Sleep Difficulties and Cognition for 10 Years in a National Sample of U.S. Older Adults

Association of reported sleep disturbances with objectively assessed mild cognitive impairment among adults in the United States

Background

Sleep is a multifaceted phenomenon influenced by both duration and quality. Various sleep disturbances have been associated with mild cognitive impairment, but the role of specific disturbances in mild cognitive impairment pathophysiology remains unclear. This study investigated the associations between distinct sleep disturbances and mild cognitive impairment in adults aged 50 and older using nationally representative data.

Methods

Longitudinal data from the Health and Retirement Study were analyzed to explore the association between mild cognitive impairment and three types of sleep disturbances: trouble falling asleep, trouble waking up, and waking up too early. Logistic regression models estimated unadjusted (Model 1) and adjusted associations accounting for sex, race/ethnicity, age, social determinants of health (Model 2), general health (Model 3), depression (Model 4), and pain and physical activity (Model 5).

Results

The study cohort included 8877 participants aged ⩾50 years in 2018 (baseline) who were followed up in 2020. Overall, 15.4% reported trouble falling asleep, 23.2% reported trouble waking up, and 12.8% reported waking up too early and being unable to fall back asleep most of the time. Among older adults, approximately 13.1% reported experiencing mild cognitive impairment; The prevalence of mild cognitive impairment was even higher in those who experienced sleep disturbances. The unadjusted odds ratio (uOR) for experiencing trouble falling asleep most of the time was 1.69 (95% CI: 1.42-2.03), for trouble waking up most of the time was 1.31 (95% CI: 1.10-1.57), and for waking up early most of the time was 1.88 (95% CI: 1.51-2.35). However, these positive associations attenuated depending on the covariate adjustment.

Conclusions

Nearly one in seven adults had mild cognitive impairment. The relationship between sleep disturbances and mild cognitive impairment has been challenging to delineate. Our findings demonstrate a positive association between sleep disturbances and mild cognitive impairment, although these associations were sensitive to covariate adjustments. These findings suggest multifaceted pathways for reducing the risk of mild cognitive impairment.

Relationship between cognitive function and sleep quality in middle-aged and older adults for minimizing disparities and achieving equity in health: Evidence from multiple nationwide cohorts

BACKGROUND

Cognitive decline, a heavy burden on middle-aged and older adults as global aging is aggravated, was found to be associated with sleep quality. However, the country-between heterogeneity of the association prevented us from quantifying underlying relationship and identifying potential effect modifiers for vulnerable populations and targeted interventions.

METHODS

We collected data from 79,922 eligible adults in five nationwide cohorts, examined the respective relationships between cognitive function and sleep quality, synthesized underlying average relationships by meta-analysis, and explored effect modifiers by meta-regressions. Additionally, we conducted subgroup and interaction analyses to identify vulnerable populations and to determine their disparities in vulnerability.

RESULTS

Although country-between disparities exist, cognitive function is robustly associated with sleep quality in middle-aged and older adults worldwide, with an effect (β) of 0.015 [0.003, 0.027]. Executive function is the subdomain most relevant to sleep quality. Disparities in the effects of sleep quality on subdomains exist in populations with different sexes (orientation: βfemale/βmale = 1.615, P = 0.020), marital statuses (orientation: βunmarried/βmarried = 2.074, P < 0.001), education levels (orientation:βuneducated/βeducated = 2.074, P < 0.001) and chronic disease statuses (memory: βunhealthy/βhealthy = 1.560, P = 0.005).

CONCLUSIONS

Cognitive function decreases with worsening sleep quality in middle-aged and older adults. Vulnerability to poor sleep generally persists in singles, females, the uneducated and people with chronic diseases. To minimize disparities and achieve health equity, we advocate for targeted interventions, i.e., encouraging socialization in singles, confirming effectiveness of hormone replacement therapy in females, employing compulsory education in middle-aged and older adults.

Perceptions and Effectiveness of a Fully Automated Brief Behavioral Insomnia Therapy, Delivered by a Virtual Companion, in Older and Young Adults

Background and Objectives

One of the most common sleep disturbances in older people is insomnia. Cognitive-behavioral therapy is the first-line treatment for this condition in older adults, but in-person treatment is costly and often unavailable. In this study, in a group of older and young subjects, we aimed to compare: (a) their initial perceptions of a fully automated mobile health intervention to manage insomnia, (b) how these perceptions related to treatment completion, and (c) the effects of the intervention on insomnia severity and related outcomes.

Research Design and Methods

A case-series study was conducted with a self-selected sample of older (≥65 years) and young (18-35 years) adults (n = 5,660) who downloaded a free app, available in France, that delivers a brief behavioral intervention for insomnia aided by a virtual companion (VC). The 17-day intervention included sleep hygiene and stimulus control recommendations. Primary outcome was treatment completion (yes/no). At the beginning of the intervention, treatment acceptability and trust in the VC were assessed with 2 short questionnaires (completion rate: 1,597 users). Insomnia was evaluated with the Insomnia Severity Index.

Results

Logistic regression analyses showed that higher credibility and trust in the app's VC were associated with higher odds of treatment completion, but only in older adults (trust scores × age group: odds ratio [OR] = 1.12; 95% confidence interval [CI] = 1.01-1.25; p < .05, and credibility scores × age group: OR = 1.25 [95% CI = 1.06-1.47], p < .01). Within the subset of users who completed the intervention (n = 289), insomnia remission (χ2 = 2.72, NS) and insomnia response rates (χ2 = 2.34, NS) were comparable across both groups.

Discussion and Implications

This brief behavioral intervention appears to be efficacious for the self-management of insomnia symptoms in older adults. The integration of persuasive interaction elements, such as avatars and virtual coaches, in fully automated interventions could be particularly useful to stimulate older adults' engagement.

Clinical Trials Registration Number

NCT05074901.

Sleep duration, insomnia and cognitive performance in the Elsa-Brasil cohort: a cross-sectional analysis

OBJECTIVE

To investigate the single and combined associations between sleep disturbances (sleep duration, insomnia symptoms in the last 30 nights, and daytime tiredness) and performance in cognitive tests.

METHODS

Cross-sectional analysis of data from visit 2 (2012-2014) of the Longitudinal Study of Adult Health from a cohort of active and retired civil servants from six Brazilian capitals. Polynomial regression with quadratic term and multiple linear regression models were performed to assess single and combined associations between sleep disturbances and memory performance, fluency, executive functions, and global cognition.

RESULTS

A total of 7,248 participants were included, with a mean age of 62.7 years (standard deviation [SD]=5.9), and 55.2% were women. Inverted U-shaped associations were observed between sleep duration and performance on all cognitive abilities, suggesting that durations shorter or longer than seven hours are associated with worse performance, regardless of age. Reported insomnia was associated with worse executive function (β: -0.08; 95% confidence interval [CI]: -0.15 to -0.01), and the magnitudes of associations were higher for individuals with insomnia at two or more moments (β: -0.12; 95%CI -0.19 to -0.05) or, especially, insomnia combined with short sleep (β: -0.18; 95%CI -0.24 to -0.11). Insomnia in two or more periods was also associated with lower memory and global cognition. There was no association between any sleep disturbance tested and verbal fluency. Isolated daytime tiredness was not associated with performance in the evaluated tests.

CONCLUSION

The results suggest that extreme sleep durations are detrimental to almost all cognitive abilities investigated, whereas insomnia appears to affect more severely the executive function.

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.

Unraveling the Threads: Sleep Difficulties, Neighborhood Physical Disorder, and Subjective Cognitive Decline in Older Americans

Background

Research suggests that the neighborhood in which people live can be a risk or protective factor for various health outcomes, including cognitive decline to Alzheimer's disease. Similar to the impact of neighborhood on health outcomes, sleep difficulties have been linked to cognitive function in older adults. However, few studies have examined how neighborhood physical disorders moderate the effects of sleep on subjective cognitive decline (SCD).

Objective

The study examined the moderating effect of neighborhood factors on the relationship between sleep difficulties and SCD.

Methods

Data were obtained from 2,494 respondents (1,065 males and 1,429 females) from Wave 11 of the National Health and Aging Trends (NHATS) data. Sleep difficulties were operationalized as the presence of difficulties in falling and staying asleep. Neighborhood physical disorder (e.g., vandalism, graffiti) was based on interviewer observations of respondents' neighborhoods. SCD was operationalized as subjective reports of increasing or worse memory loss in the past 12 months and present memory rating. We utilized Linear regression to test neighborhood physical disorder as a moderator of the relationship between sleep difficulties and SCD.

Results

We found a significant interaction between sleep difficulties and neighborhood physical disorder on SCD (β=0.046, p = 0.031, 95% CI[0.00,0.51], p < 0.001). Participants who reported higher average sleep difficulties and higher levels of neighborhood physical disorder were more likely to report SCD.

Conclusions

Our findings add to inform future health interventions and policy recommendations that address modifiable sources of cognitive decline and risk of Alzheimer's disease.

Mental and physical health pathways linking insomnia symptoms to cognitive performance 14 years later

STUDY OBJECTIVES

Insomnia may be a modifiable risk factor for later-life cognitive impairment. We investigated: (1) which insomnia symptoms are associated with subsequent cognitive functioning across domains; (2) whether insomnia-cognition associations are mediated by mental and physical health; and (3) whether these associations are modified by gender.

METHODS

Participants included 2595 adults ages 51-88 at baseline (Mage=64.00 ± 6.66, 64.5% women) in the Health and Retirement Study. The frequency of insomnia symptoms (difficulty initiating sleep, night time awakenings, early awakenings, and feeling unrested upon awakening) at baseline (2002) were quantified using a modified Jenkins Sleep Questionnaire. Cognition was assessed in 2016 via the Harmonized Cognitive Assessment Protocol and operationalized with factor scores corresponding to five domains. Depressive symptoms and vascular conditions in 2014 were assessed via self-report. Structural equation models estimated total, indirect, and direct effects of insomnia symptoms on subsequent cognition through depressive symptoms and vascular diseases, controlling for baseline sociodemographic and global cognition.

RESULTS

Frequent difficulty initiating sleep was associated with poorer episodic memory, executive function, language, visuoconstruction, and processing speed 14 years later (-0.06 ≤ β ≤ -0.04; equivalent to 2.2-3.4 years of aging). Depressive symptoms explained 12.3%-19.5% of these associations and vascular disease explained 6.3%-14.6% of non-memory associations. No other insomnia symptoms were associated with cognition, and no associations were modified by gender.

CONCLUSIONS

Difficulty initiating sleep in later life may predict future cognitive impairment through multiple pathways. Future research with longitudinal assessments of insomnia, insomnia treatments, and cognition is needed to evaluate insomnia as a potential intervention target to optimize cognitive aging.

Sleep disturbance is associated with mild cognitive impairment: a community population-based cross-sectional study

BACKGROUND

Sleep is conducive to the elimination of brain metabolites and the recovery of brain function. However, the relationship between sleep disturbance and Mild Cognitive Impairment is not fully been determined.

METHODS

This was a community population-based cross-sectional study. A total of 1,443 participants from a village in the suburbs of Xi'an, China were enrolled in 2017. Sleep quality was evaluated using the Pittsburgh sleep quality index (PSQI), and sleep disturbance was defined as a PSQI score > 5. Mini-Mental State Examination (MMSE) was used to assess cognitive function and Mild Cognitive Impairment(MCI) was defined as the MMSE score less than cutoff values and meets the diagnostic criteria. Univariate and multivariate analyses were used to analyze the relationships between sleep disturbance and MCI.

RESULTS

Among 1,443 subjects, 69(4.78%) had MCI, and 830 (57.52%) had sleep disturbance. In bivariate analysis, MCI was associated with sleep disturbance (ρ = 0.094, P<0.001). In the binary logistic regression, MCI was positively associated with the sleep disturbance (OR = 2.027, 95%CI = 1.112-3.698, P = 0.021). In the internal constitution of PSQI, MCI was negatively associated with the habitual sleep efficiency (OR = 0.447, 95%CI = 0.299-0.669, P < 0.001). Compared with waking up before or at 7 am, waking up after 7 am (OR = 0.555, 95%CI = 0.309-0.995, P = 0.048), or 8 am (OR = 0.296, 95%CI = 0.097-0.902, P = 0.032) was probably more likely to have normal cognition. However, people who slept more than 8 h a day might be more likely to suffer from MCI (OR = 5.560, 95%CI = 1.419-21.789, P = 0.014).

CONCLUSION

Sleep disturbance is associated with Mild Cognitive Impairment. However, the causal relationship between them is not clear. It needs to be further studied.

Subjective cognitive decline and self-reported sleep problems: The SCIENCe project

We aim to investigate the frequency and type of sleep problems in memory clinic patients with subjective cognitive decline (SCD) and their association with cognition, mental health, brain magnetic resonance imaging (MRI), and cerebrospinal fluid (CSF) biomarkers. Three hundred eight subjects (65 ± 8 years, 44% female) were selected from the Subjective Cognitive Impairment Cohort (SCIENCe) project. All subjects answered two sleep questionnaires, Berlin Questionnaire (sleep apnea) and Pittsburgh Sleep Quality Index (sleep quality) and underwent a standardized memory clinic work-up. One hundred ninety-eight (64%) subjects reported sleep problems, based on 107 (35%) positive screenings on sleep apnea and 162 (53%) on poor sleep quality. Subjects with sleep problems reported more severe depressive symptoms, more anxiety, and more severe SCD. Cognitive tests, MRI, and CSF biomarkers did not differ between groups. Our results suggest that improvement of sleep quality and behaviors are potential leads for treatment in many subjects with SCD to relieve the experienced cognitive complaints.

Examining sleep deficiency and disturbance and their risk for incident dementia and all-cause mortality in older adults across 5 years in the United States

BACKGROUND

Sleep disturbance and deficiency are common among older adults and have been linked with dementia and all-cause mortality. Using nationally representative data, we examine the relationship between sleep disturbance and deficiency and their risk for incident dementia and all-cause mortality among older adults.

METHODS

The National Health and Aging Trends Study (NHATS) is a nationally-representative longitudinal study of Medicare beneficiaries in the US age 65 and older. Surveys that assessed sleep disturbance and duration were administered at baseline. We examined the relationship between sleep disturbance and deficiency and incident dementia and all-cause mortality over the following 5 years using Cox proportional hazards modeling, controlling for confounders.

RESULTS

Among the sample (n = 2,812), very short sleep duration (≤5 hours: HR = 2.04, 95% CI: 1.26 - 3.33) and sleep latency (>30 minutes: HR = 1.45, 95% CI: 1.03 - 2.03) were associated with incident dementia in adjusted Cox models. Difficulty maintaining alertness ("Some Days": HR = 1.49, 95% CI: 1.13 - 1.94 and "Most/Every Day": HR = 1.65, 95% CI: 1.17 - 2.32), napping ("Some days": HR = 1.38, 95% CI: 1.03 - 1.85; "Most/Every Day": HR = 1.73, 95% CI: 1.29 - 2.32), sleep quality ("Poor/Very Poor": HR = 1.75, 95% CI: 1.17 - 2.61), and very short sleep duration (≤5 hours: HR = 2.38, 95% CI: 1.44 - 3.92) were associated with all-cause mortality in adjusted Cox models.

CONCLUSIONS

Addressing sleep disturbance and deficiency may have a positive impact on risk for incident dementia and all-cause mortality among older adults.

Insomnia symptoms, fatigue, and future job exit in American older adults

BACKGROUND

As older adults prolong working life and face age-related health changes, insomnia symptoms and fatigue may jeopardize their ability to stay in the labor force. Our study explored the relationships between insomnia symptoms, fatigue, and job exit in workers aged 65 years and older.

METHODS

Data from the National Health and Aging Trends Study were used (2011-2017). The sample included 953 Medicare beneficiaries with paid work at the time of the interview. Workers were followed annually for 6 years to the time of job exit. Insomnia measures included the number and type of symptoms, and fatigue (measured as low energy). Crude and adjusted odds ratios and 95% confidence intervals were estimated within discrete-time survival analysis. Models were adjusted for health, lifestyle, and sociodemographic characteristics.

RESULTS

At baseline, approximately 49% of workers had either one or two insomnia symptoms. Difficulty falling asleep and difficulty maintaining asleep were prevalent in 35% and 37% of the sample. Fatigue was common in <30% of the sample. Workers with difficulty falling asleep were 1.29 times at higher odds to have job exit when compared with workers with no insomnia (p = 0.033). Conversely, fatigued workers were 0.73-0.77 times at lower odds to have job exit when compared with nonfatigued workers (p < 0.05).

CONCLUSION

Difficulty falling asleep negatively affects future work status, unlike feeling fatigued. Healthcare providers are encouraged to assess for insomnia and discuss treatments with workers, and workplaces should be flexible with the start of workdays to support worker longevity.