Sleep loss: a novel risk factor for insulin resistance and Type 2 diabetes

Association between Sleep Habits and Metabolically Healthy Obesity in Adults: A Cross-Sectional Study

Higher body mass index (BMI) increases the risk of cardiometabolic diseases, but nearly a third of the people living with obesity (BMI: ≥30 kg/m²) are metabolically healthy (MHO). Extreme sleep durations and poor sleep quality are associated with higher bodyweight and cardiometabolic dysfunction, but the full extent to which sleep habits may help differentiate those with MHO versus metabolically abnormal obesity (MAO) is not yet known. Data from the U.S. National Health and Nutritional Examination Survey 2005-08 was used (BMI: ≥30 kg/m²; ≥20 y; N = 1,777). The absence of metabolic syndrome was used to define MHO. Those with MHO tended to be younger, female, Non-Hispanic Black, never smokers, more physically active, and with less physician diagnosed sleep disorders than MAO. Neither sleep duration nor overall sleep quality was related to MHO in crude or multivariable adjusted analyses; however, reporting "almost always" to having trouble falling asleep (OR (95% CI): 0.40 (0.20-0.78)), waking up during the night (0.38 (0.17-0.85)), feeling unrested during the day (0.35 (0.18-0.70)), and feeling overly sleepy during the day (0.35 (0.17-0.75)) was related to lower odds of MHO. Selected sleep quality factors, but not sleep quantity or overall sleep quality, are associated with the MHO phenotype.

Obstructive sleep apnea in Type 2 diabetes and impact of continuous positive airway pressure therapy on glycemic control

BACKGROUND

Obstructive sleep apnea (OSA) and type 2 diabetes mellitus (T2DM) are two interacting epidemics both with high prevalence and morbidity. Both epidemiologic and clinical studies suggest that the majority of patients with T2DM also have OSA and untreated OSA in these patients results in poor glycemic control leading to acceleration of diabetes-related complications.

OBJECTIVES

To assess the prevalence and severity of OSA in T2DM patients and to assess the impact of OSA treatment on presenting symptoms and hemoglobin A1c (HbA1c).

METHODS

We performed polysomnography (PSG) studies and measured HbA1c in 62 consecutive patients with T2DM that were referred from various subspecialty clinics from July 2011 to August 2013.

RESULTS

In our 62 diabetic patients, 59 (95.2%) had abnormal PSG. Based on Apnea-Hypopnea Index (AHI) score, 3 (5.1%) patients had mild, 28 (47.5%) had moderate, and 28 (47.5%) had severe OSA. The mean AHI of diabetic patients was significantly more than nondiabetic patients, i.e., 25.7 versus 19.7 (P = 0.001). Variables that significantly correlated with the presence of OSA include age, gender, body mass index (BMI), hypertension, diabetes, and cardiovascular disease (P < 0.05); however, on logistic regression only BMI, hypertension, and nocturia correlated with OSA. Overall, 59% of diabetic patients showed improvement in their glycemic control as measured by HbA1c with continuous positive airway pressure (CPAP) treatment. Significant, moderate, and mild categories of treatment response were respectively observed in 7%, 20%, and 32% of patients.

CONCLUSION

Treatment of OSA with CPAP reduces HbA1c in a significant number of diabetics.

Cardiometabolic risk is associated with the severity of sleep-disordered breathing in children with obesity

BACKGROUND

The alarming progression of pediatric obesity is associated with the development of sleep-disordered breathing (SDB), and both exhibit similar adverse cardiometabolic health outcomes. Physical activity level (PAL) may counteract sleep and metabolic disturbances. The present study investigates i) the association between the metabolic syndrome in childhood obesity and SDB, ii) the impact of SDB severity on cardiometabolic risk scores and PAL in children with obesity.

METHODS

Maturation status (Tanner stages), anthropometric (height, weight, body mass index, waist circumference, body adiposity index) and cardiometabolic characteristics (systolic and diastolic blood pressure, lipid and glycemic profiles) were assessed in 83 obese children (mean±SD, age: 10.7±2.7years). PAL and SDB were investigated with a step test and interviews, and an overnight sleep monitor, respectively. The presence or absence of metabolic syndrome (MS) was established and continuous cardiometabolic risk scores were calculated (MetScore_BMI and MetScore_WC).

RESULTS

Obese children with (61.4%) and without (38.6%) MS present similar SDB. SDB severity is associated with increased insulin concentrations, MetScore_BMI and MetScore_WC (p<0.05) in obese children. There is no association between SDB and PAL.

CONCLUSIONS

In a context where no consensus exists for SDB diagnosis in children, our results suggest the influence of SDB severity on cardiometabolic risk factors. Further studies are needed to explore the association between PAL and both metabolic and sleep alterations in obese children.

J-curve relation between daytime nap duration and type 2 diabetes or metabolic syndrome: A dose-response meta-analysis

Adequate sleep is important for good health, but it is not always easy to achieve because of social factors. Daytime napping is widely prevalent around the world. We performed a meta-analysis to investigate the association between napping (or excessive daytime sleepiness: EDS) and the risk of type 2 diabetes or metabolic syndrome, and to quantify the potential dose-response relation using cubic spline models. Electronic databases were searched for articles published up to 2016, with 288,883 Asian and Western subjects. Pooled analysis revealed that a long nap (≥60 min/day) and EDS were each significantly associated with an increased risk of type 2 diabetes versus no nap or no EDS (odds ratio 1.46 (95% CI 1.23-1.74, p < 0.01) for a long nap and 2.00 (1.58-2.53) for EDS). In contrast, a short nap (<60 min/day) was not associated with diabetes (p = 0.75). Dose-response meta-analysis showed a J-curve relation between nap time and the risk of diabetes or metabolic syndrome, with no effect of napping up to about 40 minutes/day, followed by a sharp increase in risk at longer nap times. In summary, longer napping is associated with an increased risk of metabolic disease. Further studies are needed to confirm the benefit of a short nap.

Sleep Duration, Exercise, Shift Work and Polycystic Ovarian Syndrome-Related Outcomes in a Healthy Population: A Cross-Sectional Study

CONTEXT

Few studies have examined the associations between sleep duration, shiftwork, and exercise to the infrequent menstruation, hyperandrogenism, and ovarian morphological changes observed in women with polycystic ovarian syndrome (PCOS).

OBJECTIVE

To examine whether lifestyle factors, including short sleep duration, insufficient exercise, and shiftwork, alone or in combination, are associated with the reproductive and metabolic abnormalities typical of PCOS in a healthy population.

STUDY DESIGN, SIZE, DURATION

Prospective cross-sectional study of 231 women, including healthcare workers recruited for an annual health screen, healthy referral patients from the Women's Clinic and volunteers from the university community at the National University Hospital, Singapore, from 2011 to 2015.

MAIN OUTCOME MEASURES

The women completed a questionnaire, including their menstrual cycle length, sleep length, frequency of exercise and shift work. Hyperandrogenism (hirsutism score, testosterone, sex hormone binding globulin (SHBG)), ovarian morphology and function (anthral follicle count, ovarian volume, anti-mullerian hormone (AMH)), and metabolic measures (body mass index (BMI), waist hip ratio (WHR), blood pressure, fasting glucose, fasting insulin and fasting lipids) were examined through anthropometric measurements, transvaginal ultrasound scans, and blood tests.

RESULTS

No significant associations were observed between shift work, exercise or sleep duration and the androgenic and ovarian measures that define PCOS. However, women reporting fewer than 6 hours of sleep were more likely to report abnormal (short or long) menstrual cycle lengths (OR = 2.1; 95% CI, 1.1 to 4.2). Women who reported fewer than 6 hours of sleep had increased fasting insulin levels (difference in means = 2.13; 95% CI, 0.27 to 3.99 mU/L) and higher odds of insulin resistance (OR = 2.58; CI, 1.16 to 5.76). Lack of regular exercise was associated with higher mean fasting insulin (difference in means = 2.3 mU/L; 95% CI, 0.5 to 4.1) and HOMA-IR (difference in means = 0.49; 95% CI, 0.09 to 0.90) levels.

CONCLUSIONS

Women with insufficient sleep are at increased risk of menstrual disturbances and insulin resistance, but do not have the hyperandrogenism and polycystic ovarian morphology typical of PCOS.

WIDER IMPLICATIONS OF THE FINDINGS

Improved sleep duration may help reduce the risks of diabetes or infertility. Shift work, exercise or sleep duration appear not to impact the androgenic and ovarian measures that define PCOS.

Nighttime sleep duration and risk of nonalcoholic fatty liver disease: the Dongfeng-Tongji prospective study

BACKGROUND

To examine the association between self-reported nighttime sleep duration and nonalcoholic fatty liver disease (NAFLD) risk by comparing the incidence rates of NAFLD among healthy subjects with different sleep duration during the 5 years follow-up.

METHODS

8965 eligible NAFLD-free subjects with a mean age of 61.6 years (males, 43.4%) from Dongfeng-Tongji cohort study at baseline were enrolled in the study. Logistic regression analysis was used to estimate the association between sleep duration and incident NAFLD with potential confounders adjusted. Sleep duration was categorized into five groups: <6 h, 6-7 h, 7-8 h, 8-9 h, ≥9 h.

RESULT

During the 5-years of follow-up, a total of 2,197 participants were newly diagnosed as NAFLD. Compared with those reported 7-8 h per day of nighttime sleep, the multivariable-adjusted odds ratio (95% confidence intervals) were 1.21 (1.07-1.38) for those who sleep 8-9 h/day, and 1.31 (1.13-1.52) for those who sleep over 9 h/day. However, no significant association was found with short nightly sleep duration (<7 h/day).

CONCLUSION

Long nighttime sleep duration was associated with a modestly increased risk of NAFLD in a middle-aged and elderly Chinese population. Key messages Long nighttime sleep duration was associated with a modestly increased risk of NAFLD in a middle-aged and elderly Chinese population. The effect of long nighttime sleep on the risk of incident NAFLD was attenuated greatly by body mass index (BMI) in men.

Role of sleep quality in the metabolic syndrome

Emerging evidence has assigned an important role to sleep as a modulator of metabolic homeostasis. The impact of variations in sleep duration, sleep-disordered breathing, and chronotype to cardiometabolic function encompasses a wide array of perturbations spanning from obesity, insulin resistance, type 2 diabetes, the metabolic syndrome, and cardiovascular disease risk and mortality in both adults and children. Here, we critically and extensively review the published literature on such important issues and provide a comprehensive overview of the most salient pathophysiologic pathways underlying the links between sleep, sleep disorders, and cardiometabolic functioning.

Sleep Duration and the Risk of Fatty Liver Disease: A Systematic Review and Meta-analysis

Recent studies have reported inconsistent results on the association between sleep duration and the risk of fatty liver disease (FLD). Thus, we quantitatively evaluated this association by performing a systematic review and meta-analysis, based on a comprehensive electronic search in databases of PubMed, Web of Science, EMBASE, ClinicalTrials.gov, Wanfangdata and Chinese National Knowledge Infrastructure (CNKI) (updated to April 2016). Multivariate adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) were extracted and pooled by using a random-effects model. Eight eligible studies involving 97,371 participants were included. We found that neither short nor long sleep duration was significantly related with FLD risk. For short sleep duration, the pooled OR was 1.17 (95% CI = 0.98–1.38), and for long sleep duration, the pooled OR was 1.01 (95% CI = 0.72–1.41). Subgroup analyses by sex, outcome, and exposure reference also did not identify any effect of sleep duration on FLD onset. In summary, our findings suggested that short or long sleep duration was not significantly associated with FLD risk. Further cohort studies with refined designs are still warranted to validate our results.

Stimulation of the Pontine Parabrachial Nucleus Promotes Wakefulness via Extra-thalamic Forebrain Circuit Nodes

Human and animal studies have identified an especially critical role for the brainstem parabrachial (PB) complex in regulating electrocortical (electroencephalogram [EEG]) and behavioral arousal: lesions of the PB complex produce a monotonous high-voltage, slow-wave EEG and eliminate spontaneous behaviors. We report here that targeted chemogenetic activation of the PB complex produces sustained EEG and behavioral arousal in the rat. We further establish, using viral-mediated retrograde activation, that PB projections to the preoptic-basal forebrain and lateral hypothalamus, but not to the thalamus, mediate PB-driven wakefulness. We exploited this novel and noninvasive model of induced wakefulness to explore the EEG and metabolic consequences of extended wakefulness. Repeated (daily) chemogenetic activation of the PB was highly effective in extending wakefulness over 4 days, although subsequent PB activation produced progressively lesser wake amounts. Curiously, no EEG or behavioral sleep rebound was observed, even after 4 days of induced wakefulness. Following the last of the four daily induced wake bouts, we examined the brains and observed a chimeric pattern of c-Fos expression, with c-Fos expressed in subsets of both arousal- and sleep-promoting nuclei. From a metabolic standpoint, induced extended wakefulness significantly reduced body weight and leptin but was without significant effect on cholesterol, triglyceride, or insulin levels, suggesting that high sleep pressure or sleep debt per se does not, as previously implicated, result in a deleterious metabolic phenotype.

The association between sleep duration and overweight or obesity in Taiwanese adults: A cross-sectional study

BACKGROUND/OBJECTIVE

The effect of eating habits and sedentary lifestyle on obesity has been extensively examined and supported; however, few studies have examined the association of sleep duration with obesity in Taiwan. To redress this gap, this study investigated the association of sleep duration with overweight and obesity in community-dwelling Taiwanese adults.

METHODS

A cross-sectional study was performed using the 2005-2008 Nutrition and Health Survey in Taiwan (NAHSIT). A logistic regression model was used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) of the association of sleep duration with overweight and obesity. Nightly sleep duration was divided into three groups: >6 to <9h (normal), ≤6h (short), and ≥9h (long).

RESULTS

A total of 1548 adults aged 20-64 years were examined in this study. The adjusted ORs of obesity for short and long sleep duration relative to a normal sleep duration were 1.31 (95% CI 1.01, 1.76) and 1.64 (95% CI 1.04, 2.61), respectively. No significant association of sleep duration with overweight was observed.

CONCLUSIONS

The present study suggests that both short and long sleep duration are associated with obesity risk.

Association of sleep apnea and sleep duration with peripheral artery disease: The Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND AND AIMS

Numerous biological pathways linking sleep disturbances to atherosclerosis have been identified, such as insulin resistance, inflammation, hypertension, and endothelial dysfunction. Yet, the association of sleep apnea and sleep duration with peripheral artery disease (PAD) is not well characterized.

METHODS

We evaluated the cross-sectional association between objectively measured sleep and prevalent PAD in 1844 participants (mean age 68 years) who in 2010-2013 had in-home polysomnography, 7-day wrist actigraphy and ankle-brachial index (ABI) measurements. We also evaluated the relation between self-reported diagnosed sleep apnea and PAD incidence in 5365 participants followed from 2000 to 2012. PAD was defined as ABI < 0.90.

RESULTS

In cross-sectional analyses, severe sleep apnea [apnea-hypopnea index (AHI) ≥30 vs. AHI <5] was associated with greater prevalent PAD only among black participants [multivariate adjusted prevalence ratio (95% CI): 2.29 (1.07-4.89); p-interaction = 0.05]. Short and long sleep duration was also associated with a 2-fold higher prevalence of PAD as compared with those who slept 7 h/night, in the full sample. In longitudinal analyses, participants with self-reported diagnosed sleep apnea were at higher risk of incident PAD [multivariable adjusted hazard ratio (95% CI): 1.93 (1.05-3.53)], with no evidence of interaction by race/ethnicity.

CONCLUSIONS

These findings support a significant association between sleep apnea and prevalent and incident PAD, with evidence for stronger associations with objectively measured sleep apnea and cross sectional PAD in blacks. In addition, short and long sleep duration was associated with PAD. These results identify sleep disturbances as a potential risk factor for PAD.

Sleep Duration and Media Time Have a Major Impact on Insulin Resistance and Metabolic Risk Factors in Obese Children and Adolescents

BACKGROUND

Lifestyle factors sleep duration and media time during childhood differ between countries. This study examined whether sleep duration and media time affect metabolic risk factors insulin resistance (IR), blood lipid profile, and liver enzymes, and whether there is a relationship between sleep time and media time in Turkish obese children and adolescents.

METHODS

Subjects included 108 obese children and adolescents (aged 10-15 years) whose lifestyle factors were assessed using a survey containing questions about sleep durations, television viewing, media use, and demographic factors. Metabolic risk factors were compared among groups categorized according to sleep and media duration.

RESULTS

Aspartate aminotransferase (AST), alanine aminotransferase (ALT), and triglyceride (TG) levels and homeostasis model assessment of insulin resistance (HOMA-IR) values were higher in subjects who spent >5 hours/day on media. Children 10-13 years old who slept <9 hours/day were more likely to have higher insulin and HOMA-IR (p < 0.05) levels and lower high-density lipoprotein cholesterol (HDL-C) levels compared with subjects who slept 9-10 hours/day and >10 hours/day. Correlation analysis revealed a negative relationship between sleep time and media time (r = -0.471, p = 0.000).

CONCLUSIONS

Short sleep duration was associated with IR and an elevated plasma lipoprotein profile in children and adolescents. Our results suggest that insufficient sleep and excessive media exposure may contribute to metabolic risk in the context of obesity, and therefore, working to improve sleep duration and limit media time could help reduce metabolic risk in obese children and adolescents.

Fasting, Circadian Rhythms, and Time-Restricted Feeding in Healthy Lifespan

Most animals alternate periods of feeding with periods of fasting often coinciding with sleep. Upon >24 hr of fasting, humans, rodents, and other mammals enter alternative metabolic phases, which rely less on glucose and more on ketone body-like carbon sources. Both intermittent and periodic fasting result in benefits ranging from the prevention to the enhanced treatment of diseases. Similarly, time-restricted feeding (TRF), in which food consumption is restricted to certain hours of the day, allows the daily fasting period to last >12 hr, thus imparting pleiotropic benefits. Understanding the mechanistic link between nutrients and the fasting benefits is leading to the identification of fasting-mimicking diets (FMDs) that achieve changes similar to those caused by fasting. Given the pleiotropic and sustained benefits of TRF and FMDs, both basic science and translational research are warranted to develop fasting-associated interventions into feasible, effective, and inexpensive treatments with the potential to improve healthspan.

Effects of chronic sleep deprivation on glucose homeostasis in rats

Epidemiological studies have shown that chronic sleep disturbances resulted in metabolic disorders. The purpose of this study was to assess the relationship between chronic sleep deprivation (CSD) and the glucose homeostasis in rats. Twenty-four rats were randomly divided into CSD group and control (CON) group. The CSD rats were intervened by a modified multiple platform method (MMPM) to establish an animal model of chronic sleep disturbances. After 3-month intervention, all rats were subjected to an intraperitoneal glucose tolerance test (IPGTT) and an insulin tolerance test (ITT), and the body weight, aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatinine, lipid profile group, and homeostasis model assessment-IR (HOMA-IR) were measured. Both the CSD and CON groups had an attenuation of weight gain after 3-month intervention. The plasma glucose level of CSD group was higher than that of the CON group during the IPGTT (P < 0.01). The CSD rats showed a marked increase in HOMA-IR and ITT compared with the CON group (P < 0.01). There were no significant differences of AST, ALT, creatinine, and most lipid parameters between the CSD and CON groups (P > 0.05). The CSD has a marked effect on glucose homeostasis, comprising glucose intolerance and insulin resistance.

Morning and Evening Blue-Enriched Light Exposure Alters Metabolic Function in Normal Weight Adults

Increasing evidence points to associations between light-dark exposure patterns, feeding behavior, and metabolism. This study aimed to determine the acute effects of 3 hours of morning versus evening blue-enriched light exposure compared to dim light on hunger, metabolic function, and physiological arousal. Nineteen healthy adults completed this 4-day inpatient protocol under dim light conditions (<20lux). Participants were randomized to 3 hours of blue-enriched light exposure on Day 3 starting either 0.5 hours after wake (n = 9; morning group) or 10.5 hours after wake (n = 10; evening group). All participants remained in dim light on Day 2 to serve as their baseline. Subjective hunger and sleepiness scales were collected hourly. Blood was sampled at 30-minute intervals for 4 hours in association with the light exposure period for glucose, insulin, cortisol, leptin, and ghrelin. Homeostatic model assessment of insulin resistance (HOMA-IR) and area under the curve (AUC) for insulin, glucose, HOMA-IR and cortisol were calculated. Comparisons relative to baseline were done using t-tests and repeated measures ANOVAs. In both the morning and evening groups, insulin total area, HOMA-IR, and HOMA-IR AUC were increased and subjective sleepiness was reduced with blue-enriched light compared to dim light. The evening group, but not the morning group, had significantly higher glucose peak value during blue-enriched light exposure compared to dim light. There were no other significant differences between the morning or the evening groups in response to blue-enriched light exposure. Blue-enriched light exposure acutely alters glucose metabolism and sleepiness, however the mechanisms behind this relationship and its impacts on hunger and appetite regulation remain unclear. These results provide further support for a role of environmental light exposure in the regulation of metabolism.

Health Outcomes of Information System Use Lifestyles among Adolescents: Videogame Addiction, Sleep Curtailment and Cardio-Metabolic Deficiencies

BACKGROUND AND OBJECTIVE

Obesity is a rising problem among adolescents in modern societies; it results in long-term cardio-metabolic problems. Possible overlooked drivers of obesity and its consequent cardio-metabolic deficits include videogame addiction and the resulting curtailed sleep; both are growing problems among adolescents. The objective of this study is to examine possible associations among these concepts in adolescents, as a means to point to plausible interventions.

METHODS

Data were collected from 94 adolescents who play videogames and are enrolled in outpatient clinics, using surveys, wearable sleep monitors (FitBit), physical exams, and blood tests at three points in time. These data were subjected to structural equation modeling (SEM) analyses and bootstrapping-based mediation testing procedures.

RESULTS

Videogame addiction among adolescents was negatively associated with sleep duration (β = -0.24). Sleep duration was negatively associated with obesity (β = -0.30), which in turn was associated with elevated blood pressure (β = 0.26), low high-density lipoprotein cholesterol (β = -0.18), high triglycerides (β = 0.61), and high insulin resistance (β = 0.39). The model explained 36.2% of the variation in sleep duration, 32.7% of the variation in obesity, and between 12.8% and 28.1% of the variation in cardio-metabolic indicators. Post-hoc analyses indicated that curtailed sleep is a possible full mediator of the association between videogame addiction, abdominal obesity and the associated cardio-metabolic deficits.

CONCLUSION

The findings point to possible information systems use lifestyle-health links, which behooves researchers and practitioners to pay closer attention to possible adverse health outcomes of technology-related addictions. Interventions that target problematic video-gaming and sleep should be devised as a possible means for improving adolescents' long-term cardio-metabolic health.

Overview of Common Sleep Disorders and Intersection with Dermatologic Conditions

Sleep disorders are very common, often under-recognized and therefore undertreated, are associated with a myriad of medical conditions and could lead to significant impairment of quality of life. This review provides an up-to-date synopsis of common sleep disorders encompassing insufficient sleep syndrome, insomnia, circadian rhythm disorders and obstructive sleep apnea with a brief overview of epidemiology, screening, diagnostic testing and treatment. We also emphasize the emerging area of the intersection of sleep disorders and dermatologic conditions and present compelling data regarding underlying mechanisms including sleep dysfunction in relation to disorders of skin inflammation, aging and skin cancer.

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.

Vibration from freight trains fragments sleep: A polysomnographic study

As the number of freight trains on railway networks increases, so does the potential for vibration exposure in dwellings nearby to freight railway lines. Nocturnal trains in particular are of particular importance since night-time exposure may interfere with sleep. The present work investigates the impact of vibration and noise from night-time freight trains on human sleep. In an experimental polysomnographic laboratory study, 24 young healthy volunteers with normal hearing were exposed to simulated freight pass-bys with vibration amplitudes of 0.7 and 1.4 mm/s either 20 or 36 times during the night. Stronger vibrations were associated with higher probabilities of event-related arousals and awakenings (p < 0.001), and sleep stage changes (p < 0.05). Sleep macrostructure was most affected in high vibration nights with 36 events, with increased wakefulness (p < 0.05), reduced continual slow wave sleep (p < 0.05), earlier awakenings (p < 0.05) and an overall increase in sleep stage changes (p < 0.05). Subjects reported sleep disturbance due to vibration (F(4,92) = 25.9, p < 0.001) and noise (F(4,92) = 25.9, p < 0.001), with the number of trains having an effect only for the 0.7 mm/s condition (p < 0.05). The findings show that combined vibration and noise from railway freight affects the natural rhythm of sleep, but extrapolation of significance for health outcomes should be approached with caution.

Circadian gene variants influence sleep and the sleep electroencephalogram in humans

The sleep electroencephalogram (EEG) is highly heritable in humans and yet little is known about the genetic basis of inter-individual differences in sleep architecture. The aim of this study was to identify associations between candidate circadian gene variants and the polysomnogram, recorded under highly controlled laboratory conditions during a baseline, overnight, 8 h sleep opportunity. A candidate gene approach was employed to analyze single-nucleotide polymorphisms from five circadian-related genes in a two-phase analysis of 84 healthy young adults (28 F; 23.21 ± 2.97 years) of European ancestry. A common variant in Period2 (PER2) was associated with 20 min less slow-wave sleep (SWS) in carriers of the minor allele than in noncarriers, representing a 22% reduction in SWS duration. Moreover, spectral analysis in a subset of participants (n = 37) showed the same PER2 polymorphism was associated with reduced EEG power density in the low delta range (0.25-1.0 Hz) during non-REM sleep and lower slow-wave activity (0.75-4.5 Hz) in the early part of the sleep episode. These results indicate the involvement of PER2 in the homeostatic process of sleep. Additionally, a rare variant in Melatonin Receptor 1B was associated with longer REM sleep latency, with minor allele carriers exhibiting an average of 65 min (87%) longer latency from sleep onset to REM sleep, compared to noncarriers. These findings suggest that circadian-related genes can modulate sleep architecture and the sleep EEG, including specific parameters previously implicated in the homeostatic regulation of sleep.

Postprandial Metabolism of Macronutrients and Cardiometabolic Risk: Recent Developments, Emerging Concepts, and Future Directions

Cardiovascular disease (CVD) is the leading cause of death in the United States. Although the role of habitual lifestyle factors such as physical activity and dietary patterns in increasing CVD risk has long been appreciated, less is known about how acute daily activities may cumulatively contribute to long-term disease risk. Here, the term acute refers to metabolic responses occurring in a short period of time after eating, and the goal of this article is to review recently identified stressors that can occur after meals and during the sleep-wake cycle to affect macronutrient metabolism. It is hypothesized that these events, when repeated on a regular basis, contribute to the observed long-term behavioral risks identified in population studies. In this regard, developments in research methods have supported key advancements in 3 fields of macronutrient metabolism. The first of these research areas is the focus on the immediate postmeal metabolism, spanning from early intestinal adsorptive events to the impact of incretin hormones on these events. The second topic is a focus on the importance of meal components on postprandial vasculature function. Finally, some of the most exciting advances are being made in understanding dysregulation in metabolism early in the day, due to insufficient sleep, that may affect subsequent processing of nutrients throughout the day. Key future research questions are highlighted which will lead to a better understanding of the relations between nocturnal, basal (fasting), and early postmeal events, and aid in the development of optimal sleep and targeted dietary patterns to reduce cardiometabolic risk.

Sleep Disordered Breathing and Risk of Stroke in Older Community-Dwelling Men

STUDY OBJECTIVES

Men with sleep disordered breathing (SDB) may be at increased stroke risk, due to nocturnal hypoxemia, sleep loss or fragmentation, or other mechanisms. We examined the association of SDB with risk of incident stroke in a large cohort of older men.

METHODS

Participants were 2,872 community-dwelling men (mean age 76 years) enrolled in the MrOS Sleep Study, which gathered data from 2003 to 2005 at six clinical sites in the Unites States. SDB predictors (obstructive apnea-hypopnea index, apnea-hypopnea index, central apnea index, and nocturnal hypoxemia) were measured using overnight polysomnography. Incident stroke over an average follow-up of 7.3 years was centrally adjudicated by physician review of medical records.

RESULTS

One hundred fifty-six men (5.4%) had a stroke during follow-up. After adjustment for age, clinic site, race, body mass index, and smoking status, older men with severe nocturnal hypoxemia (≥ 10% of the night with SpO2 levels below 90%) had a 1.8-fold increased risk of incident stroke compared to those without nocturnal hypoxemia (relative hazard = 1.83; 95% confidence interval 1.12-2.98; P trend = 0.02). Results were similar after further adjustment for other potential covariates and after excluding men with a history of stroke. Other indices of SDB were not associated with incident stroke.

CONCLUSIONS

Older men with severe nocturnal hypoxemia are at significantly increased risk of incident stroke. Measures of overnight oxygen saturation may better identify older men at risk for stroke than measures of apnea frequency.

Sleep Restriction Enhances the Daily Rhythm of Circulating Levels of Endocannabinoid 2-Arachidonoylglycerol

STUDY OBJECTIVES

Increasing evidence from laboratory and epidemiologic studies indicates that insufficient sleep may be a risk factor for obesity. Sleep curtailment results in stimulation of hunger and food intake that exceeds the energy cost of extended wakefulness, suggesting the involvement of reward mechanisms. The current study tested the hypothesis that sleep restriction is associated with activation of the endocannabinoid (eCB) system, a key component of hedonic pathways involved in modulating appetite and food intake.

METHODS

In a randomized crossover study comparing 4 nights of normal (8.5 h) versus restricted sleep (4.5 h) in healthy young adults, we examined the 24-h profiles of circulating concentrations of the endocannabinoid 2-arachidonoylglycerol (2-AG) and its structural analog 2-oleoylglycerol (2-OG). We concomitantly assessed hunger, appetite, and food intake under controlled conditions.

RESULTS

A robust daily variation of 2-AG concentrations with a nadir around the middle of the sleep/overnight fast, followed by a continuous increase culminating in the early afternoon, was evident under both sleep conditions but sleep restriction resulted in an amplification of this rhythm with delayed and extended maximum values. Concentrations of 2-OG followed a similar pattern, but with a lesser amplitude. When sleep deprived, participants reported increases in hunger and appetite concomitant with the afternoon elevation of 2-AG concentrations, and were less able to inhibit intake of palatable snacks.

CONCLUSIONS

Our findings suggest that activation of the eCB system may be involved in excessive food intake in a state of sleep debt and contribute to the increased risk of obesity associated with insufficient sleep.

COMMENTARY

A commentary on this article appears in this issue on page 495.

Associations between sleep duration and type 2 diabetes in Taiwanese adults: A population-based study

BACKGROUND/PURPOSE

Research on the association between sleep duration and type 2 diabetes in an adult community population has been relatively scarce. The objective of this study was to analyze the association between sleep duration and the risk of diabetes in Taiwanese adults.

METHODS

Secondary data analysis was based on the database of Nutrition and Health Survey in Taiwan between 2005 and 2008. A stratified three-staged probability sampling method was used to create a cross-sectional research design and 1533 participants (733 men, 800 women, between 19 years and 64 years of age) were selected in this study. Logistic regression models were conducted to estimate the effect of sleep duration for type 2 diabetes patients.

RESULTS

The average sleep duration for all participants in this study was 7.2 ± 1.4 hours, with 35.1% of the participants having a sleep duration less than 7 hours. After controlling related confounders, such as age, sex, body mass index, abdominal circumference, total cholesterol levels, sleep disturbances, and hypertension, the risk of having diabetes for participants with ≤ 5 hours sleep was 2.04-fold (95% confidence interval, 1.05-3.95) higher than for participants with 7-8.9 hours of sleep. In particular, the risk of having diabetes for young adults (between 19 years and 44 years of age) with ≤5 hours of sleep was 5.24-fold (95% confidence interval, 1.17-23.47) higher than for young adults who reported 7-8.9 hours of sleep.

CONCLUSION

Our results show that a short sleep duration was associated with a higher prevalence of diabetes and this correlation was particularly strong in young adults.

Glucose intolerance associated with hypoxia in people living at high altitudes in the Tibetan highland

OBJECTIVES

To clarify the association between glucose intolerance and high altitudes (2900-4800 m) in a hypoxic environment in Tibetan highlanders and to verify the hypothesis that high altitude dwelling increases vulnerability to diabetes mellitus (DM) accelerated by lifestyle change or ageing.

DESIGN

Cross-sectional epidemiological study on Tibetan highlanders.

PARTICIPANTS

We enrolled 1258 participants aged 40-87 years. The rural population comprised farmers in Domkhar (altitude 2900-3800 m) and nomads in Haiyan (3000-3100 m), Ryuho (4400 m) and Changthang (4300-4800 m). Urban area participants were from Leh (3300 m) and Jiegu (3700 m).

MAIN OUTCOME MEASURE

Participants were classified into six glucose tolerance-based groups: DM, intermediate hyperglycaemia (IHG), normoglycaemia (NG), fasting DM, fasting IHG and fasting NG. Prevalence of glucose intolerance was compared in farmers, nomads and urban dwellers. Effects of dwelling at high altitude or hypoxia on glucose intolerance were analysed with the confounding factors of age, sex, obesity, lipids, haemoglobin, hypertension and lifestyle, using multiple logistic regression.

RESULTS

The prevalence of DM (fasting DM)/IHG (fasting IHG) was 8.9% (6.5%)/25.1% (12.7%), respectively, in all participants. This prevalence was higher in urban dwellers (9.5% (7.1%)/28.5% (11.7%)) and in farmers (8.5% (6.1%)/28.5% (18.3%)) compared with nomads (8.2% (5.7%)/15.7% (9.7%)) (p=0.0140/0.0001). Dwelling at high altitude was significantly associated with fasting IHG+fasting DM/fasting DM (ORs for >4500 and 3500-4499 m were 3.59/4.36 and 2.07/1.76 vs <3500 m, respectively). After adjusting for lifestyle change, hypoxaemia and polycythaemia were closely associated with glucose intolerance.

CONCLUSIONS

Socioeconomic factors, hypoxaemia and the effects of altitudes >3500 m play a major role in the high prevalence of glucose intolerance in highlanders. Tibetan highlanders may be vulnerable to glucose intolerance, with polycythaemia as a sign of poor hypoxic adaptation, accelerated by lifestyle change and ageing.

An investigation of the associations among sleep duration and quality, body mass index and insulin resistance in newly diagnosed type 2 diabetes mellitus patients

OBJECTIVES

To examine direct and indirect associations of sleep duration and quality with insulin resistance, considering body mass index (BMI) as a potential mediator in newly diagnosed type 2 diabetes mellitus patients.

METHODS

Cross-sectional data from patients enrolled in the Early Activity in Diabetes study. We studied 522 newly diagnosed type 2 diabetes mellitus patients, 65.9% male, mean age 63.5 ± 10.1 years. Of the total sample 53% had a BMI of ⩾30 kg/m(2). Participants completed a 7-day sleep diary and sleep questionnaire. Average sleep duration (minutes), average nap duration (minutes) and average number of night awakenings were derived. Objective measures of height and body weight were obtained for the BMI calculation (kg/m(2)). Insulin resistance was obtained using the homeostatic model assessment - insulin resistance (HOMA2-IR) standardized technique.

RESULTS

Average number of night awakenings was positively correlated with BMI (r= 0.22, p < 0.001) and negatively associated with logged HOMA2-IR (r= -0.16, p = 0.04). Path analysis demonstrated night awakenings were directly associated with BMI and indirectly associated with insulin resistance, whilst considering BMI as a potential mediator (p < 0.05). Sleep duration was not associated with BMI or insulin resistance (p > 0.05).

CONCLUSIONS

Sleep quality, not sleep duration, plays an important role in insulin resistance in newly diagnosed type 2 diabetes mellitus patients. BMI may mediate the relationship between indicators of sleep quality and insulin resistance. There is a need to examine the impact of improving sleep quality on obesity and insulin resistance in patients with type 2 diabetes mellitus.

The Effect of Sleep Quality on the Development of Type 2 Diabetes in Primary Care Patients

Sleep has important effects on physical and mental health, and sleep disorders are associated with increased mortality and morbidity. This study was conducted to evaluate the relationship between sleep duration or sleep quality and the risk of type 2 diabetes. The FACTS (FAmily CohorT Study in primary care) was established to investigate the relations between familial environment and health which was conducted at 22 family medicine outpatient clinics in general hospitals. Total 563 patients without diabetes who received ≥1 year follow-up examination were included in the analysis. We used the Pittsburgh Sleep Quality Index to determine sleep quality, and a score of ≥5 was considered to define poor sleep quality. Patients taking oral hypoglycemic agents, having a fasting glucose level of >126 mg/dL, or diagnosed with diabetes by physicians were classified as having diabetes. The median follow-up period was 2.5 years. Poor sleep quality was associated with a higher risk of diabetes after adjusting for age, sex, body mass index, income, physical activity, and family history of diabetes (relative risk=2.64; 95% confidence interval, 1.03-6.78). As a risk factor for the development of diabetes, poor sleep quality may independently increase the incidence of diabetes.

Association between Sleep Duration and Impaired Fasting Glucose in Korean Adults: Results from the Korean National Health and Nutrition Examination Survey 2011-2012

Background

Impaired fasting glucose (IFG) is an established risk factor for type 2 diabetes and cardiovascular disease. This study evaluated the relationship between sleep duration and IFG.

Methods

This cross-sectional study included 14,925 Korean adults (5,868 men and 9,057 women) ≥19 years of age who participated in the Korean National Health and Nutrition Examination Survey between 2011 and 2012. Blood glucose levels were measured after at least eight hours of fasting. Study subjects were categorized into three groups based on self-reported sleep duration (<7, 7–8, or >8 h/d). IFG was diagnosed according to recommendations American Diabetes Association guidelines. Multiple logistic regression analysis was performed with adjustment for covariates.

Results

In men, short sleep duration (<7 hours) was associated with increased risk of IFG (odds ratio [OR], 1.46; 95% confidence interval [CI], 1.08 to 1.96) compared to adequate sleep duration (7–8 hours), whereas long sleep duration (>8 hours) was not associated with risk of IFG (OR, 0.90; 95% CI, 0.37 to 2.18). In women, sleep duration was not associated with risk of IFG.

Conclusion

The association between sleep duration and IFG differed by sex; sleep deprivation, was associated with increased risk of IFG, especially in men.

Association between Sleep Duration and Measurable Cardiometabolic Risk Factors in Healthy Korean Women: The Fourth and Fifth Korean National Health and Nutrition Examination Surveys (KNHANES IV and V)

Study Objectives. To examine the association between sleep duration and prevalence of metabolic syndrome (MetS) and its components in healthy Korean women. Design. Cross-sectional study, using the Fourth and Fifth Korean National Health and Nutrition Examination Surveys. Methods. Among 8505 women (25-70 years) from KNHANES IV and V, participants were classified into five sleep groups based on self-reported sleep duration. MetS and its components were defined using the criteria set forth in National Cholesterol Education Program-Adult Treatment Panel III. We used multivariate logistic regression analysis. Results. After adjusting for various confounders, shorter sleep duration (≤6 h) was found to have an association with low risk of reduced high-density lipoprotein cholesterol and increased triglycerides, whereas very long sleep duration was found to have high risk of increased triglycerides. However, abdominal obesity showed an opposite trend: short sleep duration was associated with higher risk of abdominal obesity than long sleep duration. Fasting glucose levels increased as sleep duration increased, but without significance. Moreover, blood pressure was not significantly associated with sleep duration. Consequently, MetS was less prevalent in those with short sleep duration. Conclusions. Sleep duration was positively associated with MetS, especially dyslipidemia and fasting hyperglycemia, but inversely associated with abdominal obesity.

The role of sleep in the regulation of body weight

Sleep participates in the regulation of body weight. The amount of sleep and synchronization of the biological clock are both necessary to achieve the energy balance and the secretion of hormones that contribute to weight regulation. In this review, we first reconsider what normal physiological sleep is and what the normative values of sleep are in the general population. Second, we explain how the biological clock regulates the hormones that may be involved in weight control. Third, we provide some recent data on how sleep may be disturbed by sleep disorders or reduced by sleep debt with consequences on weight. Finally, we explore the relationships between sleep debt and obesity.

A pilot randomized controlled trial testing the effects of a routine-based intervention on outcomes in a behavioural weight loss programme

Background

Structured routines aimed at eating and sleep have been successfully employed in weight loss interventions for children. Although such routines are discussed in lifestyle modification programmes for adults, they are not a primary focus.

Purpose

The purpose of this study is to determine if establishing healthy eating and sleep routines may improve outcomes in a behavioural weight loss (BWL) intervention.

Methods

Twenty‐five overweight/obese participants (age = 52.4 ± 9.8; body mass index = 33.5 ± 4.1) were randomly assigned to either a 4‐week routine‐based intervention (ROU) targeting regular eating and sleep or an education control before beginning an 18‐week BWL intervention.

Results

Routine‐based intervention participants reported adhering to eating routines, with increased ‘on‐schedule’ eating (p = 0.007) and decreased ‘off‐schedule’ eating (p = 0.002) but showed no change in ‘on‐schedule’ sleep (p = 0.74). However, contrary to our hypothesis, ROU participants lost less weight than controls after 6 weeks of BWL (2.3 ± 2.5 vs. 4.6 ± 2.6 kg, p = 0.04) and achieved only modest weight loss over the full 18 weeks (ROU: 3.2 ± 4.6 vs. education control: 5.8 ± 5.7 kg, p = 0.23).

Conclusions

Focusing initially on establishing healthy sleep and eating routines led to poorer, rather than better, subsequent weight loss outcomes. Further studies using a longer initial intervention period or focusing on only sleep or eating behaviour are needed to determine whether establishing routines for eating and sleep behaviours can enhance weight loss in adults.

ÍNDICE DA QUALIDADE DO SONO DE PITTSBURGH PARA USO NA REABILITAÇÃO CARDIOPULMONAR E METABÓLICA

Introdução A qualidade do sono constitui-se em parâmetro relevante na avaliação da saúde em geral, sendo um fator relevante na determinação do risco das doenças cardiovasculares. Objetivo Validar a versão adaptada do questionário de avaliação do Índice de Qualidade do Sono de Pittsburgh (PSQI) para uso em programas de reabilitação cardiopulmonar e metabólica (RCPM). Métodos Estudo descritivo transversal realizado com 101 pacientes de ambos os sexos, com média de idade de 66,05 (± 13,9) anos. Para a análise estatística foi considerado intervalo de confiança de 95% e valor de significância p <0,05; para a análise de consistência interna foi utilizado o coeficiente de alfa de Cronbach e para a análise da relação entre componentes e itens com o escore total do questionário foi utilizado o coeficiente de correlação de Spearman. Resultados Todos os componentes do questionário apresentaram boa consistência interna com valor de 0,72. Os componentes que mais se relacionaram com o escore total foram "duração do sono" e "qualidade subjetiva do sono", sendo que o componente que menos se relacionou foi "alterações do sono". Dentre os itens a variação foi de 0,584 no item "durante a última semana, em geral, como você classificaria a qualidade do seu sono?", até -0,611 no item "durante a última semana, quantas horas você conseguia dormir durante a noite?". Foi possível observar que os itens "tossir ou roncar muito alto" e "frequência para dificuldades do sono por outras razões" não apresentaram correlação com o escore total do questionário. Conclusão A versão adaptada do PSQI mostrou-se válida para ser utilizada na avaliação do sono em programas de RCPM.

Differential increase in prevalence estimates of inadequate sleep among black and white Americans

BACKGROUND

The National Health Interview Survey (NHIS) was used to ascertain whether increases in inadequate sleep differentially affected black and white Americans. We tested the hypothesis that prevalence estimates of inadequate sleep were consistently greater among blacks, and that temporal changes have affected these two strata differentially.

METHODS

NHIS is an ongoing cross-sectional study of non-institutionalized US adults (≥18 years) providing socio-demographic, health risk, and medical factors. Sleep duration was coded as very short sleep [VSS] (<5 h), short sleep [SS] (5-6 h), or long sleep [LS] (>8 h), referenced to 7-8 h sleepers. Analyses adjusted for NHIS' complex sampling design using SAS-callable SUDAAN.

RESULTS

Among whites, the prevalence of VSS increased by 53% (1.5% to 2.3%) from 1977 to 2009 and the prevalence of SS increased by 32% (19.3% to 25.4 %); prevalence of LS decreased by 30% (11.2% to 7.8%). Among blacks, the prevalence of VSS increased by 21% (3.3% to 4.0%) and the prevalence of SS increased by 37% (24.6 % to 33.7%); prevalence of LS decreased by 42% (16.1% to 9.4%). Adjusted multinomial regression analysis showed that odds of reporting inadequate sleep for whites were: VSS (OR = 1.40, 95% CI = 1.13-1.74, p < 0.001), SS (OR = 1.34, 95 % CI = 1.25-1.44, p < 0.001), and LS (OR = 0.94, 95% CI = 0.85-1.05, NS). For blacks, estimates were: VSS (OR = 0.83, 95% CI = 0.60-1.40, NS), SS (OR = 1.21, 95% CI = 1.05-1.50, p < 0.001), and LS (OR = 0.84, 95% CI = 0.64-1.08, NS).

CONCLUSIONS

Blacks and whites are characteristically different regarding the prevalence of inadequate sleep over the years. Temporal changes in estimates of inadequate sleep seem dependent upon individuals' race/ethnicity.

[Sleep duration and metabolism]

Sleep duration has gradually diminished during the last decade while obesity and type 2 diabetes have become epidemics. Experimental sleep curtailment leads to increased appetite, hormonal disturbances and, especially, insulin resistance. Numerous epidemiological studies have therefore examined whether habitual short sleep is associated with obesity and type 2 diabetes. A large majority of cross-sectional studies have confirmed an association between short, and also long sleep duration and obesity in adults more than in the elderly. Short sleep is strongly associated to obesity in children and adolescents. Prospective studies, including studies in children, are not conclusive with regard to the effect of short sleep on the incidence of obesity. Both short and long sleep durations are associated with diabetes, but only short sleep duration seems predictive of future diabetes. Insomnia seems to be a strong contributor to short sleep duration but the association of insomnia with obesity is not clear. Insomnia is associated with type 2 diabetes and also predictive of a higher incidence. Other studies have shown that short sleep duration and insomnia are associated with, and sometime predictive of, other components of the metabolic syndrome, especially hypertension and the risk of coronary disease. The treatment of short sleep duration and insomnia with regard to their effects on the metabolic syndrome merits further study.

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.

The relationship between insomnia with short sleep duration is associated with hypercholesterolemia: a cross-sectional study

AIM

To examine the association between insomnia with short sleep duration and hypercholesterolemia in Taiwanese adults.

BACKGROUND

Previous studies mostly focused on the association between sleep duration and hyperlipidemia, but the results were not consistent. Besides, very few studies extensively examined the association between insomnia and hypercholesterolemia. This study hypothesized that insomnia with short sleep duration is associated with hypercholesterolemia.

DESIGN

Secondary data analysis. This study analysed the latest database of the cross-sectional Nutrition and Health Survey in Taiwan which was released on 2011 (data collected between 2005-2008) and collected data using stratified three-staged probability sampling design.

METHODS

This study analysed 1533 participants aged between 19-64 (733 males and 800 females) and used logistic regression model to calculate the odds ratio and the 95% confidence interval of insomnia with short sleep duration to hypercholesterolemia. Controlled confounders included age, gender, sample weight, body mass index, waist circumference, fasting plasma glucose, hypertension and diabetes.

RESULTS

Insomnia with 5-6 hours of sleep duration was significantly associated with hypercholesterolemia. The odds ratio of mild insomnia or moderate/severe insomnia with 5-6 hours of sleep duration to hypercholesterolemia was higher, compared with the reference group (without insomnia and >6 hours of sleep duration).

CONCLUSION

Insomnia with short sleep duration was associated with increased odds of hypercholesterolemia. Caregivers in clinical practice should watch out for the effect brought by this novel factor.

Sleep Disturbances and Glucose Metabolism in Older Adults: The Cardiovascular Health Study

OBJECTIVE

We examined the associations of symptoms of sleep-disordered breathing (SDB), which was defined as loud snoring, stopping breathing for a while during sleep, and daytime sleepiness, and insomnia with glucose metabolism and incident type 2 diabetes in older adults.

RESEARCH DESIGN AND METHODS

Between 1989 and 1993, the Cardiovascular Health Study recruited 5,888 participants ≥65 years of age from four U.S. communities. Participants reported SDB and insomnia symptoms yearly through 1989-1994. In 1989-1990, participants underwent an oral glucose tolerance test, from which insulin secretion and insulin sensitivity were estimated. Fasting glucose levels were measured in 1989-1990 and again in 1992-1993, 1994-1995, 1996-1997, and 1998-1999, and medication use was ascertained yearly. We determined the cross-sectional associations of sleep symptoms with fasting glucose levels, 2-h glucose levels, insulin sensitivity, and insulin secretion using generalized estimated equations and linear regression models. We determined the associations of updated and averaged sleep symptoms with incident diabetes in Cox proportional hazards models. We adjusted for sociodemographics, lifestyle factors, and medical history.

RESULTS

Observed apnea, snoring, and daytime sleepiness were associated with higher fasting glucose levels, higher 2-h glucose levels, lower insulin sensitivity, and higher insulin secretion. The risk of the development of type 2 diabetes was positively associated with observed apnea (hazard ratio [HR] 1.84 [95% CI 1.19-2.86]), snoring (HR 1.27 [95% CI 0.95-1.71]), and daytime sleepiness (HR 1.54 [95% CI 1.13-2.12]). In contrast, we did not find consistent associations between insomnia symptoms and glucose metabolism or incident type 2 diabetes.

CONCLUSIONS

Easily collected symptoms of SDB are strongly associated with insulin resistance and the incidence of type 2 diabetes in older adults. Monitoring glucose metabolism in such patients may prove useful in identifying candidates for lifestyle or pharmacological therapy. Further studies are needed to determine whether insomnia symptoms affect the risk of diabetes in younger adults.

Diurnal rhythms in the human urine metabolome during sleep and total sleep deprivation

Understanding how metabolite levels change over the 24 hour day is of crucial importance for clinical and epidemiological studies. Additionally, the association between sleep deprivation and metabolic disorders such as diabetes and obesity requires investigation into the links between sleep and metabolism. Here, we characterise time-of-day variation and the effects of sleep deprivation on urinary metabolite profiles. Healthy male participants (n = 15) completed an in-laboratory study comprising one 24 h sleep/wake cycle prior to 24 h of continual wakefulness under highly controlled environmental conditions. Urine samples were collected over set 2-8 h intervals and analysed by (1)H NMR spectroscopy. Significant changes were observed with respect to both time of day and sleep deprivation. Of 32 identified metabolites, 7 (22%) exhibited cosine rhythmicity over at least one 24 h period; 5 exhibiting a cosine rhythm on both days. Eight metabolites significantly increased during sleep deprivation compared with sleep (taurine, formate, citrate, 3-indoxyl sulfate, carnitine, 3-hydroxyisobutyrate, TMAO and acetate) and 8 significantly decreased (dimethylamine, 4-DTA, creatinine, ascorbate, 2-hydroxyisobutyrate, allantoin, 4-DEA, 4-hydroxyphenylacetate). These data indicate that sampling time, the presence or absence of sleep and the response to sleep deprivation are highly relevant when identifying biomarkers in urinary metabolic profiling studies.

Prevalence of Obesity and Metabolic Syndrome in Adult Population of Selected Regions of the Czech Republic. Relation to Eating Habits and Smoking

Prevalence of the metabolic syndrome is around 25% in Europe but its occurrence grows in both genders with increasing age and weight. Lifestyle factors may contribute to the risk of developing metabolic syndrome. The objective of this study was to determine the relationship between metabolic syndrome and eating habits as well as length of sleep and smoking. Participants (519 women and 286 men aged 18–65 years) were chosen by random selection and questioned about their eating habits, sleep length and smoking. This information was combined with anthropometric and clinical parameters of metabolic syndrome. The female group was divided into two subgroups depending on climacteric stage (before and after menopause). Metabolic syndrome prevalence does not differ between regions in neither female (29.9%) nor male (32.5%) group. Body mass index ≥25 was detected in 50.4% of all women and 65.7% of men; 23.5% of all women and 21.7% men had body mass index ≥30. In conclusion, metabolic syndrome prevalence was proved to depend on eating habits and family heredity. Positive correlation between the above mentioned factors demonstrated itself in the total sample but not in individual regions. Metabolic syndrome prevalence in Czech adults is comparable with neighbouring countries. No significant interregional differences in metabolic syndrome prevalence within the Czech Republic were detected. In conclusion, relationship between eating habits and metabolic syndrome was confirmed.

Interactions between sleep, stress, and metabolism: From physiological to pathological conditions

Poor sleep quality due to sleep disorders and sleep loss is highly prevalent in the modern society. Underlying mechanisms show that stress is involved in the relationship between sleep and metabolism through hypothalamic–pituitary–adrenal (HPA) axis activation. Sleep deprivation and sleep disorders are associated with maladaptive changes in the HPA axis, leading to neuroendocrine dysregulation. Excess of glucocorticoids increase glucose and insulin and decrease adiponectin levels. Thus, this review provides overall view of the relationship between sleep, stress, and metabolism from basic physiology to pathological conditions, highlighting effective treatments for metabolic disturbances.

Role of the clock gene Rev-erbα in metabolism and in the endocrine pancreas

Several hormones are regulated by circadian rhythms to adjust the metabolism to the light/dark cycles and feeding/activity patterns throughout the day. Circadian rhythms are mainly governed by the central clock located in the suprachiasmatic nucleus but also by clocks present in peripheral organs, like the endocrine pancreas. Plasma glucose levels and the main pancreatic hormones insulin and glucagon also exhibit daily variations. Alterations in circadian rhythms are associated with metabolic disturbances and pathologies such as obesity and diabetes. The molecular components of central and peripheral clocks and their regulatory mechanisms are well established. Among the different clock genes, Rev-erbα is considered one of the key links between circadian rhythms and metabolism. Rev-erbα is a critical part of a negative feedback loop in the core circadian clock and modulates the clock oscillatory properties. In addition, Rev-erbα plays an important role in the regulation of lipid and glucose metabolism, thermogenesis, adipocyte and muscle differentiation as well as mitochondrial function. In the endocrine pancreas, Rev-erbα regulates insulin and glucagon secretion and pancreatic β-cell proliferation. In the present review, we discuss all these subjects and, particularly, the role of the clock gene Rev-erbα in the endocrine pancreas.