditional sleep characteristics were also determined from actigraphy data: total sleep time (TST), sleep latency (SL), sleep efficiency (SE), and wake after sleep onset (WASO). The HF group demonstrated significantly lower mesor and amplitude than the reference group (p < .01). The HF group had significantly greater TST (p < .01), but the groups had similar SE, SL, and WASO. Despite similar sleep characteristics to healthy older adults, overall rest-activity patterns were significantly dampened in those with HF.

The Role of Heart Failure, Daytime Sleepiness, and Disturbed Sleep on Cognition.

Disturbed sleep and daytime sleepiness may interfere with possible direct relationships between heart failure (HF) and cognition, yet there is limited research investigating this relationship. We aimed to investigate possible mediating roles of disturbed sleep and daytime sleepiness on the relationship between HF and selected cognitive domains among individuals with and without HF. In a cross-sectional design study, we examined the data of 841 older adults with and without HF from the Aging, Demographics, and Memory Study (ADAMS). We found individuals with HF were likely to have a higher degree of disturbed sleep and daytime sleepiness. Both disturbed sleep and daytime sleepiness were significant predictors of cognition. We found that only daytime sleepiness mediated the relationship between the presence of HF and cognitive domains, such as in attention, memory, and executive function after controlling for covariates. Interventions to improve daytime sleepiness among individuals with HF may also help improving cognition.

A Narrative Review of How Sleep-Related Breathing Disorders and Cardiovascular Diseases Are Linked: An Update for Advanced Practice Registered Nurses.

PURPOSE/OBJECTIVES: Sleep-related breathing disorders (SRBDs), including obstructive sleep apnea and central sleep apnea, are common among patients with cardiovascular disease (CVD), but clinicians often do not pay enough attention to SRBDs. The purpose of this narrative review is to update advanced practice registered nurses on the literature focusing on the relationship between SRBDs and CVD (eg, hypertension, heart failure, coronary artery disease, arrhythmias, and stroke) and on treatments that can improve SRBDs in patients with CVD. DESCRIPTION OF THE PROJECT: We conducted an electronic search of the literature published between 1980 and 2016 from PubMed, Cumulative Index to Nursing and Allied Health Literature, Web of Science, Academic Search Premier, and related health resource Web sites to address the aims of this study. OUTCOMES: Fifty-six primary research articles (42 observational studies and 14 experimental and quasi-experimental studies) were selected based on our study aims and inclusion criteria. The studies revealed that individuals with CVD are at a greater risk for SRBDs and that SRBDs can worsen CVD. The findings from the studies also suggest that positive airway treatment could improve both SRBDs and CVD. CONCLUSIONS: This review found a close relationship between SRBDs and CVD. Advanced practice registered nurses are in key positions to identify and help patients manage SRBDs. In particular, advanced practice registered nurses can educate staff and establish standards of practice to improve outcomes for patients with CVD.

Is sleep quality related to cognition in individuals with heart failure?

OBJECTIVE: To examine how self-reported sleep quality and daytime symptoms are associated with selected domains of cognitive function among individuals with heart failure (HF). BACKGROUND: HF patients suffer from poor sleep quality and cognitive decline. The relationship between sleep and cognition has not been well documented among individuals with HF. METHODS: In this descriptive, cross-sectional study, 68 individuals with HF (male: 63%, mean age = 72 years, SD = 11) completed sleep questionnaires and a neuropsychological battery. RESULTS: Participant had mean Pittsburgh Sleep Quality Index score of 5.04 (SD = 2.8). Regression analyses demonstrated neither sleep quality or excessive daytime sleepiness (EDS) were related to cognitive function, but daytime dysfunction was related to lower letter fluency and attention index. CONCLUSION: Contrary to some earlier reports, subjective sleep and EDS in this group of individuals was not associated with cognitive decline.

Preoperative intra-aortic balloon pumping in high-risk cardiac surgery patients.

Intra-aortic balloon pumping increases myocardial oxygen supply and decreases myocardial oxygen demand by inflation and deflation of the balloon. This leads to increased perfusion of the coronary arteries during diastole. This technology has been used for critically ill cardiac patients for more than 30 years. The literature suggests that preoperative use of an intra-aortic balloon pump can be effective in high-risk coronary artery bypass grafting patients. Preoperative benefits of this technology may yield positive outcomes in terms of hemodynamic effect, decreased length of stay in both the intensive care unit and the hospital, and the reduction of complications. However, the intra-aortic balloon pump must be used with a profound understanding of proper mechanism and function, monitoring, and observation for potential complications. This requires excellent critical care nursing management.