Chronobiology, endocrinology, and energy- and food-reward homeostasis

The Importance of Sleep in Overcoming Childhood Obesity and Reshaping Epigenetics

The development of childhood obesity is a complex process influenced by a combination of genetic predisposition and environmental factors, such as sleep, diet, physical activity, and socioeconomic status. Long-term solutions for decreasing the risk of childhood obesity remain elusive, despite significant advancements in promoting health and well-being in school and at home. Challenges persist in areas such as adherence to interventions, addressing underlying social determinants, and individual differences in response to treatment. Over the last decade, there has been significant progress in epigenetics, along with increased curiosity in gaining insights into how sleep and lifestyle decisions impact an individual's health. Epigenetic modifications affect the expression of genes without causing changes to the fundamental DNA sequence. In recent years, numerous research studies have explored the correlation between sleep and the epigenome, giving a better understanding of DNA methylation, histone modification, and non-coding RNAs. Although significant findings have been made about the influence of sleep on epigenetics, a notable gap exists in the literature concerning sleep-related genes specifically associated with childhood obesity. Consequently, it is crucial to delve deeper into this area to enhance our understanding. Therefore, this review primarily focuses on the connection between sleep patterns and epigenetic modifications in genes related to childhood obesity. Exploring the interplay between sleep, epigenetics, and childhood obesity can potentially contribute to improved overall health outcomes. This comprehensive review encompasses studies focusing on sleep-related genes linked to obesity.

The association between sleep and early pubertal development in Chinese children: a school population-based cross-sectional study

Background

There is an increasing tendency toward early pubertal development, and sleep might be related to pubertal onset. We aimed to investigate the association of sleep duration and bedtime with early pubertal development.

Methods

This was a cross-sectional study of 8,007 children (53.6% boys) from Qufu city, Shandong province and Zhongshan city, Guangdong province, China. Data on sleep duration and bedtime were obtained by questionnaire. Early pubertal development was the primary outcome and it was evaluated by the pediatrician according to Tanner staging. Logistic regression models were used to separately examine the association between sleep duration or bedtime and early pubertal development, controlling body mass index (BMI), dietary pattern, soft drink, feeding pattern and mother's BMI.

Results

In boys, short sleep duration was strongly related to early pubertal development [OR (95%CI): 4.26 (1.30, 13.94)], and this association was intensified after adjusted BMI, dietary pattern, soft drink, feeding pattern and mother's BMI. In girls, OR (95%CI) was 1.62 (1.04, 2.51), and increased after controlling BMI. Bedtime was associated with early pubertal development on weekdays [OR (95%CI): 6.39 (1.54, 26.45) in boys and 1.93 (1.23, 3.05) in girls], but not on weekends [OR (95%CI): 2.49 (0.61, 10.21) in boys; 1.31 (0.76, 2.25) in girls].

Conclusion

This study underscores the positive association between the risk of early pubertal development and insufficient sleep duration and late bedtime.

Chrononutrition behaviors, sugar-sweetened beverage consumption, sleep quality and the association with body mass index among Malaysian women

The present study aimed to determine the association between chrononutrition behaviors, sugar-sweetened beverage intake, and sleep quality among Malaysian women. A cross-sectional study using a validated, self-administered Chrononutrition Profile Questionnaire, Beverage Questionnaire and Sleep Quality Index were conducted among 934 Malaysian women. Multinomial logistic regression was performed to obtain odds ratios of being overweight/underweight and to test the association with poor sleep quality. 40% of Malaysian women were either overweight or obese and 65.4% had poor sleep quality. We found that breakfast skipping (OR: 4.101; CI: 2.378-7.070), poor evening eating (OR: 4.073; CI: 1.631-10.186), and eating the largest meal at night (OR: 6.970; CI: 1.944-24.994) increased the odds of being underweight. On the other hand, the daily consumption of 100% fruit juices (OR: 1.668; CI: 1.058-1.731), daily consumption of sweetened coffee or tea (OR: 1.707; CI: 1.162-2.508) and consumption of diet soft drinks by 6 times or fewer (OR: 1.484; CI: 1.066-2.064) are associated with increased odds of being overweight. However, when adjusted, only poor evening latency (AOR: 16.638; CI: 1.986-139.383) revealed an increased odd of being underweight. The highest odds predicting poor sleep quality were found for eating the largest meal during dinner (OR: 3.696; CI: 1.967-6.945) and (AOR: 2.194; CI: 1.119-4.304) when adjusted. Hence, the result indicates that multifactorial impacts on women's body weight and recommendations to adjust chrononutrition and sugar-sweetened beverages intake in lifestyle must be done carefully considering other parameters together.

Weight Loss and Sleep, Current Evidence in Animal Models and Humans

Sleep is a vital process essential for survival. The trend of reduction in the time dedicated to sleep has increased in industrialized countries, together with the dramatic increase in the prevalence of obesity and diabetes. Short sleep may increase the risk of obesity, diabetes and cardiovascular disease, and on the other hand, obesity is associated with sleep disorders, such as obstructive apnea disease, insomnia and excessive daytime sleepiness. Sleep and metabolic disorders are linked; therefore, identifying the physiological and molecular pathways involved in sleep regulation and metabolic homeostasis can play a major role in ameliorating the metabolic health of the individual. Approaches aimed at reducing body weight could provide benefits for both cardiometabolic risk and sleep quality, which indirectly, in turn, may determine an amelioration of the cardiometabolic phenotype of individuals. We revised the literature on weight loss and sleep, focusing on the mechanisms and the molecules that may subtend this relationship in humans as in animal models.

Adjustment to lockdown in children and adolescents with narcolepsy in France

STUDY OBJECTIVES

The goal of the current study was to explore the effect of a 2-month quarantine on children and adolescents with narcolepsy and to describe the changes in their sleep, mood, and metabolism during this period.

METHODS

The study involved 77 patients aged 7 to 23 years with a diagnosis of narcolepsy. Participants had to answer multiple-choice questions to characterize the changes and modifications in their own habits and state of health.

RESULTS

Participants reported changes in daytime sleep, nighttime sleep schedules, treatment intake, food intake, weight, and amount of screen time. Most patients reported deterioration in their memory and attention abilities as well as a decrease in their work efficiency. Mood appeared to be less affected, although it deteriorated in less than one-third of the participants who reported feeling sad more often.

CONCLUSIONS

The prolonged and complete lockdown seemed to have an effect on children and adolescents with narcolepsy, and changes are often considered by the participants to depend on or to determine an overall quality of adaptation to the situation. This study highlights the importance of maintaining and strengthening time markers in individuals with narcolepsy and should help to establish guidelines that would apply in future quarantine situations.

CITATION

de Laclause AP, Konofal E, Bokov P, Delclaux C, Lecendreux M. Adjustment to lockdown in children and adolescents with narcolepsy in France. J Clin Sleep Med. 2022;18(9):2247-2252.

The role of leptin in indirectly mediating "somatic anxiety" symptoms in major depressive disorder

BACKGROUND

Leptin is a multifunctional hormone secreted from adipose tissue, which plays a core role in regulating energy intake and expenditure. Evidence has demonstrated that leptin receptors are located in brain areas involved in emotional processing, and major depressive disorder (MDD) is characterized by dysfunction of emotional processing. Taken together, these features suggest that leptin may play a potential role in the pathophysiology of MDD. However, the precise roles of leptin in modulating depressive symptoms in MDD remain unclear.

METHODS

Participants [18 drug-naïve MDD patients, 15 unaffected first-degree relatives of MDD patients (FDR-MDD), and 40 healthy controls] completed clinical assessments and provided blood samples for measurement of leptin levels. We evaluated the effect of leptin on clinical status (MDD or FDR-MDD) and symptomatic dimensionalities of MDD using mediation analysis.

RESULTS

We found that leptin was increased in MDD patients and this only predicted "somatic anxiety" symptoms. Furthermore, leptin was a significant and indirect mediator of the association between clinical status (MDD or FDR-MDD) and "somatic anxiety" symptoms.

CONCLUSION

Our finding that leptin was a significant and indirect mediator of clinical status (MDD or FDR-MDD) and "somatic anxiety" symptoms suggests that leptin may indirectly affect somatic depressive symptoms in MDD. Our findings may provide a theoretical basis for novel clinical interventions in MDD.

Rhythmic neuronal activities of the rat nucleus of the solitary tract are impaired by high-fat diet - implications for daily control of satiety

Temporal partitioning of daily food intake is crucial for survival and involves the integration of internal circadian states and external influences such as the light-dark cycle and dietary composition. These intrinsic and extrinsic factors are interdependent with misalignment of circadian rhythms promoting body weight gain, while consumption of a calorie-dense diet elevates the risk of obesity and blunts circadian rhythms. Recently, we defined the circadian properties of the dorsal vagal complex of the brainstem, a structure implicated in the control of food intake and autonomic tone, but whether and how 24 h rhythms in this area are influenced by diet remains unresolved. Here we focused on a key structure of this complex, the nucleus of the solitary tract (NTS). We used a combination of immunohistochemical and electrophysiological approaches together with daily monitoring of body weight and food intake to interrogate how the neuronal rhythms of the NTS are affected by a high-fat diet. We report that short-term consumption of a high-fat diet increases food intake during the day and blunts NTS daily rhythms in neuronal discharge. Additionally, we found that a high-fat diet dampens NTS responsiveness to metabolic neuropeptides, and decreases orexin immunoreactive fibres in this structure. These alterations occur without prominent body weight gain, suggesting that a high-fat diet acts initially to reduce activity in the NTS to disinhibit mechanisms that suppress daytime feeding. KEY POINTS: The dorsal vagal complex of the rodent hindbrain possesses intrinsic circadian timekeeping mechanisms In particular, the nucleus of the solitary tract (NTS) is a robust circadian oscillator, independent of the master suprachiasmatic clock Here, we reveal that rat NTS neurons display timed daily rhythms in their neuronal activity and responsiveness to ingestive cues These daily rhythms are blunted or eliminated by a short-term high-fat diet, together with increased consumption of calories during the behaviourally quiescent day Our results help us better understand the circadian control of satiety by the brainstem and its malfunctioning under a high-fat diet.

Reproducibility and associations with obesity and insulin resistance of circadian-rhythm parameters in free-living vs. controlled conditions during the PREVIEW lifestyle study

BACKGROUND

Circadian rhythm is altered in individuals with obesity and insulin resistance, showing a smaller amplitude, less stability, and increased intradaily variation.

OBJECTIVE

We compared reproducibility of circadian-rhythm parameters over time and under free-living vs. controlled conditions in participants with obesity and pre-diabetes after 2- and 3-year weight-loss maintenance during the 3-year PREVIEW (PREVention of diabetes through lifestyle intervention and population studies In Europe and around the World) study. Associations of obesity and insulin resistance with circadian-rhythm parameters were assessed.

SUBJECTS AND METHODS

Circadian-rhythm parameters were determined using continuous wrist-temperature measurements in free-living environments at year 2 (n = 24; age 56.8 ± 10.3 y; body mass index (BMI) = 30 ± 3.9 kg/m²; homeostatic model assessment of insulin resistance (HOMA-IR) 2.4 ± 1.1), at year 3 (n = 97; age 61.7 ± 7.8; BMI = 29.7 ± 3.9; HOMA-IR 2.9 ± 2.1), and at year 3 in a controlled condition (n = 38; age 63.4 ± 6.7; BMI = 28.7 ± 3.9; HOMA-IR 3.8 ± 1.4). Reproducibility was assessed by analyzing repeatability coefficients (CR), differences, and associations, over time as well as between conditions. Associations of BMI and HOMA-IR with circadian-rhythm parameters were assessed at y-3 in both conditions using factor analysis, followed by Pearson's correlations.

RESULTS

Reproducibility of circadian-rhythm parameters over time in the free-living environments was high (CR 0.002-5.26; no significant differences; associated amplitudes r = 0.57; p < 0.01). In contrast, reproducibility between different conditions was low (CR 0.02-11.36; significant differences between most parameters (p < 0.05); yet associated amplitudes r = 0.59; p < 0.01). In the controlled vs. free-living condition circadian-rhythm was more stable; BMI and HOMA-IR were associated with the physiological amplitude-related parameters (r = -0.45; p < 0.01; r = -0.33; p < 0.05). In the free-living environment, BMI and behavioral circadian-rhythm parameters indicating circadian alignment, contributed most to the explained variation (47.1%), and were inversely associated (r = -0.22; p < 0.05), while HOMA-IR was inversely associated with stability-related circadian-rhythm parameters (r = -0.21; p < 0.05).

CONCLUSIONS

Circadian rhythm was highly reproducible over time in the free-living environments, yet different under different conditions, being more stable in the controlled condition. BMI may play a significant role in circadian alignment and vice versa in the free-living environment.

Obese mice weight loss role on nonalcoholic fatty liver disease and endoplasmic reticulum stress treated by a GLP-1 receptor agonist

BACKGROUND/OBJECTIVES

The weight loss following Semaglutide treatment, a GLP-1 receptor agonist, might be responsible for some effects observed on the nonalcoholic fatty liver disease of obese mice.

SUBJECTS/METHODS

Two groups of C57BL/6 male mice (n = 30/group) were fed the diets Control (C) or high-fat (HF) for 16 weeks. Then, separated into six new groups for an additional four weeks (n = 10/group) and treated with Semaglutide (S, 40 µg/kg) or paired feeding (PF) with S groups (C; C-S; C-PF; HF; HF-S; HF-PF).

RESULTS

Semaglutide reduced energy consumption leading to weight loss. Simultaneously it improved glucose intolerance, glycated hemoglobin, insulin resistance/sensitivity, plasma lipids, and gastric inhibitory polypeptide. Semaglutide and paired feeding mitigated liver steatosis and adipose differentiation-related protein (Plin2) expression. Semaglutide also improved hormones and adipokines, reduced lipogenesis and inflammation, and increased beta-oxidation. Semaglutide lessened liver glucose uptake and endoplasmic reticulum (ER) stress. Among the 14 genes analyzed, 13 were modified by Semaglutide (93 %, six genes were changed exclusively by Semaglutide, and seven other genes were affected by the combination of Semaglutide and paired feeding). In seven genes, the paired diet showed no effect (50% of the genes tested). No marker was affected exclusively by paired feeding.

CONCLUSIONS

Semaglutide and the consequent weight loss reduced obese mice liver inflammation, insulin resistance, and ER stress. However, weight loss alone did show few or no action on some significant study findings, like liver steatosis, leptin, insulin, resistin, and amylin. Furthermore, hepatic inflammation mediated by MCP-1 and partially by TNF-alpha and IL6 were also not reduced by weight loss. Furthermore, weight loss alone did not lessen hepatic lipogenesis as determined by the findings of SREBP-1c, CHREBP, PPAR-alpha, and SIRT1. Semaglutide was implicated in improving glucose uptake and lessening ER stress by reducing GADD45, independent of weight loss.

Adropin as a potential mediator of the metabolic system-autonomic nervous system-chronobiology axis: Implementing a personalized signature-based platform for chronotherapy

Adropin is a peptide hormone, which plays a role in energy homeostasis and controls glucose and fatty acid metabolism. Its levels correlate with changes in carbohydrate-lipid metabolism, metabolic diseases, central nervous system function, endothelial function and cardiovascular disease. Both metabolic pathways and adropin are regulated by the circadian clocks. Here, we review the roles of the autonomic nervous system and circadian rhythms in regulating metabolic pathways and energy homeostasis. The beneficial effects of chronotherapy in various systems are discussed. We suggest a potential role for adropin as a mediator of the metabolic system-autonomic nervous system axis. We discuss the possibility of establishing an individualized adropin and circadian rhythm-based platform for implementing chronotherapy, and variability signatures for improving the efficacy of adropin-based therapies are discussed.

Protocol for a single-centre, parallel-group, randomised, controlled, superiority trial on the effects of time-restricted eating on body weight, behaviour and metabolism in individuals at high risk of type 2 diabetes: the REStricted Eating Time (RESET) study

INTRODUCTION

The aim of this study is to investigate the effects of time-restricted eating (TRE) on change in body weight and describe changes in behaviour and metabolism in individuals at high risk of type 2 diabetes.

METHODS AND ANALYSIS

The REStricted Eating Time (RESET) study is a randomised controlled parallel-group open-label trial. 100 women and men with (1) overweight (body mass index (BMI)≥25 kg/m²) and prediabetes (glycated haemoglobin 39-47 mmol/mol); or (2) obesity (BMI≥30 kg/m²) will be randomised to a control group (habitual living) or TRE (self-selected 10-hours eating window within the period from 06:00 to 20:00 in a 1:1 ratio. Testing is scheduled at baseline and after 6 weeks (mid-intervention), 3 months (post-intervention) and 6 months (follow-up). The primary outcome is change in body weight after 3 months of intervention. Secondary outcomes include changes in body composition; measures of glucose metabolism including glycaemic variability, hormones and metabolites; subjective and metabolic markers of appetite, food preferences and reward; dietary intake; physical activity, sleep, chronotype; gastric emptying, gastrointestinal transit time and motility; respiratory and glycolytic capacities; the plasma proteome and metabolome; blood pressure, resting heart rate and heart rate variability; and resting energy expenditure and substrate oxidation. Motivation and feasibility will be examined based on interviews at baseline and after 3 months. After the 3-month intervention, a 3-month follow-up period and subsequent testing are scheduled to assess maintenance and longer-term effects.

ETHICS AND DISSEMINATION

The study has been approved by the Ethics Committee of the Capital Region of Denmark (H-18059188) and the Danish Data Protection Agency. The study will be conducted in accordance with the Declaration of Helsinki. Results from the study will address whether TRE is effective and feasible in improving health outcomes in individuals at risk of lifestyle-related diseases and can potentially inform the design of feasible health recommendations.

TRIAL REGISTRATION NUMBER

NCT03854656.

Challenging energy balance - during sensitivity to food reward and modulatory factors implying a risk for overweight - during body weight management including dietary restraint and medium-high protein diets

Energy balance is a key concept in the etiology and prevalence of obesity and its co-morbidities, as well as in the development of possible treatments. If energy intake exceeds energy expenditure, a positive energy balance develops and the risk for overweight, obesity, and its co-morbidities increases. Energy balance is determined by energy homeostasis, and challenged by sensitivity to food reward, and to modulatory factors such as circadian misalignment, high altitude, environmental temperature, and physical activity. Food reward and circadian misalignment increase the risk for overweight and obesity, while high altitude, changes in environmental temperature, or physical activity modulate energy balance in different directions. Modulations by hypobaric hypoxia, lowering environmental temperature, or increasing physical activity have been hypothesized to contribute to body weight loss and management, yet no clear evidence has been shown. Dietary approach as part of a lifestyle approach for body weight management should imply reduction of energy intake including control of food reward, thereby sustaining satiety and fat free body mass, sustaining energy expenditure. Green tea catechins and capsaicin in red pepper in part meet these requirements by sustaining energy expenditure and increasing fat oxidation, while capsaicin also suppresses hunger and food intake. Protein intake of at least 0,8 g/kg body weight meets these requirements in that it, during decreased energy intake, increases food intake control including control of food reward, and counteracts adaptive thermogenesis. Prevention of overweight and obesity is underscored by dietary restraint, implying control of sensitivity to challenges to energy balance such as food reward and circadian misalignment. Treatment of overweight and obesity may be possible using a medium-high protein diet (0,8-1,2 g/kg), together with increased dietary restraint, while controlling challenges to energy balance.

Intermittent fasting, adipokines, insulin sensitivity, and hypothalamic neuropeptides in a dietary overload with high-fat or high-fructose diet in mice

The intermittent fasting (IF) might have benefits on metabolism and food intake. Twelve-week old C57BL/6 J mice were fed a control diet (C, 10% kcal fat), a high-fat diet (HF, 50% kcal fat) or a high-fructose diet (HFru, 50% kcal fructose) for 8 weeks, then half of the animals in each group underwent IF (24 h fed, 24 h fasting) for an additional 4 weeks. Although food intake on the fed day remained the same for all groups, all fasting groups showed a reduction in body mass compared to their counterparts. IF reduced total cholesterol, triacylglycerol, fasting glucose, fasting insulin resistance index, and plasma leptin, but increased plasma adiponectin. IF reduced Leptin gene expression in the HF-IF group, but increased proinflammatory markers in the hypothalamus, also in the C-IF group. Both groups HFru-IF and C-IF, showed alterations in the leptin signaling pathway (Leptin, OBRb, and SOCS3), mainly in the HFru-IF group, suggesting leptin resistance. NPY and POMC neuropeptides labeled the neurons of the hypothalamus by immunofluorescence, corroborating qualitatively other quantitative findings of the study. In conclusion, current results are convincing in demonstrating the IF effect on central regulation of food intake control, as shown by NPY and POMC neuropeptide expressions, resulting in a lower weight gain. Besides, IF improves glycemia, lipid metabolism, and consequently insulin and leptin resistance. However, there is increased expression of inflammatory markers in mouse hypothalamus challenged by the HF and HFru diets, which in the long term may induce adverse effects.

Sleep Extension Increases the Effect of Caloric Restriction Over Body Weight and Improves the Chronic Low-Grade Inflammation in Adolescents With Obesity

PURPOSE

Diminution of sleep may be associated with obesity. However, evidence that extending sleep duration might favor weight loss is insufficient. The aim of this study was to compare the effect of dietary restriction with or without prescription of sleep extension on weight loss in adolescents with obesity.

METHODS

A total of 52 adolescents with obesity (24 males and 28 females) received a diet with 500 calories restriction, randomly allocated to groups without (n = 27) and with sleep extension (n = 25) for 4 weeks. We collected data on anthropometry, caloric intake, and self-reported sleep diaries. Serum interleukin 6, tumor necrosis factor α, leptin, and insulin levels were quantified by enzyme-linked immunosorbent assay. Cortisol and 6-sulfatoxymelatonin excretions were measured in the first urine collection in the morning by liquid chromatography-mass spectrometry. Measurements were carried out at baseline and at the end of the intervention.

RESULTS

After diet, weight decreased in both groups. Sleep extension, improved weight loss (p < .00001), and waist girth reduction (p = .00003), with diminution of insulin (p = .002) and interleukin 6 levels (p = .02). Caloric restriction was less effective in adolescent females. No differences in cortisol or 6-sulfatoxymelatonin excretion were found.

CONCLUSIONS

A sleep extension favors weight loss in adolescents under caloric restriction and improves inflammation and metabolic conditions, thus supporting a possible additional benefit to diet in the treatment of obesity in adolescents.

Sleep Duration as an Indirect Link Between Sleep Timing and Weight in Midlife Women

Objective: Midlife women are at risk of obesity. Poor sleep outcomes including inadequate sleep duration and variable sleep timing are risk factors for obesity, but there is a lack of understanding on how specific sleep constructs uniquely or concurrently are associated with weight outcomes in this population. This study examined the unique association of sleep timing with weight outcomes and how sleep timing works in conjunction with sleep duration to influence weight in midlife women. Materials and Methods: An archival analysis was performed using the Midlife in the United States-II study (MIDUS-II). The sample consisted of 132 midlife women (40-64; M = 52.9, standard deviation = 6.94). Sleep timing (mean sleep time, variability) and duration were measured through actigraphy and daily sleep diaries. Weight was assessed using body mass index (BMI) and waist circumference measures. Results: PROCESS mediation and moderation analyses assessed direct, indirect, and moderating pathways. Sleep duration emerged as an indirect link between sleep timing (mean and variability) and weight outcomes (95% CI = 0.0001-0.0123; 95% CI = 0.0007-0.0378; 95% CI = 0.0079-0.1006). Sleep timing (95% CI = -0.0144 to 0.0076; 95% CI = -0.0358 to 0.0219) and sleep time variability (95% CI = -0.0124 to 0.0438; 95% CI = -0.0533 to 0.0939) were not directly associated with BMI or waist circumference. Also, sleep timing and duration did not interact to influence weight outcomes. Conclusions: Sleep duration, rather than sleep timing, is associated with weight outcomes, and is an indirect link in the sleep timing and weight outcomes association. Future work is needed to further disentangle the impact of sleep on weight in midlife women using prospective studies, implementing daily assessments of sleep behavior.

A Specialized Medical Management Program to Address Post-operative Weight Regain in Bariatric Patients

INTRODUCTION

Although bariatric surgery results in massive weight loss, weight regain over time up to as much as 25% is not uncommon. Weight regain in this population often leads to long-term weight loss failure and non-compliance in clinical follow-up and program recommendations.

METHODS

We analyzed early weight outcomes at 3 and 6 months of 48 bariatric patients referred to an individualized, multidisciplinary medical management program at the Center for Obesity Medicine (COM) to address weight regain in 2015 and compared to a group of matched non-bariatric patients. The medical management center, under the direction of a medical obesity specialist and complementary to the surgical program and multidisciplinary team, addressed weight regain with intensive lifestyle (diet, activity, anti-stress therapy, behavioral counseling, sleep) and with medical intervention (one or more anti-obesity medications).

RESULTS

According to early findings, the average percentage post-operative weight regain of patients entering the weight management program was 20% above nadir and time since surgery averaged 6 years (range = 1 to 20 years) with a mean weight loss of - 2.3 kg after 3 months and - 4.4 kg at 6 months into the program. Individuals most successful with weight loss were those treated with anorexigenic pharmaceuticals. Weight and percent weight loss were significantly greater for the non-surgical than the surgical patients at 3 and 6 months (p < 0.05).

CONCLUSIONS

A medically supervised weight management program complementary to surgery is beneficial for the treatment of weight regain and may prove important in assisting the surgical patient achieve long-term weight loss success.

Cross-sectional and Prospective Associations of Actigraphy-Assessed Sleep Regularity With Metabolic Abnormalities: The Multi-Ethnic Study of Atherosclerosis

OBJECTIVE

To cross-sectionally and prospectively investigate the association between irregular sleep patterns, a potential marker for circadian disruption, and metabolic abnormalities.

RESEARCH DESIGN AND METHODS

In the Multi-Ethnic Study of Atherosclerosis, participants completed 7-day actigraphy at exam 5 (2010-2013) and were prospectively followed throughout exam 6 (2016 to 2017). Sleep regularity was quantified by the 7-day SD of actigraphy-assessed sleep duration and sleep onset timing. Metabolic abnormalities were defined by 1) the National Cholesterol Education Program Adult Treatment Panel III criteria and 2) a data-driven clustering of metabolic factors.

RESULTS

In the exam 5 cross-sectional analysis adjusted for sociodemographic and lifestyle factors (n = 2,003), every 1-h increase in the sleep duration SD was associated with 27% (95% CI 1.10, 1.47) higher odds of metabolic syndrome, and every 1-h increase in the sleep timing SD was associated with 23% (95% CI 1.06, 1.42) higher odds. The associations remained significant with additional adjustment for sleep-related factors including sleep duration. In the prospective analysis (n = 970), the corresponding fully adjusted odds ratio (OR) was 1.27 (95% CI 0.97, 1.65) for sleep duration and 1.36 (1.03, 1.80) for sleep timing. Compared with the cluster of few metabolic changes, every 1-h increase in sleep variability was associated with almost doubled odds for the cluster characterized by incidence of multiple metabolic abnormalities (OR 1.97 [95% CI 1.18, 3.30] for sleep duration and OR 2.10 [95% CI 1.25, 3.53] for sleep timing).

CONCLUSIONS

Increased variability in sleep duration and timing was associated with higher prevalence and incidence of metabolic abnormalities even after consideration of sleep duration and other lifestyle factors.

[Pathophysiological aspects of neuro-endocrine regulation system in patients with obstructive sleep apnea syndrome]

AIM

To reveal the changes in the pituitary-thyroid, pituitary-gonadal, adrenal components and in the prolactinergic system of neuroendocrine regulation in patients with severe obstructive sleep apnea syndrome (OSAS).

MATERIAL AND METHODS

The study involved 51 men aged 46-55 years. The main group (BG) included 37 patients with severe OSAS. The duration of clinical manifestations of OSAS was 10.5±1.5 years. OSAS was verified on the basis of clinical and functional studies and polysomnographic monitoring in accordance with the AASM criteria (2014). The control group (CG) consisted of 14 age-matched men without sleep-disordered breathing. The body mass index in BG was 34.2±1.8 compared to 28.2±2.1 kg/m² in CG. Serum concentrations of thyroid-stimulating hormone (TTG), free thyroxine (T4), triiodothyronine (T3), cortisol, prolactin, testosterone, luteonizing (LH) and follicle-stimulating (FSH) hormones were determined by the immunoradiological method using the standard DIA test system (Russia) and the analyzer 'Immunotest-800'.

RESULTS

Patients with severe OSAS had decreased concentration of free thyroxine (T4) and decreased activity of thyroid stimulating hormone (TSH) (р<0.001), increased concentration of prolactin and cortisol (р<0.001), decreased concentration of luteinizing hormone (LH), follicle-stimulating hormone (FSH) and testosterone compared to the controls (р<0.001).

CONCLUSION

The changes in the hypothalamic-pituitary-gonadal system are a manifestation of disturbances of the mechanisms of self-regulation and compensation that indicates the presence of maladaptive reactions of the neuroendocrine system.

Assessment of maximal fat oxidation during exercise: A systematic review

Maximal fat oxidation during exercise (MFO) and the exercise intensity eliciting MFO (Fat_max ) are considered biological markers of metabolic health and performance. A wide range of studies have been performed to increase our knowledge about their regulation by exercise and/or nutritional intervention. However, numerous data collection and analysis approaches have been applied, which may have affected the MFO and Fat_max estimation. We aimed to systematically review the available studies describing and/or comparing different data collection and analysis approach factors that could affect MFO and Fat_max estimation in healthy individuals and patients. Two independent researchers performed the search. We included all original studies in which MFO and/or Fat_max were estimated by indirect calorimetry through an incremental graded exercise protocol published from 2002 to 2019. This systematic review provides key information about the factors that could affect MFO and Fat_max estimation: ergometer type, metabolic cart used, warm-up duration and intensity, stage duration and intensities imposed in the graded exercise protocol, time interval selected for data analysis, stoichiometric equation selected to estimate fat oxidation, data analysis approach, time of the day when the test was performed, fasting time/previous meal before the test, and testing days for MFO/Fat_max and maximal oxygen uptake assessment. We suggest that researchers measuring MFO and Fat_max should take into account these key methodological issues that can considerably affect the accuracy, validity, and reliability of the measurement. Likewise, when comparing different studies, it is important to check whether the above-mentioned key methodological issues are similar in such studies to avoid ambiguous and unacceptable comparisons.

Salivary alpha-amylase and hormones levels of young adults with different body composition

The aim of this study was to assess the differences in salivary biomarker levels of young adults classified according to body fat accumulation. One hundred and thirty-four volunteers were evaluated (mean age 21 ± 2 years). Body composition was calculated through skinfold thickness: supra-iliac, biceps, and triceps, sub-scapular. Body fat percentage (BF%) was used to classify subjects according to fat tissue accumulation: normal-weight (n = 37, 19 females, 18 males), overweight (n = 42, 30 females, 12 males), and obese (n = 55, 42 females, 13 males). Saliva samples were collected 30 min after awakening to determine salivary levels of 17-beta-estradiol. For salivary cortisol and alpha-amylase activity (sAA) three samples were obtained, just after awakening, 30 min after awakening and at bedtime. Oral contraceptive intake was considered for the female group. The results showed that overweight and obese females using oral contraceptive presented lower levels of 17-β-estradiol than normal-weight females. In overweight and obese males, sAA levels were higher 30 min post-awakening when compared with the normal-weight group. The comparison of sAA levels within time showed no difference for males; obese females showed significant higher values at bedtime than 30 min post-awakening. The salivary cortisol concentration showed higher values at morning decreasing significantly at bedtime for all groups. Concluding, differences in 17-β-estradiol and sAA levels were found in females and males, respectively, according to body fat accumulation, showing the usefulness of salivary biomarkers in the study of systemic conditions. PRACTICAL APPLICATIONS: Saliva is an advantageous biological fluid in innovative methods for diagnosis. Besides being a noninvasive method, salivary steroid measurements have the potential to provide a convenient assessment of serum free steroid concentrations.

Links between the circadian rhythm, obesity and the microbiome

Obesity is linked to a wide range of serious illnesses. In addition to the important impact on the health of the individual, obesity also has a substantial impact on the economy. Disruption of physiological day-night cycles could contribute to the increased incidence of obesity. According to the American National Sleep Federation, the percentage of the people who reported a sleep duration of six hours or less increased from 12 to 37 % over ten years. Insufficient sleep leads not only to an increase of the total calorie intake but changes the meal preference in favor of palatable foods and meals with high carbohydrate content. A decrease of leptin and increase of ghrelin levels caused by sleep deficiency can also play a role. In addition to the higher caloric intake, the timing of food consumption should be taken into account. The same meal eaten during the night versus the day is associated with increased postprandial glucose and triglyceride levels. The gut microbiome has also been recently understood as an endocrine system, with links between the gut microbiome and circadian rhythm changes possibly influencing increased obesity.

Hypothalamic Dysfunction in Obesity and Metabolic Disorders

The hypothalamus is the brain region responsible for the maintenance of energetic homeostasis. The regulation of this process arises from the ability of the hypothalamus to orchestrate complex physiological responses such as food intake and energy expenditure, circadian rhythm, stress response, and fertility. Metabolic alterations such as obesity can compromise these hypothalamic regulatory functions. Alterations in circadian rhythm, stress response, and fertility further contribute to aggravate the metabolic dysfunction of obesity and contribute to the development of chronic disorders such as depression and infertility.At cellular level, obesity caused by overnutrition can damage the hypothalamus promoting inflammation and impairing hypothalamic neurogenesis. Furthermore, hypothalamic neurons suffer apoptosis and impairment in synaptic plasticity that can compromise the proper functioning of the hypothalamus. Several factors contribute to these phenomena such as ER stress, oxidative stress, and impairments in autophagy. All these observations occur at the same time and it is still difficult to discern whether inflammatory processes are the main drivers of these cellular dysfunctions or if the hypothalamic hormone resistance (insulin, leptin, and ghrelin) can be pinpointed as the source of several of these events.Understanding the mechanisms that underlie the pathophysiology of obesity in the hypothalamus is crucial for the development of strategies that can prevent or attenuate the deleterious effects of obesity.

A Novel Insight of Effects of a 3-Hz Binaural Beat on Sleep Stages During Sleep

The dichotic presentation of two almost equivalent pure tones with slightly different frequencies leads to virtual beat perception by the brain. In this phenomenon, the so-called binaural beat has a frequency equaling the difference of the frequencies of the two pure tones. The binaural beat can entrain neural activities to synchronize with the beat frequency and induce behavioral states related to the neural activities. This study aimed to investigate the effect of a 3-Hz binaural beat on sleep stages, which is considered a behavioral state. Twenty-four participants were allocated to experimental and control groups. The experimental period was three consecutive nights consisting of an adaptation night, a baseline night, and an experimental night. Participants in both groups underwent the same procedures, but only the experimental group was exposed to the 3-Hz binaural beat on the experimental night. The stimulus was initiated when the first epoch of the N2 sleep stage was detected and stopped when the first epoch of the N3 sleep stage detected. For the control group, a silent sham stimulus was used. However, the participants were blinded to their stimulus group. The results showed that the N3 duration of the experimental group was longer than that of the control group, and the N2 duration of the experimental group was shorter than that of the control group. Moreover, the N3 latency of the experimental group was shorter.

Interventions that stimulate healthy sleep in school-aged children: a systematic literature review

Background

Healthy sleep among children has social, physical and mental health benefits. As most of today’s children do not meet the healthy sleep recommendations, effective interventions are urgently needed. This systematic review summarizes the characteristics and effectiveness of interventions aiming to stimulate healthy sleeping in a general population of school-aged children.

Methods

The search engines PubMed, Embase, Web of Science, PsycInfo and the Cochrane Database Library were systematically searched up to March 2016. We included all studies evaluating interventions targeting healthy sleep duration and/or bedtime routines of children aged 4–12 years. All steps in this systematic review, i.e. search, study selection, quality assessment and data extraction, were performed following CRD Guidelines and reported according to the PRISMA Statement.

Results

Eleven studies were included, of which only two were of strong quality. The interventions varied in terms of targeted determinants and intervention setting. Overall, no evidence was found favoring a particular intervention strategy. One intervention that delayed school start time and two multi-behavioral interventions that targeted both the school and home setting showed promising effects in terms of increasing sleep duration.

Conclusion

Due to few high quality studies, evidence for the effectiveness of any particular intervention strategy to stimulate healthy sleep in children is still inconclusive. However, the more effective interventions in stimulating healthy sleep duration and adherence to regular bedtimes were mostly multi-behavioral interventions that included creating daily healthy routines and combined intervention settings (e.g. home and school). In conclusion, high-quality studies evaluating systematically developed interventions are needed to move this field forward.

Obesity, Hypersomnolence, and Quality of Sleep: the Impact of Bariatric Surgery

PURPOSE

Obesity is commonly associated with poor sleep, excessive daytime sleepiness (EDS) and depressive mood but the impact of bariatric surgery on these conditions is incompletely understood. This study aimed to investigate the course of EDS and sleep quality in bariatric surgery patients in relation with changes in body weight and depressive symptoms.

METHODS

In patients consecutively submitted to bariatric surgery, baseline and postoperative sleep quality were evaluated by the Pittsburgh Sleep Quality Index (PSQI), excessive daytime sleepiness by the Epworth Sleepiness Scale (ESS), risk for OSA by the Berlin Questionnaire (BQ), and depressive symptoms by the Beck Depression Inventory-Short Form (BDI). Comorbidities were assessed by interview and chart review.

RESULTS

Sixty patients (M/F = 9/51) with a mean (±SD) age of 34.7 ± 9.2 years and body mass index (BMI) of 46.04 ± 7.52 kg/m² were studied. Bariatric surgery improved PSQI score (6.4 ± 3.8 versus 4.1 ± 2.8; p < 0.001), ESS score (8.1 ± 4.7 versus 6.0 ± 3.3; p < 0.001), BDI score (9.8 ± 7.0 versus 4.7 ± 4.6; p = 0.001), and risk for OSA (68.3 versus 5%). Twelve of the 18 subjects with baseline EDS (ESS ≥ 10) developed normal ESS score after surgery. In these subjects, significant postoperative improvement in depressive symptoms score was observed (12.0 ± 9.0 versus 5.5 ± 5.0; p = 0.041), in contrast to the remaining six cases with persistent EDS, who showed no significant change in these symptoms (5.5 ± 5.0 versus 3.2 ± 3.1; p = 0.416).

CONCLUSION

Bariatric surgery has a beneficial effect on sleep quality and EDS. Postoperative improvement in EDS can be related to a reduction in depressive symptoms.

Is a SIMPLe smartphone application capable of improving biological rhythms in bipolar disorder?

BACKGROUND

Biological rhythms (BR) disturbance has been suggested as a potential mediator of mood episodes in Bipolar Disorder (BD). The Biological Rhythms Interview of Assessment in Neuropsychiatry (BRIAN) was designed as an assessment tool to evaluate BR domains comprehensively. In the context of a trial evaluating a smartphone application delivering personalized psychoeducational contents for BD (SIMPLe 1.0), the main aim of this study is to evaluate the potential impact of SIMPLe 1.0 in BR regulation using the BRIAN scale.

METHODS

51 remitted BD patients were asked to use the application for 3 months. Paired t-test analyses were employed to compare baseline and follow-up BRIAN´s total and domains scores. The sample was divided into completers and non-completers of the study to evaluate differences between groups regarding BRIAN scores using ANCOVA analyses.

RESULTS

The BRIAN's mean total score of the whole sample significantly decreased from baseline to post-intervention (35.89 (SD 6.64) vs. 31.18 (SD 6.33), t = 4.29, p = 0.001). At post-intervention, there was a significant difference between groups regarding the total BRIAN mean score (29.47 (SD 6.21) completers vs. 35.92 (SD 3.90) non-completers, t = 2.50, p = 0.02). This difference was maintained after conducting a one-way ANCOVA controlling for pre-intervention BRIAN scores, F (1, 46) = 10.545, p=0.002.

LIMITATIONS

A limited sample, pre-post measures, and a short study timeframe could have affected the results. Additional factors affecting BR, such as medication, could not be ruled out.

CONCLUSION

Our results suggest that there are potential positive effects of a psychoeducational smartphone application as an adjunctive to treatment as usual on BD patients' BR.

Obstructive sleep apnea and hormones - a novel insight

Obstructive sleep apnea (OSA), a disorder characterized by repetitive collapse of the upper respiratory tract during sleep, occurs in about 4% of middle-aged men and 2% of women. The incidence of the disorder is rising due to an increase in obesity and ageing of the population. Patients with obstructive sleep apnea are at elevated risk of some endocrinal and metabolic disorders, which may lead to serious consequences including shortening of life expectancy. The recognition and understanding of interactions between local upper airway dysfunction and its endocrinal consequences is therefore vital. In this review we will focus on the influence of OSA on bone metabolism and endocrine homeostasis.

Shift Work: Disrupted Circadian Rhythms and Sleep-Implications for Health and Well-Being

PURPOSE OF REVIEW

Our 24/7 society is dependent on shift work, despite mounting evidence for negative health outcomes from sleep displacement due to shift work. This paper reviews short- and long-term health consequences of sleep displacement and circadian misalignment due to shift work.

RECENT FINDINGS

We focus on four broad health domains: metabolic health; risk of cancer; cardiovascular health; and mental health. Circadian misalignment affects these domains by inducing sleep deficiency, sympathovagal and hormonal imbalance, inflammation, impaired glucose metabolism, and dysregulated cell cycles. This leads to a range of medical conditions, including obesity, metabolic syndrome, type II diabetes, gastrointestinal dysfunction, compromised immune function, cardiovascular disease, excessive sleepiness, mood and social disorders, and increased cancer risk.

SUMMARY

Interactions of biological disturbances with behavioral and societal factors shape the effects of shift work on health and well-being. Research is needed to better understand the underlying mechanisms and drive the development of countermeasures.

Diet-Induced Obesity and Circadian Disruption of Feeding Behavior

Feeding behavior shows a rhythmic daily pattern, which in nocturnal rodents is observed mainly during the dark period. This rhythmicity is under the influence of the hypothalamic suprachiasmatic nucleus (SCN), the main biological clock. Nevertheless, various studies have shown that in rodent models of obesity, using high-energy diets, the general locomotor activity and feeding rhythms can be disrupted. Here, we review the data on the effects of diet-induced obesity (DIO) on locomotor activity and feeding patterns, as well as the effect on the brain sites within the neural circuitry involved in metabolic and rewarding feeding behavior. In general, DIO may alter locomotor activity by decreasing total activity. On the other hand, DIO largely alters eating patterns, producing increased overall ingestion and number of eating bouts that can extend to the resting period. Furthermore, within the hypothalamic areas, little effect has been reported on the molecular circadian mechanism in DIO animals with ad libitum hypercaloric diets and little or no data exist so far on its effects on the reward system areas. We further discuss the possibility of an uncoupling of metabolic and reward systems in DIO and highlight a gap of circadian and metabolic research that may help to better understand the implications of obesity.

Circadian Rhythms of Carbohydrate Metabolism in Women with Different Types of Obesity

Blood levels of glucose and immunoreactive insulin were assessed in women with android and gynoid types of obesity or normal body weight (control group) in the dynamics of oral glucose tolerance test in the morning and in the evening. In the control group, the mean concentrations of glucose and immunoreactive insulin were significantly higher in the evening at all test terms (0, 60 and 120 min), which is indicative of physiological insulin resistance in the evening. In the group of women with gynoid obesity, no difference in the levels of glucose and immunoreactive insulin was revealed in the morning and evening tests, but in the evening tests, glucose (60 and 120 min) and immunoreactive insulin (120 min) levels were lower than in the control group. In the group of women with android obesity, the evening glucose level on minutes 60 and 120 of the test was higher than in the morning, but immunoreactive insulin did not vary throughout the day and on minutes 60 and 120 it surpassed the corresponding parameter in the control group by 2-4 times. In case of gynoid obesity, glucose load was followed by hyperinsulinemia and hypoglycemia; in android obesity, it was followed by hyperinsulinemia, hyperglycemia, and insulin resistance irrespective of the time of the day.

Metabolic disturbances: role of the circadian timing system and sleep

The incidence of metabolic disorders such as obesity and diabetes is on the rise, and food quality is not alone to blame. Sleep disturbances, altered feeding time and circadian disruption are linked to metabolic disturbances in many clinical research studies and cross-sectional analyses. This review tried to summarize the role of the circadian timing system and sleep on energy and metabolic homeostasis. We also tried to explain the molecular and endocrine mechanisms behind circadian misalignment and sleep disorders that lead to metabolic disorders.

Associations of common chronic non-communicable diseases and medical conditions with sleep-related problems in a population-based health examination study

A cross-sectional population-based survey, the National FINRISK 2012 Study, designed to monitor chronic diseases and their risk factors in Finland. A random sample of 10,000 adults aged 25-74 years, and of them, 64% (n=6424) participated the study. Participants subjectively reported the total durations for sleep and naps (n=6238), sleep quality (n=5878), bedtimes and wake-up times separately for working days and weekends yielding the amount of sleep debt (n=5878), and the seasonal variation in sleep duration (n=4852). The participants were asked whether they were diagnosed or treated for common chronic diseases in the past 12 months. Logistic regression models were adopted to analysis and adjusted for a range of covariates as potential confounding factors. Total sleep duration and nap duration prolonged in depression and other mental disorder (p<.001 for all). Seasonal variation in sleep duration was associated with depression (p=.014), hypertension (p=.018) and angina pectoris (p=.024). Participants with gallstones, cardiac insufficiency, depression, or degenerative arthritis had poor sleep quality (odds ratios of 1.6-6.3, p=.001 or less for each). Those with degenerative arthritis had sleep debt less (p<.05) and those with angina pectoris more (p<.05) than individuals without these medical conditions. Depression is significantly associated with sleep problems, albeit no sleep debt. Cardiovascular diseases, degenerative arthritis, and gallstones had significant associations with one or more sleep problems. There is therefore a need for more successful management of sleep problems in chronic diseases to improve the quality of life, to reduce treatment relapses, and to increase health and longevity in a population.

Changes in taste preference and steps taken after sleep curtailment

A substantial proportion of the population does not achieve the recommended amount of sleep. Previous work demonstrates that sleep alterations perturb energy balance by disrupting appetite hormones, increasing energy intake, and decreasing physical activity. This study explored the influence of sleep duration on taste perception as well as effects on dietary intake and physical activity. Participants (n=24 habitual short sleepers and n=27 habitual long sleepers, 82.4% female, 88.2% white, 25.2±7.7years) completed two randomized taste visits; one following short sleep duration (≤7h) and one following long sleep duration (>7h). Taste perception measures included sweet and salt detection thresholds (ascending 3-alternative, forced-choice method), as well as sweet preference (Monell 2-series, forced-choice, paired-comparison, tracking method). Steps and sleep were tracked via FitBit, an activity monitoring device. Dietary intake was assessed using 24-hour recalls and analyzed using Nutritionist Pro. Habitual long-sleepers had a higher sweet taste preference (p=0.042) and took fewer steps (p=0.036) following sleep curtailment compared to the night where they slept >7h but did not experience changes in dietary intake or detection thresholds. Habitual short-sleepers did not experience changes in taste perception, activity, or dietary intake following sleep alteration. Habitual long-sleepers may be at greater risk of gaining weight when typical sleep patterns are disrupted.

Sleep, circadian rhythm and body weight: parallel developments

Circadian alignment is crucial for body-weight management, and for metabolic health. In this context, circadian alignment consists of alignment of sleep, meal patterns and physical activity. During puberty a significant reduction in sleep duration occurs, and pubertal status is inversely associated with sleep duration. A consistent inverse association between habitual sleep duration and body-weight development occurs, independent of possible confounders. Research on misalignment reveals that circadian misalignment affects sleep-architecture and subsequently disturbs glucose–insulin metabolism, substrate oxidation, leptin- and ghrelin concentrations, appetite, food reward, hypothalamic–pituitary–adrenal-axis activity and gut-peptide concentrations enhancing positive energy balance and metabolic disturbance. Not only aligning meals and sleep in a circadian way is crucial, also regular physical activity during the day strongly promotes the stability and amplitude of circadian rhythm, and thus may serve as an instrument to restore poor circadian rhythms. Endogenicity may play a role in interaction of these environmental variables with a genetic predisposition. In conclusion, notwithstanding the separate favourable effects of sufficient daily physical activity, regular meal patterns, sufficient sleep duration and quality sleep on energy balance, the overall effect of the amplitude and stability of the circadian rhythm, perhaps including genetic predisposition, may integrate the separate effects in an additive way.

Bedtime Variability and Metabolic Health in Midlife Women: The SWAN Sleep Study

STUDY OBJECTIVES

Circadian misalignment, as seen in shift workers, can disrupt metabolic processes. Associations between sleep timing in nonshift workers and metabolic health are unknown. We examined sleep timing and indices of metabolic health in a community sample of midlife women.

METHODS

Caucasian (n = 161), African American (n = 121) and Chinese (n = 56) non-shift-working women aged 48-58 y who were not taking insulin-related medications, participated in the Study of Women's Health Across the Nation (SWAN) Sleep Study and were subsequently examined approximately 5.39 (standard deviation = 0.71) y later. Daily diary-reported bedtimes were used to calculate four measures of sleep timing: mean bedtime, bedtime variability, bedtime delay and bedtime advance. Body mass index (BMI) and insulin resistance (homeostatic model assessment-insulin resistance, HOMA-IR) were measured at two time points. Linear regressions evaluated whether sleep timing was associated with BMI and HOMA-IR cross-sectionally and prospectively.

RESULTS

In cross-sectional models, greater variability in bedtime and greater bedtime delay were associated with higher HOMA-IR (β = 0.128; P = 0.007, and β = 0.110; P = 0.013, respectively) and greater bedtime advance was associated with higher BMI (β = 0.095; P = 0.047). Prospectively, greater bedtime delay predicted increased HOMA-IR at Time 2 (β = 0.152; P = 0.003). Results were partially explained by shifted sleep timing on weekends.

CONCLUSION

Frequent shifts in sleep timing may be related to metabolic health among non-shift working midlife women.

COMMENTARY

A commentary on this article appears in this issue on page 269.

Dietary and Policy Priorities for Cardiovascular Disease, Diabetes, and Obesity: A Comprehensive Review

Suboptimal nutrition is a leading cause of poor health. Nutrition and policy science have advanced rapidly, creating confusion yet also providing powerful opportunities to reduce the adverse health and economic impacts of poor diets. This review considers the history, new evidence, controversies, and corresponding lessons for modern dietary and policy priorities for cardiovascular diseases, obesity, and diabetes mellitus. Major identified themes include the importance of evaluating the full diversity of diet-related risk pathways, not only blood lipids or obesity; focusing on foods and overall diet patterns, rather than single isolated nutrients; recognizing the complex influences of different foods on long-term weight regulation, rather than simply counting calories; and characterizing and implementing evidence-based strategies, including policy approaches, for lifestyle change. Evidence-informed dietary priorities include increased fruits, nonstarchy vegetables, nuts, legumes, fish, vegetable oils, yogurt, and minimally processed whole grains; and fewer red meats, processed (eg, sodium-preserved) meats, and foods rich in refined grains, starch, added sugars, salt, and trans fat. More investigation is needed on the cardiometabolic effects of phenolics, dairy fat, probiotics, fermentation, coffee, tea, cocoa, eggs, specific vegetable and tropical oils, vitamin D, individual fatty acids, and diet-microbiome interactions. Little evidence to date supports the cardiometabolic relevance of other popular priorities: eg, local, organic, grass-fed, farmed/wild, or non-genetically modified. Evidence-based personalized nutrition appears to depend more on nongenetic characteristics (eg, physical activity, abdominal adiposity, gender, socioeconomic status, culture) than genetic factors. Food choices must be strongly supported by clinical behavior change efforts, health systems reforms, novel technologies, and robust policy strategies targeting economic incentives, schools and workplaces, neighborhood environments, and the food system. Scientific advances provide crucial new insights on optimal targets and best practices to reduce the burdens of diet-related cardiometabolic diseases.

Circadian Clocks as Modulators of Metabolic Comorbidity in Psychiatric Disorders

Psychiatric disorders such as schizophrenia, bipolar disorder, and major depressive disorder are often accompanied by metabolic dysfunction symptoms, including obesity and diabetes. Since the circadian system controls important brain systems that regulate affective, cognitive, and metabolic functions, and neuropsychiatric and metabolic diseases are often correlated with disturbances of circadian rhythms, we hypothesize that dysregulation of circadian clocks plays a central role in metabolic comorbidity in psychiatric disorders. In this review paper, we highlight the role of circadian clocks in glucocorticoid, dopamine, and orexin/melanin-concentrating hormone systems and describe how a dysfunction of these clocks may contribute to the simultaneous development of psychiatric and metabolic symptoms.

Sleep and nighttime energy consumption in early childhood: a population-based cohort study

BACKGROUND

Shorter sleep is a risk factor for weight gain in young children. Experimental studies show that sleep deprivation is associated with higher nighttime energy intake, but no studies have examined the patterning of energy intake in relation to nighttime sleep duration in young children.

OBJECTIVES

The objectives of the study were to test the hypothesis that shorter-sleeping children would show higher nighttime energy intake and to examine whether the additional calories were from drinks, snacks or meals.

METHODS

Participants were 1278 families from the Gemini twin cohort, using data from one child per family selected at random to avoid clustering effects. Nighttime sleep duration was measured at 16 months of age using the Brief Infant Sleep Questionnaire. Energy intake by time of day and eating episode (meal, snack, drink) were derived from 3-day diet diaries completed when children were 21 months.

RESULTS

Consistent with our hypothesis, shorter-sleeping children consumed more calories at night only (linear trend P < 0.001), with those sleeping <10 h consuming on average 120 calories (15.2% of daily intake) more at night than those sleeping ≥13 h. The majority of nighttime intake was from milk drinks. Associations remained after adjusting for age, sex, birth weight, gestational age, maternal education, weight and daytime sleep.

CONCLUSIONS

Shorter-sleeping, young children consume more calories, predominantly at night, and from milk drinks. Parents should be aware that providing milk drinks at night may contribute to excess intake. This provides a clear target for intervention that may help address associations between sleep and weight observed in later childhood.

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.

Sleep efficiency as a determinant of insulin sensitivity in overweight and obese adolescents

Insulin resistance (IR) occurs in a transient manner during puberty. Obese adolescents may be at risk for persistent IR during puberty. The objective of the study is to review the literature on the association of the anthropometry and lifestyle characteristics with insulin sensitivity in overweight and obese adolescents, and include data from a new study. Relevant papers were selected and reviewed. In addition, 137 overweight and obese adolescents (42 male/95 female, age 14.4 ± 2.3 years, BMI z-score +3.3 ± 0.7, HOMA-IR 3.4 ± 1.8) from the Centre for Overweight Adolescent and Children's Healthcare (MUMC+) were included in this study. Anthropometrics, Tanner stages, sleep characteristics, food intake behaviour and physical activity were determined, and possible associations with homeostasis model assessment of insulin resistance (HOMA-IR) were tested.

RESULTS

Overweight and obese adolescents with unfavourable fat partitioning and family history of NIDDM are at risk for persistent IR. Overweight and obese adolescents from the new cohort showed a higher HOMA-IR postpubertally. BMI z-score, age, pubertal stage and prepubertally total sleeping time (TST) and sleep efficiency (SE) were identified as significant contributors. Overweight and obese adolescents showed a persistently higher instead of transiently higher HOMA-IR during puberty, associated with BMI z-score, age, pubertal stage and prepubertally less TST and SE.

The Influence of Portion Size and Timing of Meals on Weight Balance and Obesity

This review focuses on the influence of portion size and temporal distribution of food intake on weight balance and obesity in adults. The inconsistency of definitions in the area of meal patterns is also discussed. The conclusion is that regular eating habits might facilitate weight balance, while unplanned snacking as well as consuming the major part of the energy intake at the end of the day seem to be unfavourable. Altogether, the research suggests that large portions promote over-consumption and, therefore, limiting portion size of energy dense foods and drinks with added sugar could be recommended. Even if more research is needed, these factors should be taken into consideration in recommendations for obesity prevention.

Does Circadian Disruption Play a Role in the Metabolic-Hormonal Link to Delayed Lactogenesis II?

Breastfeeding improves maternal and child health. The American Academy of Pediatrics recommends exclusive breastfeeding for 6 months, with continued breastfeeding for at least 1 year. However, in the US, only 18.8% of infants are exclusively breastfed until 6 months of age. For mothers who initiate breastfeeding, the early post-partum period sets the stage for sustained breastfeeding. Mothers who experience breastfeeding problems in the early post-partum period are more likely to discontinue breastfeeding within 2 weeks. A major risk factor for shorter breastfeeding duration is delayed lactogenesis II (DLII; i.e., onset of milk "coming in" more than 72 h post-partum). Recent studies report a metabolic-hormonal link to DLII. This is not surprising because around the time of birth the mother's entire metabolism changes to direct nutrients to mammary glands. Circadian and metabolic systems are closely linked, and our rodent studies suggest circadian clocks coordinate hormonal and metabolic changes to support lactation. Molecular and environmental disruption of the circadian system decreases a dam's ability to initiate lactation and negatively impacts milk production. Circadian and metabolic systems evolved to be functional and adaptive when lifestyles and environmental exposures were quite different from modern times. We now have artificial lights, longer work days, and increases in shift work. Disruption in the circadian system due to shift work, jet-lag, sleep disorders, and other modern life style choices are associated with metabolic disorders, obesity, and impaired reproduction. We hypothesize that DLII is related to disruption of the mother's circadian system. Here, we review literature that supports this hypothesis, and describe interventions that may help to increase breastfeeding success.