Rest-activity circadian rhythm and sleep quality in patients with binge eating disorder

Recent findings suggest that altered rest-activity circadian rhythms (RARs) are associated with a compromised health status. RARs abnormalities have been observed also in several pathological conditions, such as cardiovascular, neurological, and cancer diseases. Binge eating disorder (BED) is the most common eating disorder, with a prevalence of 3.5% in women and 2% in men. BED and its associate obesity and motor inactivity could induce RARs disruption and have negative consequences on health-related quality of life. However, the circadian RARs and sleep behavior in patients with BED has been so far assessed only by questionnaires. Therefore, the purpose of this study was to determine RARs and sleep parameters by actigraphy in patients with BED compared to a body mass index-matched control group (Ctrl). Sixteen participants (eight obese women with and eight obese women without BED diagnosis) were recruited to undergo 5-day monitoring period by actigraphy (MotionWatch 8®, CamNtech, Cambridge, UK) to evaluate RARs and sleep parameters. In order to determine the RARs, the actigraphic data were analyzed using the single cosinor method. The rhythmometric parameters of activity levels (MESOR, amplitude and acrophase) were then processed with the population mean cosinor.

The Actiwatch Sleep Analysis Software (Cambridge Neurotecnology, Cambridge, UK) evaluated the sleep patterns. In each participant, we considered seven sleep parameters (sleep onset: S-on; sleep offset: S-off; sleep duration: SD; sleep latency: SL; movement and fragmentation index: MFI; immobility time: IT; sleep efficiency: SE) calculated over a period of five nights.

The population mean cosinor applied to BED and Ctrl revealed the presence of a significant circadian rhythm in both groups (p < 0.001). The MESOR (170.0 vs 301.6 a.c., in BED and Ctrl, respectively; p < 0.01) and amplitude (157.66 vs 238.19 a.c., in BED and Ctrl, respectively p < 0.05) differed significantly between the two groups. Acrophase was not different between BED and Ctrl, as well as all sleep parameters. Both groups displayed a low level of sleep quality (SE 80.7% and 75.7% in BED and Ctrl, respectively). These data provided the first actigraphy-based evidence of RARs disruption and sleep behavior disorder in patients with BED. However, while sleep disorders could be reasonably ascribed to overweight/obesity and the related lower daily physical activity, RARs disruption in this pathology should be ascribed to factors other than reduced physical activity. The circadian timing approach can represent a novel potential tool in the treatment of patients with eating disorders. These data provide exploratory evidence of behavioral association in a small population of patients that, if confirmed in a wider number of subjects and across different populations, may lead to a revision and enhancement of interventions in BED patients.     

Sleep quality and sleep duration,but not circadian parameters are associated with decreased insulin sensitivity in Type 1 diabetes

ABSTRACT

The objective of this cross-sectional analysis was to investigate in 109 adults with type 1 diabetes the relationship between sleep, circadian parameters and insulin sensitivity, as assessed by estimated glucose disposal rate (eGDR). In multiple regression analysis only poor sleep quality and sleep duration were negatively associated with eGDR (β = ?0.219 [95%CI:-1.977; ?0.445], p = .002 for poor sleep quality; β = ?0.183 [95%CI: ?0.645; ?0.111], p = .006 for sleep duration) independent of age, gender, smoking status and body mass index. In conclusion, poor sleep quality and longer sleep duration were significant predictors of decreased insulin sensitivity. Social jetlag, chronotype, and sleep debt had no effect on insulin sensitivity.     

Is there a 24-hour rhythm in alcohol craving and does it vary by sleep/circadian timing?

ABSTRACT

Increasing evidence implicates sleep/circadian factors in alcohol use; however, the role of such factors in alcohol craving has received scant attention. Prior research suggests a 24-hour rhythm in related processes (e.g., reward motivation), but more research directly investigating a rhythm in craving is needed. Moreover, prior evidence is ambiguous whether such a rhythm in alcohol craving may vary by sleep/circadian timing. To examine these possibilities, 36 late adolescents (18–22 years of age; 61% female) with regular alcohol use but without a current alcohol use disorder were recruited to complete smartphone reports of alcohol craving intensity six times a day for two weeks. During these two weeks, participants wore wrist actigraphs and completed two in-lab assessments (on Thursday and Sunday) of dim light melatonin onset (DLMO). Average actigraphically derived midpoint of sleep on weekends and average DLMO were used as indicators of sleep and circadian timing, respectively. Multilevel cosinor analysis revealed a 24-hour rhythm in alcohol craving. Findings across the sleep and circadian timing variables converged to suggest that sleep/circadian timing moderated the 24-hour rhythm in alcohol craving. Specifically, people with later sleep/circadian timing had later timing of peak alcohol craving. These findings add to the growing evidence of potential circadian influences on reward-related phenomena and suggest that greater consideration of sleep and circadian influences on alcohol craving may be useful for understanding alcohol use patterns and advancing related interventions.     

Clock polymorphisms and circadian rhythms phenotypes in a sample of the Brazilian population

A Clock polymorphism T to C situated in the 3' untranslated region (3'-UTR) has been associated with human diurnal preference. At first, Clock 3111C had been reported as a marker for evening preference. However these data are controversial, and data both corroborating and denying them have been reported. This study hypothesizes that differences in Clock genotypes could be observed if extreme morning-type subjects were compared with extreme evening-type subjects, and the T3111C and T257G polymorphisms were studied. The possible relationship between both polymorphisms and delayed sleep phase syndrome (DSPS) was also investigated. An interesting and almost complete linkage disequilibrium between the polymorphisms T257G in the 5' UTR region and the T3111C in the 3' UTR region of the Clock gene is described. Almost always, a G in position 257 corresponds to a C in position 3111, and a T in position 257 corresponds to a T in position 3111. The possibility of an interaction of these two regions in the Clock messenger RNA structure that could affect gene expression was analyzed using computer software. The analyses did not reveal an interaction between those two regions, and it is unlikely that this full allele correspondence affects Clock gene expression. These results show that there is no association between either polymorphism T3111C or T257G in the Clock gene with diurnal preference or delayed sleep phase syndrome (DSPS). These controversial data could result from the possible effects of latitude and clock genes interaction on circadian phenotypes.     

An emerging role for Cullin-3 mediated ubiquitination in sleep and circadian rhythm

Although the neurophysiological correlates of sleep have been thoroughly described, genetic mechanisms that control sleep architecture, long surmised from ethological studies, family histories and clinical observations, have only been investigated during the past decade. Key contributions to the molecular understanding of sleep have come from studies in Drosophila, benefitting from a strong history of circadian rhythm research. For instance, a number of recent papers have highlighted the role of the E3 ubiquitin ligase Cullin-3 in the regulation of circadian rhythm and sleep. We propose that different Cullin-3 substrate adaptors may affect specific molecular pathways and diverse aspects of circadian rhythm and sleep. We have previously shown that mutations in BTBD9, a risk factor for Restless Legs Syndrome (RLS) encoding a Cullin-3 substrate adaptor, lead to reduced dopamine, increased locomotion and sleep fragmentation. Here, we propose that Cullin-3 acts together with BTBD9 to limit the accumulation of iron regulatory proteins in conditions of iron deficiency. Our model is consistent with clinical observations implicating iron homeostasis in the pathophysiology of RLS and predicts that lack of BTBD9 leads to misregulation of cellular iron storage, inactivating the critical biosynthetic enzyme Tyrosine Hydroxylase in dopaminergic neurons, with consequent phenotypic effects on sleep.     

Circadian rhythm gene expression and daily melatonin levels vary in athletes and sedentary males

The circadian rhythm is a 24-h cycle in which cells control metabolic and physiological processes throughout the day. In this study, we compared the expression patterns of major circadian rhythm-related genes: from blood of Bmal1, Ror-α, Cry1, Per2, Per1, and Nr1d1. In addition, changes in patterns of melatonin levels were observed in 16 subjects, eight males rugby players and eight males who did not exercise regularly. Blood was collected at 6:00, 10:00, 18:00, and 22:00. Bmal1, Ror-α, Cry1, Per2 (p < 0.001), Per1 (p < 0.01), and Nr1d1 (p < 0.05) genes related to circadian rhythm was higher in rugby players than in sedentary males. However, melatonin levels were higher in sedentary males than in rugby players (p < 0.05). These results indicate that long-term exercise in athletes can increase the expression of genes related to circadian rhythm and these may have an effect on daily melatonin levels as well.     

Relationships among sleep timing,sleep duration and glycemic control in Type 2 diabetes in Thailand

There is evidence that the sleep and circadian systems play a role in glucose metabolism. In addition to physiological factors, sleep is also affected by behavioral, environmental, cultural and social factors. In this study, we examined whether morning or evening preference, sleep timing and sleep duration are associated with glycemic control in patients with type 2 diabetes residing in Thailand. Two hundred and ten type 2 diabetes patients who were not shift workers completed an interview and questionnaires to collect information on diabetes history, habitual sleep duration and sleep timing. Chronotype, an individual’s tendency for being a “morning” or “evening” person, was assessed using the Composite Score of Morningness (CSM), which reflects an individual’s subjective preference for activities in the morning or evening, as well as mid-sleep time on weekend nights (MSF), which reflects their actual sleep behavior. Most recent hemoglobin A1c (HbA1c) values were retrieved from medical records. Evening preference (as indicated by lower CSM), later bedtime on weekends, and shorter sleep duration correlated with higher HbA1c (r?=??0.18, p?=?0.01; r?=?0.17, p?=?0.01 and r?=??0.17, p?=?0.01, respectively), while there was no association between MSF or wake up time and glycemic control. In addition, later bedtime on weekends significantly correlated with shorter sleep duration (r?=??0.34, p?<?0.001). Hierarchical regression analyses adjusting for age, sex, body mass index, insulin use and diabetes duration revealed that later bedtime on weekends was significantly associated with poorer glycemic control (B?=?0.018, p?=?0.02), while CSM was not. Mediation analysis revealed that this association was fully mediated by sleep duration. In summary, later bedtime on weekends was associated with shorter sleep duration and poorer glycemic control in patients with type 2 diabetes. It is likely that patients with later weekend bedtimes curtail their sleep by waking up earlier. Exploring the potential reasons for this phenomenon (e.g. cultural influences, metropolitan lifestyle, environmental factors, family and social obligations) specific to a Thai population may help identify behavioral modifications (i.e. earlier bedtime and/or sleep duration extension) that could possibly lead to improved glycemic control in this population.     

Diurnal rhythm in mRNA expression of genes encoding amino acid transporter and circadian gene cry in intestinal mucosa of piglets

Long chain PUFA contents in plasma and liver both exhibited diurnal rhythms in pigs. However, whether mRNA expression of amino acid transporter and circadian gene Cry in intestinal mucosa is also rhythmic is yet to be known. The purpose of this study aims to investigate the diurnal rhythm in mRNA expression of genes encoding amino acid transporter and whether their rhythm was related to the expression of circadian gene Cry in intestinal mucosa of piglets. Thirty-six piglets (Duroc?×?Landrace?×?Large Yorkshire) at the age of 35 days were selected and fed for three weeks, and then samples were collected at 3:00 am (Clo3), 7:00 am (Clo7), 11:00 am (Clo11), 3:00 pm (Clo15), 7:00 pm (Clo19), and 11:00 pm (Clo23) at the age of 56 days. At each time point, small intestinal mucosa samples were collected from duodenum, jejunum, and ileum for detection of mRNA expression of the amino acid transporters and circadian gene Cry. The results showed that mRNA expression of most amino acid transporters in intestinal mucosa was higher at night and lower during the daytime. Expression of SLC1A2, SLC6A20, SLC7A1, and SLC6A14 in duodenal mucosa reached the peak at Clo3 and Clo7; the diurnal rhythm of expression of SLC1A2, SLC6A20, and SLC7A1 was similar to Cry1, while the diurnal rhythm of expression of SLC6A14 had a similar trend to Cry2. Expression of SLC16A10, SLC1A2, and SLC7A1 in jejunal mucosa reached the peak at Clo7, while SLC6A14 reached the peak at Clo3; the diurnal rhythm of expression of SLC1A2 showed a similarity with Cry1, while the diurnal rhythm of expression of SLC16A10, SLC7A1, and SLC6A14 was similar to Cry2. Expression of SLC6A14, SLC6A20, and SLC7A1 in ileal mucosa reached the peak at Clo3; the diurnal rhythm of expression of SLC6A20 has a similarity with Cry1, while the diurnal rhythm of expression of SLC7A1 and SLC6A14 was similar to Cry2. The results suggested that the mRNA expression of most genes encoding amino acid transporters exhibited diurnal rhythms in the intestinal mucosa of piglets, and SLC7A1, SLC6A14, and SLC1A2 have a similar rhythm with circadian clock genes Cry1 and 2, and they reached the peak at Clo3 and Clo7.     

Cell signaling,receptors, electrical effects and therapy in circadian rhythm

Abstract

Circadian rhythm has been the object of much attention. This review addresses the aspects of cell signaling, receptors, therapy and electrical effects in a multifaceted fashion. The pineal gland, which produces the important hormones melatonin and serotonin, exerts a prominent influence, in addition to the supraschiasmatic nucleus. Many aspects involve free radicals which have played a widespread role in biochemistry.     

Association between coffee,tobacco, and alcohol daily consumption and sleep/wake cycle: an actigraphy study in euthymic patients with bipolar disorders

ABSTRACT

Individuals with bipolar disorder (BD) have higher than average rates of coffee, tobacco and alcohol use. These substances may have deleterious effects on sleep quality and quantity, which may destabilize sleep/wake cycles and negatively impact the clinical course and prognosis of BD. The use of these substances may also be perceived as a self-medication attempt, for example, to induce sleep or to increase vigilance during the day. The objective of the current study was to investigate associations between the self-reported daily use of coffee, tobacco, and alcohol, and objective measures of sleep and activity patterns in adult individuals with BD. A sample of 147 euthymic individuals with BD were assessed for daily coffee, tobacco and alcohol consumption and 21 days of actigraphy monitoring. Actigraphic measures of sleep quantity and daytime activity were compared between groups classified as coffee+/coffee-, tobacco+/tobacco- and alcohol+/alcohol-, defined according to their current daily use. Then, we examined potential correlations between sleep/wake cycle parameters and the amount of daily consumption of each substance. Multivariable analyses identified associations between the use of coffee, tobacco, and alcohol and several sleep and activity parameters, such as between coffee, alcohol, and the relative amplitude of activity (respectively, p = .003 and p = .005), between alcohol and M10 onset (onset time of the 10 most active hours during the 24-h cycle) (p = .003), and between coffee and sleep duration (p = .047). This study supports the hypothesis that there is a relationship, whose direction would be bidirectional, between the daily use of these substances and the sleep/wake cycle in euthymic individuals with BD. These preliminary results require replications in other retrospective and prospective samples. They may have a clinical impact on psycho-education strategies to be proposed to individuals with BD.     

Circadian gene methylation profiles are associated with obesity,metabolic disturbances and carbohydrate intake

The circadian clock regulates the daily rhythms of several physiological and behavioral processes. Disruptions in clock genes have been associated with obesity and related comorbidities. This study aimed to analyze the association of DNA methylation signatures at circadian rhythm pathway genes with body mass index (BMI), metabolic profiles and dietary intakes. DNA methylation profiling was determined by microarray in white blood cells from 474 adults from the Methyl Epigenome Network Association (MENA) project. Kyoto Encyclopedia of Genes and Genomes database was used to identify the genes integrating the circadian rhythm pathway. Network enrichment analyses were performed with the PathDIP platform. Associations between circadian methylation patterns with anthropometric measurements, the metabolic profile, clinical data and dietary intakes were analyzed. DNA methylation patterns of nine CpG sites at six circadian rhythm pathway genes were strongly correlated with BMI (false discovery rates <0.0001). These CpGs encompassed cg09578018 (RORA), cg20406576 (PRKAG2), cg10059324 (PER3), cg01180628 (BHLHE40), cg23871860 (FBXL3), cg16964728 (RORA), cg14129040 (CREB1), cg07012178 (PRKAG2) and cg24061580 (PRKAG2). Interestingly, network enrichment analyses revealed that the six BMI-associated genes statistically contributed to the regulation of the circadian rhythm pathway (p = 1.9E-10). In addition, methylation signatures at cg09578018 (RORA), cg24061580 (PRKAG2), cg01180628 (BHLHE40) and cg10059324 (PER3) also correlated with insulin resistance (p < 0.0001) and mean arterial blood pressure (p < 0.0001). Furthermore, relevant correlations (p < 0.05) between methylation at cg09578018 (RORA) and cg01180628 (BHLHE40) with total energy and carbohydrate intakes were found. This investigation revealed potential associations of DNA methylation profiles at circadian genes with obesity, metabolic disturbances and carbohydrate intake, with potential impact on weight homeostasis.     

COVID-19 pandemic lockdown-induced altered sleep/wake circadian rhythm,health complaints and stress among traffic police personnel in India

ABSTRACT

COVID-19 is a highly contagious disease caused by Severe Acute Respiratory Syndrome coronavirus-2, capable of high human transmission. To protect against the COVID-19 pandemic, the World Health Organization proposed intervening guidance that included movement restrictions, isolation, restriction of national and international travel or movement, and full or partial closure of organizations and institutions. Police personnel play a vital role in safeguarding the spread of COVID-19; thus, potentially causing severe stress due to increased consignment and direct exposure to infection during duty. The study aimed to determine the effect of the added stress of the COVID-19 pandemic and population lockdown on the sleep/wake 24 h rhythm of traffic police. A concise online questionnaire survey was conducted among the traffic police personnel of India. Collected data were analyzed statistically. Disorientation of working schedule, fear of being vulnerable to disease, pressure of maintaining law, and orders during lockdown increased stress level. The survey identified discontinuation of sleep, shift of mid-sleep time, increase in depression, plus stress and anxiety among traffic police personnel that affected their chronobiological milieu. Proper awareness of adequate health and safety measures, use of personnel protection equipment, regular conversation with family members, and meditation can help reduce stress during this pandemic situation.     

Long and short sleep duration are both associated with suicidal ideation in Korean employees

Sleep and Biological Rhythms - The aim of this study was to investigate the association between self-reported sleep duration and suicidal ideation in Korean employees. We studied 204,629 employees...     

Influence of circadian disruption on neurotransmitter levels,physiological indexes,and behaviour in rats

Brain monoamines – such as noradrenaline (NA), dopamine (DA) and serotonin (5-HT) – regulate several important physiological functions, including the circadian rhythm. The purpose of this study was to examine changes in NA, DA and 5-HT levels in various brain regions and their effect on core body temperature (T_c), heart rate (HR) and locomotor activity (Act) in rats following exposure to an artificial light/dark (LD) cycle. For this, male Wistar rats were housed at an ambient temperature (T_a) of 23?°C and 50% relative humidity with free access to food and water. Rats were exposed to either natural (12?h:12?h) or artificial (6?h:6?h) LD cycles for 1 month, after which each brain region was immediately extracted and homogenized to quantify the amounts of NA, DA and 5-HT by high-performance liquid chromatography. Behavioural changes were also monitored by the ambulatory activity test (AAT). Notably, we found that artificial LD cycles disrupted the physiological circadian rhythms of T_c, HR and Act. Although the 5-HT levels of rats with a disrupted circadian rhythm decreased in cell bodies (dorsal and median raphe nuclei) and projection areas (frontal cortex, caudate putamen, preoptic area and suprachiasmatic nucleus) relative to the control group, NA levels increased both in the cell body (locus coeruleus) and projection area (paraventricular hypothalamus). No significant changes were found with respect to DA. Moreover, circadian rhythm-disrupted rats also showed anxious behaviours in AAT. Collectively, the results of this study suggest that the serotonergic and noradrenergic systems, but not the dopaminergic system, are affected by artificial LD cycles in brain regions that control several neural and physiological functions, including the regulation of physiological circadian rhythms, stress responses and behaviour.     

Time-related eating patterns and chronotype are associated with diet quality in pregnant women

Animal studies strongly suggest that timed feeding can have beneficial physiological effects, including protection against the obesogenic and metabolic consequences of a high-fat diet. However, the relationship between variables related to the timing of eating and diet quality in pregnancy women, which is considered as a period of nutritional vulnerability, is still poorly described in the literature. Therefore, the aim of the present study was to investigate the associations between time-related eating patterns and chronotype with diet quality of pregnant women. This cross-sectional study was conducted with 100 pregnant women in the first gestational trimester (≤12 weeks of gestation). The information regarding food intake was obtained by three 24-Hour Dietary Recall (24HR). Time-related eating patterns, i.e., the interval between the first and the last meal (eating duration), nightly fasting, time of the first and last meals, and number of meals eating on a day were determined. Chronotype was derived using the mid-sleep time on free days on weekends, with a further correction for calculated sleep debt. Diet quality was evaluated using the Brazilian Healthy Eating Index-Revised (BHEI-R), validated for the Brazilian population. Linear regression modeling analyses adjusted for confounders were used to investigate the association between time-related eating patterns and chronotype with diet quality. The BHEI-R total score was negatively associated with time of the first meal (β = ?0.355; p = 0.002; r² adjusted = 0.141), and positively associated with eating duration (β = 0.262; p = 0.024; r² adjusted = 0.086) and number of meals (β = 0.273; p = 0.019; r² adjusted = 0.091). In addition, the score of total fruit component was negatively associated with chronotype (β = ?0.236; p = 0.033; r² adjusted = 0.078), time of the first meal (β = ?0.393; p = 0.001; r² adjusted = 0.171), and positively associated with eating duration (β = 0.259; p = 0.022; r² adjusted = 0.087) and number of meals (β = 0.376; p = 0.001; r² adjusted = 0.159). The score for whole fruit component was negatively associated with time of the first meal (β = ?0.388; p = 0.001; r² adjusted = 0.152), and positively associated with number of meals (β = 0.403; p = 0.001; r² adjusted = 0.164). A longer eating duration, earlier time of the first meal, higher number of meals and morningness tendency are associated with a better diet quality in the first gestational trimester – higher scores of the total BHEI-R and/or fruit components. We suggest that nutritional guidelines should consider time-related eating patterns and chronotype to ensure good diet quality of pregnant women since the beginning of gestation, contributing on prevention of metabolic-nutritional complications.     

Late chronotypes are associated with neoadjuvant chemotherapy-induced nausea and vomiting in women with breast cancer

Neoadjuvant chemotherapy, that is, the administration of chemotherapy before surgery, has been commonly used for locally advanced breast cancer to improve the surgical outcomes and increase the opportunity for breast-conserving therapy. Women with breast cancer often receive an anthracycline-based regimen as the neoadjuvant chemotherapy, which is associated with a high risk of emesis. Despite the development of novel antiemetics, chemotherapy-induced nausea and vomiting (CINV) has been commonly reported as a major adverse effect, affecting the quality of life of the patients. However, the factors predicting CINV in women with breast cancer undergoing neoadjuvant chemotherapy remain unclear. In this single-institution, prospective, observational study conducted at an outpatient cancer centre in the Republic of Korea from November 2013 to March 2016, we analysed women with breast cancer who planned to be treated with neoadjuvant chemotherapy before surgery. Candidate factors associated with CINV were assessed before neoadjuvant chemotherapy using the Munich Chronotype Questionnaire, Pittsburgh Sleep Quality Index and Hospital Anxiety and Depression Scale. CINV was assessed after chemotherapy by using the Multinational Association of Supportive Care in Cancer Antiemesis Tool. Of a total of 143 participants, 7 patients were lost to follow-up and 2 patients were excluded due to changes in their treatment plan; thus, 134 patients were finally included in the analyses. Overall, 48.5% of the participants experienced CINV, with delayed CINV prevalence (42.5%) being more common than acute (39.6%). In the univariate analyses, overall CINV was significantly associated with late chronotypes (odds ratio [OR], 3.49; 95% confidence interval [CI], 1.37–8.87; p = 0.009), a history of nausea/vomiting (OR, 2.19; 95% CI, 1.10–4.37; p = 0.026) and anxiety (OR, 2.25; 95% CI, 1.05–4.81; p = 0.036). In the multivariate analyses, late chronotypes (OR, 3.53; 95% CI, 1.27–9.79; p = 0.015) and a history of nausea/vomiting (OR, 2.83; 95% CI, 1.31–6.13; p = 0.008) remained significantly associated with CINV. In conclusion, in women with breast cancer undergoing neoadjuvant chemotherapy before surgery, late chronotypes were found to have an increased risk of CINV; these data suggest that clinicians need to assess and consider the chronotype in the management of CINV.     

Relationships between chronotype,social jetlag,sleep, obesity and blood pressure in healthy young adults

Sleep disturbances, chronotype and social jetlag (SJL) have been associated with increased risks for major chronic diseases that take decades to develop, such as obesity, metabolic syndrome and cardiovascular disease. Potential relationships between poor sleep, chronotype and SJL as they relate to metabolic risk factors for chronic disease have not been extensively investigated. This prospective study examined chronotype, SJL and poor sleep in relation to both obesity and elevated blood pressure among healthy young adults.

SJL and objective sleep measures (total sleep time, sleep onset latency, wake after sleep onset and sleep efficiency) were derived from personal rest/activity monitoring (armband actigraphy) among 390 healthy adults 21–35 years old. Participants wore the device for 6–10 days at 6-month intervals over a 2-year period (n = 1431 repeated observations). Chronotypes were categorized into morning, intermediate and evening groups using repeated measures latent class analysis. Means of SJL and sleep measures among latent chronotype groups were compared using partial F-tests in generalized linear mixed models. Generalized linear mixed models also were used to generate odds ratios (ORs) with 95% confidence intervals (CIs) examining the relationship between repeated measures of chronotype, SJL, sleep and concurrent anthropometric outcome measures (body mass index, percentage of body fat, waist-to-hip ratio, waist-to-height ratio), systolic blood pressure and diastolic blood pressure.

Sleep latency ≥12 min was associated with increased odds of a high waist-to-height ratio (OR = 1.37; CI: 1.03–1.84). Neither chronotype nor SJL was independently associated with anthropometric outcomes or with blood pressure. Relationships between poor sleep and anthropometric outcomes or blood pressure varied by chronotype. Morning types with total sleep time <6 h, sleep efficiency <85% or wake after sleep onset ≥60 min were more likely to have an increased percentage of body fat, waist-to-hip ratio and waist-to-height ratio relative to those with an intermediate chronotype. Similarly, sleep latency ≥12 min was associated with increased odds of elevated systolic blood pressure (OR = 1.90; CI: 1.15–3.16, p_interaction = 0.02) among morning versus intermediate chronotypes. No relationships between poor sleep and obesity or elevated blood pressure were observed among evening chronotypes.

The results from this study among healthy young adults suggest that poor sleep among morning types may be more strongly associated with obesity and elevated blood pressure relative to those with an intermediate (neutral) chronotype. Sleep-related metabolic alterations among different chronotypes warrant further investigation.     

Androgen receptor gene polymorphisms are associated with aggression in Japanese Akita Inu

We tested for an association between variable number of tandem repeats in the canine androgen receptor (AR) gene and personality differences in Japanese Akita Inu dogs. The polymorphic trinucleotide (CAG) repeat region coding for glutamine in exon 1 of the AR gene was genotyped using genomic DNA obtained from 171 dogs. Three alleles (23, 24 and 26 repeats) were detected, and the allele frequency differed with the coat colour. We assessed the personality profiles of 100 fawn-coloured dogs (54 males and 46 females) based on a questionnaire answered by each dog's owner. The questionnaire consisted of five sub-scales (sociability, playfulness, neuroticism, aggressiveness, distractibility), and the psychometric properties were acceptable based upon internal consistency of the subscales. We found that male dogs with a short allele conferring increased AR function had higher aggressiveness scores than male dogs with longer alleles. By contrast, no evidence was found for a relationship between AR gene variants and personality in females. To our knowledge, our findings provide the first evidence of polymorphism in the AR gene being associated with canine aggression.     

Late chronotype and high social jetlag are associated with burnout in evening-shift workers: Assessment using the Chinese-version MCTQshift

Chronotypes are associated with shift work tolerance and sleep in shift workers, and sleep mediates the impact of shift work on mental health. However, the role of chronotype in the association between shift work and mental health has not been clarified. In this study, we aimed to examine the association between chronotype and burnout in shift workers, using the validated Munich ChronoType Questionnaire for shift workers (MCTQ^shift). A total of 288 shift workers with irregular shift frequencies were recruited and completed the Chinese-version MCTQ^shift and the Morningness–Eveningness Questionnaire (MEQ). Chronotypes were assessed by the calculation of corrected mid-sleep time (MSF_SC) from mid-sleep time on free days (MSF) based on their exact shift schedules. Another 26 evening-shift nurses were monitored with actigraphy for at least two consecutive evening shifts and the following two free days. Burnout was evaluated using the Copenhagen Burnout Inventory. We found that MSF^E_SC, MSF^E and mid-sleep time on workdays (MSW^E) had normal distributions and correlated significantly with MEQ scores (r = ? 0.47, ?0.45 and ?0.47, respectively; all p < 0.001). MSW was more closely correlated with actigraphy-derived mid-sleep time on the free day before workdays than that on workdays (r = 0.61 and 0.48, respectively, p < 0.05). Sleep duration was significantly longer on workdays among evening-shift workers who slept late on workdays than those who slept early (β = 0.59, p < 0.001). After demographic and work characteristics were adjusted for in linear regression models, late chronotype and high social jetlag were associated with burnout scores in evening-shift workers. In conclusion, the Chinese-version MCTQ^shift is a valid tool for chronotype assessment. Interventions to improve sleep in shift workers should be tailored to chronotype due to variations in sleep behavior. Late chronotype may be an inherent feature of mental health problems, because the association with burnout was significant in both day workers in previous studies and shift workers.