Evening binge alcohol disrupts cardiovagal tone and baroreflex function during polysomnographic sleep

Study ObjectivesBinge alcohol consumption is associated with increased cardiovascular risk. The effects of evening binge alcohol consumption (i.e. 4–5 beverages within 2 h) on the vagal components of HRV and cardiovagal baroreflex sensitivity (cvBRS) during sleep remain largely equivocal. The present study examined the effects of evening binge alcohol consumption on nocturnal cardiac vagal tone and baroreflex sensitivity during stage N2, slow wave (SWS), and rapid eye movement (REM) sleep. We hypothesized that evening binge drinking would reduce HRV and cvBRS in each sleep stage.MethodsFollowing a familiarization night within the laboratory, twenty-three participants were examined following a night of binge alcohol consumption and a fluid control (randomized, crossover design). A quality nocturnal beat-to-beat blood pressure signal was obtained in both conditions in 16 participants (seven men, nine women; 25 ± 1 years).ResultsBinge drinking reduced both the high frequency (HF) and time-domain components (i.e. pNN50 and RMSSD) of HRV in stage N2 sleep, SWS, and REM. In addition, cvBRS up-up (vagal activation) was reduced following binge alcohol consumption in stage N2 (21 ± 3 vs. 15 ± 3 ms/mmHg, p = 0.035) and REM (15[11–28] vs. 11[9–18] ms/mmHg, p = 0.009). Binge alcohol consumption reduced cvBRS down-down (vagal withdrawal) in stage N2 (23 ± 2 vs. 14 ± 2 ms/mmHg, p < 0.001), SWS (20[14–30] vs. 14[9–17] ms/mmHg, p = 0.022), and REM (14[11–24] vs. 10[7–15] ms/mmHg, p = 0.006).ConclusionsEvening binge alcohol consumption disrupts cardiac vagal tone and baroreflex function during nearly all sleep stages. These findings provide mechanistic insight into the potential role of binge drinking and alcohol abuse on cardiovascular risk.Clinical Trials DetailsAlcohol and Neural Cardiovascular Control in Binge Drinkers, www.clinicaltrials.gov/ct2/show/{"type":"clinical-trial","attrs":{"text":"NCT03567434","term_id":"NCT03567434"}}NCT03567434, {"type":"clinical-trial","attrs":{"text":"NCT03567434","term_id":"NCT03567434"}}NCT03567434.     

Effects of nocturnal wearing of dentures on the quality of sleep and oral-health-related quality in edentate elders with untreated sleep apnea: a randomized cross-over trial

Study ObjectivesThis study aims to assess whether the nocturnal wear of dentures has an effect on the quality of sleep and oral-health-related quality of life of the edentulous elderly with untreated sleep apnea.MethodsA single-blind randomized cross-over design with two sequences and two periods was used. Participants (n = 77) were randomly assigned either to sequence 1 (nocturnal wear followed by nocturnal nonwear of the denture for 30–30 days) or sequence 2 (nocturnal nonwear followed by nocturnal wear of denture for 30–30 days). The primary sleep outcome was the quality of sleep, assessed through sleep fragmentation measured as Apnea–Hypopnea Index (AHI) and respiratory arousal from portable polysomnography. Secondary outcomes were daytime sleepiness, sleep quality (Pittsburgh Sleep Quality Index, PSQI) and oral-health-related quality of life measured by validated questionnaires.ResultsThe mean paired difference in AHI scores for the period of wearing versus not wearing dentures at night was small 1.0 event per hour (p = 0.50; 95% confidence interval (CI) = −2.0 to 4.1). The mean respiratory arousal index was higher when wearing dentures at night than when not wearing dentures at night, with a mean paired difference of 2.3 events per hour (p = 0.05; 95% CI = 0.0 to 4.6). No difference in sleepiness and PSQI were noted. Wearing dentures at night resulted in a statistically significantly higher mean score of psychological discomfort when compared to not wearing dentures at night.ConclusionsThe results provide some support to usual practice guidelines to remove dentures at night in edentulous elders suffering from sleep apnea.Clinical trial registrationNCT01868295.     

Electroencephalographic sleep macrostructure and sleep spindles in early infancy

Study ObjectivesSleep features in infancy are potential biomarkers for brain maturation but poorly characterized. We describe normative values for sleep macrostructure and sleep spindles at 4–5 months of age.MethodsHealthy term infants were recruited at birth and had daytime sleep electroencephalograms (EEGs) at 4–5 months. Sleep staging was performed and five features were analyzed. Sleep spindles were annotated and seven quantitative features were extracted. Features were analyzed across sex, recording time (am/pm), infant age, and from first to second sleep cycles.ResultsWe analyzed sleep recordings from 91 infants, 41% females. Median (interquartile range [IQR]) macrostructure results: sleep duration 49.0 (37.8–72.0) min (n = 77); first sleep cycle duration 42.8 (37.0–51.4) min; rapid eye movement (REM) percentage 17.4 (9.5–27.7)% (n = 68); latency to REM 36.0 (30.5–41.1) min (n = 66). First cycle median (IQR) values for spindle features: number 241.0 (193.0–286.5), density 6.6 (5.7–8.0) spindles/min (n = 77); mean frequency 13.0 (12.8–13.3) Hz, mean duration 2.9 (2.6–3.6) s, spectral power 7.8 (4.7–11.4) µV², brain symmetry index 0.20 (0.16–0.29), synchrony 59.5 (53.2–63.8)% (n = 91). In males, spindle spectral power (µV²) was 24.5% lower (p = .032) and brain symmetry index 24.2% higher than females (p = .011) when controlling for gestational and postnatal age and timing of the nap. We found no other significant associations between studied sleep features and sex, recording time (am/pm), or age. Spectral power decreased (p < .001) on the second cycle.ConclusionThis normative data may be useful for comparison with future studies of sleep dysfunction and atypical neurodevelopment in infancy. Clinical Trial Registration: BABY SMART (Study of Massage Therapy, Sleep And neurodevelopMenT) (BabySMART)URL: https://clinicaltrials.gov/ct2/show/results/NCT03381027?view=results.ClinicalTrials.gov Identifier: NCT03381027     

Suicidal ideation is associated with nighttime wakefulness in a community sample

Study ObjectivesNocturnal wakefulness is a risk factor for suicide and suicidal ideation in clinical populations. However, these results have not been demonstrated in general community samples or compared to sleep duration or sleep quality. The present study explored how the timing of wakefulness was associated with suicidal ideation for weekdays and weekends.MethodsData were collected from 888 adults aged 22–60 as part of the Sleep and Healthy Activity, Diet, Environment, and Socialization study. Suicidal ideation was measured by the Patient Health Questionnaire-9, while timing of wakefulness was estimated from the Sleep Timing Questionnaire. Binomial logistic regressions estimated the association between nocturnal (11 pm–5 am) and morning (5 am–11 am) wakefulness and suicidal ideation.ResultsNocturnal wakefulness was positively associated with suicidal ideation on weekdays (OR: 1.44 [1.28–1.64] per hour awake between 11:00 pm and 05:00 am, p < 0.0001) and weekends (OR: 1.22 [1.08–1.39], p = 0.0018). Morning wakefulness was negatively associated with suicidal ideation on weekdays (OR: 0.82 [0.72–0.92] per hour awake between 05:00 am and 11:00 am, p = 0.0008) and weekends (OR: 0.84 [0.75–0.94], p = 0.0035). These associations remained significant when adjusting for sociodemographic factors. Additionally, nocturnal wakefulness on weekdays was associated with suicidal ideation when accounting for insomnia, sleep duration, sleep quality, and chronotype (OR 1.25 [1.09–1.44] per hour awake, p = 0.002).ConclusionWakefulness at night was consistently associated with suicidal ideation. Additionally, morning wakefulness was negatively associated with suicidal ideation in some models. Although these findings are drawn from a non-clinical sample, larger longitudinal studies in the general population are needed to confirm these results.     

Sleep symptomatology is associated with greater subjective cognitive concerns: findings from the community-based Healthy Brain Project

Study ObjectivesTo examine if sleep symptomatology was associated with subjective cognitive concerns or objective cognitive performance in a dementia-free community-based sample.MethodsA total of 1,421 middle-aged participants (mean ± standard deviation = 57 ± 7; 77% female) from the Healthy Brain Project completed the Pittsburgh Sleep Quality Index, Insomnia Severity Index, and Epworth Sleepiness Scale to measure sleep quality, insomnia symptom severity, and daytime sleepiness, respectively. Participants were classified as having no sleep symptomatology (normal scores on each sleep measure), moderate sleep symptomatology (abnormal scores on one sleep measure), or high sleep symptomatology (abnormal scores on at least two sleep measures), using established cutoff values. Analysis of covariance was used to compare objective cognitive function (Cogstate Brief Battery) and subjective cognitive concerns (Modified Cognitive Function Instrument) across groups.ResultsFollowing adjustments for age, sex, education, mood, and vascular risk factors, persons classified as having high sleep symptomatology, versus none, displayed more subjective cognitive concerns (d = 0.24) but no differences in objective cognitive performance (d = 0.00–0.18). Subjective cognitive concerns modified the association between sleep symptomatology and psychomotor function. The strength of the relationship between high sleep symptomatology (versus none) and psychomotor function was significantly greater in persons with high as compared with low cognitive concerns (β ± SE = −0.37 ± 0.16; p = 0.02).ConclusionsMore severe sleep symptomatology was associated with greater subjective cognitive concerns. Persons reporting high levels of sleep symptomatology may be more likely to display poorer objective cognitive function in the presence of subjective cognitive concerns.     

Sleep-dependent prospective memory consolidation is impaired with aging

Study ObjectivesExisting literature suggests that sleep-dependent memory consolidation is impaired in older adults but may be preserved for personally relevant information. Prospective memory (PM) involves remembering to execute future intentions in a timely manner and has behavioral importance. As previous work suggests that N3 sleep is important for PM in young adults, we investigated if the role of N3 sleep in PM consolidation would be maintained in older adults.MethodsForty-nine young adults (mean age ± SD: 21.8 ± 1.61 years) and 49 healthy older adults (mean age ± SD: 65.7 ± 6.30 years) were randomized into sleep and wake groups. After a semantic categorization task, participants encoded intentions comprising four related and four unrelated cue-action pairs. They were instructed to remember to perform these actions in response to cue words presented during a second semantic categorization task 12 h later that encompassed either daytime wake (09:00 am–21:00 pm) or overnight sleep with polysomnography (21:00 pm–09:00 am).ResultsThe significant condition × age group × relatedness interaction suggested that the sleep benefit on PM intentions varied according to age group and relatedness (p = 0.01). For related intentions, sleep relative to wake benefitted young adults’ performance (p < 0.001) but not older adults (p = 0.30). For unrelated intentions, sleep did not improve PM for either age group. While post-encoding N3 was significantly associated with related intentions’ execution in young adults (r = 0.43, p = 0.02), this relationship was not found for older adults (r = −0.07, p = 0.763).ConclusionsThe age-related impairment of sleep-dependent memory consolidation extends to PM. Our findings add to an existing body of work suggesting that the link between sleep and memory is functionally weakened in older adulthood.     

Altered K-complex morphology during sustained inspiratory airflow limitation is associated with next-day lapses in vigilance in obstructive sleep apnea

Study ObjectivesDetermine if changes in K-complexes associated with sustained inspiratory airflow limitation (SIFL) during N2 sleep are associated with next-day vigilance and objective sleepiness.MethodsData from thirty subjects with moderate-to-severe obstructive sleep apnea who completed three in-lab polysomnograms: diagnostic, on therapeutic continuous positive airway pressure (CPAP), and on suboptimal CPAP (4 cmH₂O below optimal titrated CPAP level) were analyzed. Four 20-min psychomotor vigilance tests (PVT) were performed after each PSG, every 2 h. Changes in the proportion of spontaneous K-complexes and spectral characteristics surrounding K-complexes were evaluated for K-complexes associated with both delta (∆SWAK), alpha (∆αK) frequencies.ResultsSuboptimal CPAP induced SIFL (14.7 (20.9) vs 2.9 (9.2); %total sleep time, p < 0.001) with a small increase in apnea–hypopnea index (AHI3A: 6.5 (7.7) vs 1.9 (2.3); p < 0.01) versus optimal CPAP. K-complex density (num./min of stage N2) was higher on suboptimal CPAP (0.97 ± 0.7 vs 0.65±0.5, #/min, mean ± SD, p < 0.01) above and beyond the effect of age, sex, AHI3A, and duration of SIFL. A decrease in ∆SWAK with suboptimal CPAP was associated with increased PVT lapses and explained 17% of additional variance in PVT lapses. Within-night during suboptimal CPAP K-complexes appeared to alternate between promoting sleep and as arousal surrogates. Electroencephalographic changes were not associated with objective sleepiness.ConclusionsSustained inspiratory airflow limitation is associated with altered K-complex morphology including the increased occurrence of K-complexes with bursts of alpha as arousal surrogates. These findings suggest that sustained inspiratory flow limitation may be associated with nonvisible sleep fragmentation and contribute to increased lapses in vigilance.     

Cognitive effects of split and continuous sleep schedules in adolescents differ according to total sleep opportunity

Study ObjectivesWe compared the basic cognitive functions of adolescents undergoing split (nocturnal sleep + daytime nap) and continuous nocturnal sleep schedules when total sleep opportunity was either below or within the recommended range (i.e. 6.5 or 8 h).MethodsAdolescent participants (age: 15–19 year) in the 8-h split (n = 24) and continuous (n = 29) sleep groups were compared with 6.5-h split and continuous sleep groups from a previous study (n = 58). These protocols involved two baseline nights (9-h time-in-bed [TIB]), 5 nights of sleep manipulation, 2 recovery nights (9-h TIB), followed by a second cycle of sleep manipulation (3 nights) and recovery (2 nights). Cognitive performance, subjective sleepiness, and mood were evaluated daily; sleep was assessed using polysomnography.ResultsSplitting 6.5 h of sleep with a mid-afternoon nap offered a boost to cognitive function compared to continuous nocturnal sleep. However, when total TIB across 24 h increased to 8 h, the split and continuous sleep groups performed comparably in tests evaluating vigilance, working memory, executive function, processing speed, subjective sleepiness, and mood.ConclusionsIn adolescents, the effects of split sleep on basic cognitive functions vary by the amount of total sleep obtained. As long as the total sleep opportunity across 24 h is within the recommended range, students may fulfill sleep requirements by adopting a split sleep schedule consisting of a shorter period of nocturnal sleep combined with a mid-afternoon nap, without significant impact on basic cognitive functions.Clinical trial registration{"type":"clinical-trial","attrs":{"text":"NCT04044885","term_id":"NCT04044885"}}NCT04044885.     

The acute effects of aerobic exercise on sleep in patients with unipolar depression: a randomized controlled trial

Study ObjectivesInsomnia increases the risk of negative disease trajectory, relapse, and suicide in patients with depression. We aimed at investigating the effects of a single bout of aerobic exercise, performed after 02:00 pm, on the subsequent night’s sleep in patients with depression.MethodsThe study was designed as a two-arm parallel-group, randomized, outcome assessor-blinded, controlled, superiority trial. Patients between 18 and 65 years of age with a primary diagnosis of unipolar depression were included. The intervention was a single 30-minute bout of moderate aerobic exercise. The control group sat and read for 30 minutes. The primary outcome was sleep efficiency measured by polysomnography. Secondary outcomes were other polysomnographic variables, subjective sleep quality, daytime sleepiness, mood states, and adverse events.ResultsNinety-two patients were randomized to the exercise (N = 46) or control group (N = 46). There were no clinically relevant differences at baseline. Intent-to-treat analysis ANCOVA of follow-up sleep efficiency, adjusted for baseline levels and minimization factors, did not detect a significant effect of the allocation (β = −0.93, p = 0.59). There was no evidence for significant differences between both groups in any other objective or subjective sleep outcomes, daytime sleepiness, or adverse events. The intervention had an immediate positive effect on mood states, including depressiveness (β = −0.40, p = 0.003).ConclusionsThis is the first trial to study the effects of a single bout of aerobic exercise on sleep in patients with depression to the best of our knowledge. Aerobic exercise had no effect on sleep efficiency but had a strong beneficial effect on mood and did not increase adverse outcomes. These results add to the growing body of evidence that, contrary to sleep hygiene recommendations, exercise after 02:00 pm is not detrimental for sleep.Clinical Trial RegistrationClinicaltrials.gov, https://clinicaltrials.gov/ct2/show/NCT03673397. Protocol registered on September 17, 2018.     

Sleep changes following statin therapy: a systematic review and meta-analysis of randomized placebo-controlled polysomnographic trials

Introduction

Statin use might be associated with an increased risk of sleep disturbances including insomnia, but the evidence regarding sleep changes following statin therapy has not been conclusive. Therefore we assessed the impact of statin therapy on sleep changes through a systematic review and meta-analysis of available randomized controlled trials (RCTs).

Material and methods

We searched MEDLINE and SCOPUS up to October 1, 2014 to identify placebo-controlled RCTs investigating the effect of statin therapy on sleep changes. A meta-analysis was performed using either a fixed-effects or a random-effect model according to the I2 statistic. Effect size was expressed as weighted mean difference (WMD) and 95% confidence interval (CI).

Results

Overall, the impact of statin therapy on polysomnography (PSG) indices of sleep was reported in 5 trials comprising 9 treatment arms. Overall, statin therapy had no significant effect on total sleep duration (WMD: –7.75 min, 95% CI: –18.98, 3.48, p = 0.176), sleep efficiency (WMD: 0.09%, 95% CI: –2.27, 2.46, p = 0.940), entries to stage I (WMD: 0.36, 95% CI: –0.91, 1.63, p = 0.580), or latency to stage I (WMD: –1.92 min, 95% CI: –4.74, 0.89, p = 0.181). In contrast, statin therapy significantly reduced wake time (WMD: –4.43 min, 95% CI: –7.77, –0.88, p = 0.014) and number of awakenings (WMD: –0.40, 95% CI: –0.46, –0.33, p < 0.001). Meta-regression did not suggest any correlation between changes in wake time and awakening episodes with duration of treatment and LDL-lowering effect of statins.

Conclusions

The results indicated that statins have no significant adverse effect on sleep duration and efficiency, entry to stage I, or latency to stage I sleep, but significantly reduce wake time and number of awakenings.     

Sleepiness is a signal to go to bed: data and model simulations

Study ObjectivesAssess the validity of a subjective measure of sleepiness as an indicator of sleep drive by quantifying associations between intraindividual variation in evening sleepiness and bedtime, sleep duration, and next morning and subsequent evening sleepiness, in young adults.MethodsSleep timing and sleepiness were assessed in 19 students in late autumn and late spring on a total of 771 days. Karolinska Sleepiness Scales (KSS) were completed at half-hourly intervals at fixed clock times starting 4 h prior to participants’ habitual bedtime, and in the morning. Associations between sleepiness and sleep timing were evaluated by mixed model and nonparametric approaches and simulated with a mathematical model for the homeostatic and circadian regulation of sleepiness.ResultsIntraindividual variation in evening sleepiness was very large, covering four or five points on the 9-point KSS scale, and was significantly associated with subsequent sleep timing. On average, a one point higher KSS value was followed by 20 min earlier bedtime, which led to 11 min longer sleep, which correlated with lower sleepiness next morning and the following evening. Associations between sleepiness and sleep timing were stronger in early compared to late sleepers. Model simulations indicated that the directions of associations between sleepiness and sleep timing are in accordance with their homeostatic and circadian regulation, even though much of the variance in evening sleepiness and details of its time course remain unexplained by the model.ConclusionSubjective sleepiness is a valid indicator of the drive for sleep which, if acted upon, can reduce insufficient sleep.     

Effects of ad libitum food intake,insufficient sleep and weekend recovery sleep on energy balance

Study ObjectivesInsufficient sleep is believed to promote positive energy balance (EB) and weight gain. Increasing weekend sleep duration to “recover” from weekday sleep loss is common, yet little is known regarding how weekend recovery sleep influences EB. We conducted a randomized controlled trial to assess how: (1) 2 days and 8 days of insufficient sleep and (2) ad libitum weekend recovery sleep impact EB (energy intake [EI] – energy expenditure [EE]).MethodsFollowing ten baseline days with 9 h per night sleep opportunities, participants completed one of three 10-day experimental protocols with ad libitum EI: control (9 h sleep opportunities; n = 8; 23 ± 5 years [mean ± SD]); sleep restriction (SR; 5 h sleep opportunities; n = 14; 25 ± 5 years); sleep restriction with weekend recovery sleep (SR + WR; 5 days insufficient sleep, 2 days ad libitum weekend recovery sleep, 3 days recurrent insufficient sleep; n = 14; 27 ± 4 years).ResultsTwenty-four hour EB increased (p < 0.001; main effect) by an average of 797.7 ± 96.7 (±SEM) kcal during the 10-day experimental protocol versus baseline with no significant differences between groups. Percent change from baseline in 24 h-EE was higher (p < 0.05) on day 2 of insufficient sleep (SR and SR + WR groups; 10 ± 1%) versus adequate sleep (control group; 4 ± 3%).ConclusionsIn this between-group study, the effects of adequate sleep and insufficient sleep, with or without or weekend recovery sleep, on 24 h-EB were similar. Examining EB and body weight changes using within-subject cross-over designs and “free-living” conditions outside the laboratory (e.g. sleep extension) are needed to advance our understanding of the links between insufficient sleep, weekend recovery sleep and weight-gain.     

Racial disparities in sleep-related cardiac function in young,healthy adults: implications for cardiovascular-related health

Study ObjectivesConsiderable evidence shows that individuals from marginalized racial/ethnic groups in the United States experience greater rates of sleep disturbance and cardiovascular complications. Because sleep is a modifiable factor that is critically involved in cardiovascular health, improved understanding of the association between sleep and cardiovascular health during early adulthood can prevent cardiovascular disparities. This study examined racial/ethnic differences in cardiovascular function during sleep using heart rate and heart-rate-variability analyses.MethodsParticipants in this laboratory-based sleep study included healthy, “good sleepers” who were in early adulthood and resided in the United States at the time of participation (14 non-Hispanic Black [NHB; age = 30.9 (6.6), 57% female], 12 Asian [Asian, age = 26.0 (5.2), 42% female], and 24 non-Hispanic white [NHW; age = 24.6 (5.8), 79% female]).ResultsAfter adjusting for demographic factors and an apnea–hypopnea index, we found significantly higher heart rate within NREM Stage 2 (N2) (b = −22.6, p = .04) and REM sleep (b = −25.8, p =.048) and lower heart rate variability during N2 sleep (b = −22.6, p = .04) among NHB individuals compared with NHW individuals. Furthermore, NHB and Asian participants demonstrated significantly lower percent of time in slow wave sleep (SWS) compared with NHW participants (NHB: b = −22.6, p =.04; Asian: b = −22.6, p = .04). Individuals’ percent of time in SWS significantly mediated differences in heart rate during N2 (indirect = 0.94, 95% CI [0.03, 2.68]) and REM sleep (indirect = 1.02, 95% CI [0.04, 3.04]).ConclusionsOur results showed disparities in sleep-related cardiovascular function in early adulthood that are mediated by SWS. These data suggest targeting sleep health in early adulthood might help reduce cardiovascular disease burden on individuals from marginalized groups.     

Poor sleep correlates with biomarkers of neurodegeneration in mild traumatic brain injury patients: a CENC study

Study ObjectivesSleep disorders affect over half of mild traumatic brain injury (mTBI) patients. Despite evidence linking sleep and neurodegeneration, longitudinal TBI-related dementia studies have not considered sleep. We hypothesized that poor sleepers with mTBI would have elevated markers of neurodegeneration and lower cognitive function compared to mTBI good sleepers and controls. Our objective was to compare biomarkers of neurodegeneration and cognitive function with sleep quality in warfighters with chronic mTBI.MethodsIn an observational warfighters cohort (n = 138 mTBI, 44 controls), the Pittsburgh Sleep Quality Index (PSQI) was compared with plasma biomarkers of neurodegeneration and cognitive scores collected an average of 8 years after injury.ResultsIn the mTBI cohort, poor sleepers (PSQI ≥ 10, n = 86) had elevated plasma neurofilament light (NfL, $\bar{x}$ = 11.86 vs 7.91 pg/mL, p = 0.0007, d = 0.63) and lower executive function scores by the categorical fluency ($\bar{x}$ = 18.0 vs 21.0, p = 0.0005, d = –0.65) and stop-go tests ($\bar{x}$ = 30.1 vs 31.1, p = 0.024, d = –0.37). These findings were not observed in controls (n = 44). PSQI predicted NfL (beta = 0.22, p = 0.00002) and tau (beta = 0.14, p = 0.007), but not amyloid β42. Poor sleepers showed higher obstructive sleep apnea (OSA) risk by STOP-BANG scores ($\bar{x}$ = 3.8 vs 2.7, p = 0.0005), raising the possibility that the PSQI might be partly secondary to OSA.ConclusionsPoor sleep is linked to neurodegeneration and select measures of executive function in mTBI patients. This supports implementation of validated sleep measures in longitudinal studies investigating pathobiological mechanisms of TBI related neurodegeneration, which could have therapeutic implications.     

Blunted rest–activity rhythms link to higher body mass index and inflammatory markers in children

Study ObjectivesDisturbances of rest–activity rhythms are associated with higher body mass index (BMI) in adults. Whether such relationship exists in children is unclear. We aimed to examine cross-sectional associations of rest–activity rhythm characteristics with BMI z-score and obesity-related inflammatory markers in school-age children.MethodsParticipants included 411 healthy children (mean ± SD age 10.1 ± 1.3 years, 50.8% girls) from a Mediterranean area of Spain who wore wrist accelerometers for 7 consecutive days. Metrics of rest–activity rhythm were derived using both parametric and nonparametric approaches. Obesity-related inflammatory markers were measured in saliva (n = 121).ResultsIn a multivariable-adjusted model, higher BMI z-score is associated with less robust 24-h rest–activity rhythms as represented by lower relative amplitude (–0.16 [95% CI –0.29, –0.02] per SD, p = 0.02). The association between BMI z-score and relative amplitude persisted with additional adjustment for sleep duration, and attenuated after adjustment for daytime activity level. Less robust rest–activity rhythms were related to increased levels of several salivary pro-inflammatory markers, including C-reactive protein, which is inversely associated with relative amplitude (–32.6% [–47.8%, –12.9%] per SD), independently of BMI z-score, sleep duration, and daytime activity level.ConclusionBlunted rest–activity rhythms are associated with higher BMI z-score and salivary pro-inflammatory markers already at an early age. The association with BMI z-score seem to be independent of sleep duration, and those with pro-inflammatory markers further independent of BMI z-score and daytime activity. Novel intervention targets at an early age based on improving the strength of rest–activity rhythms may help to prevent childhood obesity and related inflammation.Clinical Trials Registration{"type":"clinical-trial","attrs":{"text":"NCT02895282","term_id":"NCT02895282"}}NCT02895282     

Determinants of postpartum sleep duration and sleep efficiency in minority women

Study ObjectivesTo examine demographic, psychosocial, and behavioral determinants of postpartum sleep duration and sleep efficiency among a cohort of black and Latina women.MethodsData were from 148 women (67% black, 32% Latina) at 5 months postpartum, recruited from an academic medical center in Philadelphia. Relevant demographic, psychosocial and behavioral predictors were assessed via questionnaire. Nocturnal sleep was objectively measured for 1 week using wrist actigraphy. Sleep duration was examined as a continuous variable and in categories (<7 versus ≥7 h per night); sleep efficiency was examined as a continuous variable. Independent multiple linear regression models were built to evaluate significant determinants of sleep.ResultsAdjusted models revealed that breastfeeding, having a bedtime after midnight, and being employed were associated with shorter sleep duration (–25–33 min, all p < 0.05). Multiparity, being unmarried, being employed, breastfeeding, having a bedtime after midnight, bedsharing, and responding to infant awakenings by getting up immediately rather than waiting a few minutes to see if the infant fell back asleep, were all significant determinants of sleeping <7 h per night (OR varying: 2.29–4.59, all p < 0.05). Bedsharing was the only variable identified from the multiple regression model that associated with poorer sleep efficiency (–3.8%, p < 0.05).ConclusionsFindings may inform interventions for improving postpartum sleep in socioeconomically disadvantaged, racial/ethnic minority postpartum women.     

Meta-analysis of age and actigraphy-assessed sleep characteristics across the lifespan

Study ObjectivesSleep quantity and continuity vary across the lifespan. Actigraphy is a reliable and widely used behavioral measure of sleep in research and personal health monitoring. This meta-analysis provides a novel examination of whether age (in years) is associated with actigraphy-assessed sleep across the lifespan.MethodsA systematic search of PubMed, Embase.com, Cochrane CENTRAL, and PsycINFO using “actigraphy” and “sleep” terms provided 7079 titles/abstracts; studies of individuals with known psychiatric or medical comorbidities were excluded. Ninety-one articles (N = 23 365) provided data for six meta-analyses examining sleep duration (k = 89), sleep efficiency (k = 58), bedtime (k = 19) and waketime (k = 9) for individuals ages 6–21, and bedtime (k = 7) and waketime (k = 7) for individuals ages 22 and older.ResultsAt older ages, sleep duration was shorter (r = −0.12) and sleep efficiency was lower (r = −0.05). Older age was associated with later bedtime (r = 0.37) and wake-up time (r = 0.24) from ages 6–21, whereas older age was associated with earlier bedtime (r = −0.66) and wake-up time (r = −0.59) for ages 22 and above. The strength of these associations was modified by study continent, but not by any other moderator.ConclusionsAge was negatively associated with actigraphy-assessed sleep duration and efficiency, but the effects were small in magnitude. On the other hand, large associations were observed between age and sleep timing, despite a smaller literature and the absence of analyzable data for ages 30–60. Changes in sleep timing, rather than changes in sleep duration or continuity, may better characterize the effects of age on human sleep.     

Longitudinal associations of sleep problems with alcohol and cannabis use from adolescence to emerging adulthood

Study ObjectivesThis study examined longitudinal associations of sleep problems with alcohol and cannabis use across six annual waves of data from adolescence to emerging adulthood.MethodsParticipants were 3,265 youth from California (ages 16–22 across waves). At each wave, past-month alcohol use and cannabis use, mental health, and several dimensions of sleep health (i.e. social jetlag, bedtimes, time in bed, trouble sleeping) were assessed via questionnaire. Parallel process latent growth models examined the association between sleep and alcohol or cannabis use trajectories and the role of mental health in contributing to such trajectories.ResultsSmaller declines in social jetlag (r = 0.11, p = 0.04), increases in trouble sleeping (r = 0.18, p < 0.01), and later weekday (r = 0.16, p < 0.01) and weekend bedtimes (r = 0.25, p < 0.01) were associated with increases in likelihood of alcohol use over time. Declines in weekend TIB (r = −0.13, p = 0.03), as well as increases in weekday TIB (r = 0.11, p = 0.04) and later weekday (r = 0.18, p < 0.01) and weekend bedtime (r = 0.24, p < 0.01), were associated with increases in likelihood of cannabis use over time. Most associations remained significant after controlling for time-varying mental health symptoms.ConclusionsTrajectories of sleep health were associated with trajectories of alcohol and cannabis use during late adolescence to emerging adulthood. Improving sleep is an important target for intervention efforts to reduce the risk of substance use during this critical developmental transition.     

Associations of insomnia symptoms with subsequent health services use among community-dwelling U.S. older adults

Study ObjectivesDetermine the association of insomnia symptoms with subsequent health services use, in a representative sample of U.S. older adults.MethodsParticipants were 4,289 community-dwelling Medicare beneficiaries who had continuous fee-for-service Medicare coverage 30 days before, and 1 year after the National Health and Aging Trends Study (NHATS) Round 1 interview. Participants reported past-month insomnia symptoms (i.e. sleep onset latency >30 min, difficulty returning to sleep) which we categorized as 0, 1, or 2 symptoms. Outcomes were health services use within 1 year of interviews from linked Medicare claims: emergency department (ED) visits, hospitalizations, 30-day readmissions, home health care (all measured as yes/no), and number of hospitalizations and ED visits.ResultsOverall, 18.5% of participants were hospitalized, 28.7% visited the ED, 2.5% had a 30-day readmission, and 11.3% used home health care. After adjustment for demographics, depressive and anxiety symptoms, medical comorbidities, and BMI, compared to participants with no insomnia symptoms, those with two insomnia symptoms had a higher odds of ED visits (odds ratio [OR) = 1.60, 95% confidence interval [CI] = 1.24–2.07, p < 0.001), hospitalizations (OR = 1.29, 95% CI = 1.01–1.65, p < 0.05), and 30-day readmissions (OR = 1.88, 95% CI = 1.88–3.29, p < 0.05). Reporting 2 insomnia symptoms, versus no insomnia symptoms, was associated with a greater number of ED visits and hospitalizations (incidence rate ratio (IRR) = 1.52, 95% CI = 1.23–1.87, p < 0.001; IRR = 1.21, 95% CI = 1.02–1.44, p < 0.05, respectively) after adjusting for demographic and health characteristics.ConclusionsAmong older adults, insomnia symptoms are associated with greater health services use, including emergency department use, hospitalization, and 30-day readmission. Targeting insomnia may lower health services use.     

Evening administration of melatonin and bright light: Interactions on the EEG during sleep and wakefulness

Both the pineal hormone melatonin and light exposure are considered to play a major role in the circadian regulation of sleep. In a placebo- controlled balanced cross-over design, we investigated the acute effects of exogenous melatonin (5 mg p.o. at 20.40 hours) with or without a 3-h bright light exposure (5000 lux from 21.00 hours–24.00 hours) on subjective sleepiness, internal sleep structure and EEG power density during sleep and wakefulness in healthy young men. The acute effects of melatonin, bright light and their interaction were measured on the first day (treatment day), possible circadian phase shifts were assessed on the post-treatment day. On the treatment day, the evening rise in subjective sleepiness was accelerated after melatonin and protracted during bright light exposure. These effects were also reflected in specific changes of EEG power density in the theta/alpha range during wakefulness. Melatonin shortened and bright light increased sleep latency. REMS latency was reduced after melatonin administration but bright light had no effect. Slow-wave sleep and slow-wave activity during the first non-rapid eye movement (NREMS) episode were suppressed after melatonin administration and rebounded in the second NREMS episode, independent of whether light was co-administered or not. Self rated sleep quality was better after melatonin administration whereas the awakening process was rated as more difficult after bright light. On the post-treatment day after evening bright light, the rise in sleepiness and the onset of sleep were delayed, independent of whether melatonin was co-administered or not. Thus, although acute bright light and melatonin administration affected subjective sleepiness, internal sleep structure and EEG power density during sleep and wakefulness in a additive manner, the phase shifting effect of a single evening bright light exposure could not be blocked by exogenous melatonin