Slow-wave sleep and the risk of type 2 diabetes in humans

The therapeutic properties of ketogenic diets, slow-wave sleep, and circadian synchrony

PURPOSE OF REVIEW

To summarize emerging connections between sleep, ketogenic diets, and health.

RECENT FINDINGS

Mechanisms involved in the therapeutic benefits of ketogenic diets continue to be elucidated. Concurrently, the importance of sleep quality and circadian rhythms in their effects on metabolic and cognitive health is increasingly appreciated. Advances in the understanding of the actions of adenosine, nicotinamide adenine dinucleotide, and slow-wave sleep underscore connections between these areas of research.

SUMMARY

Many molecular pathways activated during ketogenic diets are known to modulate sleep-wake cycles, circadian rhythms, and sleep stages. Ketogenic diets often have beneficial effects on sleep at the same time as having beneficial effects on particular medical conditions. Enhancement of slow-wave sleep and rejuvenation of circadian programming may be synergistic with or causally involved in the benefits of ketogenic diets.

A metabolic function of the hippocampal sharp wave-ripple

The hippocampus has previously been implicated in both cognitive and endocrine functions1-15. We simultaneously measured electrophysiological activity from the hippocampus and interstitial glucose concentrations in the body of freely behaving rats to identify an activity pattern that may link these disparate functions of the hippocampus. Here we report that clusters of sharp wave-ripples recorded from the hippocampus reliably predicted a decrease in peripheral glucose concentrations within about 10 min. This correlation was not dependent on circadian, ultradian or meal-triggered fluctuations, could be mimicked with optogenetically induced ripples in the hippocampus (but not in the parietal cortex) and was attenuated to chance levels by pharmacogenetically suppressing activity of the lateral septum, which is the major conduit between the hippocampus and the hypothalamus. Our findings demonstrate that a function of the sharp wave-ripple is to modulate peripheral glucose homeostasis, and offer a mechanism for the link between sleep disruption and blood glucose dysregulation in type 2 diabetes16-18.

Slow-wave sleep and obstructive sleep apnea in patients with type 2 diabetes mellitus

PURPOSE

This study aimed to analyze sleep architecture and obstructive sleep apnea (OSA) in patients with type 2 diabetes and clarify the association between sleep characteristics and glycemic control.

METHODS

All participants underwent metabolism-related laboratory testing and a cross-sectional analysis of nocturnal polysomnography for sleep parameter analysis. Data were analyzed using the chi-squared test, a one-way analysis of variance, and Kruskal-Wallis test to compare the differences among three groups (type 2 diabetes, prediabetes, and control groups). The prevalence of OSA was evaluated using descriptive statistics and comparing the group divided into HbA1c quartiles. Univariate and multivariate linear regression analyses were used to determine factors associated with glycemic control.

RESULTS

Of 75 study participants (age 57.3 ± 4.1 years, 32 men), there were 25 participants each in the type 2 diabetes, prediabetes, and control groups. Participants with type 2 diabetes had significantly decreased slow-wave sleep duration (77.9 ± 30.0 min, p = 0.026) and shortened rapid eye movement sleep latency (median 75 min, p = 0.018) compared with those in the prediabetes and control groups. Forty-five participants (60%) had OSA (apnea-hypopnea index ≥ 5/h), 18 of whom were in the type 2 diabetes group. The prevalence of OSA in this group was 72%. The prevalence of moderate-to-severe OSA was significantly higher in the type 2 diabetes group than in the control group (p = 0.025) and in groups with HbA1c levels of > 6.7% than in groups with HbA1c levels of < 5.3% (p = 0.007). Multiple regression analysis showed that dyslipidemia (β = 0.179, p = 0.000) and slow-wave sleep duration (β =  - 0.113, p = 0.008) were independently associated with the HbA1c level.

CONCLUSION

Our results suggest that increasing slow-wave sleep is positively associated with glycemic control.

Neural Mechanism Underlying the Sleep Deprivation-Induced Abnormal Bistable Perception

Quality sleep is vital for physical and mental health. No matter whether sleep problems are a consequence of or contributory factor to mental disorders, people with psychosis often suffer from severe sleep disturbances. Previous research has shown that acute sleep deprivation (SD) can cause transient brain dysfunction and lead to various cognitive impairments in healthy individuals. However, the relationship between sleep disturbance and bistable perception remains unclear. Here, we investigated whether the bistable perception could be affected by SD and elucidated the functional brain changes accompanying SD effects on bistable perception using functional magnetic resonance imaging. We found that the 28-h SD resulted in slower perceptual transitions in healthy individuals. The reduced perceptual transition was accompanied by the decreased activations in rivalry-related frontoparietal areas, including the right superior parietal lobule, right frontal eye field, and right temporoparietal junction. We speculated that SD might disrupt the normal function of these regions crucial for bistable perception, which mediated the slower rivalry-related perceptual transitions in behavior. Our findings revealed the neural changes underlying the abnormal bistable perception following the SD. It also suggested that SD might offer a new window to understand the neural mechanisms underlying the bistable perception.

Altered slow-wave sleep activity in children with rapid-onset obesity with hypothalamic dysregulation, hypoventilation, and autonomic dysregulation syndrome

STUDY OBJECTIVES

Rapid-onset obesity with hypothalamic dysregulation, hypoventilation, and autonomic dysregulation (ROHHAD) is a rare condition. Little is known about sleep/wake and slow-wave activity in this condition, although the central hypothalamic dysfunction associated with autonomic dysregulation would make the occurrence of SWA deregulation most likely.

METHODS

Two children with clinical presentation of ROHHAD syndrome were evaluated, diagnosed, and treated. Their polysomnographic studies were compared with 4 matched children with obstructive sleep apnea and 6 controls.

RESULTS

Children that were clinically diagnosed with ROHHAD exhibited significantly weaker slow-wave activity power and shallower slow-wave activity slopes during the first 2 sleep cycles compared with children with obstructive sleep apnea or controls.

CONCLUSIONS

This study shows that children with ROHHAD have suppressed slow-wave activity, possibly because of hypothalamic dysregulation that may contribute to their rapid-onset obesity and excessive daytime sleepiness.

Effect of morning versus evening exercise training on sleep, physical activity, fitness, fatigue and quality of life in overweight and obese adults

This study compares the effectiveness of a 12-week moderate exercise training program (METP), performed in the morning versus the evening, on sleep, physical activity, physical fitness, sleepiness, fatigue and health-related quality of life (HRQoL) in overweight and obese patients. Sedentary and inactive overweight/obese adults (n = 36) were included in METP and randomized into two groups: morning group (GM) and evening group (GE). Twenty-eight participants successfully completed METP (3 × 90 min exercise session per week for 12 weeks, completion rates >80%). Sleep, physical activity, and bedtime temperature were measured using accelerometry and infrared tympanic temperature during 3 separate weeks of the study (Week1, Week6, and Week12). Participants also took part in baseline and endpoint assessments including physical fitness as well as subjective physical activity, chronotype, sleep quality, sleepiness, fatigue and HRQoL. METP did not impact objective sleep quality differently between the two groups (morning vs evening). Bedtime and mid-sleep were advanced when METP was done in the morning whereas they were delayed when METP was practiced in the early evening (p = .003). Beside this finding, no valuable differences between the two groups were noted in all the remaining measures. METP resulted in improvements of body composition, cardiorespiratory and muscular endurance, as well as a favorable impact on subjective sleep quality, diurnal sleepiness, fatigue and HRQoL in both groups (all p < .05). Evening METP could be an effective alternative for overweight/obese adults when morning METP is not possible.

Associations between sleep disturbances, diabetes and mortality in the UK Biobank cohort: A prospective population-based study

Non-communicable diseases, including diabetes, are partly responsible for the deceleration of improvements of life expectancy in many countries. Diabetes is also associated with sleep disturbances. Our aim was to determine whether sleep disturbances, particularly in people with diabetes, were associated with increased mortality risk. Data from the UK Biobank were analysed (n = 487,728, mean follow-up time = 8.9 years). The primary exposure was sleep disturbances, assessed through the question: Do you have trouble falling asleep at night or do you wake up in the middle of the night? The primary outcome was mortality. We also dichotomized sleep disturbances into "never/sometimes" versus "usually" (frequently), and combined with the presence/absence of diabetes: 24.2% of participants reported "never/rarely" experiencing sleep disturbances, 47.8% "sometimes" and 28.0% "usually". In age- and sex-adjusted models, frequent sleep disturbances were associated with an increased risk of all-cause mortality (hazard ratio [HR], 1.31; 95% confidence interval [CI], 1.26-1.37), which remained significant in the fully adjusted model (HR 1.13, 95% CI 1.09-1.18). The presence of both diabetes and frequent sleep disturbances was associated with greater risk of all-cause mortality than either condition alone. In the fully adjusted model, the hazard ratio for all-cause mortality was 1.11 (95% CI, 1.07-1.15) for frequent sleep disturbances alone, 1.67 (95% CI, 1.57-1.76) for diabetes alone and 1.87 for both (95% CI, 1.75-2.01). Frequent sleep disturbances (experienced by more than one quarter of the sample) were associated with increased risk of all-cause mortality. Mortality risk was highest in those with both diabetes and frequent sleep disturbances. Complaints of difficulty falling or staying asleep merit attention by physicians.

Systematic decrease of slow-wave sleep after a guided imagery designed to deepen sleep in low hypnotizable subjects

Slow-wave sleep is one of the most important restorative components of sleep and central for our health and cognitive functioning. Although the amount of slow-wave sleep depends on sleep drive, age and other factors, also the pre-sleep mental state might influence sleep depth. We had shown that a pre-sleep hypnotic suggestion to sleep more deeply increased slow-wave sleep duration in hypnotizable subjects. In contrast, low-hypnotizable participants decreased sleep depth after this intervention. A possible reason might be an aversion to and active resistance against hypnosis. To overcome this potential opposition, we introduced the procedure as 'guided imagery'. We replaced the hypnotic induction by a breathing relaxation. Importantly, the suggestion 'to sleep more deeply' remained identical. We expected that these changes would make it easier for low-hypnotizable subjects to benefit from the suggestion. In contrast, young healthy low-hypnotizable participants did not show positive effects. Similar to our previous studies, they exhibited a reduced slow-wave sleep duration after the intervention. Additionally, the ratio between slow-wave activity and beta band power decreased. Subjective sleep quality remained unaffected. Our results indicate that suggestions to sleep more deeply result in decreased sleep depth in low-hypnotizable participants regardless of the mental technique (guided imagery versus hypnosis). Thus, the aversion against hypnosis per se cannot explain the detrimental effect of the intervention on slow-wave sleep in low-hypnotizable subjects. The results support the notion that our mental state before sleep can influence subsequent slow-wave sleep. However, the mechanisms of the contradictory decrease in low-hypnotizable subjects remain unknown.

Contribution of sleep characteristics to the association between obstructive sleep apnea and dyslipidemia

OBJECTIVES/BACKGROUND

Little information is available about the association of obstructive sleep apnea (OSA) with atherogenic dyslipidemia and the contribution of sleep characteristics to lipid alterations. We compare dyslipidemia prevalence among non-apneic subjects and mild-severe OSA patients to identify the sleep characteristics that are independently associated with dyslipidemia and serum lipid levels in OSA patients.

PATIENTS/METHODS

We recruited 809 consecutive patients who had been referred for polysomnography study by OSA suspicion. Anthropometric characteristics, body composition and comorbidities were recorded. Spirometry and 24-h ambulatory blood pressure monitoring were performed the same day of the sleep study. The day after attended polysomnography, fasting blood samples were drawn to measure the lipid profile.

RESULTS

Dyslipidemia prevalence increased with the presence of OSA, from non-OSA subjects to mild, moderate and severe OSA patients (31%, 33%, 42% and 51%, respectively; p < 0.001). After adjusting for sex, age, body mass index and smoking habit, only severe OSA had an independent association with dyslipidemia when compared to non-OSA subjects (adjusted odds ratio 1.71, 95%CI 1.09 to 2.69, p = 0.019). In OSA patients, multivariate logistic regression identified active smoking, apnea-hypopnea index (AHI) and mean nocturnal saturation as variables independently associated with dyslipidemia. However, in these patients, arousal index, slow wave sleep duration and REM latency were also independently associated with cholesterol and low-density lipoprotein levels.

CONCLUSIONS

The association between dyslipidemia and OSA is limited to severe patients, with high AHI and nocturnal hypoxemia. However, sleep fragmentation and increased sympathetic activity could also contribute to OSA-related lipid dysregulation.

Objective and subjective sleep measures are associated with HbA1c and insulin sensitivity in the general population: Findings from the ORISCAV-LUX-2 study

AIM

To analyze the association of objective and subjective sleep measures with HbA1c and insulin sensitivity in the general population.

METHODS

Using a cross-sectional design, data from 1028 participants in the ORISCAV-LUX-2 study from the general population in Luxembourg were analyzed. Objective sleep measures were assessed using accelerometers whereas subjective measures were assessed using the Pittsburgh Sleep Quality Index (PSQI) questionnaire. Sleep measures were defined as predictors, while HbA1c and quantitative insulin sensitivity check index (QUICKI) scores were considered outcomes. Linear and spline regression models were fitted by progressively adjusting for demographic and lifestyle variables in the total sample population as well as by stratified analyses using gender, obesity status, depressive symptoms and diabetes status.

RESULTS

In fully adjusted models, total and deep sleep durations were associated with lower HbA1c (mmol/mol) levels, whereas sleep coefficients of variation (%) and poor sleep efficiency, as measured by PSQI scores (units), were associated with higher HbA1c levels. In stratified models, such associations were observed mainly in men, and in subjects who had depressive symptoms, were overweight and no diabetes. In addition, total sleep, deep sleep, coefficients of variation and poor sleep efficiency as measured by PSQI revealed non-linear associations. Similarly, greater insulin sensitivity was associated with longer total sleep time and with PSQI-6 (use of sleep medication).

CONCLUSION

Associations were more frequently observed between sleep characteristics and glycaemic control with the use of objective sleep measures. Also, such associations varied within subgroups of the population. Our results highlight the relevance of measuring sleep patterns as key factors in the prevention of diabetes.

Effects of Dinner Timing on Sleep Stage Distribution and EEG Power Spectrum in Healthy Volunteers

PURPOSE

Eating time and sleep habits are important modifiable behaviors that affect metabolic health, but the relationship between food intake and sleep remains incompletely understood. Observational data suggest that late food intake is associated with impaired sleep quality. We examined the effect of routine dinner (RD, 5 hours before bedtime) vs late dinner (LD, 1 hour before bedtime) on sleep architecture in healthy volunteers.

PARTICIPANTS AND METHODS

This was a post hoc analysis of a randomized crossover study of RD vs LD with a fixed sleep opportunity in a laboratory setting. On each of the two visits, 20 healthy adult volunteers (10 women) received an isocaloric meal followed by overnight polysomnography. Sleep architecture over the course of the night was assessed using visual sleep staging and EEG spectral power analysis and was compared between RD and LD. We modeled the proportions of spectral power in alpha, beta, delta, and theta bands as functions of dinner timing, time of night, and their interaction with mixed-effect spline regression.

RESULTS

Conventional sleep stages were similar between the 2 visits. LD caused a 2.5% initial increase in delta power and a reciprocal 2.7% decrease in combined alpha and beta power (p<0.0001). These effects diminished as sleep continued with a reversal of these patterns in the latter part of the night.

CONCLUSION

Contrary to the existing literature, shifting dinner timing from 5 hours before sleep to 1 hour before sleep in healthy volunteers did not result in significant adverse changes in overnight sleep architecture. In fact, LD was associated with deeper sleep in the beginning of the night and lighter sleep in the latter part of the night in healthy volunteers. This novel manifestation of postprandial hypersomnia may have therapeutic potential in patients with sleep disorders.

The Effect of Obstructive Sleep Apnea and Continuous Positive Airway Pressure Therapy on Skeletal Muscle Lipid Content in Obese and Nonobese Men

Obstructive sleep apnea (OSA), independently of obesity (OBS), predisposes to insulin resistance (IR) for largely unknown reasons. Because OSA-related intermittent hypoxia triggers lipolysis, overnight increases in circulating free fatty acids (FFAs) including palmitic acid (PA) may lead to ectopic intramuscular lipid accumulation potentially contributing to IR. Using 3-T-¹H-magnetic resonance spectroscopy, we therefore compared intramyocellular and extramyocellular lipid (IMCL and EMCL) in the vastus lateralis muscle at approximately 7 am between 26 male patients with moderate-to-severe OSA (17 obese, 9 nonobese) and 23 healthy male controls (12 obese, 11 nonobese). Fiber type composition was evaluated by muscle biopsies. Moreover, we measured fasted FFAs including PA, glycated hemoglobin A_1c, thigh subcutaneous fat volume (ScFAT, 1.5-T magnetic resonance tomography), and maximal oxygen uptake (VO₂max). Fourteen patients were reassessed after continuous positive airway pressure (CPAP) therapy. Total FFAs and PA were significantly (by 178% and 166%) higher in OSA patients vs controls and correlated with the apnea-hypopnea index (AHI) (r ≥ 0.45, P < .01). Moreover, IMCL and EMCL were 55% (P < .05) and 40% (P < .05) higher in OSA patients, that is, 114% and 103% in nonobese, 24.4% and 8.4% in obese participants (with higher control levels). Overall, PA, FFAs (minus PA), and ScFAT significantly contributed to IMCL (multiple r = 0.568, P = .002). CPAP significantly decreased EMCL (–26%) and, by trend only, IMCL, total FFAs, and PA. Muscle fiber composition was unaffected by OSA or CPAP. Increases in IMCL and EMCL are detectable at approximately 7 am in OSA patients and are partly attributable to overnight FFA excesses and high ScFAT or body mass index. CPAP decreases FFAs and IMCL by trend but significantly reduces EMCL.

Effects of macronutrient intake on sleep duration and quality: A systematic review

AIM

The aim of this systematic review was to characterise and synthesise the literature that explores the effects of macronutrient manipulation on sleep outcomes in order to provide dietary recommendations for sleep improvement.

METHODS

Intervention studies that evaluated the effects of macronutrient manipulations on sleep were identified using four databases. A study was included if it: (a) delivered a macronutrient-based dietary intervention, regardless of length; (b) included healthy human participants aged 18 and older; and (c) measured some aspect of sleep, for example, duration or quality, in some manner.

RESULTS

A total of 17 papers and 19 studies met the inclusion criteria. Included studies were organised into acute studies lasting less than 24 hours (n = 4), longer-term (≥24 hours) studies (n = 10), and energy restriction studies (n = 5). The greatest amount of support was observed for longer-term administration of higher carbohydrate diets. These interventions positively influenced rapid eye movement sleep; however, non-rapid eye movement sleep was negatively affected. The overall health outcomes of these changes are difficult to assess. Limited evidence suggests higher protein diets under conditions of energy restriction can improve sleep quality, but these effects might be restricted to individuals with overweight or obesity. Current evidence does not support the effects of acute macronutrient manipulation, defined as less than 24 hours, on sleep outcomes.

CONCLUSIONS

Manipulating carbohydrate intake for at least 24 hours appears to alter sleep outcomes among healthy individuals. Interventions were highly varied and methodological shortcomings were identified. More work is required to fully understand how macronutrient intake affects sleep outcomes.

The spectral fingerprint of sleep problems in post-traumatic stress disorder

Study Objectives

Sleep problems are a core feature of post-traumatic stress disorder (PTSD). The aim of this study was to find a robust objective measure for the sleep disturbance in patients having PTSD.

Methods

The current study assessed EEG power across a wide frequency range and multiple scalp locations, in matched trauma-exposed individuals with and without PTSD, during rapid eye movement (REM) and non-REM (NREM) sleep. In addition, a full polysomnographical evaluation was performed, including sleep staging and assessment of respiratory function, limb movements, and heart rate. The occurrence of sleep disorders was also assessed.

Results

In patients having PTSD, NREM sleep shows a substantial loss of slow oscillation power and increased higher frequency activity compared with controls. The change is most pronounced over right-frontal sensors and correlates with insomnia. PTSD REM sleep shows a large power shift in the opposite direction, with increased slow oscillation power over occipital areas, which is strongly related to nightmare activity and to a lesser extent with insomnia. These pronounced spectral changes occur in the context of severe subjective sleep problems, increased occurrence of various sleep disorders and modest changes in sleep macrostructure.

Conclusions

This is the first study to show pronounced changes in EEG spectral topologies during both NREM and REM sleep in PTSD. Importantly, the observed power changes reflect the hallmarks of PTSD sleep problems: insomnia and nightmares and may thus be specific for PTSD. A spectral index derived from these data distinguishes patients from controls with high effect size, bearing promise as a candidate biomarker.

Impact of type 1 diabetes mellitus, glucose levels, and glycemic control on sleep in children and adolescents: a case-control study

STUDY OBJECTIVES

To assess differences in habitual sleep patterns and sleep states between children and adolescents with type 1 diabetes mellitus (T1DM) and control subjects, and to explore the relationships between sleep, glucose levels, and glycemic control.

METHODS

Participants included 82 children (5-18 years); 41 with T1DM (cases), and 41 healthy control subjects group matched for age and sex. Sleep was measured by 7-day actigraphy and single-night home-based polysomnography (PSG) recordings. Hemoglobin A1c (HbA1c) and 7 days of continuous glucose monitoring (CGM) data were collected in cases. Regression analyses were used to model all within- and between-group comparisons adjusted for age, sex, and BMI z-scores.

RESULTS

There were no significant differences in sleep duration, efficiency, or awakenings as measured by actigraphy and PSG between cases and controls, nor sleep states measured by PSG. However, cases had significantly later sleep onset and offset than controls (both p < 0.05), partially moderated by age. Cases with suboptimal glycemic control (HbA1c ≥ 58 mmol/mol [≥7.5%]) had significantly shorter actigraphy-derived total sleep time (TST) (mean difference = -40 minutes; 95% confidence interval = -77, -3), with similar differences in TST measured by PSG. Cases with mean CGM glucose levels ≥10 mmol/L (≥180 mg/dL) on PSG night had significantly more stage N3 (%) sleep and less stage REM (%) sleep (both p < 0.05).

CONCLUSIONS

Short- and long-term suboptimal glycemic control in T1DM children appears to be associated with sleep alterations. Pediatric diabetes care teams should be aware of potential interrelationships between sleep and T1DM, including management and glycemic control.

Blood pressure dipping during REM and non-REM sleep in patients with moderate to severe obstructive sleep apnea

A limited number of papers have addressed the association between non-dipping-blood pressure (BP) obstructive sleep apnea (OSA), and no study has assessed BP-dipping during rapid eye movement (REM) and non-REM sleep in OSA patients. This study sought to noninvasively assess BP-dipping during REM and non-REM (NREM)-sleep using a beat-by-beat measurement method (pulse-transit-time (PTT)). Thirty consecutive OSA patients (men = 50%) who had not been treated for OSA before and who had > 20-min of REM-sleep were included. During sleep, BP was indirectly determined via PTT. Patients were divided into dippers and non-dippers based on the average systolic-BP during REM and NREM-sleep. The studied group had a a median age of 50 (42–58.5) years and a body mass index of 33.8 (27.6–37.5) kg/m². The median AHI of the study group was 32.6 (20.1–58.1) events/h (range: 7–124), and 89% of them had moderate-to-severe OSA. The prevalence of non-dippers during REM-sleep was 93.3%, and during NREM-sleep was 80%. During NREM sleep, non-dippers had a higher waist circumference and waist-hip-ratio, higher severity of OSA, longer-time spent with oxygen saturation < 90%, and a higher mean duration of apnea during REM and NREM-sleep. Severe OSA (AHI ≥ 30) was defined as an independent predictor of non-dipping BP during NREM sleep (OR = 19.5, CI: [1.299–292.75], p-value = 0.03). This short report demonstrated that BP-dipping occurs during REM and NREM-sleep in patients with moderate-to-severe OSA. There was a trend of more severe OSA among the non-dippers during NREM-sleep, and severe OSA was independently correlated with BP non-dipping during NREM sleep.

Obstructive Sleep Apnea, Glucose Tolerance, and β-Cell Function in Adults With Prediabetes or Untreated Type 2 Diabetes in the Restoring Insulin Secretion (RISE) Study

OBJECTIVE

Obstructive sleep apnea (OSA) is associated with insulin resistance and has been described as a risk factor for type 2 diabetes. Whether OSA adversely impacts pancreatic islet β-cell function remains unclear. We aimed to investigate the association of OSA and short sleep duration with β-cell function in overweight/obese adults with prediabetes or recently diagnosed, treatment-naive type 2 diabetes.

RESEARCH DESIGN AND METHODS

Two hundred twenty-one adults (57.5% men, age 54.5 ± 8.7 years, BMI 35.1 ± 5.5 kg/m²) completed 1 week of wrist actigraphy and 1 night of polysomnography before undergoing a 3-h oral glucose tolerance test (OGTT) and a two-step hyperglycemic clamp. Associations of measures of OSA and actigraphy-derived sleep duration with HbA_1c, OGTT-derived outcomes, and clamp-derived outcomes were evaluated with adjusted regression models.

RESULTS

Mean ± SD objective sleep duration by actigraphy was 6.6 ± 1.0 h/night. OSA, defined as an apnea-hypopnea index (AHI) of five or more events per hour, was present in 89% of the participants (20% mild, 28% moderate, 41% severe). Higher AHI was associated with higher HbA_1c (P = 0.007). However, OSA severity, measured either by AHI as a continuous variable or by categories of OSA severity, and sleep duration (continuous or <6 vs. ≥6 h) were not associated with fasting glucose, 2-h glucose, insulin sensitivity, or β-cell responses.

CONCLUSIONS

In this baseline cross-sectional analysis of the RISE clinical trial of adults with prediabetes or recently diagnosed, untreated type 2 diabetes, the prevalence of OSA was high. Although some measures of OSA severity were associated with HbA_1c, OSA severity and sleep duration were not associated with measures of insulin sensitivity or β-cell responses.

Effectiveness of cognitive behavior therapy for sleep disturbance and glycemic control in persons with type 2 diabetes mellitus: A community-based randomized controlled trial in China

BACKGROUND

Poor sleep quality is a common clinical feature in patients with type 2 diabetes mellitus (T2DM), and often negatively related with glycemic control. Cognitive behavioral therapy (CBT) may improve sleep quality and reduce blood sugar levels in patients with T2DM. However, it is not entirely clear whether CBT delivered by general practitioners is effective for poor sleep quality in T2DM patients in community settings.

AIM

To test the effect of CBT delivered by general practitioners in improving sleep quality and reducing glycemic levels in patients with T2DM in community.

METHODS

A cluster randomized controlled trial was conducted from September 2018 to October 2019 in communities of China. Overall 1033 persons with T2DM and poor sleep quality received CBT plus usual care or usual care. Glycosylated hemoglobin A1c (HbAlc) and sleep quality [Pittsburgh Sleep Quality Index (PSQI)] were assessed. Repeated measures analysis of variance and generalized linear mixed effects models were used to estimate the intervention effects on hemoglobin A1c and sleep quality.

RESULTS

The CBT group had 0.64, 0.50, and 0.9 lower PSQI scores than the control group at 2 mo, 6 mo, and 12 mo, respectively. The CBT group showed 0.17 and 0.43 lower HbAlc values than the control group at 6 mo and 12 mo. The intervention on mean ΔHbAlc values was significant at 12 mo (t = 3.68, P < 0.01) and that mean ΔPSQI scores were closely related to ΔHbAlc values (t = 7.02, P < 0.01). Intention-to-treat analysis for primary and secondary outcomes showed identical results with completed samples. No adverse events were reported.

CONCLUSION

CBT delivered by general practitioners, as an effective and practical method, could reduce glycemic levels and improve sleep quality for patients with T2DM in community.

Circadian Rhythms of the Hypothalamus: From Function to Physiology

The nearly ubiquitous expression of endogenous 24 h oscillations known as circadian rhythms regulate the timing of physiological functions in the body. These intrinsic rhythms are sensitive to external cues, known as zeitgebers, which entrain the internal biological processes to the daily environmental changes in light, temperature, and food availability. Light directly entrains the master clock, the suprachiasmatic nucleus (SCN) which lies in the hypothalamus of the brain and is responsible for synchronizing internal rhythms. However, recent evidence underscores the importance of other hypothalamic nuclei in regulating several essential rhythmic biological functions. These extra-SCN hypothalamic nuclei also express circadian rhythms, suggesting distinct regions that oscillate either semi-autonomously or independent of SCN innervation. Concurrently, the extra-SCN hypothalamic nuclei are also sensitized to fluctuations in nutrient and hormonal signals. Thus, food intake acts as another powerful entrainer for the hypothalamic oscillators' mediation of energy homeostasis. Ablation studies and genetic mouse models with perturbed extra-SCN hypothalamic nuclei function reveal their critical downstream involvement in an array of functions including metabolism, thermogenesis, food consumption, thirst, mood and sleep. Large epidemiological studies of individuals whose internal circadian cycle is chronically disrupted reveal that disruption of our internal clock is associated with an increased risk of obesity and several neurological diseases and disorders. In this review, we discuss the profound role of the extra-SCN hypothalamic nuclei in rhythmically regulating and coordinating body wide functions.

Role of obstructive sleep apnea in metabolic risk in PCOS

Women with polycystic ovary syndrome (PCOS) have a substantially increased risk for diabetes and cardiovascular disease. Obstructive sleep apnea (OSA) is the most common sleep disorder in PCOS. Recent population-based studies indicate a high incidence of OSA among adult women with PCOS. Obesity and increasing age are the main factors for this association. There is strong evidence indicating that OSA is an important modulator of metabolic risk in the general population. There is also some evidence to suggest that OSA may contribute to insulin resistance and glucose intolerance among women PCOS, and thus increase their metabolic risk. The potential mechanisms for adverse metabolic consequences of OSA are likely to be multiple. Whether treatment of OSA in PCOS improves metabolic outcomes requires further rigorous research.

Effects of manipulating body temperature on sleep in postmenopausal women

STUDY OBJECTIVES

A decline in sleep quality, slow wave sleep (SWS) and slow wave activity (SWA) are common in older adults. Prior studies have shown that manipulating body temperature during sleep can increase SWS/SWA. The aim of this study was to determine the effects of manipulation of body temperatures during sleep, using a high heat capacity mattress, on SWS/SWA and heart rate in post-menopausal women.

METHODS

Twenty-four healthy postmenopausal women between 40 and 75 years of age (mean age 62.4 ± 8.2 years, mean BMI 25.4 ± 3.5 kg/m²) were randomized in a single-blind, counterbalanced, cross-over manner to sleep on either a high heat capacity mattress (HHCM) or a low heat capacity mattress (LHCM) a week apart. Sleep was recorded using polysomnography during an 8-h sleep opportunity. Core and peripheral temperature were recorded using an ingestible capsule and thermochron respectively.

RESULTS

In comparison to the LHCM, sleep on HHCM exhibited a selective increase in SWS (average increase in Stage N3 of 9.6 min (2.1%), p = 0.04) and in slow oscillatory (SO) activity (0.5-1 Hz) in the first NREM/REM cycle (p = 0.04). In addition, the HHCM induced a greater reduction in core body temperature (p = 0.002). The reduction in core body temperature (first 180 min after lights out) from LHCM to HHCM was associated (r = 0.5, p = 0.012) with the increase in SO activity (SO cycle 1 and 2/cycle 3 and 4). Average heart rate was 1.6 beats/minute lower across the night on the HHCM compared to the LHCM (p = 0.001).

CONCLUSIONS

The results of this study indicate that manipulation of body temperature during sleep may be a useful approach to enhance SWS sleep in postmenopausal women.

Shaping the slow waves of sleep: A systematic and integrative review of sleep slow wave modulation in humans using non-invasive brain stimulation

The experimental study of electroencephalographic slow wave sleep (SWS) stretches over more than half a century and has corroborated its importance for basic physiological processes, such as brain plasticity, metabolism and immune system functioning. Alterations of SWS in aging or pathological conditions suggest that modulating SWS might constitute a window for clinically relevant interventions. This work provides a systematic and integrative review of SWS modulation through non-invasive brain stimulation in humans. A literature search using PubMed, conducted in May 2020, identified 3220 studies, of which 82 fulfilled inclusion criteria. Three approaches have been adopted to modulate the macro- and microstructure of SWS, namely auditory, transcranial electrical and transcranial magnetic stimulation. Our current knowledge about the modulatory mechanisms, the space of stimulation parameters and the physiological and behavioral effects are reported and evaluated. The integration of findings suggests that sleep slow wave modulation bears the potential to promote our understanding of the functions of SWS and to develop new treatments for conditions of disrupted SWS.

Effect of Interaction Between Slow Wave Sleep and Obstructive Sleep Apnea on Insulin Resistance: A Large-Scale Study

OBJECTIVE

Slow-wave sleep (SWS) and obstructive sleep apnea (OSA) have attracted recent research attention. However, their joint effects on insulin resistance (IR) remain unclear. This study explored whether SWS influences the relationship between OSA and IR.

METHODS

We enrolled potential participants in our sleep center from 2007 to 2019. We collected demographic and clinical characteristics and determined IR status. SWS was derived from polysomnography data. Logistic regression analysis was used to reveal the associations between SWS and IR.

RESULTS

In all, 6966 participants (5709 OSA and 1257 primary snoring [PS] subjects) were enrolled. Less SWS increased the risk of IR in OSA patients but not in PS patients. OSA patients with SWS <6.5% were more likely to have IR than were those with SWS >21.3%. OSA was an independent risk factor for IR after adjusting for potential confounding factors. In stratified analyses according to the percentage of SWS, OSA patients with SWS <6.5% had an odds ratio for IR of 2.461 (95% CI, 2.018-3.002) compared to the PS group after adjusting for potential confounders.

CONCLUSION

Less SWS is associated with higher odds for IR in OSA patients but not in PS patients. OSA is independently associated with IR. In addition, OSA combined with an extreme lack of SWS has a more harmful effect on the status of IR than OSA itself.

Individual Insomnia Symptom and Increased Hazard Risk of Cardiocerebral Vascular Diseases: A Meta-Analysis

Objective: Previous studies suggested that insomnia was associated with an increased risk of cardiocerebral vascular diseases (CVDs) but not clear in different insomnia symptoms. We performed a meta-analysis to investigate the association of individual insomnia symptoms and risk of CVDs. Methods: In this meta-analysis, we systematically searched published articles by using electronic databases including PubMed, Cochrane Library, MedLine, and Google Scholar. Studies were enrolled if they indicated clear insomnia symptoms, prospective, and evaluated the association of insomnia symptoms and CVD outcome in adults free of CVDs at baseline. Results: There were seven prospective cohort studies with sample sizes ranging from 2,960 to 487,200 included in this meta-analysis. Mean follow-up duration was 10.6 years. Insomnia symptoms of having difficulty initiating or maintaining sleep (DIS or DMS), non-restorative sleep (NRS), and early morning awakening (EMA) were analyzed in this study. All studies were compared under a random-effects model. NRS, DIS, and DMS were, respectively, related to 16% [hazard ratio (HR) 1.16, 95% CI 1.07-1.24], 22% (HR 1.22, 95% CI 1.06-1.40), and 14% (HR 1.14, 95% CI 1.02-1.27) higher risk of first-ever CVD incidence during the follow-up. Based on our analysis, EMA was not a risk factor of CVDs (HR 1.06, 95% CI 0.99-1.13). Conclusion: This study suggested that symptoms of DIS, DIM, or NRS were associated with a higher risk of CVD incidence in insomnia patients free of CVDs at baseline. But this association was not significant in insomnia patients complaining about EMA.

Rationale and design of the Hyperglycemic Profiles in Obstructive Sleep Apnea (HYPNOS) trial

The Hyperglycemic Profiles in Obstructive Sleep Apnea (HYPNOS) randomized clinical trial was conducted in adults with type 2 diabetes and moderate-to-severe obstructive sleep apnea (OSA) to determine whether treatment with positive airway pressure (PAP) therapy is associated with improvements in glycemic measures. Participants were randomly assigned to PAP therapy with lifestyle counseling or lifestyle counseling alone. While observational and experimental evidence indicate that intermittent hypoxemia and recurrent arousals in OSA may alter glucose metabolism and worsen glycemic measures, the effect of treating OSA with PAP therapy on these measures in type 2 diabetes is uncertain. Adequately powered randomized clinical trials have yet to be performed to demonstrate whether PAP therapy for OSA in patients with type 2 diabetes can improve glycemic measures. The HYPNOS trial was designed to determine whether PAP therapy for OSA in patients with type 2 diabetes over 3 months leads to improvements in glycemic measures including glycemic variability (standard deviation) based on Dexcom G4 Platinum continuous glucose monitoring. Secondary objectives were to assess the effects of PAP therapy for OSA on measures of: (1) glycemic variability based on Abbott Freestyle Pro Libre continuous glucose monitoring; (2) point-of-care hemoglobin A1c (HbA1c); (3) degree of post-prandial hyperglycemia as determined by 7-point self-monitoring of blood glucose; (4) clinic and ambulatory blood pressure; and (5) endothelial function. The HYPNOS trial was designed to address gaps in our understanding of the effects of PAP therapy on glucose metabolism in adults with type 2 diabetes and moderate-to-severe OSA. Trial Registration: ClinicalTrials.gov Identifier NCT02454153.

Effects of onion extract containing concentrated cysteine sulfoxides on sleep quality: a randomized, double-blind, placebo-controlled, crossover study

The objective of this randomized, double-blind, placebo-controlled, crossover study was to examine the effects of onion extract containing concentrated cysteine sulfoxides on improving sleep quality. In total, 30 healthy men and women who were dissatisfied with their sleep consumed the test food sample (onion extract tablets) for 5 days. The delta power during non-rapid eye movement sleep and the delta power per minute in the first sleep cycle increased significantly with the intake of onion extract containing concentrated cysteine sulfoxides compared with the intake of placebo. A significant decline in sleep latency was also observed. Salivary α-amylase level, a stress indicator, decreased significantly with the intake of onion extract containing concentrated cysteine sulfoxides compared with the intake of placebo. These findings indicate that onion extract containing concentrated cysteine sulfoxides alleviates stress, improves the quality of sleep and promotes smooth transition into sleep.

Sleep Extension: A Potential Target for Obesity Treatment

PURPOSE OF REVIEW

Sleep and obesity share a bidirectional relationship, and weight loss has been shown to enhance sleep. Aiming to extend sleep on its own or as part of a lifestyle intervention may attenuate health consequences of short sleep. This review highlights several sleep extension approaches, discusses feasibility of each, and summarizes findings relevant to obesity.

RECENT FINDINGS

Sleep extension in response to experimental sleep restriction demonstrates partial rescue of cardiometabolic dysfunction in some but not all studies. Adequate sleep on a nightly basis may be necessary for optimal health. While initial sleep extension interventions in habitually short sleepers have been met with obstacles, preliminary findings suggest that sleep extension or sleep hygiene interventions may improve glycemic control, decrease blood pressure, and enhance weight loss. Sleep extension has the potential to attenuate obesity risk and cardiometabolic dysfunction. There is tremendous opportunity for future research that establishes a minimum threshold for sleep extension effectiveness and addresses logistical barriers identified in seminal studies.

Glucose control upon waking is unaffected by hourly sleep fragmentation during the night, but is impaired by morning caffeinated coffee

Morning coffee is a common remedy following disrupted sleep, yet each factor can independently impair glucose tolerance and insulin sensitivity in healthy adults. Remarkably, the combined effects of sleep fragmentation and coffee on glucose control upon waking per se have never been investigated. In a randomised crossover design, twenty-nine adults (mean age: 21 (sd 1) years, BMI: 24·4 (sd 3·3) kg/m2) underwent three oral glucose tolerance tests (OGTT). One following a habitual night of sleep (Control; in bed, lights-off trying to sleep approximately 23.00-07.00 hours), the others following a night of sleep fragmentation (as Control but waking hourly for 5 min), with and without morning coffee approximately 1 h after waking (approximately 300 mg caffeine as black coffee 30 min prior to OGTT). Individualised peak plasma glucose and insulin concentrations were unaffected by sleep quality but were higher following coffee consumption (mean (normalised CI) for Control, Fragmented and Fragmented + Coffee, respectively; glucose: 8·20 (normalised CI 7·93, 8·47) mmol/l v. 8·23 (normalised CI 7·96, 8·50) mmol/l v. 8·96 (normalised CI 8·70, 9·22) mmol/l; insulin: 265 (normalised CI 247, 283) pmol/l; and 235 (normalised CI 218, 253) pmol/l; and 310 (normalised CI 284, 337) pmol/l). Likewise, incremental AUC for plasma glucose was higher in the Fragmented + Coffee trial compared with Fragmented. Whilst sleep fragmentation did not alter glycaemic or insulinaemic responses to morning glucose ingestion, if a strong caffeinated coffee is consumed, then a reduction in glucose tolerance can be expected.

Association between Self-Reported Sleep Duration and Dietary Nutrients in Korean Adolescents: A Population-Based Study

(1) Background: Adolescence is a transient period from childhood to adulthood, which is characterized by rapid physical growth and psychological changes, including sleep. Because the relationship between insufficient sleep and obesity has been observed in children and adults, the potential links between sleep, dietary intake, and nutrition have received increased attention. We aimed to examine the association of sleep duration with dietary nutrients intake in South Korean adolescents; (2) Methods: This population-based, cross-sectional study analyzed the data obtained from the Korea National Health and Nutrition Examination Survey between 2013 and 2015. Data related to 1422 adolescents aged 12–18 years (741 males and 681 females) were included in the analysis. Sleep duration was assessed using a self-reported questionnaire. Nutrient intake, including daily total energy intake, was assessed with a 24-h dietary recall questionnaire; (3) Results: Most males (84.4%) and females (86.4%) reported < 9 h of sleep per night. Short sleep duration was inversely associated with body mass index and obesity in both sexes. We found that higher intake of fiber and lower intake of sodium were associated with longer sleep duration (P < 0.05). When comparing the intake above and below the estimated average requirements (EAR), the difference in sleep duration was significant in the group that consumed vitamins B₁ and C below EAR; (4) Conclusions: The findings of this study indicate that sleep duration can be associated with intake of some nutrients, which may also be associated with obesity in adolescents. Therefore, it is possible to prevent obesity and its complications by controlling the sleep duration and intake of nutrients of adolescents.

Dynamic changes in nocturnal blood glucose levels are associated with sleep-related features in patients with obstructive sleep apnea

Obstructive sleep apnea (OSA) has a bidirectional relationship with insulin resistance conditions; however, the mechanism remains unclear. This study aimed to compare dynamic nocturnal glucose changes among patients with OSA of varying levels of severity and evaluate temporal changes associated with the cardinal features of OSA (sympathetic hyperactivation, intermittent hypoxemia, and sleep fragmentation) in nondiabetic subjects. Nocturnal glucose was measured with a continuous glucose monitoring device every 5 min during polysomnography (PSG). The OSA features were evaluated using heart rate variability (HRV), minimum saturation, and electroencephalography. Eleven subjects with moderate to severe OSA and 12 subjects with no or mild OSA were evaluated. Those with moderate to severe OSA showed an increasing trend in blood glucose levels after sleep onset, whereas those without or with mild OSA showed a decreasing trend (F = 8.933, p < 0.001). Delta band power also showed different trends during sleep between the two groups (F = 2.991, p = 0.009), and minimum saturation remained lower in the moderate to severe OSA group than in the no or mild OSA group. High degrees of coupling between nocturnal glucose levels and each OSA feature were observed. Altered trends in nocturnal glucose in moderate to severe OSA may reflect glucose intolerance and result in metabolic consequences. Managing the features of sleep-related OSA may have implications for metabolic management in the future.

Sleeping disturbances and predictor risk factors among type 2 diabetic mellitus patients

Background

Sleep disturbance is a major health issue among people with type 2 diabetes mellitus (T2DM). The Pittsburgh Sleep Quality Index (PSQI) has been the most widely used instrument to measure subjective sleep disturbance.

Aim

The aim of this study was to determine the impact of sleeping factor structure of the PSQI as potential predictor for glycosylated hemoglobin A1c (HbA1C) among people living with T2DM in the Turkish community to facilitate its use in the clinical practice and research.

Subjects and Methods

This is a cross-sectional study and participants were between the age group of 25 and 65 years old who visited the diabetes and endocrinology department of Mega Medipol University Teaching Hospital, Istanbul. The PSQI was conducted on 871 patients with T2DM. Good sleep quality was defined as PSQI score <5. Multivariate logistic regression analysis was used to estimate the associated risk factors for the T2DM.

Results

The current study showed significant differences between male and female patients with respect to their age in years, body mass index (BMI) (kg/m2), physical activity, smoking habit, sheesha smoking, income, family history of metabolic syndrome, coronary heart disease (CHD), and PSQI. The results revealed significant differences between HbA1c ≤7 and females and HbA1c >7 T2DM patients with respect to gender, BMI (kg/m2), CHD, and PSQI. The study demonstrated significant differences between sleeping categories PSQI as good, average, and poor sleeping among T2DM patients with respect to age and gender. Meanwhile, significant differences were reported between sleeping categories among T2DM patients with respect to their: number of sleeping hours, wake-up time, sleeping time, HbA1c, fasting blood glucose, uric acid, and systolic and diastolic blood pressure. This study showed very strong statistically significant correlations between low HbA1c and poor sleep quality in patients with T2DM patients, including subjective sleep quality r = 0.763, sleep latency r = 0.327, sleep duration r = 0.472, habitual sleep efficiency r = 0.575, sleep disturbances r = 0.564, use of sleep medication r = 0.728, and daytime dysfunction r = 0.734. Multivariate stepwise logistic regression analysis revealed that Vitamin D (mmol/L) (P < 0.001), HbA1c (P < 0.001), duration of DM (P < 0.001), uric acid (mmol/L) (P < 0.001), systolic blood pressure mmHg (P = 0.006), diastolic blood pressure mmHg (P = 0.015), and BMI (P = 0.024) were considered at higher risk as the predictors for sleeping quality among T2DM patients.

Conclusion

The results suggest a strong positive correlation between PSQI with HbA1c levels, systolic and diastolic blood pressure, age, BMI, among type 2 diabetic patients. This study ascertains that poor sleep quality may be due to elevated level of HbA1c, metabolic syndrome, diabetes, obesity, and/or hypertension.

Sleeping Difficulty and Subjective Short Sleep Duration are Associated with Serum N-terminal Pro-brain Natriuretic Peptide Levels in the Elderly Population

Objective It is well known that poor sleep increases the risk of heart failure (HF). However, the underlying mechanisms remain unclear. In this study, we investigated the association of poor sleep with hemodynamic stress on the left ventricle, which was a key factor for the development of HF in elderly individuals. Methods A total of 2,301 participants (≥65 years old) without cardiac disease were enrolled in this cross-sectional analysis. We evaluated the subjective sleep quality, sleeping difficulty, subjective sleep duration, use of sleeping pills, and daytime dysfunction using the Pittsburgh Sleep Quality Index, a 19-item self-reported questionnaire. We assessed serum N-terminal pro-brain natriuretic peptide (NT-proBNP) as a marker of hemodynamic stress on the left ventricle, and we defined high NT-proBNP as a serum NT-proBNP level ≥ 125 pg/mL. Results Sleeping difficulty was significantly associated with high NT-proBNP levels [odds ratio (OR), 1.46; 95% confidence interval (CI), 1.16-1.85; p<0.005]. A subjective short sleep duration was also significantly associated with high NT-proBNP levels (OR, 1.69; 95% CI, 1.03-2.75; p<0.05). A subjective poor sleep quality, the use of sleeping pills, and daytime dysfunction were not associated with serum NT-proBNP levels. All data were adjusted for the age, sex, body mass index, serum hemoglobin concentration, serum creatinine level, systolic blood pressure, diastolic blood pressure, and use of antihypertensive medications. Conclusion Poor sleep was associated with high hemodynamic stress to the left ventricle in elderly population.

Slow-wave sleep is associated with incident hypertension in patients with obstructive sleep apnea: a cross-sectional study

OBJECTIVE

This study aimed to examine the association between slow-wave sleep ([SWS] N3 stage) and the risk of hypertension in patients with obstructive sleep apnea (OSA) or primary snorers.

METHODS

A retrospective cross-sectional study of 1145 participants who were evaluated for suspected OSA at our Sleep Medical Center were included. Among these participants, 1022 had OSA and 123 were primary snorers. Logistic regression modeling was performed to evaluate the association between the prevalence of hypertension and combined OSA and SWS based on polysomnographic measurements.

RESULTS

Patients with OSA in the lowest SWS quartile (quartile 1,  < 2.0%) showed a two-fold increased risk of hypertension after adjustment for confounding factors compared with primary snorers (odds ratio, 2.13 [95% confidence interval 1.54-2.06]). In logistic analysis stratified according to SWS quartiles, there was no significant difference in the risk of hypertension between patients with OSA and primary snorers in quartile 1. However, in the highest quartile (quartile 4), SWS was significantly associated with incident hypertension in patients with OSA rather than primary snorers.

CONCLUSION

SWS is associated with prevalent hypertension in patients with OSA. Notably, a low proportion of SWS confers a stronger association with incident hypertension than OSA.

Personality Traits and the Subjective and Objective Experience of Sleep

BACKGROUND

There is growing evidence that five-factor model personality traits are associated with self-reported sleep. We test whether these associations extend to objective sleep measures in older adulthood and whether measures of objective sleep mediate the relation between personality and subjective sleep.

METHODS

A random subsample of participants in the National Social Life and Aging Project (NSHAP) wore an accelerometer for up to three nights and had information on FFM personality traits (N = 620). Participants also reported on their feelings of being rested.

RESULTS

Higher neuroticism and lower extraversion and conscientiousness were associated with more frequent wake after sleep onset, greater fragmentation, and feeling less rested. Concurrent body mass index, disease burden, perceived stress, and depressive symptoms accounted for these associations. Personality was unrelated to total time spent asleep but conscientiousness was associated with earlier and more consistent bedtimes. None of the objective sleep metrics mediated the relation between personality and subjective sleep.

CONCLUSIONS

The present research indicates that the associations typically found for personality and subjective sleep extend to objective sleep fragmentation. These objective measures, however, do not account for the relation between personality and feeling rested.

Sleep characteristics and HbA1c in patients with type 2 diabetes on glucose-lowering medication

INTRODUCTION

To examine the association of sleep duration, insomnia, and obstructive sleep apnea (OSA) with hemoglobin A1c (HbA1c) in a cohort of patients with type 2 diabetes (T2D) on glucose-lowering medications.

RESEARCH DESIGN AND METHODS

13 346 patients with T2D were included in the present analysis (mean age: 60.2 years; 56.6% were on antidiabetic drug monotherapy; 43.4% received at least two glucose-lowering medications). Sleep duration (short: ≤6 hours/day; normal: 7-8 hours/day; long: ≥9 hours/day) and frequency of insomnia symptoms were self-reported. The risk of OSA was considered high if at least two of the following conditions were fulfilled: regular snoring, frequent daytime sleepiness, and either obesity (≥30 kg/m²) or hypertension (systolic blood pressure ≥140 mm Hg or diastolic blood pressure ≥90 mm Hg). Associations between sleep variables and HbA1c were investigated by analysis of covariance or linear regression (adjusted for, eg, participants' age, sex, ethnic background, and systolic blood pressure).

RESULTS

Long sleep duration and a high risk for OSA were independently associated with higher HbA1c values (long vs normal sleep duration: +0.10% (95% CI 0.03 to 0.18); high vs low risk for OSA: +0.07% (95% CI 0.02 to 0.11), both p=0.004). No robust association was found of short sleep duration and frequent insomnia symptoms with HbA1c. Finally, a positive dose-response association between the number of sleep problems per subject (range: 0-3) and HbA1c was observed (β=0.04% (0.02 to 0.06), p=0.002). However, all significant associations were small.

CONCLUSION

Screening for and treatment of sleep problems may help lower HbA1c levels in patients with T2D on glucose-lowering medications.

Maternal Sleep-Disordered Breathing in Pregnancy and Increased Nocturnal Glucose Levels in Women with Gestational Diabetes Mellitus

BACKGROUND

Women with hyperglycemia during pregnancy are at high risk for adverse perinatal outcomes. Maternal sleep-disordered breathing (SDB) during pregnancy is common and is a risk factor for gestational diabetes mellitus (GDM). However, the relationship between SDB severity and glucose control is unknown.

RESEARCH QUESTION

Is there an association between SDB severity and glucose levels as assessed by continuous glucose monitoring in GDM?

STUDY DESIGN AND METHODS

Women with GDM underwent sleep recordings and 72-hour continuous glucose monitoring. Linear mixed models were used to estimate the association of the apnea-hypopnea index (AHI), rapid eye movement (REM)-AHI, and non-REM-AHI with mean glucose levels during nighttime (two periods: 11 pm to 3 am and 3 am to 6 am), daytime (8 am to 9 pm), and 24-hours. Models were adjusted for BMI and antihyperglycemic medications.

RESULTS

In 65 participants who were 35 ± 5 (mean ± SD) years of age with BMI of 33 ± 7 kg/m², 31% were undergoing insulin and/or metformin therapy. A ten-unit increase in AHI was associated with elevated nocturnal glucose levels (11 pm to 3 am: 0.20 mmol/L [95% CI, 0.04-0.40]) with persistent elevations into the morning (8 am: 0.26 mmol/L [95% CI, 0.08-0.4]) when adjusted for BMI and medications. REM-AHI was also associated with higher nocturnal and morning glucose levels, whereas non-REM was not. AHI was not associated with either mean daytime or 24-hour glucose levels.

INTERPRETATION

Greater severity of SDB was associated with higher nocturnal and morning glucose levels in women with GDM.

Comparing two measures of sleep depth/intensity

Study Objectives

To compare delta spectral power (delta) and odds ratio product (ORP) as measures of sleep depth during sleep restriction with placebo or a drug that increases delta.

Methods

This is a secondary analysis of data from a study of 41 healthy participants randomized to receive placebo or gaboxadol 15 mg during sleep restriction. Participants underwent in-laboratory sleep studies on two baseline, four sleep restriction (5-h), and two recovery nights. Relation between delta or ORP and sleep depth was operationally defined as the degree of association of each metric to the probability of arousal or awakening occurring during the next 30 s (arousability).

Results

ORP values in wake, N1, N2, N3, and REM were significantly different. Delta differed between both N2 and N3 and other sleep stages but not between wake and N1 or N1 and REM. Epoch-by-epoch and individual correlations between ORP and delta power were modest or insignificant. The relation between ORP and arousability was linear across the entire ORP range. Delta also changed with arousability but only when delta values were less than 300 μV2. Receiver-operating-characteristic analysis found the ability to predict imminent arousal to be significantly greater with ORP than with log delta power for all experimental conditions. Changes in ORP, but not log delta, across the night correlated with next-day physiologic sleep tendency.

Conclusions

Compared to delta power, ORP is more discriminating among sleep stages, more sensitive to sleep restriction, and more closely associated with arousability. This evidence supports ORP as a measure of sleep depth/intensity.

Evaluation of Sleep Quality in a Disaster Evacuee Environment

We aimed to evaluate sleep and sleep-related physiological parameters (heart rate variability and glucose dynamics) among evacuees by experimentally recreating the sleep environment of evacuation shelters and cars. Nine healthy young male subjects participated in this study. Two interventions, modeling the sleep environments of evacuation shelters (evacuation shelter trial) and car seats (car trial), were compared with sleep at home (control trial). Physiological data were measured using portable two-channel electroencephalogram and electrooculogram monitoring systems, wearable heart rate sensors, and flash glucose monitors. Wake after sleep onset (WASO) and stage shift were greater in both intervention trials than the control trial, while rapid-eye movement (REM) latency and non-rapid eye movement (NREM) 1 were longer and REM duration was shorter in the evacuation shelter trial than the control trial. Glucose dynamics and power at low frequency (LF.p) of heart rate variability were higher in the car trial than in the control trial. It was confirmed that sleep environment was important to maintain sleep, and affected glucose dynamics and heart rate variability in the experimental situation.

Obstructive sleep apnea and risk of type 2 diabetes mellitus: A systematic review and dose-response meta-analysis of cohort studies

BACKGROUND

This meta-analysis was performed to quantitatively evaluate the dose-response association between obstructive sleep apnea (OSA) and risk of type 2 diabetes mellitus (T2DM).

METHODS

PubMed, Embase, and Web of Science were searched up to 12 December 2018 for articles that assessed the OSA-T2DM association. Random effects models were used to analyze the quantitative association between OSA and risk of T2DM. Restricted cubic splines were used to model the dose-response association between apnea-hypopnea index (AHI), used to assess the severity of OSA according to events/h, and risk of T2DM.

RESULTS

We included 16 cohort studies in our meta-analysis. During a median follow-up of 10.5 years (range: 3.0-22.0), 19 355 T2DM cases were reported among 338 912 study participants. The pooled relative risk of T2DM was 1.40 (95% CI, 1.32-1.48) for OSA in the binary meta-analysis and 1.08 (1.01-1.14) for each 5-event/h increase in AHI value. We found a positive linear association between OSA and T2DM risk.

CONCLUSIONS

Our dose-response meta-analysis revealed a linear association between OSA and T2DM.

The wrinkling of time: Aging, inflammation, oxidative stress, and the circadian clock in neurodegeneration

A substantial body of research now implicates the circadian clock in the regulation of an array of diverse biological processes including glial function, metabolism, peripheral immune responses, and redox homeostasis. Sleep abnormalities and other forms of circadian disruption are common symptoms of aging and neurodegeneration. Circadian clock disruption may also influence the aging processes and the pathogenesis of neurodegenerative diseases. The specific mechanisms governing the interaction between circadian systems, aging, and the immune system are still being uncovered. Here, we review the evidence supporting a bidirectional relationship between aging and the circadian system. Further, we explore the hypothesis that age-related circadian deterioration may exacerbate multiple pathogenic processes, priming the brain for neurodegeneration.

Inadequate sleep as a contributor to impaired glucose tolerance: A cross-sectional study in children, adolescents, and young adults with circadian rhythm sleep-wake disorder

BACKGROUND

Sleep deprivation and circadian disruption are associated with decreased insulin sensitivity and hyperglycemia. It is uncertain whether circadian sleep-wake disorder (CRSWD), which relates to both the homeostatic sleep system and the circadian timing system, affects glycemic regulation and insulin secretion. We aimed to examine the associations among sleep duration, sleep architecture or circadian rhythm of the sleep-wake cycle, and glucose metabolism in children, adolescents, and young adults with CRSWD.

METHODS

This cross-sectional observational study of 124 patients with CRSWD took place at Hyogo Children's Sleep and Development Medical Research Center in Hyogo, Japan. The patients underwent a 3-hour oral glucose tolerance test, anthropometric measurements, sleep-log analyses, and polysomnography. Analysis of covariance models were used to assess the association between sleep architecture or circadian rhythm of sleep-wake cycle and glucose/insulin homeostasis, adjusted for confounding variables such as age, gender, standardized body mass index, and sleep apnea index.

RESULTS

Impaired glucose tolerance was detected in 25.8% of all patients with CRSWD. After adjustment for confounding variables, we found a negative association between total sleep time (TST) and the 2-hour plasma glucose level. Stage N1 (%TST) was also a significant predictor of 3-hour glucose level. However, we did not detect an association between circadian rhythm of the sleep-wake cycle and glucose/insulin measures.

CONCLUSIONS

Decreased sleep duration and increased stage N1 (%TST) were associated with hyperglycemia in patients with CRSWD. Further research should elucidate how circadian misalignment in patients with CRSWD is associated with glucose and insulin homeostasis.

[Diagnostic and therapeutic approach to nocturia in Primary Care]

Nocturia is the interruption of the main sleep, one or more times, due to the need for urination. It is associated with a decrease in the quality of life and an increase in mortality. It is a complex and multifactorial symptom in which two pathophysiological mechanisms are mainly involved. These occur alone or in combination as nocturnal polyuria or decreased bladder capacity. Nocturnal polyuria is the most frequent. The preparation of a bladder diary is the key to diagnosis. Treatment usually combines lifestyle changes and drug therapy. Desmopressin has proven to be an effective and well-tolerated treatment in patients with nocturnal polyuria. The risk of hyponatraemia should be controlled in patients treated with desmopressin.

The effect of sleep impairment on gestational diabetes mellitus: a systematic review and meta-analysis of cohort studies

OBJECTIVE

This systematic review and meta-analysis evaluated the influence of sleep duration or impairment (poor sleep quality, snoring, and obstructive sleep apnea [OSA]) on gestational diabetes mellitus (GDM) risk.

METHODS

PubMed, Embase, EBSCO, and WOS databases were searched up to March 4th, 2019. Cohort studies were included and relative risk (RR) with 95% confidence interval (CI) were used as the measure of effects. Heterogeneity was assessed by the Chi-squared and I² tests. Subgroup analyses, sensitivity analysis, and dose-response analysis were performed. The overall quality of the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

RESULTS

A total of 16 studies with 2,551,017 pregnant women and 142,103 GDM cases were included in this study. Both short and long sleep duration were associated with increased risk of GDM. There was a U-shaped relationship between sleep duration and GDM risk (P_{-nonlinearity} < 0.001), and pregnant women with 8 h of sleep presented lower GDM risk. Poor sleep quality, snoring and OSA also increased the subsequent risk of GDM.

CONCLUSIONS

Pregnant women should be made aware of the benefits of proper sleep, and those with poor sleep quality, snoring, and OSA should be screened for GDM.

Misadjustment of diurnal expression of core temperature and locomotor activity in lactating rabbits associated with maternal over-nutrition before and during pregnancy

Metabolic parameters ranging from circulating nutrient levels and substrate utilization to energy expenditure and thermogenesis are temporally modulated by the circadian timing system. During critical embryonic developmental periods, maternal over-nutrition could alter key elements in different tissues associated with the generation of circadian rhythmicity, compromising normal rhythmicity development. To address this issue, we determine whether maternal over-nutrition leads to alterations in the development of circadian rhythmicity at physiological and behavioral levels in the offspring. For this, female rabbits were fed a standard diet (SD) or high-fat and carbohydrate diet (HFCD) before mating and during gestation. Core body temperature and gross locomotor activity were continuously recorded in newborn rabbits, daily measurements of body weight and the amount of milk ingested was carried out. At the end of lactation, tissue samples, including brown adipose tissue (BAT) and white adipose tissue (WAT), were obtained for determining the expression of uncoupling protein-1 (UCP1) and cell death-inducing DNA fragmentation factor-like effector A (CIDEA) genes. HFCD pups exhibited conspicuous differences in the development of the daily rhythm of temperature and locomotor activity compared to the SD pups, including a significant increase in the daily mean core temperature, changes in the time when temperature or activity remains above the average, shifts in the acrophase, decrease in the duration and intensity of the anticipatory rise previous to nursing, and changes in frequency of the rhythms. HFCD pups exhibited a significant increase in BAT thermogenesis markers, and a decrease of these markers in WAT, indicating more heat generation by brown adipocytes and alterations in the browning process. These results indicate that maternal over-nutrition alters offspring homeostatic and chronostatic regulation at the physiological and behavioral levels. Further studies are needed to determine whether these alterations are associated with the changes in the organization of the circadian system of the progeny.

The immune-sleep crosstalk in inflammatory bowel disease

Sleep disorders are progressively common and sometimes are associated with aberrant regulation of the adaptive and innate immune responses. Sleep interruption can increase the inflammatory burden by enhancing the pro-inflammatory cytokines particularly in patients with chronic diseases such as inflammatory bowel disease (IBD). IBD is a chronic inflammatory disease characterized by immune dysregulation, dysbiosis of gut microbiome, and poor-quality life. Therefore, this review highlights the crosstalk between sleep and immune responses during the progression of IBD.

Depressive symptoms mediate the relationship between sleep disturbances and type 2 diabetes mellitus

BACKGROUND

The current study aimed at examining whether individuals diagnosed with type 2 diabetes mellitus (T2DM) have more severe sleep disturbances compared to individuals who are healthy or have prediabetes and whether depressive symptoms mediate the relationship between sleep disturbances and having T2DM.

METHODS

T2DM patients (n = 107) were compared to individuals with prediabetes (n = 48) and healthy individuals (n = 154) regarding the severity of depressive symptoms, measured via the Beck Depression Inventory-II (BDI-II), and sleep disturbances, measured via the Mini Sleep Questionnaire (MSQ). Mediation analysis examined whether depressive symptoms mediated the relationship between sleep disturbances and T2DM.

RESULTS

Compared to healthy individuals and individuals with prediabetes, T2DM patients had more depressive symptoms and higher levels of insomnia, hypersomnia, and overall more sleep disturbances. The prediabetes group did not differ from the healthy control group on these measures, and these groups were thus combined for further analysis. Sleep disturbances were correlated with severity of depressive symptoms (r =0.43). After controlling for age, gender, and ethnic background, both severity of sleep disturbances (odds ratio [OR]: 1.04; 95% CI: 1.01-1.07, P <.001) and severity of depressive symptoms (OR: 8.54, 95% CI: 3.37-21.69, P <.001) predicted T2DM. Depression symptoms mediated the relationship between sleep disturbances and T2DM, whereas the direct relationship between sleep disturbances and T2DM was nonsignificant.

CONCLUSIONS

The findings imply that sleep disturbances may contribute to the development and progression of T2DM by promoting depressive symptoms. Thus, treatments for the emotional distress associated with sleep disturbances may help reduce the risk for T2DM and the progression of the disease.