Insomnia with objective short sleep duration is associated with cognitive impairment: a first look at cardiometabolic contributors to brain health

Napping during cognitive behavioural therapy for insomnia: Friends or foes?

Cognitive and Behavioural Therapy for Insomnia (CBT-I) is the gold standard treatment for chronic insomnia, with one crucial step being the restriction of time spent in bed. This restriction often intensifies early afternoon sleepiness, leading to a natural gateway for a short recuperative nap, which might foster adherence to CBT-I over time. In practice, mental health professionals providing CBT-I lack consensus on whether or not to tolerate short naps during the CBT-I period for requesting patients. In this pilot study, we examined the effects of authorised napping on CBT-I efficiency in patients with insomnia (a napping group was compared with a matched non-napping group, n = 108). We report that napping enhanced early afternoon alertness and importantly did not affect CBT-I-mediated improvements in the Insomnia Severity Index and Beck Depression Inventory-2 and in self-reported sleep efficiency, latency, and wake after sleep onset (assessed by the sleep diaries). Further investigations using objective methods of sleep assessments are now needed to confirm that napping behaviour does not compromise the improvements enabled by CBT-I and may even strengthen adherence to the treatment.

Hyperbaric oxygen treatment for chronic insomnia at high altitude: A prospective, randomized, open-label, parallel-group trial

BACKGROUND

Hyperbaric oxygen (HBO) has been proposed to be effective for treating chronic insomnia at high altitudes.

METHODS

Patients suffering from chronic insomnia at high altitude were randomly assigned at a 1:1 ratio to either the hyperbaric oxygen (HBO) treatment group or the control group for a 10-day procedure. The primary outcome was insomnia status, which was assessed via the Pittsburgh Sleep Quality Index (PSQI) and the Insomnia Severity Index (ISI). The secondary outcomes included stratified comparisons of changes in the PSQI score and ISI score, Fatigue Severity Scale (FSS) score and Hospital Anxiety and Depression Scale (HADS) score. Analyses were performed for multiple comparisons for the primary outcomes at 2-sided 0.05 significance levels with Bonferroni corrections.

RESULTS

A total of 80 patients were randomized in this study, and the median age was 25.0 years (IQR, 21.25-29.75). For the primary outcome of sleep quality, the PSQI score after treatment was significantly lower in the HBO group than in the control group (4.6 ± 3.15 vs. 9.1 ± 4.02; adjusted mean difference [aMD] -3.96 [-5.26 to -2.66], p < 0.0001). The ISI was also significantly lower in the HBO group than in the control group (5.0 ± 4.09 vs. 9.8 ± 6.47; aMD -4.10 [95 % CI, -5.68 to -2.51], p < 0.0001). For the secondary outcomes, the HBO group showed improvements in terms of fatigue, anxiety, and depression. No serious adverse events were reported in either group.

CONCLUSION

HBO is an efficacious and safe treatment for chronic insomnia at high altitude.

TRIAL REGISTRATION

ChiCTR2100046917.

Effects of acupuncture on brain metabolism in patients with chronic partial sleep deprivation cognitive dysfunction: A case-control study

Patients with chronic partial sleep deprivation (SD) may experience cognitive dysfunction. The purpose of this study is to explore the pathways of electroacupuncture (EA) by observing the changes in brain metabolites before and after EA treatment in patients with chronic partial SD cognitive dysfunction. The research subjects included 26 chronic partial SD cognitive dysfunction patients and 27 healthy subjects. Montreal Cognitive Assessment Scale, Pittsburgh Sleep Quality Index Scale (PSQI), Stanford Sleepiness Scale, Wechsler Memory Scale, Hamilton Anxiety Scale, Hamilton Depression Scale, Stroop paradigm, psychomotor vigilance test, 2-back test task, and mood assessment test were used to assess sleep quality, cognitive function, and emotional state of subjects. Magnetic resonance spectroscopy was used to detect the basal ganglia of the brain, and the characteristics of metabolites of the 2 groups were comprehensively analyzed, and the correlation with clinical cognitive function evaluation indicators was analyzed. Compared with the control group, the Montreal Cognitive Assessment Scale and Wechsler Memory Scale scores of the observation group were reduced before treatment, while the Pittsburgh sleep quality index, Hamilton Anxiety Scale, and Hamilton Depression Scale scores were improved. The completion ability of Stroop, 2-back, and psychomotor vigilance test decreased. The GABA/Cr on the left side of the basal ganglia area increased. "Adjusting Zang-fu and Arousing Spirit" EA can improve the sleep quality and cognitive function of chronic partial sleep deprivation cognitive dysfunction patients, which may be related to regulating the levels of NAA, Cho, and GABA in the basal ganglia.

Brain Health in Sleep Disorders

Sleep is a critical determinant of brain health, influencing cognitive, emotional, and physiologic functions. The complex bidirectional relationship between sleep and brain health underscores the importance of sleep in maintaining cognitive function, regulating brain homeostasis, and facilitating the clearance of metabolic waste through the glymphatic system. Chronic sleep deprivation and sleep disorders such as insomnia and obstructive sleep apnea have been shown to negatively impact brain structures and functions. This review discusses the impact of sleep disorders on brain health. It also explores the implications of impaired sleep on cardiovascular health, immune function, and neuroplasticity.

Subtypes of Insomnia Disorder Identified by Cortical Morphometric Similarity Network

Insomnia disorder (ID) is a highly heterogeneous psychiatric disease, and the use of neuroanatomical data to objectively define biological subtypes is essential. We aimed to examine the neuroanatomical subtypes of ID by morphometric similarity network (MSN) and the association between MSN changes and specific transcriptional expression patterns. We recruited 144 IDs and 124 healthy controls (HC). We performed heterogeneity through discriminant analysis (HYDRA) and identified subtypes within the MSN strength. Differences in MSN between subtypes and HC were compared, and clinical behavioral differences were compared between subtypes. In addition, we investigated the association between MSN changes and brain gene expression in different ID subtypes using partial least squares regression to assess genetic commonalities in psychiatric disorders and further performed functional enrichment analyses. Two distinct subtypes of ID were identified, each exhibiting different MSN changes compared to HC. Furthermore, subtype 1 is characterized by objective short sleep, impaired cognitive function, and some relationships with major depressive disorder and autism spectrum disorder (ASD). In contrast, subtype 2 has normal objective sleep duration but subjectively reports poor sleep and is only related to ASD. The pathogenesis of subtype 1 may be related to genes that regulate sleep rhythms and sleep-wake cycles. In contrast, subtype 2 is more due to adverse emotion perception and regulation. Overall, these findings provide insights into the neuroanatomical subtypes of ID, elucidating the relationships between structural and molecular aspects of the relevant subtypes.

The benefit of inhibitory control training for insomnia with short sleep duration phenotype: a pilot randomized trial

BACKGROUND

Two phenotypes of insomnia disorder (ID) have been identified based on objective total sleep duration (TST): one with short sleep duration (ISSD) and another with normal sleep duration (INSD). Recent proposals suggested that insomnia with objective short-sleep duration (TST < 7 h) is associated with impaired inhibitory function, leading to a dysregulation of cortical inhibition, which may underlie its prevalence. This study investigated the status of impaired response inhibition in these two phenotypes and examined the potential different effect of response inhibition training on these two phenotypes.

METHODS

Twenty-two healthy controls (HC) and eighty-one patients with ID were recruited, with IDs further categorized into ISSD and INSD (with TST ≥ 7 h). Clinical behavior measures, including the Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index (ISI), Pre-sleep Arousal Scale (PSAS), objective sleep characteristics assessed by all-night sleep electroencephalography, and the accuracy of NoGo trials in the Go/NoGo task were compared among the three groups. Subsequently, within each ID phenotype, participants were divided into training and blank control sub-groups. The two training sub-groups completed Adaptive Go/NoGo training task (Through adaptive difficulty adjustment, the task trains participants' inhibitory control) 15 times over 3 weeks, and all IDs were assessed using sleep-related subjective and objective measures and Go/NoGo task before and after the intervention.

RESULTS

ISSD patients exhibited significantly longer sleep latency (p = 0.003) compared to HC, while wakefulness duration (p = 0.004) and light sleep duration (p < 0.001) were shorter than INSD. No significant differences in objective sleep characteristics were observed between INSD and HC. Following adaptive training, the ISSD training sub-group showed decreased scores in PSQI (p = 0.039) and ISI (p = 0.053) compared to their blank control sub-group. In the INSD groups, both training and blank control sub-groups demonstrated reductions in PSQI (p < 0.001), ISI (p < 0.001), and the cognitive arousal sub-dimension of the PSAS scores (p = 0.003) in the post-session test.

CONCLUSIONS

Impaired response inhibition is a characteristic of ISSD, potentially indicating dysfunctional cortical inhibition, whereas INSD pathogenesis may be related to cognitive-emotional arousal. Response inhibition training effectively alleviates sleep problems in ISSD. These findings provide new insights for developing precise intervention strategies in ID.

TRIAL REGISTRATION

The study was prospectively registered on May 30, 2024, in Chinese Clinical Trials registry (ChiCTR2400085063).

The association between insomnia and cognitive decline: A scoping review

OBJECTIVE

This study aimed to investigate the association between insomnia and cognitive decline to provide insights for clinical interventions and future research.

METHODS

The PubMed, Embase, Web of Science, Scopus, Cochrane Library, and ProQuest databases were systematically searched to identify studies on the association between insomnia and cognitive decline published within the last decade. The quality of the included studies was evaluated, followed by data extraction and summary analysis.

RESULTS

A total of 36 studies were included in the review. Both subjective and objective measures were utilized across 12 indices to assess sleep status, while cognitive function was evaluated using 5 scales and 34 tests. The results revealed a significantly increased risk of cognitive decline or Alzheimer's disease among patients with insomnia, alongside notable impairments in attention, memory, visuospatial abilities, executive function, and verbal memory. Comprehensive assessments of cognitive domains were more sensitive in detecting group differences compared to assessments of specific cognitive sub-functions. Furthermore, MRI analyses showed reduced gray matter volumes in regions such as the prefrontal cortex, cingulate gyrus, temporal lobe, and hippocampus, together with reduced integrity of the white matter in patients with insomnia.

CONCLUSIONS

The findings indicate a potentially bidirectional relationship between insomnia and cognitive decline, suggesting that each may influence and exacerbate the other. Insomnia may increase the risk of cognitive decline and appears to be associated with reduced gray matter volume and compromised white matter integrity in the brain, which could potentially lead to declines in attention, memory, visuospatial abilities, executive function, and verbal memory. Conversely, cognitive decline may contribute to the onset of insomnia, further deteriorating sleep quality. However, further research is necessary to fully comprehend this intricate relationship.

Emotion dysregulation mediates the relationship between sleep problems and externalizing symptoms in early adolescents: A four-wave longitudinal study

BACKGROUND

Despite the growing body of longitudinal research linking sleep problems and externalizing symptoms, regarding the direction of the effects of both variables, the results have been inconsistent. Given the mixed findings and inconsistent results in the literature, we propose that emotion dysregulation may link sleep problems and externalizing symptoms.

METHODS

The participants (N = 1281, 49.65 % female; M = 12.73 years at time 1, SD = 0.68) were middle school students who completed assessments for sleep problems, externalizing symptoms, and emotion dysregulation. The interval between each wave was six months, for two consecutive years. Autoregressive mediation models using longitudinal data and cross-sectional mediation models using baseline data were evaluated and compared through structural equation modeling.

RESULTS

The results revealed that severe sleep problems (at T1, T2, or T3) were associated with higher levels of externalizing symptoms later in adolescence (at T2, T3, or T4), but not vice versa. In addition, analyses of indirect effects indicated that emotion dysregulation mediated this link, such that greater sleep problems led to more emotion dysregulation, which, in turn, led to more externalizing symptoms.

CONCLUSION

The findings highlight the critical role that emotional regulation plays in the link between sleep problems and externalizing symptoms and emphasize the need for students as well as middle school administration to pay close attention to both the sleep and externalizing symptoms of early adolescents.

Lectin YKL-40 Level and Telomere Length are Indicators of Insomnia Disorder

OBJECTIVE

To explore the relationship between YKL-40 level, telomere length, and different subtypes of insomnia disorder.

METHODS

A total of 145 individuals suffering from insomnia were enrolled and divided into four groups according to the insomniac subtypes: difficulty initiating sleep, early morning awakening, difficulty maintaining sleep, and mixed symptoms. Eighty healthy controls were also collected at the same time. Peripheral leukocyte genomic DNA was extracted, relative telomere lengths were measured using the real-time quantitative polymerase chain reaction method, and YKL-40 levels were determined using enzyme-linked immunoassay. Logistic regression modeling was used to analyze the correlation between different insomnia subtypes, YKL-40 level, and telomere length.

RESULTS

People with telomere lengths in the lowest tertile were more likely to have trouble falling asleep (odds ratio (OR) 2.13, 95% confidence interval (CI) 1.22-3.63; p = 0.03) and had a higher frequency of mixed symptoms (OR 1.49, 95% CI 1.30-2.81; p = 0.04). People in the highest tertile of YKL-40 level had an increased chance of waking up early (OR 2.98, 95% CI 1.54-5.33; p = 0.01) and more mixed symptoms (OR 1.47, 95% CI 1.22-2.79; p = 0.02). Furthermore, using receiver operating characteristic curve analysis, the area under the curve of YKL-40 level and telomere length was 0.806 and 0.746, respectively.

CONCLUSIONS

Telomere length in patients with difficulty initiating sleep and mixed symptoms was significantly shortened and the level of YKL-40 in people who have early morning awakening and mixed symptoms was significantly increased. Our findings provide the first evidence that leukocyte telomere length and YKL-40 level are individually linked to mixed symptoms.

Insomnia with objective but not subjective short sleep duration is associated with incident cardiovascular and/or cerebrovascular disease

STUDY OBJECTIVES

Insomnia with objective short sleep duration (ISSD) has been associated with cardiometabolic outcomes (ie, hypertension or diabetes). We examined whether ISSD, based on objective or subjective sleep measures, is associated with more serious health problems, such as incident cardiovascular and/or cerebrovascular disease (CBVD).

METHODS

1,258 men and women from the Penn State Adult Cohort (56.9% women, aged 48.3 ± 12.95 years) without CBVD at baseline were followed up for 9.21 ± 4.08 years. The presence of CBVD was defined as a history of diagnosis or treatment of heart disease and/or stroke. Insomnia was defined as a complaint of insomnia with a duration ≥ 1 year. Poor sleep was defined as a complaint of difficulty falling asleep, staying asleep, nonrestorative sleep, or early morning awakening. Objective short sleep duration was defined as < 6 hours' sleep based on polysomnography. Subjective short sleep duration was based on the median self-reported percentage of sleep time (ie, < 7 hours).

RESULTS

Compared with normal sleepers with normal sleep duration, the highest risk of incident CBVD was in the ISSD group (odds ratio = 2.46, 95% confidence interval = 1.04-5.79), and the second highest was in normal sleepers with short sleep duration (odds ratio = 1.68, 95% confidence interval = 1.11-2.54). The risk of incident CBVD was not significantly increased in poor sleepers or those with insomnia with normal sleep duration. Finally, insomnia with subjective short sleep duration was not associated with increased incident CBVD.

CONCLUSIONS

These data add to the cumulative evidence that ISSD, based on objective but not subjective measures, is the more severe biological phenotype of the disorder associated with incident CBVD.

CITATION

Pejovic S, Vgontzas AN, Fernandez-Mendoza J, et al. Insomnia with objective but not subjective short sleep duration is associated with incident cardiovascular and/or cerebrovascular disease. J Clin Sleep Med. 2024;20(7):1049-1057.

A meta-analysis of the association between insomnia with objective short sleep duration and risk of hypertension

The aim of this meta-analysis was to examine the association between insomnia with objective short sleep duration (ISSD) with prevalent and incident hypertension in cross-sectional and longitudinal studies, respectively. Data were collected from 6 cross-sectional studies with 5914 participants and 2 longitudinal studies with 1963 participants. Odds ratios (ORs) for prevalent and risk ratios (RRs) for incident hypertension were calculated through meta-analyses of adjusted data from individual studies. Compared to normal sleepers with objective normal sleep duration (NNSD), ISSD was significantly associated with higher pooled OR for prevalent hypertension (pooled OR = 2.67, 95%CI = 1.45-4.90) and pooled RR for incident hypertension (pooled RR = 1.95, 95%CI = 1.19-3.20), respectively. Compared to insomnia with objective normal sleep duration, ISSD was associated with significantly higher pooled OR of prevalent hypertension (pooled OR = 1.94, 95%CI = 1.29-2.92) and pooled RR for incident hypertension (pooled RR = 2.07, 95%CI = 1.47-2.90), respectively. Furthermore, normal sleepers with objective short sleep duration were not associated with either prevalent (pooled OR = 1.21, 95%CI = 0.84-1.75) or incident (pooled RR = 0.97, 95%CI = 0.81-1.17) hypertension compared to NNSD. Our findings suggest that ISSD is a more severe phenotype of the disorder associated with a higher risk of hypertension. Objective short sleep duration might be a valid and clinically useful index of insomnia's impact on cardiovascular health.

Edward O. Bixler, PhD: from the Apollo project and chimpanzees to sleep epidemiology

What an honor to write about Dr. Edward O. Bixler's contributions to the sleep field. In 1967, Dr. Bixler published a case report on a chimpanzee with implanted brain electrodes while working at an Air Force base in New Mexico. A few years later, in 1971, he published on the sleep effects of flurazepam in individuals with insomnia together with Dr. Anthony Kales, data that he had collected when the Sleep Research & Treatment Center (SRTC) was housed at the University of California Los Angeles. Dr. Bixler, a meticulous scientist, learned from Dr. Kales, a devoted clinician, to study "the whole patient, and all aspects of sleep," a legacy that continued when the SRTC moved to Penn State in Hershey. Indeed, Dr. Bixler's tenure at Penn State from 1971 until 2019 kept the science of the SRTC focused on that premise and helped translate scientific evidence into clinical care. He not only contributed early to the pharmacology of sleep and the effects of hypnotics, but he was also a pioneer in "sleep epidemiology." His "Prevalence of sleep disorders in the Los Angeles metropolitan area" study of 1979 was the first rigorous epidemiological study on sleep disturbances. Starting in 1990, he established the Penn State Adult Cohort to estimate the prevalence and natural history of sleep-disordered breathing and other sleep disorders in adults. Inspired by life-course epidemiology, he established in 2001 the Penn State Child Cohort to estimate the same phenomena in children. This Living Legend paper captures and highlights Dr. Bixler's enduring legacy to sleep science.

Exploration of Sex and Age as Moderators Between Social Cumulative Risk and Sleep in a Representative Sample of Children and Adolescents Living in the United States

BACKGROUND

Youth who face adversity are at a disproportionate risk for poor sleep health across the life course. Identifying whether the association between adversity and poor sleep varies based upon age and sex is needed. This study aims to explore sex and age as moderators between social risk and sleep in a sample of U.S. youth.

METHODS

This study analyzed data of 32,212 U.S. youth (6-17 years) whose primary caregiver participated in the 2017-2018 National Survey of Children's Health. A social cumulative risk index (SCRI) score was calculated from 10 parental, family, and community risk indicators. Nighttime sleep duration was the number of hours the child slept during the past week. Weeknight sleep irregularity was operationalized as whether the child sometimes/rarely/never went to bed at the same time. Generalized logistic regression models estimated associations between SCRI and sleep duration/irregularity, with age and sex as moderators.

RESULTS

Age moderated the association between SCRI and short sleep (OR = 1.12, p < 0.001), such that the magnitude of the SCRI-sleep relationship was 12% greater in school-age children. Sex was not a significant moderator. In stratified models by age group, age was positively associated with short sleep in both groups, with a greater magnitude in school-age children. Female school-age children were less likely to have short sleep than males.

CONCLUSIONS

Younger children with greater social cumulative risk factors may be more vulnerable to short sleep duration. Further research into the mechanisms underlying the relationships between social risk and sleep health in school-age children is needed.

Response inhibition impairment related to altered frontal-striatal functional connectivity in insomnia disorder: A pilot and non-clinical study

BACKGROUND

It is not clear whether and how insomnia disorder (ID) impairs response inhibition ability. Fronto-striatal functional connectivity (FC) plays a critical role in response inhibition and is found be abnormal in patients with ID. In this study, we examined whether insomnia symptoms impair response inhibition in a large non-clinical sample and whether impaired response inhibition is related to abnormal fronto-striatal FC.

METHODS

One hundred and fifteen young ID patients and 160 age and sex-matched healthy controls (HC) underwent resting-state functional magnetic response imaging scans and performed the stop-signal task (SST). Performance of SST, Gray Matter Volumes (GMVs), and connections of brain regions related to fronto-striatal circuits was compared between groups. Further examined the association between response inhibition impairment and fronto-striatal FC.

RESULTS

The behavioral results showed that patients with ID had significantly longer stop-signal reaction time (SSRT) compared with the HC, reflecting the impaired response inhibition among IDs. Brain imaging results showed IDs had decreased GMVs of the Right Superior Frontal (SFG) and left Supplementary Motor area (SMA). Seed-based FC results showed that compared to HC, the ID showed decreased FC between left SMA and left Paracentral lobule, left SMA and right SMA, and right SFG and right Orbital Middle Frontal gyrus, and increased FC between right SFG and right putamen. Meanwhile, the FC between right SFG and putamen was positively correlated with SSRT in IDs.

CONCLUSIONS

The current study found significantly impaired response inhibition among ID and this impairment may be related to abnormal fronto-striatal FC in ID.

Insomnia nosology: a systematic review and critical appraisal of historical diagnostic categories and current phenotypes

Insomnia nosology has significantly evolved since the Diagnostic and Statistical Manual (DSM)-III-R first distinguished between 'primary' and 'secondary' insomnia. Prior International Classification of Sleep Disorders (ICSD) nosology 'split' diagnostic phenotypes to address insomnia's heterogeneity and the DSM nosology 'lumped' them into primary insomnia, while both systems assumed causality for insomnia secondary to health conditions. In this systematic review, we discuss the historical phenotypes in prior insomnia nosology, present findings for currently proposed insomnia phenotypes based on more robust approaches, and critically appraise the most relevant ones. Electronic databases PsychINFO, PubMED, Web of Science, and references of eligible articles, were accessed to find diagnostic manuals, literature on insomnia phenotypes, including systematic reviews or meta-analysis, and assessments of the reliability or validity of insomnia diagnoses, identifying 184 articles. The data show that previous insomnia diagnoses lacked reliability and validity, leading current DSM-5-TR and ICSD-3 nosology to 'lump' phenotypes into a single diagnosis comorbid with health conditions. However, at least two new, robust insomnia phenotyping approaches were identified. One approach is multidimensional-multimethod and provides evidence for self-reported insomnia with objective short versus normal sleep duration linked to clinically relevant outcomes, while the other is multidimensional and provides evidence for two to five clusters (phenotypes) based on self-reported trait, state, and/or life-history data. Some approaches still need replication to better support whether their findings identify true phenotypes or simply different patterns of symptomatology. Regardless, these phenotyping efforts aim at improving insomnia nosology both as a classification system and as a mechanism to guide treatment.

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.

Sleep Duration and Sarcopenia: An Updated Systematic Review and Meta-Analysis

OBJECTIVES

In adults, short and long sleep duration has been associated with sarcopenia risk. Studies have shown that various factors, including biological and psychological factors, could be the underlying cause of the association between aberrant sleep duration and sarcopenia risk. In this study, we have qualitatively and quantitatively summarized previously published studies on sleep duration to assess the relationship between sleep duration and sarcopenia risk in adults. This would aid in enhancing our understanding of recent advancements in this field and the association between sleep duration and sarcopenia risk.

DESIGN

Systematic review and meta-analysis.

SETTING AND PARTICIPANTS

In this review, we included studies evaluating the association between the duration of sleep and sarcopenia in adults in observational studies.

METHODS

Five electronic databases (PubMed, EMBASE, Cochrane Library, China National Knowledge Infrastructure, and Web of Science) were searched to April 20, 2023, to identify studies related to sarcopenia and sleep duration. Next, we calculated the odds ratios (ORs) for sarcopenia prevalence based on the adjusted data from individual studies. Statistical analyses were performed using Stata 11.0.

RESULTS

Sarcopenia prevalence was high (18%) in adults with long sleep duration. Our results showed a significant association between short duration of sleep and high sarcopenia prevalence in older adults (OR 1.2, 95% CI 1.02-1.41, I2 = 56.6%). Furthermore, a significant association was observed between all participants with long-duration sleep and high sarcopenia prevalence (OR 1.53, 95% CI 1.34-1.75, I2 = 56.8%). We also observed significant heterogeneity in the adjusted ORs.

CONCLUSIONS AND IMPLICATIONS

There was a correlation between sarcopenia and short or long sleep duration, especially in older adults. In adults with a long duration of sleep, sarcopenia prevalence was relatively high.

Clinical Spectrum and Trajectory of Innovative Therapeutic Interventions for Insomnia: A Perspective

Increasing incidences of insomnia in adults, as well as the aging population, have been reported for their negative impact on the quality of life. Insomnia episodes may be associated with neurocognitive, musculoskeletal, cardiovascular, gastrointestinal, renal, hepatic, and metabolic disorders. Epidemiological evidence also revealed the association of insomnia with oncologic and asthmatic complications, which has been indicated as bidirectional. Two therapeutic approaches including cognitive behavioral therapy (CBT) and drugs-based therapies are being practiced for a long time. However, the adverse events associated with drugs limit their wide and long-term application. Further, Traditional Chinese medicine, acupressure, and pulsed magnetic field therapy may also provide therapeutic relief. Notably, the recently introduced cryotherapy has been demonstrated as a potential candidate for insomnia which could reduce pain, by suppressing oxidative stress and inflammation. It seems that the synergistic therapeutic approach of cryotherapy and the above-mentioned approaches might offer promising prospects to further improve efficacy and safety. Considering these facts, this perspective presents a comprehensive summary of recent advances in pathological aetiologies of insomnia including COVID-19, and its therapeutic management with a greater emphasis on cryotherapy.

Sub-types of insomnia in adolescents: Insights from a quantitative/molecular twin study

Background

Insomnia with short sleep duration has been postulated as more severe than that accompanied by normal/long sleep length. While the short duration subtype is considered to have greater genetic influence than the other subtype, no studies have addressed this question. This study aimed to compare these subtypes in terms of: (1) the heritability of insomnia symptoms; (2) polygenic scores (PGS) for insomnia symptoms and sleep duration; (3) the associations between insomnia symptoms and a wide variety of traits/disorders.

Methods

The sample comprised 4000 pairs of twins aged 16 from the Twins Early Development Study. Twin models were fitted to estimate the heritability of insomnia in both groups. PGS were calculated for self-reported insomnia and sleep duration and compared among participants with short and normal/long sleep duration.

Results

Heritability was not significantly different in the short sleep duration group (A = 0.13 [95%CI = 0.01, 0.32]) and the normal/long sleep duration group (A = 0.35 [95%CI = 0.29, 0.40]). Shared environmental factors accounted for a substantial proportion of the variance in the short sleep duration group (C = 0.19 [95%CI = 0.05, 0.32]) but not in the normal/long sleep duration group (C = 0.00 [95%CI = 0.00, 0.04]). PGS did not differ significantly between groups although results were in the direction expected by the theory. Our results also showed that insomnia with short (as compared to normal/long) sleep duration had a stronger association with anxiety and depression (p < .05)-although not once adjusting for multiple testing.

Conclusions

We found mixed results in relation to the expected differences between the insomnia subtypes in adolescents. Future research needs to further establish cut-offs for 'short' sleep at different developmental stages and employ objective measures of sleep.

Insomnia disorder with objective short sleep duration (ISS) phenotype and cognitive performance: a systematic review and meta-analysis

OBJECTIVE

Insomnia disorder with objective short sleep duration (ISS) has been considered as a biologically severe subtype. The aim of this meta-analysis was to reveal the association of the ISS phenotype and cognitive performance.

METHODS

We searched PubMed, EMBASE, and the Cochrane Library for studies that observed an association of cognitive performance and insomnia with objective short sleep duration (ISS) phenotype. The "metafor" and "MAd" packages in R software (version 4.2.0) were used to calculate the unbiased standardized mean difference (Hedge's g), which was adjusted so that a negative value indicated worse cognitive performance.

RESULTS

The pooled analysis with 1339 participants revealed that the ISS phenotype was associated with overall cognitive impairments (Hedges' g = - 0.56 [- 0.89, - 0.23]), as well as specific cognitive domains including attention (Hedges' g = - 0.86 [- 1.25, - 0.47]), memory (Hedges' g = - 0.47 [- 0.82, - 0.12]), and executive function (Hedges' g = - 0.39 [- 0.76, - 0.02]). However, cognitive performance was not significantly different between insomnia disorder with objective normal sleep duration (INS) and good sleepers (p > .05).

CONCLUSION

Insomnia disorder with the ISS phenotype, but not the INS phenotype, was associated with cognitive impairments, suggesting the possible utility of treating the ISS phenotype to improve cognitive performance.

Comparison of the treatment effectiveness between lemborexant and zolpidem tartrate extended-release for insomnia disorder subtypes defined based on polysomnographic findings

STUDY OBJECTIVES

Patients with chronic insomnia may respond differently to therapeutic modalities. This study examined differences in response of individuals with 2 insomnia phenotypes-short sleep duration (I-SSD; < 6 hours) and normal sleep duration (I-NSD; ≥ 6 hours) determined by polysomnography-to treatment with lemborexant and zolpidem tartrate extended-release 6.25 mg (zolpidem ER), compared with placebo.

METHODS

Study E2006-G000-304 (Study 304; SUNRISE-1; NCT02783729) was a global, randomized, double-blind, placebo, and active comparator-controlled, parallel-group study comparing lemborexant 5 and 10 mg in individuals aged ≥ 55 years with insomnia disorder. In this analysis, changes in subjective (self-reported) variables based on sleep diaries and objective variables based on polysomnographs were assessed after 1-month administration of study drugs. Data from participants with I-SSD and I-NSD were compared.

RESULTS

In the I-SSD subgroup, both lemborexant doses provided significant benefit for sleep-onset latency (SOL), total sleep time (TST), and wake after sleep onset (WASO) vs placebo; zolpidem ER also provided significant benefit for TST and WASO, but not SOL, on both measures vs placebo. In the I-NSD subgroup, lemborexant and zolpidem ER provided significant benefit for TST and WASO vs placebo objectively but not subjectively; both doses of lemborexant provided significant benefit for SOL vs placebo subjectively, but not objectively.

CONCLUSIONS

Both drugs, but lemborexant more consistently, showed subjective and objective benefits compared with placebo in participants with insomnia with objective short sleep duration. However, neither lemborexant nor zolpidem provided consistent benefits for participants with normal sleep duration on sleep-onset and sleep maintenance variables.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Study of the Efficacy and Safety of Lemborexant in Subjects 55 Years and Older With Insomnia Disorder (SUNRISE 1); URL: https://clinicaltrials.gov/ct2/show/record/NCT02783729; Identifier: NCT02783729.

CITATION

Inoue Y, Nishida M, Kubota N, et al. Comparison of the treatment effectiveness between lemborexant and zolpidem tartrate extended-release for insomnia disorder subtypes defined based on polysomnographic findings. J Clin Sleep Med. 2023;19(3):519-528.

Longitudinal Associations Between Cybervictimization and Adolescent Sleep Problems: The Role of Anxiety and Depressive Symptoms

Adolescents who have experienced cybervictimization are at risk for sleep problems. However, there is a gap in knowledge about the mechanism that would explain this link. The study used a longitudinal design to test if cybervictimization predicted adolescents' sleep problems 6 and 12 months later, and whether these patterns could be explained in part by emotional distress in response to the victimization. Participants were 1987 Chinese adolescents (56.1% males) ages 10 to 14 (M = 12.32, SD = 0.53) at baseline. Data were collected over the course of 1 year, in three waves 6 months apart. The adolescents completed questionnaires regarding cybervictimization, sleep problems, depressive symptoms, and anxiety symptoms at all three time points. Autoregressive cross-lagged models showed that cybervictimization predicted later sleep problems after controlling for traditional peer victimization, and anxiety and depressive symptoms mediated this link. Multivariate latent growth models showed that the developmental trajectories of cybervictimization, sleep problems, anxiety symptoms, and depressive symptoms were related in complex ways over time. Measures of study variables were self-reported, and generalizability may be limited by a sample of adolescents from school in China. These results are important because of their implications for prevention and treatment of adolescents' sleep problems evoked by cybervictimization.

Insomnia with objective short sleep duration is associated with hypertension

Insomnia with objective short sleep duration has been proposed as the most biologically severe phenotype of the disorder associated with cardiometabolic morbidity in population-based samples. In this study, we investigated the association between insomnia with objective short sleep duration and hypertension in a large clinical sample. We studied 348 patients diagnosed with chronic insomnia disorder based on International Classification of Sleep Disorders Third Edition criteria and 150 normal sleepers. Objective short sleep duration was defined by the median total sleep time of the sample (< 7 hr) measured with 1-night polysomnography. Hypertension was defined based on blood pressure levels, antihypertensive medication use and/or a physician diagnosis. After adjusting for potential confounders, patients with chronic insomnia disorder who slept < 7 hr were associated with 2.8-fold increased odds of hypertension compared with normal sleepers who slept ≥ 7 hr (odds ratio = 2.81, 95% confidence interval = 1.068-7.411) or < 7 hr (odds ratio = 2.75, 95% confidence interval = 1.005-7.542), whereas patients with chronic insomnia disorder who slept ≥ 7 hr (odds ratio = 1.52, 95% confidence interval = 0.537-4.285) or normal sleepers who slept < 7 hr (odds ratio = 1.07, 95% confidence interval = 0.294-3.904) were not significantly associated with increased odds of hypertension compared with normal sleepers who slept ≥ 7 hr. Linear regression analyses showed that, for every hour decrease in total sleep time, systolic and diastolic blood pressure increased by 1.014 mmHg (p = 0.045) and 0.923 mmHg (p = 0.015), respectively, in patients with chronic insomnia disorder but not in normal sleepers. Our findings further support that insomnia with objective short sleep duration is a risk factor for hypertension, and objective short sleep duration may be a useful marker of the biological severity of chronic insomnia disorder in clinical practice.

Sleep deprivation and NLRP3 inflammasome: Is there a causal relationship?

In the modern era, sleep deprivation (SD) is one of the most common health problems that has a profound influence on an individual's quality of life and overall health. Studies have identified the possibility that lack of sleep can stimulate inflammatory responses. NLRP3 inflammasome, a key component of the innate immune responses, initiates inflammatory responses by enhancing proinflammatory cytokine release and caspase-1-mediated pyroptosis. In this study, NLRP3 modification, its proinflammatory role, and potential targeted therapies were reviewed with regard to SD-induced outcomes. A growing body of evidence has showed the importance of the mechanistic connections between NLRP3 and the detrimental consequences of SD, but there is a need for more clinically relevant data. In animal research, (i) some animals show differential vulnerability to the effects of SD compared to humans. (ii) Additionally, the effects of sleep differ depending on the SD technique employed and the length of SD. Moreover, paying attention to the crosstalk of all the driving factors of NLRP3 inflammasome activation such as inflammatory responses, autonomic control, oxidative stress, and endothelial function is highly recommended. In conclusion, targeting NLRP3 inflammasome or its downstream pathways for therapy could be complicated due to the reciprocal and complex relationship of SD with NLRP3 inflammasome activation. However, additional research is required to support such a causal claim.

Both Short and Long Sleep Durations Are Associated with Poor Cognition and Memory in Chinese Adults Aged 55+ Years-Results from China Health and Nutrition Survey

We aimed to examine the associations between sleep duration and cognitive functions and memory in older Chinese adults attending the China Health and Nutrition Survey. A total of 7924 participants 55 years and older who reported their sleep duration and had a cognitive screen test in 2004, 2006, and 2015 were included in the analysis. Mixed-effects logistic regression models were used to assess the associations. A short sleep duration (≤6 h/day) and long sleep duration (≥10 h/day) were positively associated with a low global cognitive score (odds ratio-OR: 1.23, 95% CI: 1.01-1.50; OR: 1.47, 95% CI: 1.17-1.79, respectively). Both short sleepers and long sleepers had an increased risk of self-reported poor memory (OR: 1.63, 95% CI: 1.39-1.91; OR: 1.48, 95% CI: 1.25-1.74, respectively). No differences in the above associations were found for income, education, and urbanity. In conclusion, both the short and long sleep duration were associated with declined cognition and memory. Maintaining a normal sleep duration may aid in the prevention of cognitive function decline in older adults.

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.

Effect of Long-Term Benzodiazepines for Chronic Insomnia on Cognitive Function and Waking Electroencephalography: A Case-Control Study

OBJECTIVE

The relationship between benzodiazepine use and cognitive decline in insomnia patients has been reported, but still conflicting. Thus, we tried to determine whether long-term exposure of benzodiazepine might be associated with changes of cognition and electroencephalography (EEG) findings in patients with chronic insomnia.

METHODS

Insomniacs using benzodiazepines (n=29), drug-free insomniacs (n=27), and age- and sex-matched controls (n=28) were recruited. Neurocognitive function tested with Korean version of the Consortium to Establish a Registry for Alzheimer's Disease Assessment Packet Neuropsychological Assessment Battery, quantitative EEG in awake state, and information of benzodiazepine usage were obtained.

RESULTS

Drug-free insomniacs reported more severe symptoms than insomniacs using benzodiazepine (p<0.001). Insomniacs using benzodiazepine showed a decrease of executive function in Trail Making Test A than drug-free insomniacs and controls (0.73±0.66 vs. 1.27±0.38 vs. 1.09±0.47, p<0.001) and in categorical fluency than drug-free insomniacs (-0.01±0.99 vs. 1.26±0.97, p=0.002). However, such decrease of executive function was not proportional to daily dose or cumulative dose of benzodiazepine. The EEG was not significantly different between insomniacs using benzodiazepine and drug-free insomniacs, while EEG of insomniacs showed low relative theta power in frontal and parietal regions but high relative beta power in frontal region than that of controls.

CONCLUSION

Benzodiazepine users with chronic insomnia showed an impairment of executive function compared to drug-free insomniacs and controls although they showed relatively decreased severity of insomnia symptoms. Chronic insomniacs showed a hyper-arousal manifestation in front-parietal region of brain regardless of benzodiazepine exposure.

Cognitive Function and Sleep in Caregivers of Persons Living with Dementia

Poor sleep is prevalent among caregivers of persons living with dementia and increases their risk for cognitive impairment and decline. In this cross-sectional, correlational study, we compared the cognitive function scores of caregivers with poor sleep with the demographically adjusted normed scores of the National Institutes of Health Toolbox Cognition Battery. Caregivers completed a 14-day sleep diary. On average, caregivers (n = 28) were 65.14 (±10.08) years, female, and White. Their average crystallized cognitive function composite score was significantly higher and their average fluid cognitive function composite score was significantly lower than the normative scores. Caregivers performed significantly worse on the processing speed domain measure. Poor sleep may affect how caregivers, including highly educated caregivers, process and respond to information, thus can influence how they safely perform complex caregiving tasks. Health care providers should consistently assess caregivers' sleep and cognitive abilities to promptly identify changes and provide timely interventions.

Impact of objectively-measured sleep duration on cardiometabolic health: A systematic review of recent evidence

Cardiometabolic disease is a spectrum of diseases including, cardiovascular diseases, and metabolic syndrome. It is the leading cause of morbidity and mortality worldwide, with premature deaths being preventable. Currently, sleep has emerged as a potential target for cardiometabolic disease prevention. Several epidemiological studies have provided ample evidence that objectively measured short sleep duration increases the risk of cardiometabolic disease. However, the findings are inconsistent, and few studies measure sleep duration on cardiometabolic profiles objectively. Therefore, in this review, we focused on the recently published literature that explored the association between objectively measured sleep duration and cardiometabolic profiles (cardiovascular diseases, type 2 diabetes mellitus, and metabolic syndrome), seeking more insights regarding the applicability and, in turn, the impact of objectively measured sleep duration on cardiometabolic health, which is relatively understudied. We retrieved the information manually from PubMed, Google Scholar, HINARI, and the Cochrane Library from 2015 to 2022 using appropriate search terms, we included 49 articles. In this review, we found a strong relationship between objectively measured sleep duration and the risk of cardiometabolic disease, indicating that objectively measured short sleep durations increase cardiometabolic risks. In general, the association between objectively measured sleep duration and increased cardiometabolic risks (CMR) has been well-documented in higher-income countries. Several studies found that longer sleep duration was associated with a more favorable cardiometabolic profile in early adolescence, independent of other risk factors. On the other hand, objectively measured short sleep duration is associated with adverse cardiometabolic health outcomes such as coronary heart disease, hypertension, type 2 diabetes mellitus, and metabolic syndrome.

Hypothalamic-pituitary-adrenal (HPA) axis response to exogenous corticotropin-releasing hormone (CRH) is attenuated in men with chronic insomnia

Although insomnia is by far the most common sleep disorder, our understanding of its neurobiology is limited. Insomnia, particularly when associated with objective sleep disturbance, has been associated with activation of the hypothalamic-pituitary-adrenal axis. The objective of this experimental study was to compare the response of the hypothalamic-pituitary-adrenal axis to ovine corticotropin-releasing hormone, a stress test, in men with insomnia versus controls. Circulating adrenocorticotropic hormone and cortisol levels were assayed before (-30 min, -15 min), at (0 min) and after (+5 min, +15 min, +30 min, +60 min, +90 min, +120 min) exogenous ovine corticotropin-releasing hormone administration in 23 men (11 insomnia, 12 controls), who underwent four consecutive nights of in-lab polysomnography. Men with insomnia compared with controls demonstrated markedly and significantly shorter total sleep time (368.4 ± 8.99 min versus 411.61 ± 8.61 min; p < 0.01) and lower sleep efficiency (76.77 ± 1.80% versus 86.04 ± 1.72%; p < 0.01) on polysomnography, and showed decreased adrenocorticotropic hormone and cortisol levels after ovine corticotropin-releasing hormone administration. Adrenocorticotropic hormone levels at 15 min and 30 min were significantly lower in men with insomnia than in controls (p < 0.05). Similarly, the peak levels of cortisol at +60 min, and the total and net area under the curve levels of this hormone were significantly lower in men with insomnia than controls (all p < 0.01). Adrenocorticotropic hormone and cortisol response to ovine corticotropin-releasing hormone administration was attenuated in men with insomnia associated with objective sleep disturbance, suggesting that objectively defined insomnia subtypes have a disrupted hypothalamic-pituitary-adrenal axis function and highlight the need to develop treatments targeting the underlying hypothalamic-pituitary-adrenal axis dysregulation.

Associations between fecal short-chain fatty acids and sleep continuity in older adults with insomnia symptoms

Insomnia is a disorder characterized by difficulty falling asleep and poor sleep continuity and is associated with increased risks for physical and cognitive decline. Insomnia with short sleep duration is considered the most biologically severe phenotype of the disorder. Evidence suggests that short-chain fatty acids (SCFAs), the main byproducts of fiber fermentation in the gut, may affect sleep via gut–brain communications. This study explores associations between SCFAs and sleep continuity and compares SCFA concentrations in short vs. normal sleep insomnia phenotypes in older adults. Fifty-nine participants with insomnia symptoms (≥ 65 years), completed 2 weeks of objective sleep monitoring (actigraphy), and were divided into short and normal sleep duration phenotypes via cluster analysis. Sleep measures included total sleep time (TST), sleep onset latency (SOL), sleep efficiency (SE), and wake after sleep onset (WASO). Stool samples were collected and fecal SCFA concentrations were determined by gas-chromatography-mass-spectrometry (GCMS). Higher concentrations of acetate, butyrate, and propionate, and total SCFAs, were associated with lower SE and longer SOL after controlling for Body Mass Index (BMI). Concentrations were higher in the short sleep duration phenotype. Age, BMI, TST, and SOL explained 40.7% of the variance in total SCFAs. Findings contribute to understanding pathways along the gut–brain axis and may lead to the use of SCFAs as biomarkers of insomnia phenotypes.