Sleep loss and inflammation

Recovery of the immune system after exercise

The notion that prolonged, intense exercise causes an "open window" of immunodepression during recovery after exercise is well accepted. Repeated exercise bouts or intensified training without sufficient recovery may increase the risk of illness. However, except for salivary IgA, clear and consistent markers of this immunodepression remain elusive. Exercise increases circulating neutrophil and monocyte counts and reduces circulating lymphocyte count during recovery. This lymphopenia results from preferential egress of lymphocyte subtypes with potent effector functions [e.g., natural killer (NK) cells, γδ T cells, and CD8⁺ T cells]. These lymphocytes most likely translocate to peripheral sites of potential antigen encounter (e.g., lungs and gut). This redeployment of effector lymphocytes is an integral part of the physiological stress response to exercise. Current knowledge about changes in immune function during recovery from exercise is derived from assessment at the cell population level of isolated cells ex vivo or in blood. This assessment can be biased by large changes in the distribution of immune cells between blood and peripheral tissues during and after exercise. Some evidence suggests that reduced immune cell function in vitro may coincide with changes in vivo and rates of illness after exercise, but more work is required to substantiate this notion. Among the various nutritional strategies and physical therapies that athletes use to recover from exercise, carbohydrate supplementation is the most effective for minimizing immune disturbances during exercise recovery. Sleep is an important aspect of recovery, but more research is needed to determine how sleep disruption influences the immune system of athletes.

Impaired Sleep Quality is Associated With More Significant Lower Urinary Tract Symptoms in Male Shift Workers

OBJECTIVE

To determine the association between sleep quality and severity of lower urinary tract symptoms (LUTS) in men working nonstandard shifts, a population at risk of poor sleep quality.

METHODS

Men who presented to a single andrology clinic between July and October 2014 and worked nonstandard shifts completed the International Prostate Symptom Score (IPSS) and responded to questions regarding their work habits, sleep quality, and physical or cognitive function. We assessed the relationship between age, sleep quality, physical or cognitive function, and severity of LUTS.

RESULTS

A total of 228 men with a mean ± standard deviation age of 41.8 ± 5.7 (range 21-76) years reported working nonstandard shifts, with the majority working these shifts for more than 1 year (81%). Men with difficulties falling asleep reported more severe LUTS than men who did not have difficulty falling asleep (IPSS score 9 vs 6, P <.001). Men who reported difficulty staying asleep or falling back asleep after awakening also reported more severe LUTS (IPSS scores 6 vs 13, P = .004; 5 vs 13, P <.001, respectively). Men with a decreased sense of well-being or decreased physical or cognitive function also reported more severe LUTS (IPSS score 6 vs 9, P <.0010; 6 vs 10, P = .016, respectively). All findings were independent of subject age.

CONCLUSION

Men working nonstandard shifts who have difficulty falling asleep, staying asleep, and falling back asleep report more severe LUTS than men without similar sleep difficulties. Men with a decreased sense of well-being or decreased physical or cognitive function also report worse LUTS. These findings implicate sleep quality as a possible risk factor for LUTS symptom severity.

Sleep extension increases IGF-I concentrations before and during sleep deprivation in healthy young men

Sleep deprivation is known to suppress circulating trophic factors such as insulin-like growth factor (IGF)-I and brain-derived neurotrophic factor (BDNF). This experiment examined the effect of an intervention involving 6 nights of extended sleep before total sleep deprivation on this catabolic profile. In a randomized crossover design, 14 young men (age range: 26–37 years) were either in an extended (EXT; time in bed: 2100–0700 h) or habitual (HAB: 2230–0700 h) sleep condition, followed by 3 days in the laboratory with blood sampling at baseline (B), after 24 h of sleep deprivation (24h-SD), and after 1 night of recovery sleep (R). In the EXT condition compared with the HAB condition, free IGF-I levels were significantly higher at B, 24h-SD, and R (P < 0.001), and those of total IGF-I at B and 24h-SD (P < 0.05). EXT did not influence growth hormone, IGF binding protein 3, BDNF, insulin, and glucose levels. The only effect of 24 h of sleep deprivation was for insulin levels, which were significantly higher after R compared with B. In a healthy adult, additional sleep over 1 week increased blood concentrations of the anabolic factor IGF-I before and during 24 h of sleep deprivation and after the subsequent recovery night without effects on BDNF. With further research, these findings may prove to be important in guiding effective lifestyle modifications to limit physical or cognitive deficits associated with IGF-I decrease with age.

Affective disturbance in rheumatoid arthritis: psychological and disease-related pathways

In addition to recurrent pain, fatigue, and increased rates of physical disability, individuals with rheumatoid arthritis (RA) have an increased prevalence of some mental health disorders, particularly those involving affective or mood disturbances. This narrative Review provides an overview of mental health comorbidities in RA, and discusses how these comorbidities interact with disease processes, including dysregulation of inflammatory responses, prolonged difficulties with pain and fatigue, and the development of cognitive and behavioural responses that could exacerbate the physical and psychological difficulties associated with RA. This article describes how the social context of individuals with RA affects both their coping strategies and their psychological responses to the disease, and can also impair responses to treatment through disruption of patient-physician relationships and treatment adherence. Evidence from the literature on chronic pain suggests that the resulting alterations in neural pathways of reward processing could yield new insights into the connections between disease processes in RA and psychological distress. Finally, the role of psychological interventions in the effective and comprehensive treatment of RA is discussed.

Clinical Relevance of Sleep Duration: Results from a Cross-Sectional Analysis Using NHANES

STUDY OBJECTIVES

To assess the clinical relevance of sleep duration, hours slept were compared by health status, presence of insomnia, and presence of depression, and the association of sleep duration with BMI and cardiovascular risk was quantified.

METHODS

Cross-sectional analysis of subjects in the US National Health and Nutrition Examination Surveys using adjusted linear and logistic regressions.

RESULTS

A total of 22,281 adults were included, 37% slept ≤ 6 hours, 36% were obese, and 45% reported cardiovascular conditions. Mean sleep duration was 6.87 hours. Better health was associated with more hours of sleep. Subjects with poor health reported sleeping 46 min, (95% CI -56.85 to -35.67) less than subjects with excellent health. Individuals with depression (vs. not depressed) reported 40 min less sleep, (95% CI -47.14 to -32.85). Individuals with insomnia (vs. without insomnia) reported 39 min less sleep, (95% CI -56.24 to -22.45). Duration of sleep was inversely related to BMI; for every additional hour of sleep, there was a decrease of 0.18 kg/m(2) in BMI, (95% CI -0.30 to -0.06). The odds of reporting cardiovascular problems were 6.0% lower for every hour of sleep (odds ratio = 0.94, 95% CI [0.91 to 0.97]). Compared with subjects who slept ≤ 6 h, subjects who slept more had lower odds of reporting cardiovascular problems, with the exception of subjects ≥ 55 years old who slept ≥ 9 hours.

CONCLUSIONS

Long sleep duration is associated with better health. The fewer the hours of sleep, the greater the BMI and reported cardiovascular disease. A difference of 30 minutes of sleep is associated with substantive impact on clinical well-being.

An insight of sleep disorders in Africa

Sleep is a recurrent physiologic and fundamental process in every human being, regardless of ethnicity, gender, birthplace, or occupation; however, the features of sleep are swayed by genetic background and environmental influences. All these factors have an intricate relationship, and arise from a complex and assorted genetic repertoire in the alleles that promote a higher genetic variation in human populations. Sleep disorders have become an uprising public health problem in the modern society; in addition, the correlation between sleep disorders and the development of late chronic diseases has been extensively studied, finding an important causality between them. Therefore, an adequate evaluation of the current situation in a developing continent such as Africa is essential to develop satisfactory health policies. In this review, we will reprise several aspects that influence the sleep-wake cycle in individuals with African heritage (including African Americans and sub-Saharan Africans), such as genetic background, HIV infection, tropical diseases, immunological markers, cultural aspects, and place them into Africa's context in order to have a better comprehension of its situation.

Using Drosophila as an integrated model to study mild repetitive traumatic brain injury

Traumatic brain injury (TBI) is a major cause of morbidity and mortality worldwide. In addition, there has been a growing appreciation that even repetitive, milder forms of TBI (mTBI) can have long-term deleterious consequences to neural tissues. Hampering our understanding of genetic and environmental factors that influence the cellular and molecular responses to injury has been the limited availability of effective genetic model systems that could be used to identify the key genes and pathways that modulate both the acute and long-term responses to TBI. Here we report the development of a severe and mild-repetitive TBI model using Drosophila. Using this system, key features that are typically found in mammalian TBI models were also identified in flies, including the activation of inflammatory and autophagy responses, increased Tau phosphorylation and neuronal defects that impair sleep-related behaviors. This novel injury paradigm demonstrates the utility of Drosophila as an effective tool to validate genetic and environmental factors that influence the whole animal response to trauma and to identify prospective therapies needed for the treatment of TBI.

Prolonged sleep restriction induces changes in pathways involved in cholesterol metabolism and inflammatory responses

Sleep loss and insufficient sleep are risk factors for cardiometabolic diseases, but data on how insufficient sleep contributes to these diseases are scarce. These questions were addressed using two approaches: an experimental, partial sleep restriction study (14 cases and 7 control subjects) with objective verification of sleep amount, and two independent epidemiological cohorts (altogether 2739 individuals) with questions of sleep insufficiency. In both approaches, blood transcriptome and serum metabolome were analysed. Sleep loss decreased the expression of genes encoding cholesterol transporters and increased expression in pathways involved in inflammatory responses in both paradigms. Metabolomic analyses revealed lower circulating large HDL in the population cohorts among subjects reporting insufficient sleep, while circulating LDL decreased in the experimental sleep restriction study. These findings suggest that prolonged sleep deprivation modifies inflammatory and cholesterol pathways at the level of gene expression and serum lipoproteins, inducing changes toward potentially higher risk for cardiometabolic diseases.

Breast cancer survival among young women: a review of the role of modifiable lifestyle factors

Almost 7 % of breast cancers are diagnosed among women age 40 years and younger in Western populations. Clinical outcomes among young women are worse. Early age-of-onset increases the risk of contralateral breast cancer, local and distant recurrence, and subsequent mortality. Breast cancers in young women (BCYW) are more likely to present with triple-negative (TNBC), TP53-positive, and HER-2 over-expressing tumors than among older women. However, despite these known differences in breast cancer outcomes and tumor subtypes, there is limited understanding of the basic biology, epidemiology, and optimal therapeutic strategies for BCYW. Several modifiable lifestyle factors associated with reduced risk of developing breast cancer have also been implicated in improved prognosis among breast cancer survivors of all ages. Given the treatment-related toxicities and the extended window for late effects, long-term lifestyle modifications potentially offer significant benefits to BCYW. In this review, we propose a model identifying three main areas of lifestyle factors (energy imbalance, inflammation, and dietary nutrient adequacy) that may influence survival in BCYW. In addition, we provide a summary of mechanisms of action and a synthesis of previous research on each of these topics.

Altered sleep structure in patients with end-stage renal disease

OBJECTIVE

Although symptoms of sleep disturbances are widely recognized in end-stage renal disease (ESRD), the effect of uremia on sleep structure has not been well investigated. We hypothesized that compared to individuals without ESRD, those with ESRD would have altered sleep structure after controlling for the severity of sleep apnea (SA).

METHODS

We studied 57 ESRD patients (42 men) and 57 controls (46 men) who had undergone polysomnography. Control subjects were matched to the ESRD patients by age, body mass index (BMI), frequency of periodic leg movements per hour of sleep, and the frequency of apneas and hypopneas per hour of sleep [apnea-hypopnea index (AHI)].

RESULTS

The AHI and the percentage of patients with an AHI ≥15 were similar between ESRD and control groups. However, total (p = 0.002), rapid eye movement (REM) (p = 0.007), and non-REM (p = 0.022) sleep times were lower in ESRD patients than in the control group. In a multivariable analysis adjusted for age, sex, AHI, BMI, arousal index, and diabetes, ESRD remained independently associated with lower REM (p = 0.021) and total sleep times (p = 0.026).

CONCLUSION

ESRD is independently associated with reduced total and REM sleep times after controlling for the severity of SA and other variables. Although we could not identify the cause of reduced sleep times, these could be related to uremia or fluid overload or both. Accordingly, our data provide a strong rationale for examining the effects of intensifying dialysis on sleep structure in ESRD patients.

Experimentally manipulated sleep duration in adolescents with asthma: Feasibility and preliminary findings

OBJECTIVE

To examine the impact of sleep duration on lung function and asthma symptoms in adolescents.

METHODS

Ten adolescents with asthma (60% female, 60% Caucasian, mean age = 13.7 years, range 12-17) completed a 3-week randomized, cross-over sleep manipulation protocol. Following a week of self-selected sleep duration, adolescents were randomized to a five-night deficient sleep opportunity (6.5 hr in bed) or a healthy sleep opportunity (10 hr in bed) obtained by systematically changing bedtimes. Wake time remained consistent across all 3 weeks (including weekends). Daily reports of sleep patterns and asthma symptoms, actigraphy, and daily peak expiratory flow rates (PEFR), as well as weekly spirometry and exhaled nitric oxide were collected.

RESULTS

Participants averaged 3.2 hr less sleep (P < 0.001) per night in the short sleep condition versus the long sleep condition. Further, they had an 8.4% decrease overnight in PEFR (P = 0.007), and reported more asthma symptoms interfering with activities in the past 24 hr (P = 0.02) in the short sleep condition than the long sleep condition. No significant differences between experimental weeks were found for weekly spirometry or exhaled nitric oxide.

CONCLUSIONS

This pilot study demonstrated the feasibility of a cross-over sleep manipulation protocol in adolescents with asthma. Since overnight decrease in PEFR is a marker of nocturnal asthma, and has been associated with the severity of daytime airflow limitation, these early-stage results suggest that shortened sleep duration may exacerbate adolescent asthma and associated functional impairments.

Traditional and Emerging Lifestyle Risk Behaviors and All-Cause Mortality in Middle-Aged and Older Adults: Evidence from a Large Population-Based Australian Cohort

BACKGROUND

Lifestyle risk behaviors are responsible for a large proportion of disease burden worldwide. Behavioral risk factors, such as smoking, poor diet, and physical inactivity, tend to cluster within populations and may have synergistic effects on health. As evidence continues to accumulate on emerging lifestyle risk factors, such as prolonged sitting and unhealthy sleep patterns, incorporating these new risk factors will provide clinically relevant information on combinations of lifestyle risk factors.

METHODS AND FINDINGS

Using data from a large Australian cohort of middle-aged and older adults, this is the first study to our knowledge to examine a lifestyle risk index incorporating sedentary behavior and sleep in relation to all-cause mortality. Baseline data (February 2006- April 2009) were linked to mortality registration data until June 15, 2014. Smoking, high alcohol intake, poor diet, physical inactivity, prolonged sitting, and unhealthy (short/long) sleep duration were measured by questionnaires and summed into an index score. Cox proportional hazards analysis was used with the index score and each unique risk combination as exposure variables, adjusted for socio-demographic characteristics. During 6 y of follow-up of 231,048 participants for 1,409,591 person-years, 15,635 deaths were registered. Of all participants, 31.2%, 36.9%, 21.4%, and 10.6% reported 0, 1, 2, and 3+ risk factors, respectively. There was a strong relationship between the lifestyle risk index score and all-cause mortality. The index score had good predictive validity (c index = 0.763), and the partial population attributable risk was 31.3%. Out of all 96 possible risk combinations, the 30 most commonly occurring combinations accounted for more than 90% of the participants. Among those, combinations involving physical inactivity, prolonged sitting, and/or long sleep duration and combinations involving smoking and high alcohol intake had the strongest associations with all-cause mortality. Limitations of the study include self-reported and under-specified measures, dichotomized risk scores, lack of long-term patterns of lifestyle behaviors, and lack of cause-specific mortality data.

CONCLUSIONS

Adherence to healthy lifestyle behaviors could reduce the risk for death from all causes. Specific combinations of lifestyle risk behaviors may be more harmful than others, suggesting synergistic relationships among risk factors.

Short sleep duration and dietary intake: epidemiologic evidence, mechanisms, and health implications

Links between short sleep duration and obesity, type 2 diabetes, hypertension, and cardiovascular disease may be mediated through changes in dietary intake. This review provides an overview of recent epidemiologic studies on the relations between habitual short sleep duration and dietary intake in adults from 16 cross-sectional studies. The studies have observed consistent associations between short sleep duration and higher total energy intake and higher total fat intake, and limited evidence for lower fruit intake, and lower quality diets. Evidence also suggests that short sleepers may have irregular eating behavior deviating from the traditional 3 meals/d to fewer main meals and more frequent, smaller, energy-dense, and highly palatable snacks at night. Although the impact of short sleep duration on dietary intake tends to be small, if chronic, it may contribute to an increased risk of obesity and related chronic disease. Mechanisms mediating the associations between sleep duration and dietary intake are likely to be multifactorial and include differences in the appetite-related hormones leptin and ghrelin, hedonic pathways, extended hours for intake, and altered time of intake. Taking into account these epidemiologic relations and the evidence for causal relations between sleep loss and metabolism and cardiovascular function, health promotion strategies should emphasize improved sleep as an additional factor in health and weight management. Moreover, future sleep interventions in controlled studies and sleep extension trials in chronic short sleepers are imperative for establishing whether there is a causal relation between short sleep duration and changes in dietary intake.

Therapeutic implications of the choroid plexus-cerebrospinal fluid interface in neuropsychiatric disorders

The choroid plexus (CP) comprises an epithelial monolayer that forms an important physical, enzymatic and immunologic barrier, called the blood-cerebrospinal fluid barrier (BCSFB). It is a highly vascularized organ located in the brain ventricles that is key in maintaining brain homeostasis as it produces cerebrospinal fluid (CSF) and has other important secretory functions. Furthermore, the CP-CSF interface plays a putative role in neurogenesis and has been implicated in neuropsychiatric diseases such as the neurodevelopmental disorders schizophrenia and autism. A role for this CNS border was also implicated in sleep disturbances and chronic and/or severe stress, which are risk factors for the development of neuropsychiatric conditions. Understanding the mechanisms by which disturbance of the homeostasis at the CP-CSF interface is involved in these different chronic low-grade inflammatory diseases can give new insights into therapeutic strategies. Hence, this review discusses the different roles that have been suggested so far for the CP in these neuropsychiatric disorders, with special attention to potential therapeutic applications.

Leukocyte telomere length and hippocampus volume: a meta-analysis

Leukocyte telomere length has been shown to correlate to hippocampus volume, but effect estimates differ in magnitude and are not uniformly positive. This study aimed primarily to investigate the relationship between leukocyte telomere length and hippocampus gray matter volume by meta-analysis and secondarily to investigate possible effect moderators. Five studies were included with a total of 2107 participants, of which 1960 were contributed by one single influential study. A random-effects meta-analysis estimated the effect to r = 0.12 [95% CI -0.13, 0.37] in the presence of heterogeneity and a subjectively estimated moderate to high risk of bias. There was no evidence that apolipoprotein E (APOE) genotype was an effect moderator, nor that the ratio of leukocyte telomerase activity to telomere length was a better predictor than leukocyte telomere length for hippocampus volume. This meta-analysis, while not proving a positive relationship, also is not able to disprove the earlier finding of a positive correlation in the one large study included in analyses. We propose that a relationship between leukocyte telomere length and hippocamus volume may be mediated by transmigrating monocytes which differentiate into microglia in the brain parenchyma.

Sleep Disorders Among People With Schizophrenia: Emerging Research

Up to 80 % of individuals with schizophrenia spectrum disorders experience sleep disturbances, which impact physical and mental health, as well as quality of life. In this paper, we review and integrate emerging literature, published between 2012 and 2014, regarding approaches to diagnosis and treatment of major sleep disorders for people with schizophrenia spectrum disorders, including insomnia, obstructive sleep apnea (OSA), circadian rhythm dysfunction, and restless legs syndrome (RLS). We advocate for (1) the need to evaluate the utility of nonpharmacological approaches in people with schizophrenia spectrum disorders; (2) documentation of guidelines to assist providers in clinically tailoring such interventions when their clients experience positive, negative, and/or cognitive symptoms; (3) research on the best ways providers can capitalize on clients' self-identified needs and motivation to engage in sleep treatments through shared decision making; and (4) the importance of investigating whether and how mental health and sleep treatment services should be better connected to facilitate access for people with schizophrenia spectrum disorders. Assessment and tailored treatment of sleep disorders within mental health treatment settings has the potential to reduce sleep problems and improve functioning, quality of life, and recovery of this population.

Effects of exercise on brain and peripheral inflammatory biomarkers induced by total sleep deprivation in rats

Background

Physical exercise induces neuroprotection through anti-inflammatory effects and total sleep deprivation is reported an inflammatory process. We examined whether 7 weeks of exercise training attenuates markers of inflammation during total sleep deprivation (24-h wakefulness) in the rat brain and periphery.

Methods

Four groups of 10 rats were investigated: Sedentary control, Sedentary sleep-deprived, Exercised control, and Exercised sleep-deprived. Sleep deprivation and exercise training were induced using slowly rotating wheels and a motorized treadmill. We examined mRNA expression of pro-inflammatory (IL-1β, TNF-α, and IL-6) cytokine-related genes using real-time PCR, and protein levels in the hippocampus and frontal cortex, as well as circulating concentrations.

Results

Compared to Sedentary control rats, hippocampal and cortical IL-1β mRNA expressions in Sedentary sleep-deprived rats were up-regulated (p < 0.05 and p < 0.01 respectively). At the protein level, hippocampal IL-1β and TNF-α and cortical IL-6 contents were higher in Sedentary sleep-deprived rats (p < 0.001, p < 0.05, p < 0.05, respectively). Peripherally, TNF-α, IL-6 and norepinephrine concentrations were higher in Sedentary sleep-deprived rats compared to Sedentary control (p < 0.01, p < 0.001, p < 0.01, respectively). Exercise training reduced the sleep deprivation-induced hippocampal IL-1β increases (mRNA expression and protein content) (p < 0.05 and p < 0.001), and TNF-α content (p < 0.001). At the periphery, exercise reduced sleep deprivation-induced increase of IL-6 concentration (p < 0.05) without effect on TNF-α and norepinephrine.

Conclusions

We demonstrate that a 7-week exercise training program before acute total sleep deprivation prevents pro-inflammatory responses in the rat hippocampus, particularly the IL-1β cytokine at the gene expression level and protein content.

Insulin resistance, glucose intolerance and diabetes mellitus in obstructive sleep apnoea

Obstructive sleep apnoea (OSA) is a highly prevalent disorder, which conveys an increased risk of cardiovascular disease and death. Type 2 diabetes mellitus (T2DM), glucose intolerance and insulin resistance (IR) are common in subjects with OSA, but a shared intimate relationship with obesity makes discerning an independent link challenging. Nonetheless, mechanistic studies suggest that OSA could contribute to impaired glucose metabolism via the effects of sleep fragmentation, sympathetic excitation and intermittent hypoxia (IH) on pancreatic B-cell function, insulin sensitivity, and systemic inflammation. In particular, emerging data suggest that IH may have an important detrimental effect on adipose tissue function and inflammation. Similarly, data from population-and clinic-level studies suggest that OSA is independently related with the prevalence and incidence of T2DM and IR, and may also lead to worse glycaemic control in diabetics. However, the ability of continuous positive airway pressure (CPAP) therapy to make a meaningful impact on T2DM or IR remains uncertain. In this review we explore the available evidence linking OSA with IR, glucose intolerance and T2DM, and discuss potential pathobiological mechanisms by which sleep disordered breathing can affect metabolic health.

The Impact of Sleep Restriction and Simulated Physical Firefighting Work on Acute Inflammatory Stress Responses

OBJECTIVES

This study investigated the effect restricted sleep has on wildland firefighters' acute cytokine levels during 3 days and 2 nights of simulated physical wildfire suppression work.

METHODS

Firefighters completed multiple days of physical firefighting work separated by either an 8-h (Control condition; n = 18) or 4-h (Sleep restriction condition; n = 17) sleep opportunity each night. Blood samples were collected 4 times a day (i.e., 06:15, 11:30, 18:15, 21:30) from which plasma cytokine levels (IL-6, IL-8, IL-1β, TNF-α, IL-4, IL-10) were measured.

RESULTS

The primary findings for cytokine levels revealed a fixed effect for condition that showed higher IL-8 levels among firefighters who received an 8-h sleep each night. An interaction effect demonstrated differing increases in IL-6 over successive days of work for the SR and CON conditions. Fixed effects for time indicated that IL-6 and IL-4 levels increased, while IL-1β, TNF-α and IL-8 levels decreased. There were no significant effects for IL-10 observed.

CONCLUSION

Findings demonstrate increased IL-8 levels among firefighters who received an 8-h sleep when compared to those who had a restricted 4-h sleep. Firefighters' IL-6 levels increased in both conditions which may indicate that a 4-h sleep restriction duration and/or period (i.e., 2 nights) was not a significant enough stressor to affect this cytokine. Considering the immunomodulatory properties of IL-6 and IL-4 that inhibit pro-inflammatory cytokines, the rise in IL-6 and IL-4, independent of increases in IL-1β and TNF-α, could indicate a non-damaging response to the stress of simulated physical firefighting work. However, given the link between chronically elevated cytokine levels and several diseases, further research is needed to determine if firefighters' IL-8 and IL-6 levels are elevated following repeated firefighting deployments across a fire season and over multiple fire seasons.

Exploring association between sleep deprivation and chronic periodontitis: A pilot study

Background:

Sleep deprivation has become a global phenomenon, and epidemiologic data indicate that short sleep duration adversely impacts human physical health. Underlying mechanisms involve modulation of immune-inflammatory mechanisms. These changes might contribute to potentiation of destructive periodontal disease. Therefore, the present study aimed to assess if there is an association of sleep deprivation with chronic periodontal diseases.

Materials and Methods:

Sixty subjects were categorized into 3 groups (n = 20 each) viz. clinically healthy, gingivitis and periodontitis. Periodontal status of subjects was assessed by gingival index and pocket probing depth. All the study subjects were administered Pittsburgh Sleep Quality Index (PSQI) questionnaire for the assessment of sleep deprivation.

Results:

Present investigation revealed that mean PSQI was highest in the periodontitis group as compared to other two groups and the difference among three groups was statistically significant.

Conclusion:

The present study with preliminary results suggestive of the association of sleep deprivation with severity of periodontal disease, definitely calls on for future studies with larger samples.

Increased risk of erectile dysfunction among patients with sleep disorders: a nationwide population-based cohort study

AIMS

Few studies have investigated the relationship between sleep disorders (SD) and erectile dysfunction (ED). Therefore, this study explored whether patients with SD in an Asian population are at an increased risk of developing ED.

METHODS

This longitudinal nationwide population-based cohort study investigated the incidence and risk of developing ED in 34,548 men newly diagnosed with SD between 2002 and 2008 from the National Health Insurance Research Database. A total of 138,192 controls without SD were randomly recruited from the general population and frequency matched according to age and sex. The follow-up period began from the date of entering the study cohort until the date of an ED event, censoring, or 31 December 2010. We conducted Cox proportional hazard regression analyses to estimate the effects of SD on the risk of ED.

RESULTS

The SD cohort had a 2.11-fold adjusted hazard ratio (HR) of subsequent ED development compared with the non-SD cohort [95% confidence interval (CI) = 1.89-2.37]. The incidence of ED increased with age for both cohorts and was higher for the patients in the SD cohort. Compared with the participants without SD or comorbidities, the patients without SD with any comorbidity exhibited a 1.79-fold risk of developing ED (95% CI = 1.54-2.09); the highest risk was for those with both SD and any comorbidity (HR = 3.34, 95% CI = 2.82-3.95). Furthermore, SD patients who had a particular number of comorbidities showed the dose-response effect of developing ED.

CONCLUSION

This nationwide cohort study determined that ED risk evidently increased in SD patients compared with the general population.

Effect of long-term sleep restriction and subsequent recovery sleep on the diurnal rhythms of white blood cell subpopulations

While acute modifications of sleep duration induces a wide array of immune function alterations, less is known of how longer periods with insufficient sleep affect immune functions and how they return to normal once recovery sleep is obtained. The purpose of the present study was to investigate the effects of five days of restricted sleep and a subsequent 7-day period of sleep recovery on white blood cell (WBC) subpopulation count and diurnal rhythms. Nine healthy males participated in a sleep protocol consisting of two baseline days (8h of sleep/night), five nights with restricted sleep (4h of sleep/night) and seven days of recovery sleep (8h of sleep/night). During nine of these days, blood was drawn hourly during night-time end every third hour during daytime, and differential WBC count was analyzed. Gradual increase across the days of sleep restriction was observed for total WBC (p<.001), monocytes (p<.001), neutrophils (p<.001) and lymphocytes (p<.05). Subsequent recovery sleep resulted in a gradual decrease in monocytes (p<.001) and lymphocytes (p=.001), but not in neutrophils that remained elevated over baseline level at the end of the 7-day recovery period. These effects were associated with altered diurnal rhythms of total WBC and neutrophils, restricted sleep being associated with higher levels during the night and at awakening, resulting in a flattening of the rhythm. The diurnal alterations were reversed when recovery sleep was allowed, although the amplitude of total WBC, neutrophils and monocytes was increased at the end of the recovery period in comparison to baseline. Altogether, these data show that long-term sleep restriction leads to a gradual increase of circulating WBC subpopulations and alterations of the respective diurnal rhythms. Although some of the effects caused by five days of restricted sleep were restored within the first days of recovery, some parameters were not back to baseline even after a period of seven recovery days.

Influence of sleep deprivation and circadian misalignment on cortisol, inflammatory markers, and cytokine balance

Cortisol and inflammatory proteins are released into the blood in response to stressors and chronic elevations of blood cortisol and inflammatory proteins may contribute to ongoing disease processes and could be useful biomarkers of disease. How chronic circadian misalignment influences cortisol and inflammatory proteins, however, is largely unknown and this was the focus of the current study. Specifically, we examined the influence of weeks of chronic circadian misalignment on cortisol, stress ratings, and pro- and anti-inflammatory proteins in humans. We also compared the effects of acute total sleep deprivation and chronic circadian misalignment on cortisol levels. Healthy, drug free females and males (N=17) aged 20-41 participated. After 3weeks of maintaining consistent sleep-wake schedules at home, six laboratory baseline days and nights, a 40-h constant routine (CR, total sleep deprivation) to examine circadian rhythms for melatonin and cortisol, participants were scheduled to a 25-day laboratory entrainment protocol that resulted in sleep and circadian disruption for eight of the participants. A second constant routine was conducted to reassess melatonin and cortisol rhythms on days 34-35. Plasma cortisol levels were also measured during sampling windows every week and trapezoidal area under the curve (AUC) was used to estimate 24-h cortisol levels. Inflammatory proteins were assessed at baseline and near the end of the entrainment protocol. Acute total sleep deprivation significantly increased cortisol levels (p<0.0001), whereas chronic circadian misalignment significantly reduced cortisol levels (p<0.05). Participants who exhibited normal circadian phase relationships with the wakefulness-sleep schedule showed little change in cortisol levels. Stress ratings increased during acute sleep deprivation (p<0.0001), whereas stress ratings remained low across weeks of study for both the misaligned and synchronized control group. Circadian misalignment significantly increased plasma tumor necrosis factor-alpha (TNF-α), interleukin 10 (IL-10) and C-reactive protein (CRP) (p<0.05). Little change was observed for the TNF-α/IL-10 ratio during circadian misalignment, whereas the TNF-α/IL-10 ratio and CRP levels decreased in the synchronized control group across weeks of circadian entrainment. The current findings demonstrate that total sleep deprivation and chronic circadian misalignment modulate cortisol levels and that chronic circadian misalignment increases plasma concentrations of pro- and anti-inflammatory proteins.

The interactive effects of nocturnal sleep and daytime naps in relation to serum C-reactive protein

BACKGROUND AND AIM

C-reactive protein (CRP) is a general marker of inflammation that has been differentially linked with sleep. Elevated CRP (ie, high inflammation) has been associated with either short/insufficient sleep duration or long sleep duration, both, or neither. Daytime napping has also been tied to increased and decreased inflammation. We attempted to unify these findings by examining the relationship between CRP and sleep duration in conjunction with napping in a healthy young adult cohort.

PARTICIPANTS

Participants were young adults (mean age = 29.05 years, n = 2147) from the National Longitudinal Study of Adolescent Health (Add Health) cohort, a nationally representative longitudinal sample.

METHODS/RESULTS

Analysis of covariance (ANCOVA) tests examined whether self-reported sleep duration (short, medium, or long) and nap frequency (none-few days/week; most days/week; every day) interacted in relation to CRP. Standard covariates (ie, age, gender, race/ethnicity, body mass index, physical activity, depression, snoring, systolic blood pressure, clinical symptoms, and household income) were used. There was a linear increase in CRP with increased napping [contrast estimate = 0.265, 95% confidence interval (CI) (0.045-0.485), P = 0.018]. There was also an interaction between sleep duration and napping frequency in relation to CRP (F4,2128 = 2.90, P = 0.021). Inflammation differed between nap groups within the long and short sleep groups.

CONCLUSIONS

Our results suggest that increased napping is an independent predictor of inflammation in young adults. These results also provide evidence for interactive effects of inflammation, nocturnal sleep, and daytime naps. Our findings confirm that excess sleep, insufficient sleep, frequent napping, and infrequent napping can all be linked with elevated CRP, but these relationships depend on both nocturnal and daytime sleep patterns. These analyses will guide future work to more specifically examine sleep-inflammation processes and directionality.

Sleep characteristics as predictor variables of stress systems markers in insomnia disorder

This study investigates the extent to which sleep characteristics serve as predictor variables for inflammatory, hypothalamic-pituitary-adrenal and autonomic systems markers. Twenty-nine participants with a diagnosis of insomnia disorder based on the Diagnostic Statistical Manual of Mental Disorders, Fifth Edition (age 25.3 ± 1.6 years, insomnia duration 6.6 ± 0.8 years) and 19 healthy control sleepers (age 25.4 ± 1.4 years) underwent a 2-week at-home evaluation keeping a sleep diary and wearing an actigraph, followed by a visit to the Research Center to measure blood pressure, and collect blood and urine samples. The actigraphy- and diary-based variables of sleep duration, sleep-onset latency, wake after sleep onset and sleep fragmentation/number of night-time awakenings were averaged and entered as dependent variables in regression analyses. Composite scores were calculated for the autonomic (blood pressure, norepinephrine), inflammatory (monocyte counts, interleukin-6, C-reactive protein) and hypothalamic-pituitary-adrenal systems (cortisol), and used as predictor variables in regression models. Compared with controls, individuals with insomnia had a shorter sleep duration (P < 0.05), and a higher hypothalamic-pituitary-adrenal and inflammatory composite score (P < 0.05). The higher inflammatory score was mainly due to higher circulating monocytes (P < 0.05), rather than differences in interleukin-6 or C-reactive protein. In persistent insomnia disorder, cortisol is upregulated and associated with actigraphy- and diary-based wake after sleep onset, suggesting that wake after sleep onset may serve as a marker to identify individuals at increased risks for disorders associated with a hyperactive hypothalamic-pituitary-adrenal system. The absence of autonomic and pro-inflammatory changes (interleukin-6, C-reactive protein), despite a substantial decrease in actigraphic sleep duration, may relate to a higher resilience to the adverse biological consequences of insomnia in this young age group.

Association of Markers of Inflammation with Sleep and Physical Activity Among People Living with HIV or AIDS

This study examined associations of sleep and minutes spent in moderate-vigorous physical activity (MVPA) with C-reactive protein (CRP) and interleukin (IL)-6 among persons living with HIV. Cross-sectional analyses (n = 45) focused on associations of inflammatory outcomes (i.e., CRP and IL-6) with actigraph-derived sleep duration, latency, and efficiency; sleep onset; wake time; and wake-after-sleep-onset; as well as MVPA. Least square means for CRP and IL-6 by levels of sleep and MVPA were computed from general linear models. Individuals below the median of sleep duration, above the median for sleep onset, and below the median of MVPA minutes had higher CRP or IL-6 levels. Generally, individuals with both low MVPA and poor sleep characteristics had higher inflammation levels than those with more MVPA and worse sleep. Understanding the combined impact of multiple lifestyle/behavioral factors on inflammation could inform intervention strategies to reduce inflammation and therefore, chronic disease risk.

Acute sleep fragmentation induces tissue-specific changes in cytokine gene expression and increases serum corticosterone concentration

Sleep deprivation induces acute inflammation and increased glucocorticosteroids in vertebrates, but effects from fragmented, or intermittent, sleep are poorly understood. Considering the latter is more representative of sleep apnea in humans, we investigated changes in proinflammatory (IL-1β, TNF-α) and anti-inflammatory (TGF-β1) cytokine gene expression in the periphery (liver, spleen, fat, and heart) and brain (hypothalamus, prefrontal cortex, and hippocampus) of a murine model exposed to varying intensities of sleep fragmentation (SF). Additionally, serum corticosterone was assessed. Sleep was disrupted in male C57BL/6J mice using an automated sleep fragmentation chamber that moves a sweeping bar at specified intervals (Lafayette Industries). Mice were exposed to bar sweeps every 20 s (high sleep fragmentation, HSF), 120 s (low sleep fragmentation, LSF), or the bar remained stationary (control). Trunk blood and tissue samples were collected after 24 h of SF. We predicted that HSF mice would exhibit increased proinflammatory expression, decreased anti-inflammatory expression, and elevated stress hormones in relation to LSF and controls. SF significantly elevated IL-1β gene expression in adipose tissue, heart (HSF only), and hypothalamus (LSF only) relative to controls. SF did not increase TNF-α expression in any of the tissues measured. HSF increased TGF-β1 expression in the hypothalamus and hippocampus relative to other groups. Serum corticosterone concentration was significantly different among groups, with HSF mice exhibiting the highest, LSF intermediate, and controls with the lowest concentration. This indicates that 24 h of SF is a potent inducer of inflammation and stress hormones in the periphery, but leads to upregulation of anti-inflammatory cytokines in the brain.

Sleep disorders and increased risk of autoimmune diseases in individuals without sleep apnea

STUDY OBJECTIVES

To explore the association between the non-apnea sleep disorder (NSD) and autoimmune diseases.

DESIGN

Cohort study.

SETTING

Nationwide database research.

PARTICIPANTS

84,996 adult patients with NSD diagnoses recorded in the Taiwan National Health Insurance Research Database between 2000 and 2003, after excluding those with antecedent autoimmune diseases. A comparison cohort of 84,996 participants was formed by age-, gender-, income-, and urbanization-matched controls.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

The two cohorts were followed up for occurrence of autoimmune diseases, including rheumatoid arthritis (RA), ankylosing spondylitis (AS), systemic lupus erythematosus (SLE), Sjögren's syndrome (SS), and systemic sclerosis (SSc). A Cox proportional hazards regression model was used for muti-variate adjustment. In patients with NSD, the overall risk for incident autoimmune diseases was significantly higher than in controls (adjusted hazard ratio [HR] = 1.47, 95% confidence interval [CI] = 1.41-1.53). With regard to individual diseases, the risks for SLE, RA, AS and SS among NSD patients were also significantly higher than in controls (HR [95% CI] for SLE, RA, AS, and SS were 1.81 [1.50-2.18], 1.45 [1.36-1.54], 1.53 [1.38-1.70], and 1.51 [1.43-1.60], respectively), whereas the increased risk for SSc did not reach statistical significance (HR: 1.36 [0.82-2.26]).

CONCLUSION

Patients with non-apnea sleep disorder were associated with a higher risk for developing autoimmune diseases.

Subchronic sleep restriction causes tissue-specific insulin resistance

CONTEXT

Short sleep duration is associated with an increased risk of type 2 diabetes. Subchronic sleep restriction (SR) causes insulin resistance, but the mechanisms and roles of specific tissues are unclear.

OBJECTIVE

The purpose of this article was to determine whether subchronic SR altered (1) hepatic insulin sensitivity, (2) peripheral insulin sensitivity, and (3) substrate utilization.

DESIGN

This was a randomized crossover study in which 14 subjects underwent 2 admissions separated by a washout period. Each admission had 2 acclimatization nights followed by 5 nights of either SR (4 hours time in bed) or normal sleep (8 hours time in bed). MAIN OUTCOME MEASURE/METHODS: Insulin sensitivity (measured by hyperinsulinemic-euglycemic clamp) and hepatic insulin sensitivity (measured by stable isotope techniques) were measured. In addition, we assayed stress hormone (24-hour urine free cortisol, metanephrine, and normetanephrine), nonesterified fatty acid (NEFA), and β-hydroxybutyrate (β-OH butyrate) levels. Resting energy expenditure (REE) and respiratory quotient (RQ) were measured by indirect calorimetry.

RESULTS

Compared to normal sleep, whole-body insulin sensitivity decreased by 25% (P = .008) with SR and peripheral insulin sensitivity decreased by 29% (P = .003). Whereas hepatic insulin sensitivity (endogenous glucose production) did not change significantly, percent gluconeogenesis increased (P = .03). Stress hormones increased modestly (cortisol by 21%, P = .04; metanephrine by 8%, P = .014; normetanephrine by 18%, P = .002). Fasting NEFA and β-OH butyrate levels increased substantially (62% and 55%, respectively). REE did not change (P = 0.98), but RQ decreased (0.81 ± .02 vs 0.75 ± 0.02, P = .045).

CONCLUSION

Subchronic SR causes unique metabolic disturbances characterized by peripheral, but not hepatic, insulin resistance; this was associated with a robust increase in fasting NEFA levels (indicative of increased lipolysis), decreased RQ, and increased β-OH butyrate levels (indicative of whole-body and hepatic fat oxidation, respectively). We postulate that elevated NEFA levels are partially responsible for the decrease in peripheral sensitivity and modulation of hepatic metabolism (ie, increase in gluconeogenesis without increase in endogenous glucose production). Elevated cortisol and metanephrine levels may contribute to insulin resistance by increasing lipolysis and NEFA levels.

Persistent insomnia is associated with mortality risk

BACKGROUND

Insomnia has been associated with mortality risk, but whether this association is different in subjects with persistent vs intermittent insomnia is unclear. Additionally, the role of systemic inflammation in such an association is unknown.

METHODS

We used data from a community-based cohort to determine whether persistent or intermittent insomnia, defined based on persistence of symptoms over a 6-year period, was associated with death during the following 20 years of follow-up. We also determined whether changes in serum C-reactive protein (CRP) levels measured over 2 decades between study initiation and insomnia determination were different for the persistent, intermittent, and never insomnia groups. The results were adjusted for confounders such as age, sex, body mass index, smoking, physical activity, alcohol, and sedatives.

RESULTS

Of the 1409 adult participants, 249 (18%) had intermittent and 128 (9%) had persistent insomnia. During a 20-year follow-up period, 318 participants died (118 due to cardiopulmonary disease). In adjusted Cox proportional-hazards models, participants with persistent insomnia (adjusted hazards ratio [HR] 1.58; 95% confidence interval [CI], 1.02-2.45) but not intermittent insomnia (HR 1.22; 95% CI, 0.86-1.74) were more likely to die than participants without insomnia. Serum CRP levels were higher and increased at a steeper rate in subjects with persistent insomnia as compared with intermittent (P = .04) or never (P = .004) insomnia. Although CRP levels were themselves associated with increased mortality (adjusted HR 1.36; 95% CI, 1.01-1.82; P = .04), adjustment for CRP levels did not notably change the association between persistent insomnia and mortality.

CONCLUSIONS

In a population-based cohort, persistent, and not intermittent, insomnia was associated with increased risk for all-cause and cardiopulmonary mortality and was associated with a steeper increase in inflammation.

Effects of sleep deprivation on action potential and transient outward potassium current in ventricular myocytes in rats

BACKGROUND

Sleep deprivation contributes to the development and recurrence of ventricular arrhythmias. However, the electrophysiological changes in ventricular myocytes in sleep deprivation are still unknown.

MATERIAL AND METHODS

Sleep deprivation was induced by modified multiple platform technique. Fifty rats were assigned to control and sleep deprivation 1, 3, 5, and 7 days groups, and single ventricular myocytes were enzymatically dissociated from rat hearts. Action potential duration (APD) and transient outward current (Ito) were recorded using whole-cell patch clamp technique.

RESULTS

Compared with the control group, the phases of APD of ventricular myocytes in 3, 5, and 7 days groups were prolonged and APD at 20% and 50% level of repolarization (APD20 and APD50) was significantly elongated (The APD20 values of control, 1, 3, 5, and 7 days groups: 5.66±0.16 ms, 5.77±0.20 ms, 8.28±0.30 ms, 11.56±0.32 ms, 13.24±0.56 ms. The APD50 values: 50.66±2.16 ms, 52.77±3.20 ms, 65.28±5.30 ms, 83.56±7.32 ms, 89.24±5.56 ms. P<0.01, n=18). The current densities of Ito significantly decreased. The current density-voltage (I-V) curve of Ito was vitally suppressed downward. The steady-state inactivation curve and steady-state activation curve of Ito were shifted to left and right, respectively, in sleep deprivation rats. The inactivation recovery time of Ito was markedly retarded and the time of closed-state inactivation was markedly accelerated in 3, 5, and 7 days groups.

CONCLUSIONS

APD of ventricular myocytes in sleep deprivation rats was significantly prolonged, which could be attributed to decreased activation and accelerated inactivation of Ito.

Sleep deprivation and divergent toll-like receptor-4 activation of cellular inflammation in aging

OBJECTIVES

Sleep disturbance and aging are associated with increases in inflammation, as well as increased risk of infectious disease. However, there is limited understanding of the role of sleep loss on age-related differences in immune responses. This study examines the effects of sleep deprivation on toll-like receptor activation of monocytic inflammation in younger compared to older adults.

DESIGN, SETTING, AND PARTICIPANTS

Community-dwelling adults (n = 70) who were categorized as younger (25-39 y old, n = 21) and older (60-84 y old, n = 49) participants, underwent a sleep laboratory-based experimental partial sleep deprivation (PSD) protocol including adaptation, an uninterrupted night of sleep, sleep deprivation (sleep restricted to 03:00-07:00), and recovery.

MEASUREMENT AND RESULTS

Blood samples were obtained each morning to measure toll-like receptor-4 activation of monocyte intracellular production of the inflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). Partial sleep deprivation induced a significant increase in the production of IL-6 and/or TNF-α that persisted after a night of recovery sleep (F(2,121.2) = 3.8, P < 0.05). Age moderated the effects of sleep loss, such that younger adults had an increase in inflammatory cytokine production that was not present in older adults (F(2,121.2) = 4.0, P < 0.05).

CONCLUSION

Older adults exhibit reduced toll-like receptor 4 stimulated cellular inflammation that, unlike in younger adults, is not activated after a night of partial sleep loss. Whereas sleep loss increases cellular inflammation in younger adults and may contribute to inflammatory disorders, blunted toll-like receptor activation in older adults may increase the risk of infectious disease seen with aging.

Association between sleep duration and mortality is mediated by markers of inflammation and health in older adults: the Health, Aging and Body Composition Study

STUDY OBJECTIVES

Inflammation may represent a common physiological pathway linking both short and long sleep duration to mortality. We evaluated inflammatory markers as mediators of the relationship between sleep duration and mortality in community-dwelling older adults.

DESIGN

Prospective cohort with longitudinal follow-up for mortality outcomes.

SETTING

Pittsburgh, Pennsylvania, and Memphis, Tennessee.

PARTICIPANTS

Participants in the Health, Aging and Body Composition (Health ABC) Study (mean age 73.6 ± 2.9 years at baseline) were sampled and recruited from Medicare listings.

MEASUREMENTS AND RESULTS

Baseline measures of subjective sleep duration, markers of inflammation (serum interleukin-6, tumor necrosis factor-α, and C-reactive protein) and health status were evaluated as predictors of all-cause mortality (average follow-up = 8.2 ± 2.3 years). Sleep duration was related to mortality, and age-, sex-, and race-adjusted hazard ratios (HR) were highest for those with the shortest (< 6 h HR: 1.30, CI: 1.05-1.61) and longest (> 8 h HR: 1.49, CI: 1.15-1.93) sleep durations. Adjustment for inflammatory markers and health status attenuated the HR for short (< 6 h) sleepers (HR = 1.06, 95% CI = 0.83-1.34). Age-, sex-, and race-adjusted HRs for the > 8-h sleeper group were less strongly attenuated by adjustment for inflammatory markers than by other health factors associated with poor sleep with adjusted HR = 1.23, 95% CI = 0.93-1.63. Inflammatory markers remained significantly associated with mortality.

CONCLUSION

Inflammatory markers, lifestyle, and health status explained mortality risk associated with short sleep, while the mortality risk associated with long sleep was explained predominantly by lifestyle and health status.

Sleep habits and diabetes

Sleep duration has been constantly decreasing over the past 50 years. Short sleep duration, sleep quality and, recently, long sleep duration have all been linked to poor health outcomes, increasing the risk of developing metabolic diseases and cardiovascular events. Beyond the duration of sleep, the timing of sleep may also have consequences. Having a tendency to go early to bed (early chronotype) compared with the habit of going to bed later (late chronotype) can interfere considerably with social schedules (school, work). Eventually, a misalignment arises in sleep timing between work days and free days that has been described as 'social jet lag'. The present review looks at how different sleep habits can interfere with diabetes, excluding sleep breathing disorders, and successively looks at the effects of sleep duration, chronotype and social jet lag on the risk of developing diabetes as well as on the metabolic control of both type 1 and type 2 diabetes. Finally, this review addresses the current state of knowledge of physiological mechanisms that could be linking sleep habits and metabolic health.

Sleep in elite athletes and nutritional interventions to enhance sleep

Sleep has numerous important physiological and cognitive functions that may be particularly important to elite athletes. Recent evidence, as well as anecdotal information, suggests that athletes may experience a reduced quality and/or quantity of sleep. Sleep deprivation can have significant effects on athletic performance, especially submaximal, prolonged exercise. Compromised sleep may also influence learning, memory, cognition, pain perception, immunity and inflammation. Furthermore, changes in glucose metabolism and neuroendocrine function as a result of chronic, partial sleep deprivation may result in alterations in carbohydrate metabolism, appetite, food intake and protein synthesis. These factors can ultimately have a negative influence on an athlete’s nutritional, metabolic and endocrine status and hence potentially reduce athletic performance. Research has identified a number of neurotransmitters associated with the sleep–wake cycle. These include serotonin, gamma-aminobutyric acid, orexin, melanin-concentrating hormone, cholinergic, galanin, noradrenaline, and histamine. Therefore, nutritional interventions that may act on these neurotransmitters in the brain may also influence sleep. Carbohydrate, tryptophan, valerian, melatonin and other nutritional interventions have been investigated as possible sleep inducers and represent promising potential interventions. In this review, the factors influencing sleep quality and quantity in athletic populations are examined and the potential impact of nutritional interventions is considered. While there is some research investigating the effects of nutritional interventions on sleep, future research may highlight the importance of nutritional and dietary interventions to enhance sleep.

Daytime napping, sleep duration and serum C reactive protein: a population-based cohort study

OBJECTIVES

To explore whether daytime napping and sleep duration are linked to serum C reactive protein (CRP), a pro-inflammatory marker, in an older aged British population.

DESIGN

Cross-sectional study.

SETTING

European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk study.

PARTICIPANTS

A total of 5018 men and women aged 48-92 years reported their sleep habits and had serum CRP levels measured.

OUTCOME AND MEASURES

CRP was measured (mg/L) during 2006-2011 in fresh blood samples using high-sensitivity methods. Participants reported napping habits during 2002-2004, and reported sleep quantity during 2006-2007. Multivariable linear regression models were used to examine the association between napping and log-transformed CRP, and geometric mean CRP levels were calculated.

RESULTS

After adjustment for age and sex, those who reported napping had 10% higher CRP levels compared with those not napping. The association was attenuated but remained borderline significant (β=0.05 (95% CI 0.00 to 0.10)) after further adjustment for social class, education, marital status, body mass index, physical activity, smoking, alcohol intake, self-reported health, pre-existing diseases, systolic blood pressure, hypnotic drug use, depression and in women-only hormone replacement therapy use. The geometric means (95% CI) of CRP levels were 2.38 (2.29 to 2.47) mg/L and 2.26 (2.21 to 2.32) mg/L for those who reported napping and no napping, respectively. A U-shaped association was observed between time spent in bed at night and CRP levels, and nighttime sleep duration was not associated with serum CRP levels. The association between napping and CRP was stronger for older participants, and among extremes of time spent in bed at night.

CONCLUSIONS

Daytime napping was associated with increased CRP levels in an older aged British population. Further studies are needed to determine whether daytime napping is a cause for systemic inflammation, or if it is a symptom or consequence of underlying health problems.

Sleep Is Not for Slackers

Sufficient sleep is as important as healthy eating and regular exercise to maintain a healthy lifestyle. However, many individuals do not obtain enough sleep or follow healthy sleep hygiene recommendations. The interaction of both biological and behavioral factors may affect sleep. Recommendations of healthy sleep habits that may assist in improving sleep quality and quantity are discussed in this article.

Sleep duration and age-related changes in brain structure and cognitive performance

STUDY OBJECTIVES

To investigate the contribution of sleep duration and quality to age-related changes in brain structure and cognitive performance in relatively healthy older adults.

DESIGN

Community-based longitudinal brain and cognitive aging study using a convenience sample.

SETTING

Participants were studied in a research laboratory.

PARTICIPANTS

Relatively healthy adults aged 55 y and older at study commencement.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Participants underwent magnetic resonance imaging and neuropsychological assessment every 2 y. Subjective assessments of sleep duration and quality and blood samples were obtained. Each hour of reduced sleep duration at baseline augmented the annual expansion rate of the ventricles by 0.59% (P = 0.007) and the annual decline rate in global cognitive performance by 0.67% (P = 0.050) in the subsequent 2 y after controlling for the effects of age, sex, education, and body mass index. In contrast, global sleep quality at baseline did not modulate either brain or cognitive aging. High-sensitivity C-reactive protein, a marker of systemic inflammation, showed no correlation with baseline sleep duration, brain structure, or cognitive performance.

CONCLUSIONS

In healthy older adults, short sleep duration is associated with greater age-related brain atrophy and cognitive decline. These associations are not associated with elevated inflammatory responses among short sleepers.

CITATION

Lo JC, Loh KK, Zheng H, Sim SK, Chee MW. Sleep duration and age-related changes in brain structure and cognitive performance.

Assessment of sleep problems in children with familial Mediterranean fever

AIMS

This study aimed to investigate sleep patterns, sleep disturbances and possible factors that are associated with sleep disturbances among children with familial Mediterranean fever (FMF).

PATIENTS AND METHODS

Fifty-one patients with FMF and 84 age- and sex-matched healthy controls were enrolled in the study. The patients who had an attack during the last 2 weeks were not included. Demographic data, FMF symptoms, disease duration, dose of colchicine, disease severity score, number of attacks in the last year, MEFV mutation and serum C-reactive protein (CRP) levels were recorded for each patient. A Children's Sleep Habits Questionnaire was performed.

RESULTS

The total sleep scores of the patients with FMF were significantly higher than the control group. Total sleep durations were similar between FMF patients and controls. Children with FMF had significantly higher scores regarding sleep-onset delay, sleep anxiety, night wakings and sleep-disordered breathing when compared to healthy controls. There was a significant positive correlation between number of attacks in the last year and sleep onset delay, night wakings and sleep disordered-breathing. Disease severity score and CRP levels were not associated with any of the subscale scores. The patients with exertional leg pain had significantly higher total sleep scores than the ones without. Furthermore, patients with exertional leg pain had significantly higher subscale scores regarding sleep onset delay, parasomnias and sleep-disordered breathing.

CONCLUSION

This study showed for the first time that children with FMF had more sleep disturbances than their healthy peers. Higher numbers of attacks and exertional leg pain were associated with poor sleep quality. In conclusion, this study underlines the need to assess and manage sleep problems in children with FMF.

Interactions between sleep, circadian function, and glucose metabolism: implications for risk and severity of diabetes

Sleep disturbances, including sleep insufficiency and sleep fragmentation, have been linked to abnormal glucose metabolism and increased diabetes risk. Well-controlled laboratory studies have provided insights regarding the underlying mechanisms. Several large prospective studies suggest that these sleep disturbances are associated with an increased risk of incident diabetes. Obstructive sleep apnea, which combines sleep fragmentation and hypoxemia, is a major risk factor for insulin resistance and possibly diabetes. Whether glycemic control in type 2 diabetes patients can be improved by treating sleep apnea remains controversial. Recently, sleep disturbances during pregnancy and their relationship to gestational diabetes and hyperglycemia have received considerable attention owing to potential adverse effects on maternal and fetal health. Additionally, evidence from animal models has identified disruption of the circadian system as a putative risk factor for adverse metabolic outcomes. The purpose of this review is to provide an update on the current state of knowledge linking sleep disturbances, circadian dysfunction, and glucose metabolism. Experimental, prospective, and interventional studies are discussed.

Cellular aging and restorative processes: subjective sleep quality and duration moderate the association between age and telomere length in a sample of middle-aged and older adults

STUDY OBJECTIVES

To examine whether subjective sleep quality and sleep duration moderate the association between age and telomere length (TL).

DESIGN

Participants completed a demographic and sleep quality questionnaire, followed by a blood draw.

SETTING

Social Neuroscience Laboratory.

PARTICIPANTS

One hundred fifty-four middle-aged to older adults (age 45-77 y) participated. Participants were excluded if they were on immunosuppressive treatment and/or had a disease with a clear immunologic (e.g., cancer) component.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Subjective sleep quality and sleep duration were assessed using the Pittsburgh Sleep Quality Index (PSQI) and TL was determined using peripheral blood mononuclear cells (PBMCs). There was a significant first-order negative association between age and TL. Age was also negatively associated with the self-reported sleep quality item and sleep duration component of the PSQI. A significant age × self-reported sleep quality interaction revealed that age was more strongly related to TL among poor sleepers, and that good sleep quality attenuated the association between age and TL. Moreover, adequate subjective sleep duration among older adults (i.e. greater than 7 h per night) was associated with TL comparable to that in middle-aged adults, whereas sleep duration was unrelated to TL for the middle-aged adults in our study.

CONCLUSIONS

The current study provides evidence for an association between sleep quality, sleep duration, and cellular aging. Among older adults, better subjective sleep quality was associated with the extent of cellular aging, suggesting that sleep duration and sleep quality may be added to a growing list of modifiable behaviors associated with the adverse effects of aging.

Poor sleep quality potentiates stress-induced cytokine reactivity in postmenopausal women with high visceral abdominal adiposity

Sleep disturbance is a key behavioral risk factor for chronic medical conditions observed at high rates among overweight and obese individuals. Systemic inflammation, including that induced by stress, may serve as a common biological mechanism linking sleep, adiposity, and disease risk. To investigate these relationships, 48 postmenopausal women (mean age=61.8) completed a standardized laboratory stress task during which time blood was collected at baseline and 30, 50 and 90+ min after stressor onset to assess circulating levels of interleukin (IL)-6, IL-10, and IL-6/IL-10 ratio. Self-reported global sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI) while adiposity was estimated by body mass index. Sagittal diameter was obtained in clinic to estimate visceral abdominal adiposity. Multi-level growth curve models revealed that poorer self-reported sleep quality was associated with greater stress-induced increases in IL-6/IL-10 ratio. In terms of adiposity, higher sagittal diameter, but not BMI, was associated with greater IL-6 reactivity (p's<0.05). Further, associations between sleep quality and cytokine reactivity varied as a function of sagittal diameter. Among poor sleepers (1 SD above mean of PSQI score), stress-induced increases in IL-6 and IL-6/IL-10 ratio were significantly steeper in those with high visceral adiposity (1 SD above the mean of sagittal diameter) compared to those with low visceral adiposity (1 SD below the mean of sagittal diameter). In sum, poorer sleep quality and greater visceral adiposity, separately and especially in combination, are associated with greater stress-related increases in systemic inflammation. This research may help elucidate the complex link between sleep, obesity and inflammatory disease risk.

Circadian rhythm, sleep pattern, and metabolic consequences: an overview on cardiovascular risk factors

Sleep duration is a risk factor for cardiovascular disease. Alteration in sleep pattern can induce the loss of circadian rhythmicity. Chronically, this desynchronization between endogenous rhythm and behavioral cycles can lead to an adverse metabolic profile, a proinflammatory condition and can increase the risk of cardiovascular disease. The circadian cycle can vary due to environmental cues. The circadian pacemaker is located in the suprachiasmatic nuclei; this central clock coordinates the circadian rhythm in the central nervous system and peripheral tissues. The mechanisms involved in sleep disturbance, circadian misalignment and adverse metabolic effects have yet to be fully elucidated. This review looks over the association among sleep alteration, circadian rhythm and the development of risk factors implicated in cardiovascular disease.

A twin study of genetic influences on diurnal preference and risk for alcohol use outcomes

OBJECTIVE

The population-based University of Washington Twin Registry (UWTR) was used to examine (1) genetic influences on chronobiology and (2) whether these genetic factors influence alcohol-use phenotypes.

METHODS

We used a reduced Horne-Östberg Morningness-Eveningness Questionnaire (rMEQ) to survey UWTR participants for diurnal preference. Frequency and quantity of alcohol use, as well as binge drinking (6+ drinks per occasion), were assessed on a 5-point Likert scale. Both diurnal preference and alcohol use were self-reported. Twin data were analyzed by using structural equation models.

RESULTS

The sample consisted of 2,945 participants (mean age = 36.4 years), including 1,127 same-sex and opposite-sex twin pairs and 691 individual twins. The rMEQ range was 4-25, with a mean score of 15.3 (SD 4.0). Diurnal "morning types" comprised 30.7% (N = 903) of participants, while 17.4% (N = 513) were "evening types." Regarding alcohol use, 21.2% (N = 624) reported never drinking. Among drinkers, 35.7% (N = 829) reported ≥ 3 drinks per occasion and 48.1% (N = 1,116) reported at least one instance of binge drinking. Genetic influences accounted for 37% of the variance in diurnal preference, with the remaining 63% due to non-shared environmental influences. Genetic propensities toward diurnal eveningness were significantly associated with increased alcohol quantity (β = -0.17; SE = 0.05, p < 0.001) and increased binge drinking (β = -0.19; SE = 0.04, p < 0.001), but not with frequency of alcohol use. Environmental paths between diurnal preference and alcohol use phenotypes were not significant.

CONCLUSIONS

Genetic influences on diurnal preference confer elevated risk for problematic alcohol use, including increased quantity and binge drinking. Differences in circadian rhythm may be an important and understudied pathway of risk for genetic influences on alcohol use.