Nature and Science of Sleep最新文献

Objective: To investigate the prevalence of dry eye disease (DED) among children and adolescents aged 9 to 19 years in Fengyang County, and to explore the associations of sleep duration and social jetlag with DED, with the aim of providing scientific evidence for sleep-based interventions to prevent DED in this population.

Methods: Between November and December 2023, 14 primary and secondary schools were randomly selected in Fengyang County, Chuzhou City, Anhui Province, China. Students from Grade 4 to Grade 12 (aged 9-19 years) were invited to participate. A trained professional conducted clinical assessments to evaluate DED, and participants completed self-administered questionnaires to report their sleep behaviors. Sleep quality was assessed by an item from Pittsburgh Sleep Quality Index. Chi-square tests and independent-samples t-tests were used to compare sociodemographic characteristics between DED and non-DED groups. Logistic regression models were applied to examine the associations of sleep duration, social jetlag, and their interaction with DED after adjusting for potential confounders.

Results: The overall prevalence of DED among children and adolescents in Fengyang County was 51%. After adjusting for confounders, binary logistic regression analysis showed that students who slept less than 9 hours per night had a significantly higher likelihood of DED (OR = 1.37, 95% CI: 1.21-1.68), and those with social jetlag ≥1 hour also had an elevated risk of DED (OR = 1.28, 95% CI: 1.07-1.54). Notably, the group with sleep duration ≥ 9 h combined with social jet lag ≥ 1 h showed a significant positive association with DED after adjusting for sleep quality (OR = 1.77, 95% CI: 1.35-2.33).

Conclusion: Both insufficient sleep duration and significant social jetlag are associated with an increased risk of DED in children and adolescents. These findings suggest the need for targeted sleep education programs in schools that emphasize not only sufficient sleep duration but also consistent sleep-wake schedules between weekdays and weekends to promote ocular health among youth.

Aim: Obstructive sleep apnea (OSA) is characterized by repetitive upper airway collapse during sleep, resulting in frequent cortical arousals. However, currently used frequency-based arousal metrics do not sufficiently capture the heterogeneity and clinical significance of arousal responses. The odds ratio product (ORP) is a novel electroencephalographic marker that provides a continuous assessment of sleep depth and has the potential to serve as an objective measure of arousal intensity.

Purpose: This study aimed to quantify the intensity of arousals in untreated OSA patients using the ORP, and to explore the relationships between arousal intensity, respiratory event features, and subjective sleepiness.

Patients and methods: We retrospectively analysed data from 1057 adults with untreated OSA enrolled in the APPLES cohort. EEG spectral power was mapped to ORP values, and arousal intensity for each event was objectively calculated based on deviations in ORP from baseline. A total of 258,121 arousal events were included. Mixed-effects modelling was used to assess the impact of event type, duration, latency, sleep stage, position, and inter-individual variability on arousal intensity. Stepwise multiple regression explored associations between individual arousal intensity and subjective sleepiness.

Results: Arousal intensity increased significantly with the duration of preceding respiratory events, and was markedly higher than that of spontaneous arousals. The association between respiratory events and arousal intensity was stronger for apneas than for hypopneas, while deep sleep stage and lateral posture significantly reduced arousal response. Inter-individual variability was pronounced. Higher baseline arousal intensity was independently associated with increased subjective daytime sleepiness, after adjusting for known confounders.

Conclusion: ORP-derived arousal intensity provides a quantitative biomarker of cortical arousal. Arousal intensity is shaped by respiratory event characteristics, sleep architecture, and intrinsic individual traits. Although slight, arousal intensity is independently associated with subjective daytime sleepiness.

Purpose: To assess the effects of magnesium bisglycinate supplementation on insomnia symptoms in healthy adults reporting poor sleep quality.

Patients and methods: This randomized, double-blind, placebo-controlled trial enrolled 155 adults aged 18-65 years with self-reported poor sleep quality. Participants were randomly assigned to either magnesium bisglycinate supplementation (250 mg elemental magnesium, daily) or placebo capsules. Sleep quality was assessed using the Insomnia Severity Index (ISI) and additional psychological questionnaires at baseline and multiple time points throughout the study. Generalized linear mixed models (GLMM) adjusted for baseline ISI scores, age, sex, body mass index, and occupation were applied.

Results: The magnesium bisglycinate group showed a significantly greater reduction in ISI scores compared to the placebo group from baseline to Week 4 (-3.9 [95% CI: -5.8 to -2.0] vs -2.3 [95% CI: -4.1 to -0.4], respectively; p = 0.049). The effect size was small (Cohen's d = 0.2), indicating a modest benefit. Exploratory analyses suggested notably greater improvements among participants reporting lower baseline dietary magnesium intake, potentially indicating a subgroup of high responders. No significant differences were observed in other psychological outcomes.

Conclusion: Magnesium bisglycinate supplementation modestly improved insomnia severity in adults reporting poor sleep quality. Future research should include objective sleep assessments, longer intervention periods, and better characterization of potential high responders by systematically assessing baseline dietary magnesium intake and status.

Clinical trial registration name: Effect of magnesium bisglycinate supplementation on sleep and fatigue parameters in healthy adults reporting poor sleep quality; https://drks.de/search/en/trial/DRKS00031494 DRKS-ID: DRKS00031494.

Introduction: Type 2 diabetes (T2D) shows bidirectional relationships with polysomnographic measures. However, no studies have searched systematically for novel polysomnographic biomarkers of T2D. We therefore investigated if state-of-the-art explainable machine learning (ML) models could identify new polysomnographic biomarkers predictive of incident T2D.

Methods: We applied explainable ML models to longitudinal cohort study data from 536 males who were free of T2D at baseline and identified 52 cases of T2D at follow-up (mean 8.3, range 3.5-10.5 years). Beyond ranking biomarker importance, we explored how the explainable ML model approach can identify novel relationships, assist in hypothesis testing, and provide insights into risk factors.

Results: The top five most predictive biomarkers included waist circumference, glucose, and three novel sleep biomarkers: the number of 3% desaturations in non-supine sleep, mean heart rate in supine sleep, and mean hypopnea duration. Explainable machine learning identified a significant association between the number of non-supine desaturation events (threshold of 19 events) and incident T2D (Odds ratio = 2.4 [95% CI 1.2-4.8], P = 0.013). No significant associations were found using continuous or quartiled versions of non-supine desaturation. Additionally, the model provided an individualized risk factor breakdown, supporting a more personalized approach to precision sleep medicine.

Conclusion: Explainable ML supports the role of established biomarkers and reveals novel biomarkers of T2D likely to help guide further hypothesis testing and validation of more robust and clinically useful biomarkers. Although further validation is needed, these proof-of-concept data support the benefits of explainable ML in prospective data analysis.

Purpose: To compare the efficacy differences between acupuncture and sham acupuncture in adult primary insomnia through Bayesian network meta-analysis, analyze the impact of different types of sham acupuncture on efficacy, and explore the basis for the control setting.

Methods: A literature search of seven databases, including PubMed and Embase, until April 23, 2025, included randomized controlled trials (RCTs) comparing AT with noninvasive sham acupuncture (NISA), superficial acupuncture (SA), and non-acupuncture therapy (NAT) for treating PI in adults. The statistical analyses were conducted using R (version 4.4.1) and Stata (version 15.1). The protocol was registered with the International Prospective Register of Systematic Reviews (CRD420251012912).

Results: This meta-analysis incorporated 33 RCTs encompassing 3004 participants, with most studies originating from China. The results showed that at the treatment endpoint and after 4 weeks, AT significantly improved subjective sleep quality (Pittsburgh Sleep Quality Index, PSQI) compared to SA and NISA, exceeding the minimum clinically important difference (MCID: 2.5 points). Specifically, at the endpoint, AT vs SA (MD: -3.66; 95% CI: -4.48 to -2.84) and AT vs NISA (MD: -4.35; 95% CI: -5.67 to -3) were significant, while differences among SA, NISA, and NAT were not. Based on the surface under the cumulative rank curve (SUCRA), AT ranked first (99.9%), followed by SA (47.8%), NAT (31.9%), and NISA (20.4%). No significant differences were found between AT, NISA, and SA regarding objective sleep parameters.

Conclusion: AT significantly improved subjective sleep quality in patients with PI, though its impact on objective sleep measures was limited. When designing RCTs of acupuncture for PI, NISA is recommended as the sham acupuncture control. However, due to geographical limitations, the study results may be difficult to generalize. Future research should focus on monitoring objective sleep parameters and conducting international, multicenter RCTs involving diverse cultural populations.

Objective: A low arousal threshold (AT) appears to contribute to obstructive sleep apnea (OSA) pathogenesis. However, the role of low AT in OSA and overlap syndrome (OVS) is still unclear. This study is aimed to investigate the value of the AT score, a new method for qualifying AT, for examining the relationship between OSA and OVS, including chronic obstructive pulmonary disease (COPD) and asthma.

Methods: In this retrospective study, a total of 3400 adults diagnosed with OSA at a sleep medicine center were finally included. All patients were stratified into low-, high- and very high-AT score groups according to the previous logistic regression for qualifying AT. Multivariate logistic regression was conducted to evaluate the association between AT score and OVS prevalence. We compared this association with that of the apnea hypopnea index (AHI).

Results: 40.3%, 42.9% and 16.8% of OSA patients had low-, high- and very high AT score, respectively. Compared with the very high AT score, the low AT score was independently associated with the prevalence of COPD (OR = 2.17, 95% CI = 1.09-4.32) and asthma (OR = 4.54, 95% CI = 2.52-8.17). With decreasing AT score, the adjusted ORs of the comorbidities increased stepwise, particularly in some subgroups based on sex, age and BMI. Conversely, the classification of AHI did not show similar values.

Conclusion: In individuals with OSA, low AT is a common pathophysiological feature associated with COPD and asthma. The AT score is a new and effective indicator for evaluating the relationship between OSA and OVS.

Purpose: The objective of this study is to compare sleep measurements by a consumer-wearable with research-standard actigraphy coupled with sleep diaries in free-living female adults.

Methods: Forty-seven females in the Nurses' Health Study 3 (NHS3) participated in the Sleep and Physical Activity Validation Substudy (SPAVS), where they were asked to concurrently wear a consumer wearable (Fitbit Charge, Models 3 or 5) and a research-grade accelerometer (Actigraph, GT3X+ or Actisleep) on the same wrist and fill out a smartphone-based sleep diary for fourteen consecutive days. We compared measures of total sleep time (TST), time in bed (TIB), and sleep efficiency (SE) from the consumer wearable with actigraphy measures as our research-standard reference for TST and SE and self-reported sleep diary as our reference for TIB. We calculated mean absolute percent error (MAPE) and intra-class correlations (ICC), as well as Bland-Altman analyses to compute mean difference and limits of agreement.

Results: For all three measures, the consumer wearable underestimated sleep parameters relative to research-standard actigraphy, with a mean bias of -16.0 minutes and -11.2 minutes for TST and TIB, respectively, and -1.0% for SE. In terms of agreement, TST (MAPE = 11.18%; ICC = 0.79) and TIB (MAPE = 10.45%; ICC = 0.74) had similar MAPES and ICCs, while and SE (MAPE = 5.09%; ICC = 0.39) had a lower ICC.

Conclusion: In the NHS3 SPAVS, the wearable sleep measurements modestly underestimated wrist actigraphy measures of TST, TIB, and SE from sleep over multiple days; within sleep measures assessed, TST and TIB had greater agreement with research-grade accelerometry than SE.

Purpose: Chronotype can be used to describe individual's circadian preference in behavioral and circadian rhythm, representing the preferences for earlier or later sleep times. This study aimed to investigate the association of chronotype with hypertension and metabolic parameters in middle-aged and older adults.

Patients and methods: A total of 945 participants were recruited from December 2023 to December 2024 at First Affiliated Hospital of University of Science and Technology of China. Chronotype was determined using the full Morningness-Eveningness Questionnaire, with higher scores indicating preference for morning chronotype. Chronotype was dichotomized at the median score in current cohort, classifying 447 participants as morning chronotypes and 498 as evening chronotypes. Anthropometric measurements and biochemical analyses were also conducted. Multivariable logistic, linear regression, and restricted cubic spline (RCS) analyses were employed to evaluate association between chronotype, metabolic parameters, and hypertension.

Results: After adjustment for covariates, evening chronotype was significantly associated with hypertension risk (OR = 1.60, 95% CI: 1.17-2.17), compared with morning chronotype. The RCS analysis suggested a significant nonlinearity association between chronotype score and hypertension (P for nonlinear = 0.047). Furthermore, higher chronotype score was significantly associated with decreased levels of total cholesterol [TC, β (95% CI): -0.12 (-0.19, -0.04)], low-density lipoprotein-cholesterol [LDL-C, β (95% CI): -0.21 (-0.33, -0.08)] and serum uric acid [SUA, β (95% CI): -0.09 (-0.18, -0.01)], but with increased levels of aspartate aminotransferase [AST, β (95% CI): 0.16 (0.05, 0.27)]. In discrimination model, chronotype was associated with hypertension independently of TC, SUA, alanine transaminase, and alkaline phosphatase, with model's AUC of 0.779 (95% CI: 0.749-0.808).

Conclusion: In middle-aged and older adults, preference for morning chronotype was associated with decreased levels of TC, LDL-C, and SUA, but with increased levels of AST. Moreover, evening chronotype was significantly independently associated with increased risk of hypertension.

Insights into the mysteries of dreaming and waking conscious experience can be gained by considering fundamental concepts in memory research. To support this assertion, we first provide an overview of the conscious/nonconscious distinction in memory research and then summarize the memory theory of consciousness (MToC). According to the MToC, the brain system responsible for explicit memory is also responsible for all our conscious experiences-perceptions, thoughts, memories, imaginings, and dreams. Ordinarily, we experience a continuity of consciousness, even when we wake from a period of sleep. On the other hand, memory dysfunction can disrupt this continuity across sleep and lead to disorientation upon awakening. The relationship between sleep and consciousness comes into sharper focus when considering the proposition that most sleep-based memory processing is below the surface of what we can experience. During sleep, stored information is reactivated in the service of memory consolidation and, unlike dreams, this memory processing remains in the realm of implicit memory. We further propose that many multifarious memories can be simultaneously reactivated through this sleep-based processing, engaging both the hippocampus and cerebral cortex. At the same time, fragments of information from a subset of reactivated memories may be strung together to create a consciously experienced storyline or dream. In keeping with the MToC, we emphasize that conscious experiences, both while awake and while dreaming, are not read-outs of external reality even though they are typically experienced as such. Sensory experiences seem direct and instantaneous, but they are indirect and delayed because they require sensory processing to reach the explicit-memory system. Furthermore, because we remain oblivious to the unconscious memory processing that pervades our sleep, people generally underestimate the impact of sleep on our subsequent recollections and habits in the wake state. In sum, memory research enriches our understanding of consciousness in many ways.

Purpose: Data on the prevalence and correlates of rapid eye movement (REM)-related obstructive sleep apnea (REM-OSA) in narcolepsy remains limited. This study aimed to assess the prevalence and independent associated factors with OSA and REM-OSA in patients with narcolepsy, and to compare the distribution of REM-OSA between patients with narcolepsy and matched controls without narcolepsy.

Patients and methods: This retrospective study of a prospectively collected cohort included 190 adult patients with narcolepsy (narcolepsy type 1 [NT1] = 119, narcolepsy type 2 [NT2] = 71) who underwent polysomnography and multiple sleep latency test at the University Sleep Disorders Center, King Saud University Medical City, between January 2007 and February 2022. REM-OSA was defined as an apnea-hypopnea index (AHI) ≥5, AHI-REM/AHI-non-rapid eye movement (NREM) ≥2, AHI-NREM <8, and REM sleep duration >10.5 minutes. A total of 106 patients with narcolepsy were diagnosed with OSA. A control group of 122 patients with OSA but without narcolepsy, matched by age, sex, AHI, and BMI, was used for comparison. Logistic regression identified independent associated factors with OSA and REM-OSA.

Results: OSA was diagnosed in 106 patients with narcolepsy (55.8%). REM-OSA was present in 26.4% of these cases, with a slightly higher prevalence in NT2 (30%) than in NT1 (24%). REM-OSA showed a trend toward higher prevalence in the narcolepsy group compared to controls (26.4% vs 17.2%, OR: 1.73, 95% CI: 0.91-3.27, p = 0.09). Male sex, BMI, and arousal index were independent correlates of OSA among patients with narcolepsy. REM-OSA was independently associated with arousal index and REM sleep duration.

Conclusion: OSA and REM-OSA are common in patients with narcolepsy. REM-OSA was more prevalent in the narcolepsy group than in matched controls, suggesting a potential association between narcolepsy and REM-OSA that warrants investigation in larger cohorts.