Sleep difficulties, incident dementia and all-cause mortality among older adults across 8 years: Findings from the National Health and Aging Trends Study

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

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

Prolonged sleep duration as a predictor of cognitive decline: A meta-analysis encompassing 49 cohort studies

Despite numerous studies have explored the association between sleep duration and cognition, the link between sleep duration trajectories and cognition remains underexplored. This systematic review aims to elucidate this correlation. We analyzed 55 studies from 14 countries, comprising 36 studies focusing on sleep duration, 20 on insomnia, and 13 on hypersomnia. A total of 10,767,085 participants were included in 49 cohort studies with a mean follow-up duration of 9.1 years. A non-linear association between sleep duration and cognitive decline was identified. Both long (risk ratio (RR):1.35, 95 % confidence intervals (CIs):1.23-1.48) and short sleep durations (RR: 1.12, 95 % CIs:1.03-1.22) were associated with an elevated risk of cognitive decline compared to moderate sleep duration. Additionally, hypersomnia (RR:1.26, 95 % CIs: 1.15-1.39) and insomnia (RR: 1.16, 95 % CIs: 1.002-1.34) were also linked to an increased risk. Moreover, prolonged sleep duration posed a higher risk of cognitive decline than stable sleep duration (RR:1.42, 95 % CIs:1.27-1.59). Importantly, transitioning from short or moderate to long sleep duration, as well as persistent long sleep duration, exhibited higher RRs for cognitive decline (RRs: 1.94, 1.40, and 1.28, respectively) compared to persistent moderate sleep duration. Our findings underscore the significance of prolonged sleep duration, alongside short and long sleep durations, with an elevated risk of cognitive decline. The association is tied to the degree of sleep duration changes. Our study highlights the importance of considering changes in sleep patterns over time, not just static sleep durations.

Cerebral perfusion is not impaired in persons with moderate obstructive sleep apnoea when awake

PURPOSE

It is well established that, together with a multitude of other adverse effects on health, severe obstructive sleep apnoea causes reduced cerebral perfusion and, in turn, reduced cerebral function. Less clear is the impact of moderate obstructive sleep apnoea (OSA). Our aim was to determine if cerebral blood flow is impaired in people diagnosed with moderate OSA.

METHODS

Twenty-four patients diagnosed with moderate OSA (15 ≤ apnoea-hypopnea index (AHI) < 30) were recruited (aged 32-72, median 59 years, 10 female). Seven controls (aged 42-73 years, median 62 years, 4 female) with an AHI < 5 were also recruited. The OSA status of all participants was confirmed at baseline by unattended polysomnography and they had an MRI arterial-spin-labelling scan of cerebral perfusion.

RESULTS

Neither global perfusion nor voxel-wise perfusion differed significantly between the moderate-OSA and control groups. We also compared the average perfusion across three regional clusters, which had been found in a previous study to have significant perfusion differences with moderate-severe OSA versus control, and found no significant difference in perfusion between the two groups. The perfusions were also very close, with means of 50.2 and 51.8 mL/100 g/min for the moderate-OSAs and controls, respectively, with a negligible effect size (Cohen's d = 0.10).

CONCLUSION

We conclude that cerebral perfusion is not impaired in people with moderate OSA and that cerebral flow regulatory mechanisms can cope with the adverse effects which occur in moderate OSA. This is an important factor in clinical decisions for prescription of continuous positive airway pressure therapy (CPAP).

Mid-life sleep is associated with cognitive performance later in life in aging American Indians: data from the Strong Heart Study

Background

Sleep-related disorders have been associated with cognitive decline and neurodegeneration. American Indians are at increased risk for dementia. Here, we aim to characterize, for the first time, the associations between sleep characteristics and subsequent cognitive performance in a sample of aging American Indians.

Methods

We performed analyses on data collected in two ancillary studies from the Strong Heart Study, which occurred approximately 10 years apart with an overlapping sample of 160 American Indians (mean age at follow-up 73.1, standard deviation 5.6; 69.3% female and 80% with high school completion). Sleep measures were derived by polysomnography and self-reported questionnaires, including sleep timing and duration, sleep latency, sleep stages, indices of sleep-disordered breathing, and self-report assessments of poor sleep and daytime sleepiness. Cognitive assessment included measures of general cognition, processing speed, episodic verbal learning, short and long-delay recall, recognition, and phonemic fluency. We performed correlation analyses between sleep and cognitive measures. For correlated variables, we conducted separate linear regressions. We analyzed the degree to which cognitive impairment, defined as more than 1.5 standard deviations below the average Modified Mini Mental State Test score, is predicted by sleep characteristics. All regression analyses were adjusted for age, sex, years of education, body mass index, study site, depressive symptoms score, difference in age from baseline to follow-up, alcohol use, and presence of APOE e4 allele.

Results

We found that objective sleep characteristics measured by polysomnography, but not subjective sleep characteristics, were associated with cognitive performance approximately 10 years later. Longer sleep latency was associated with worse phonemic fluency (β = -0.069, p = 0.019) and increased likelihood of being classified in the cognitive impairment group later in life (odds ratio 1.037, p = 0.004). Longer duration with oxygen saturation < 90% was associated with better immediate verbal memory, and higher oxygen saturation with worse total learning, short and long-delay recall, and processing speed.

Conclusion

In a sample of American Indians, sleep characteristics in midlife were correlated with cognitive performance a decade later. Sleep disorders may be modifiable risk factors for cognitive impairment and dementia later in life, and suitable candidates for interventions aimed at preventing neurodegenerative disease development and progression.

Long-term quality of life of testicular cancer survivors differs according to applied adjuvant treatment and tumour type

PURPOSE

To evaluate the quality of life (QoL) in long-term testicular cancer (TC) survivors.

METHODS

QoL was assessed in TC survivors treated between March 1976 and December 2004 (n = 625) using the EORTC-QLQ-C30 questionnaire, including a TC module. The assessment was performed at two time points (2006: response rate: n = 201/625 (32.2%), median follow-up (FU): 12.9 years (range 1.1-30.9); 2017: response rate: n = 95/201 (47.3%), median FU: 26.2 years (range: 13.0-41.2)). TC survivors were grouped according to treatment strategy, tumour entity, clinical stage and prognosis group. Linear and multiple linear regression analyses were performed, with age and time of follow-up as possible confounders.

RESULTS

Radiation therapy (RT) compared to retroperitoneal lymph node dissection (RPLND) was associated with a higher impairment of physical function (2017: β =  - 9.038; t(84) =  - 2.03; p = 0.045), role function (2017: β =  - 12.764; t(84) =  - 2.00; p = 0.048), emotional function (2006: β =  - 9.501; t(183) =  - 2.09; p = 0.038) and nausea (2006: β = 6.679; t(185) = 2.70; p = 0.008). However, RT was associated with a lower impairment of sexual enjoyment (2017: symptoms: β = 26.831; t(64) = 2.66; p = 0.010; functional: β = 22.983; t(65) = 2.36; p = 0.021). Chemotherapy (CT), compared to RPLND was associated with a higher impairment of role (2017: β =  - 16.944; t(84) =  - 2.62; p = 0.011) and social function (2017: β =  - 19.160; t(79) =  - 2.56; p = 0.012), more insomnia (2017: β = 19.595; t(84) = 2.25; p = 0.027) and greater concerns about infertility (2017: β = 19.830; t(80) = 2.30; p = 0.024). In terms of tumour type, nonseminomatous germ cell tumour (NSGCT) compared to seminoma survivors had significantly lower impairment of nausea (2006: β =  - 4.659; t(187) =  - 2.17; p = 0.031), appetite loss (2006: β =  - 7.554; t(188) =  - 2.77; p = 0.006) and future perspective (2006: β =  - 12.146; t(175) =  - 2.08; p = 0.039). On the other hand, surviving NSGCT was associated with higher impairment in terms of sexual problems (2006: β = 16.759; t(145) = 3.51; p < 0.001; 2017: β = 21.207; t(63) = 2.73; p = 0.008) and sexual enjoyment (2017: β =  - 24.224; t(66) =  - 2.76; p = 0.008).

CONCLUSIONS

The applied adjuvant treatment and the tumour entity had a significant impact on the long-term QoL of TC survivors, even more than 25 years after the completion of therapy. Both RT and CT had a negative impact compared to survivors treated with RPLND, except for sexual concerns. NSGCT survivors had a lower impairment of QoL compared to seminoma survivors, except in terms of sexual concerns.

IMPLICATIONS FOR CANCER SURVIVORS

Implications for cancer survivors are to raise awareness of aspects of long-term and late effects on QoL in TC survivors; offer supportive care, such as psycho-oncological support or lifestyle modification, if a deterioration in QoL is noticed; and avoid toxic treatment without compromising a cure whenever possible.

Association between sleep problems and functional disability in community-dwelling older adults

BACKGROUND

Sleep problems are frequently observed in older adults. They can lead to changes in the individual's physical, occupational, cognitive, and social functioning, compromising the performance of activities of daily living and contributing to the occurrence of functional disability. This study evaluated the association between sleep problems and functional disability in community-dwelling older adults.

METHODS

This was a cross-sectional study with data from 10,507 Brazilian community-dwelling older adults participating in the 2013 National Health Survey. The exposure variable was self-reported sleep problems in the last two weeks. The outcome measure was functional disability assessed from self-reported questionnaires, categorized into basic activities of daily living (BADL) and instrumental activities of daily living (IADL), and defined as not being able to perform or having little or a lot of difficulty in at least one of the activities investigated in the domain of interest.

RESULTS

Older adults who reported sleep problems had 1.53 (95%CI: 1.34; 1.75) and 1.42 (95%CI: 1.26; 1.59) greater odds of having a disability in BADL and IADL when compared to individuals who reported having no sleep problems.

CONCLUSIONS

Older adults with sleep problems were more likely to have a functional disability, both in BADL and IADL. Thus, it is important to implement strategies to screen for sleep problems in older adults in primary health care as a preventive strategy for functional disability.

[Blue light and intraocular lenses (IOLs): Beliefs and realities]

The first intraocular lenses (IOLs) used for cataract surgery transmitted both ultraviolet (UV) radiation and visible light to the retina. Colorless UV-blocking IOLs were introduced and rapidly adopted in the 1980s. Yellow-tinted blue-blocking (also known as blue-filtering) IOLs were marketed in the early 1990s. Blue-blocking IOLs were intended to simulate age-related crystalline lens yellowing to reduce the cyanopsia that some patients experienced after cataract surgery. When blue-filtering IOLs were introduced in North America, however, blue-blocking chromophores were advocated as a way to protect patients from age-related macular degeneration (AMD) despite the lack of evidence that normal environmental light exposure causes AMD. The "blue light hazard" is a term that describes the experimental finding that acute, abnormally intense light exposures are potentially more phototoxic to the retina when short rather than long wavelengths are used. Thus, in brief exposures to intense light sources such as welding arcs, ultraviolet radiation is more hazardous than blue light, which is more hazardous than longer wavelength green or red light. International commissions have cautioned that the blue light hazard does not apply to normal indoor or outdoor light exposures. Nonetheless, the hazard is used for commercial purposes to suggest misleadingly that ambient environmental light can cause acute retinal phototoxicity and increase the risk of AMD. Very large epidemiological studies show that blue-blocking IOLs do not reduce the risk or progression of AMD. Additionally, blue-filtering IOLs or spectacles cannot decrease glare disability, because they decrease image and glare illuminance in the same proportion. Blue light is essential for older adults' scotopic photoreception needed to reduce the risk of nighttime falling and related injuries. It is also critical for circadian photoreception that is essential for good health, sleep and cognitive performance. Unfortunately, age-related pupillary miosis, retinal rod and ganglion cell photoreceptor degeneration and decreased outdoor activity all reduce the amount of healthful blue light available to older adults. Blue-restricting IOLs further reduce the available blue light at a time when older adults need it most. Patients and ophthalmologists are exposed to hypothesis-based advertisements for blue-filtering optical devices that suppress short wavelength light critical for vision in dim lighting and for good physical and mental health. Spectacle and intraocular lens selections should be based on scientific fact, not conjecture. Ideal IOLs should improve photoreception rather than limit it permanently. Practice efficiency, surgical convenience and physician-manufacturer relationships may eliminate a patient's opportunity to choose between colorless blue-transmitting IOLs and yellow-tinted, blue-restricting IOLs. Cataract surgeons ultimately determine whether their patients have the opportunity to make an informed choice about their future photoreception.

Case report: Diagnosis and intervention of a non-24-h sleep-wake disorder in a sighted child with a psychiatric disorder

Circadian rhythm sleep-wake disorders (CRSWD) are sleep dysfunctions related to circadian functioning. They are characterized by symptoms of insomnia or excessive sleepiness that occur because the intrinsic circadian pacemaker is not entrained to a 24-h light/dark cycle. Affected individuals with a free-running disorder or hypernycthemeral syndrome (N24SWD) have a longer sleep-wake cycle that produces a sleep pattern that typically delays each day. The disorder is seen in 70% of blind people, and among people with healthy vision, it is a rare pathology. Among sighted cases, 80% are young men and 28% have a psychiatric disorder. The patient was a 14-year-old boy with a psychiatric pathology diagnosed with a PANDAS syndrome (pediatric autoimmune neuropsychiatric disorders associated with streptococci), a sudden acute and debilitating onset of intense anxiety and mood lability accompanied by obsessive compulsive-like issues and/or tics, in association with a streptococcal A infection that occurs immediately prior to the symptoms. As a comorbidity, he exhibited severe insomnia due to an irregular sleep pattern that strongly delayed his sleep schedule day to day. It affected his daily routines, as he was not going to school, and aggravated, furthermore, the psychiatric symptoms. He was referred for sleep consultation, where the case was explored by ambulatory circadian monitoring (ACM) using the novel system Kronowise® (Chronolab, University of Murcia) and diagnosed with a non-24-h sleep-wake disorder (N24SWD). The first treatment approach for the patient was focused on improving symptoms during the acute infection and psychiatric symptoms. Additionally, sleep pathology was treated by light therapy and melatonin. After 8 months and different trials, it was possible to establish a treatment to normalize the symptoms and fix his sleep rhythm in a normal schedule as well as to reduce anxious symptoms during the day. The association of PANDAS and N24SWD has not previously been reported in the literature.

Interrelationship of Sleep Disturbances and Cognitive Status on Mortality

Sleep disturbances may promote the development and advancement of Alzheimer's disease. Our purpose was to determine if sleep disturbances were associated with earlier mortality while accounting for cognition. The National Alzheimer's Coordinating Center database was used to evaluate mortality risk conferred by sleep, and the Montreal Cognitive Assessment score determined cognitive status. Demographics, sleep disturbances, cognitive status, and comorbid/other neuropsychiatric conditions were examined as predictors of survival time via Cox regression. The sample (N = 31,110) had a median age [interquartile range] of 72 [66, 79] years, MoCA score of 23 [16, 26], and survival time of 106.0 months [104.0,108.0]; 10,278 (33%) died during follow-up; 21% (n = 6461) experienced sleep disturbances. Sleep disturbances impacted survival time depending on cognition, with the greatest effect in transition from normal to cognitive impairment (P < .001). Findings support that sleep disturbances negatively impact survival time, and the impact of sleep disturbances on survival time is interrelated with cognition.

Relationship between night shift and sleep problems, risk of metabolic abnormalities of nurses: a 2 years follow-up retrospective analysis in the National Nurse Health Study (NNHS)

BACKGROUND AND PURPOSE

Efforts to improve nurses' physical and mental health are critical to ensuring the safety and quality of the healthcare system. Long-term studies targeting the relevancy of nurses' occupation characteristics with health conditions remain insufficient. This study aimed to examine the relationship between nurses' night shift and sleep problems and metabolic abnormalities risk.

METHODS

This study was a part of the National Nurse Health Study, an ambispective cohort study in China, in 2021. Based on an integration physical examination data system, this study carried out a retrospective analysis of 730 nurses from 2018 to 2020 and combined with a questionnaire survey in 2021. The STROBE guidelines were adopted for reporting.

RESULTS

In the 23 (23.0, 24.0) months follow-up, higher night shift load was associated with more sleep problems such as shortened sleep duration, sleep disorders, poor sleep quality, and sleep deprivation. Moreover, night shift load was associated with chronic diseases risk factors, increasing body mass index and body fat, with more night shift density, increasing the occurrence of low levels of high-density lipoprotein cholesterol, high triglyceride, triglyceride/high-density lipoprotein cholesterol ratio, and serum uric acid.

CONCLUSION

The night shift load has become an occupational health concern, contributing to chronic diseases relevant metabolic risk factors and negative influence on sleep health. Focus on the strategies to improve the sleep quality of nurses undergoing night shift work, optimize work scheduling and ongoing monitor the relevant risk factors are essential to enhance the stability and well-being of the nursing workforce.

CLINICAL TRIALS REGISTRATION INFORMATION

NCT04572347, on October 1, 2020. https://www.

CLINICALTRIALS

gov/ct2/show/NCT04572347.

Association of cardiometabolic multimorbidity with motoric cognitive risk syndrome in older adults

INTRODUCTION

Motoric cognitive risk syndrome (MCR) is a predementia syndrome that is characterized by cognitive complaints and slow gait. Cardiometabolic multimorbidity (CMM) is associated with an increased risk of dementia. However, the relationship between CMM and MCR is still unclear.

METHODS

We included 4744 participants (aged 65+ years) without MCR at baseline from the National Health and Aging Trends Study (NHATS), who were followed-up from 2011 to 2018. CMM was defined as the presence of two or more cardiometabolic diseases (including diabetes mellitus, heart disease, and stroke).

RESULTS

CMM was significantly associated with an increased risk of MCR (hazard ratio [HR] 1.41, 95% confidence interval [CI] 1.13-1.75) in fully adjusted models. Consistent results were observed from stratified analyses of different subgroups. Increasing numbers of cardiometabolic diseases were dose-dependently associated with increased MCR risk (HR 1.33, 95% CI 1.20-1.48).

DISCUSSION

CMM is associated with an increased risk of MCR in older adults.

HIGHLIGHTS

Motoric cognitive risk syndrome (MCR) is a predementia syndrome characterized by slow gait speed and cognitive complaints.Cardiometabolic multimorbidity was associated with an increased MCR risk.An increased number of cardiometabolic diseases were dose-dependently associated with increased MCR risk.

Interactive association between insomnia symptoms and sleep duration for the risk of dementia-a prospective study in the Swedish National March Cohort

OBJECTIVE

Given the importance of sleep in maintaining neurocognitive health, both sleep duration and quality might be component causes of dementia. However, the possible role of insomnia symptoms as risk factors for dementia remain uncertain.

METHODS

We prospectively studied 22,078 participants in the Swedish National March Cohort who were free from dementia and stroke at baseline. Occurrence of dementia was documented by national registers during a median follow-up period of 19.2 years. Insomnia symptoms and sleep duration were ascertained by Karolinska Sleep Questionnaire. Multivariable Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI).

RESULTS

Compared to participants without insomnia at baseline, those who reported any insomnia symptom experienced a greater incidence of dementia during follow-up (HR 1.08, 95% CI: 1.03, 1.35). Difficulty initiating sleep versus non-insomnia (HR 1.24, 95% CI: 1.02, 1.52), but not difficulty maintaining sleep or early morning awakening was associated with an increased risk of dementia. Short sleep duration was associated with increased risk of dementia (6 h vs. 8 h, HR 1.29, 95% CI: 1.11-1.51; 5 h vs. 8 h, HR 1.26, 95% CI: 1.00-1.57). Stratified analyses suggested that insomnia symptoms increased the risk of dementia only amongst participants with ≥7 h sleep (vs. non-insomnia HR 1.24, 95% CI: 1.00-1.54, P = 0.05), but not amongst short sleepers (<7 h). Short sleep duration also did not further inflate the risk of dementia amongst insomniacs.

CONCLUSION

Insomnia and short sleep duration increase the risk of dementia amongst middle-aged to older adults.

The burden of untreated insomnia disorder in a sample of 1 million adults: a cohort study

BACKGROUND

Insomnia disorder is a highly prevalent, significant public health concern associated with substantial and growing health burden. There are limited real-world data assessing the burden of insomnia disorder on daytime functioning and its association with comorbidities. The objective of this study was to leverage large-scale, real-world data to assess the burden of untreated insomnia disorder in terms of daytime impairment and clinical outcomes.

METHODS

This United States medical claims database study compares patients diagnosed with insomnia disorder but not receiving treatment ('untreated insomnia' cohort) to patients without an insomnia disorder diagnosis and without treatment ('non-insomnia' cohort). International Classification of Disease, Tenth Revision codes were used as a proxy to represent the three symptom domains (Sleepiness, Alert/Cognition, Mood) of the Insomnia Daytime Symptoms and Impacts Questionnaire (IDSIQ), a newly developed and validated tool used in clinical studies to assess daytime functioning in insomnia disorder. Chronic Fatigue (R53.83) and Other Fatigue (R53.83), Somnolence (R40.0) and Disorientation (R41.0) were selected as categories representing one or more IDSIQ domains. Clinical outcomes included cardiovascular events, psychiatric disorders, cognitive impairment and metabolic disorders.

RESULTS

Approximately 1 million patients were included (untreated insomnia: n = 139,959; non-insomnia: n = 836,975). Compared with the 'non-insomnia' cohort, the 'untreated insomnia' cohort was more likely to experience daytime impairments, with mean differences in occurrences per 100 patient-years for: (a) fatigue, at 27.35 (95% confidence interval [CI] 26.81, 27.77, p < 0.01); (b) dizziness, at 4.66 (95% CI 4.40, 4.90, p < 0.01); (c) somnolence, at 4.18 (95% CI 3.94, 4.43, p < 0.01); and (d) disorientation, at 0.92 (95% CI 0.77, 1.06, p < 0.01). During the 1-year look-back period, patients in the 'untreated insomnia' cohort were also more likely to have been diagnosed with arterial hypertension (40.9% vs. 26.3%), psychiatric comorbidities (40.1% vs. 13.2%), anxiety (29.2% vs. 8.5%), depression (26.1% vs. 8.1%) or obesity (21.3% vs. 11.1%) compared with those in the 'non-insomnia' cohort.

CONCLUSIONS

This large-scale study confirms the substantial burden of insomnia disorder on patients in a real-world setting, with significant daytime impairment and numerous comorbidities. This reinforces the need for timely insomnia disorder diagnosis and treatments that improve both sleep, as well as daytime functioning.

Neutrophil activation may trigger tau burden contributing to cognitive progression of chronic sleep disturbance in elderly individuals not living with dementia

BACKGROUND

To investigate the complex connection between chronic sleep disturbance (CSD) and cognitive progression.

METHODS

The Alzheimer's Disease Neuroimaging Initiative (ADNI) database was used to assign 784 non-dementia elderly into two groups: a normal sleep group (528 participants) and a CSD group (256 participants) via the Neuropsychiatric Inventory (NPI)-sleep subitem. Blood transcriptomics, blood neutrophil, cerebrospinal fluid (CSF) biomarkers of Alzheimer's disease (AD), and neutrophil-related inflammatory factors were measured. We also investigated gene set enrichment analysis (GSEA), Cox proportional hazards model for risk factors, and mediation and interaction effects between indicators. Cognitive progression is defined as the progression from cognitively normal to mild cognitive impairment (MCI)/dementia or from MCI to dementia.

RESULTS

CSD could significantly affect cognitive function. The activated neutrophil pathways for cognitive progression in CSD were identified by transcriptomics GSEA, which was reflected by increased blood neutrophil level and its correlation with cognitive progression in CSD. High tau burden mediated the influence of neutrophils on cognitive function and exacerbated the CSD-related risk of left hippocampal atrophy. Elevated neutrophil-related inflammatory factors were observed in the cognitive progression of CSD and were associated with brain tau burden.

CONCLUSIONS

Activated neutrophil pathway triggering tau pathology may underline the mechanism of cognitive progression in CSD.

Pain and mild cognitive impairment among adults aged 50 years and above residing in low- and middle-income countries

BACKGROUND

Previous studies on the association between pain and cognitive decline or impairment have yielded mixed results, while studies from low- and middle-income countries (LMICs) or specifically on mild cognitive impairment (MCI) are scarce. Thus, we investigated the association between pain and MCI in LMICs and quantified the extent to which perceived stress, sleep/energy problems, and mobility limitations explain the pain/MCI relationship.

METHODS

Data analysis of cross-sectional data from six LMICs from the Study on Global Ageing and Adult Health (SAGE) were performed. MCI was based on the National Institute on Aging-Alzheimer's Association criteria. "Overall in the last 30 days, how much of bodily aches or pain did you have?" was the question utilized to assess pain. Associations were examined by multivariable logistic regression analysis and meta-analysis.

RESULTS

Data on 32,715 individuals aged 50 years and over were analysed [mean (SD) age 62.1 (15.6) years; 51.7% females]. In the overall sample, compared to no pain, mild, moderate, and severe/extreme pain were dose-dependently associated with 1.36 (95% CI = 1.18-1.55), 2.15 (95% CI = 1.77-2.62), and 3.01 (95% CI = 2.36-3.85) times higher odds for MCI, respectively. Mediation analysis showed that perceived stress, sleep/energy problems, and mobility limitations explained 10.4%, 30.6%, and 51.5% of the association between severe/extreme pain and MCI.

CONCLUSIONS

Among middle-aged to older adults from six LMICs, pain was associated with MCI dose-dependently, and sleep problems and mobility limitations were identified as potential mediators. These findings raise the possibility of pain as a modifiable risk factor for developing MCI.

Association between Sleep Onset Problem and Subjective Cognitive Complaints among Japanese Older Adults during the Coronavirus Disease 2019 Pandemic

Older adults are more likely to have age-related sleep problems, which may result in the reduction of cognitive functions. This study was designed to examine the relationship between sleep onset problem and subjective cognitive complaints (SCC) among community-dwelling older adults during the coronavirus disease 2019 pandemic. In this study, 186 older adults aged 65 and above were enrolled and were instructed to respond to an online survey. This survey comprised questions regarding sleep quality (four items such as sleep duration, use of sleep medication), SCC (six domains), and sociodemographic information (eight items such as age, gender, stress condition). We classified the participants into two groups according to the presence or absence of sleep onset problem and examined the relationship between each SCC domain. The sleep onset problem (+) (n = 70) group had significantly higher frequency of scheduled memory decline, misplacement, disorientation in time, word recall decline, and forgetfulness. Furthermore, the sleep onset problem affected the participants' scheduled memory after adjusted for potential covariates (OR, 2.28; 95%CI, 1.13-4.73; p = 0.02). Older adults with sleep onset problem may need to be evaluated for SCC and supported in term of both sleep status and SCC.

Sex- and age-specific all-cause mortality in insomnia with hypnotics: Findings from Japan multi-institutional Collaborative Cohort Study

OBJECTIVE

Findings on the increased mortality risk in individuals with insomnia are inconsistent across studies. Rather than improving insomnia by sleep control, hypnotic use may be one factor in the increased risk of death; however, the effects of hypnotics on mortality remains unclear. This study aimed to examine the association between all-cause mortality and hypnotic use in a large sample, while adjusting for the effects of comorbidities.

METHODS

Overall, 92,527 individuals aged 35-69 years were followed up for mortality in the Japan Multi-Institutional Collaborative Cohort Study. Regular use of hypnotics was assessed using a self-administered questionnaire. Since cancer history carries a substantial risk of death and is associated with the treatment of insomnia with hypnotics, participants with a cancer history were excluded. The hazard ratio (HR) and 95% confidence interval (CI) for all-cause mortality related to hypnotic use were estimated using a Cox proportional hazard model with adjustments for covariates including sleeping hours and comorbidities (body mass index, ischemic heart disease, stroke, and diabetes).

RESULTS

During the follow-up (mean, 8.4 ± 2.5 years), 1,492 mortalities were recorded, and the prevalence of taking hypnotics was 4.2%. Hypnotic use was associated with significantly greater risk of all-cause mortality, even after adjustment for the covariates (HR, 1.32; 95% CI, 1.07-1.63). The association between hypnotic use and all-cause mortality was robust in males (HR, 1.51; 95% CI, 1.15-1.96), and participants aged <60 years (HR, 1.75; 95% CI, 1.21-2.54).

CONCLUSIONS

Our study revealed sex-age specific associations between hypnotic use and all-cause mortality.

Frontal grey matter microstructure is associated with sleep slow waves characteristics in late midlife

STUDY OBJECTIVES

The ability to generate slow waves (SW) during non-rapid eye movement (NREM) sleep decreases as early as the 5th decade of life, predominantly over frontal regions. This decrease may concern prominently SW characterized by a fast switch from hyperpolarized to depolarized, or down-to-up, state. Yet, the relationship between these fast and slow switcher SW and cerebral microstructure in ageing is not established.

METHODS

We recorded habitual sleep under EEG in 99 healthy late midlife individuals (mean age = 59.3 ± 5.3 years; 68 women) and extracted SW parameters (density, amplitude, frequency) for all SW as well as according to their switcher type (slow vs. fast). We further used neurite orientation dispersion and density imaging (NODDI) to assess microstructural integrity over a frontal grey matter region of interest (ROI).

RESULTS

In statistical models adjusted for age, sex, and sleep duration, we found that a lower SW density, particularly for fast switcher SW, was associated with a reduced orientation dispersion of neurites in the frontal ROI (p = 0.018, R2β* = 0.06). In addition, overall SW frequency was positively associated with neurite density (p = 0.03, R2β* = 0.05). By contrast, we found no significant relationships between SW amplitude and NODDI metrics.

CONCLUSIONS

Our findings suggest that the complexity of neurite organization contributes specifically to the rate of fast switcher SW occurrence in healthy middle-aged individuals, corroborating slow and fast switcher SW as distinct types of SW. They further suggest that the density of frontal neurites plays a key role for neural synchronization during sleep.

TRIAL REGISTRATION NUMBER

EudraCT 2016-001436-35.

High dose melatonin increases sleep duration during nighttime and daytime sleep episodes in older adults

Aging is associated with changes in sleep, and improving sleep may have important consequences for the health, cognition, and quality of life of older adults. Many prescription sleep aids increase the risk of nighttime falls, have adverse effects on next-day cognition, and are associated with increased mortality. Melatonin, a hormone secreted at night, increases sleep duration in young adults but only when administered during the day when endogenous levels are low. In a month-long cross-over study, we randomized 24 healthy older (age >55, mean 64.2 ± 6.3 years) participants to receive 2 weeks of placebo and 2 weeks of either a low (0.3 mg) or high (5.0 mg) dose of melatonin 30 min before lights out. Sleep was polysomnographically recorded and was scheduled during both the biological day and night using a forced desynchrony design. Although 0.3 mg melatonin had a trend towards increasing sleep efficiency (SE) overall, this was due to its effects on sleep during the biological day. In contrast, 5 mg melatonin significantly increased SE during both biological day and night, mainly by increasing the duration of Stage 2 non-rapid eye movement sleep and slightly shortening awakenings. Melatonin should be further explored as a sleep aid for older adults.

Sleep problems and mild cognitive impairment among adults aged ≥50 years from low- and middle-income countries

BACKGROUND

The limited available literature suggests that sleep problems are linked to an increased risk of mild cognitive impairment (MCI). However, this association has been little studied to date in low-income settings.

OBJECTIVE

To investigate the association between sleep problems and MCI in a large sample of adults from six low-and middle-income countries (LMICs).

DESIGN

Cross-sectional.

SETTING

Study on Global Ageing and Adult Health (SAGE).

SUBJECTS

32,715 individuals aged ≥50 years with preservation in functional abilities [age range 50-114 years; 51.7% females].

METHODS

MCI was defined using the National Institute on Aging-Alzheimer's Association criteria. Sleep problems were assessed by the question "Overall in the last 30 days, how much of a problem did you have with sleeping, such as falling asleep, waking up frequently during the night or waking up too early in the morning?" and categorized as "None", "Mild", "Moderate", "Severe/Extreme". Multivariable logistic regression analysis and meta-analysis were conducted.

RESULTS

Compared to no sleep problems, mild, moderate, and severe/extreme sleep problems were associated with significant 1.40, 1.83, and 2.69 times higher odds for MCI with similar associations being observed between age groups and sex. Severe/extreme sleep problems were positively associated with MCI (i.e., OR > 1) in the six countries studied with the overall estimate being OR = 1.80 (95% CI = 1.50-2.16), and a low level of between-country heterogeneity was observed (I² = 28.2%).

CONCLUSIONS

Sleep problems were associated with higher odds for MCI. Interventions to improve sleep quality among middle-aged and older adults in LMICs may be an effective strategy in reducing risk of MCI and dementia.