Midpoint of sleep on school days is associated with depression among adolescents

Depression is a serious and prevalent disease among adolescents. Identifying possible factors involved with its genesis and presentation is an important task for researchers and clinical practitioners. The individual’s chronotype and social jetlag have been associated with depression in different populations. However, information on this is lacking among adolescents. The objective of this cross-sectional study was to examine the relationship between chronotype (midpoint of sleep) and social jetlag with the presence of depression symptoms in young students. We assessed 351 students aged 12–21?years old. They answered a questionnaire on demographic characteristics, the Munich Chronotype Questionnaire (MCTQ) and the Beck Depression Inventory (BDI). Demographic characteristics (age, sex and classes’ schedule) and circadian rhythmic variables for school and free days (sunlight exposure, sleep duration, midpoint of sleep and social jetlag) were taken as factors and the presence of at least mild depression symptoms as outcome. In univariate analysis, girls (χ²?=?5.01, p?≤?0.05) and evening students (χ²?=?6.63, p?≤?0.05) were more frequently present among the depressed. Also, the depression group was significantly delayed for both midpoints of sleep during school (t?=?2.84, p?≤?0.01) and free days (t?=?2.20, p?≤?0.05). The two groups did not differ in relation to their social jetlag hours (t?=??0.68, p?=?0.501) neither subjects with two or more hours of social jetlag were more frequent among the depressed (χ²?=?1.00, p?=?0.317). In multivariate analysis, the model that best explained our outcome (R²?=?0.058, F?=?2.318, p?≤?0.05) included sex (β?=??0.12, p?≤?0.05) and the midpoint of sleep on school days (β?=??0.21, p?≤?0.001) as significant predictor variables. A sleep phase delay (later midpoints of sleep for school and free days) was associated with higher levels of depression. However, we were not able to detect similar relationship with the social jetlag hours. This could be attributed to the fact that our sample showed a smaller amount of social jetlag, possibly because even during free days a social routine, this time parents’ rules, limited the observation from what could be a natural tendency to sleep later and over. Yet, even when considering the group with more social jetlag, we did not find an association. Perhaps, this variable will only manifest its effect if it is maintained for longer periods throughout life. Additionally, when considering all the variables together, the midpoint of sleep on school days was pointed as the predictor of greatest weight for depression, together with the factor sex. Young girls, possibly earlier types, who are required to study in the evening have more chances of presenting depression symptoms. This study explicit some peculiar characteristics of the assessment of chronobiological variables in the young, such as the presence of an imposed social routine also during free days. Therefore, the expression of chronotype under the influence of the weekly social schedule (midpoint of sleep on school days) could be a more useful marker to measure the stress produced from the mismatch between external and inner rhythms rather than social jetlag. This also reinforces the importance of reconsidering the weekly routine imposed on young people.     

Depression Scores Associate With Chronotype and Social Jetlag in a Rural Population

In public health, mood disorders are among the most important mental impairments. Patients with depressive episodes exhibit daily mood variations, abnormal patterns in sleep-wake behavior, and in the daily rhythms of several endocrine-metabolic parameters. Although the relationship between the sleep/circadian processes and mood disorders is poorly understood, clock-related therapies, such as light therapy, sleep deprivation, and rigid sleep schedules, have been shown to be effective treatments. Several studies investigated the relationship between circadian phenotype (chronotype) and depression. These focused mainly on urban populations and assessed diurnal preferences (Morningness-Eveningness score) rather than the actual timing of sleep and activity. Here, we used the Beck Depression Inventory (BDI) in an essentially rural population (N?=?4051), and investigated its relation to circadian phenotype (chronotype and social jetlag), assessed with the Munich Chronotype Questionnaire (MCTQ). In our study design, we (i) normalized both chronotype and BDI scores for age and sex (MSF_sas and BDI_as, respectively); (ii) calculated individual social jetlag (misalignment of the biological and social time); and (iii) investigated the relationship between circadian phenotypes and BDI scores in a population homogeneous in respect to culture, socioeconomic factors, and daily light exposure. A 15.65% (N?=?634) of the participants showed mild to severe depressive BDI scores. Late chronotypes had a higher BDI_as than intermediate and early types, which was independent of whether or not the participants were smokers. Both chronotype and BDI_as correlated positively with social jetlag. BDI_as was significantly higher in subjects with >2?h of social jetlag than in the rest of the population—again independent of smoking status. We also compared chronotype and social jetlag distributions between BDI categories (no symptoms, minimal symptoms, and mild to severe symptoms of depression) separately for men and women and for four age groups; specifically in the age group 31–40 yrs, subjects with mild to severe BDI scores were significantly later chronotypes and suffered from higher social jetlag. Our results indicate that misalignment of circadian and social time may be a risk factor for developing depression, especially in 31- to 40-yr-olds. These relationships should be further investigated in longitudinal studies to reveal if reduction of social jetlag should be part of prevention strategies. (Author correspondence: karla.allebrandt@med.uni-muenchen.de)     

Depression scores associate with chronotype and social jetlag in a rural population

In public health, mood disorders are among the most important mental impairments. Patients with depressive episodes exhibit daily mood variations, abnormal patterns in sleep-wake behavior, and in the daily rhythms of several endocrine-metabolic parameters. Although the relationship between the sleep/circadian processes and mood disorders is poorly understood, clock-related therapies, such as light therapy, sleep deprivation, and rigid sleep schedules, have been shown to be effective treatments. Several studies investigated the relationship between circadian phenotype (chronotype) and depression. These focused mainly on urban populations and assessed diurnal preferences (Morningness-Eveningness score) rather than the actual timing of sleep and activity. Here, we used the Beck Depression Inventory (BDI) in an essentially rural population (N?=?4051), and investigated its relation to circadian phenotype (chronotype and social jetlag), assessed with the Munich Chronotype Questionnaire (MCTQ). In our study design, we (i) normalized both chronotype and BDI scores for age and sex (MSF(sas) and BDI(as), respectively); (ii) calculated individual social jetlag (misalignment of the biological and social time); and (iii) investigated the relationship between circadian phenotypes and BDI scores in a population homogeneous in respect to culture, socioeconomic factors, and daily light exposure. A 15.65% (N?=?634) of the participants showed mild to severe depressive BDI scores. Late chronotypes had a higher BDI(as) than intermediate and early types, which was independent of whether or not the participants were smokers. Both chronotype and BDI(as) correlated positively with social jetlag. BDI(as) was significantly higher in subjects with >2?h of social jetlag than in the rest of the population?again independent of smoking status. We also compared chronotype and social jetlag distributions between BDI categories (no symptoms, minimal symptoms, and mild to severe symptoms of depression) separately for men and women and for four age groups; specifically in the age group 31?40 yrs, subjects with mild to severe BDI scores were significantly later chronotypes and suffered from higher social jetlag. Our results indicate that misalignment of circadian and social time may be a risk factor for developing depression, especially in 31- to 40-yr-olds. These relationships should be further investigated in longitudinal studies to reveal if reduction of social jetlag should be part of prevention strategies. (Author correspondence: karla.allebrandt@med.uni-muenchen.de ).     

Clinical significance of social jetlag in patients with excessive daytime sleepiness

ABSTRACT

Social jetlag has recently attracted attention as the circadian misalignment between biological and social clocks. We aimed to examine social jetlag and its effect on daytime sleepiness and daily functions in patients with narcolepsy, behaviorally induced insufficient sleep syndrome (BIISS) and delayed sleep-wake phase disorder (DSPD). The levels of social jetlag (SJL_mid) and sleep-corrected social jetlag (SJL_sc) were calculated for each patient, and the effect of these social jetlag-related parameters on daytime sleepiness and daily functions were examined. Objective sleepiness measured by the mean sleep latency in the multiple sleep latency test, subjective sleepiness assessed by the Epworth sleepiness scale (ESS), health-related quality of life (HRQoL) assessed by the SF-8 health survey, and incidences of mistakes in daily activities, traffic accidents and near-miss events related to daytime sleepiness were compared among the narcolepsy (n = 39), BIISS (n = 87) and DSPD (n = 28) groups. Both SJL_mid and SJL_sc showed a negative correlation with physical HRQoL in patients with narcolepsy and a positive correlation with the ESS score in patients with DSPD. In patients with BIISS, SJL_sc reflected sleep loss rather than circadian misalignment; moreover, SJL_sc was not associated with daytime sleepiness and daily functions. Social jetlag was not associated with incidences of mistakes in daily activities, traffic accidents and near-miss events.

The state of social jetlag and its association with daily functions differed among the narcolepsy, BIISS and DSPD groups. Social jetlag represented sleep debt in BIISS, circadian misalignment in narcolepsy and both in DSPD. Our results thus show that the clinical manifestations and significance of social jetlag differ depending on the underlying sleep disorders.     

Sleep duration and social jetlag are independently associated with anxious symptoms in adolescents

Although short total sleep time (TST) is associated with increased anxious symptoms in adolescents, it is unknown whether social jetlag, a misalignment between sleep timing on the weekend and school week, is independently associated with anxious symptoms. In the current study, sleep timing, anxious symptoms, and demographic information were assessed from 3097 adolescents (48% female, mean ± SD age 15.59 ± .77 years) from the age 15 wave of the Fragile Families and Child Wellbeing Study. Social jetlag was calculated as the absolute value of the midpoint of sleep on the weekend minus the midpoint of sleep during the school week. Anxious symptoms were measured through the 6-item anxiety subscale of the Brief Symptom Inventory 18. We assessed associations between sleep variables and anxious symptoms using multiple linear regression. Adjusted analyses controlled for sex, race/ethnicity, age in years, body mass index percentile, number of other children below the age of 18 in the household, and primary caregiver (PCG) married/cohabiting with youth’s biological parent, PCG employment status, PCG household income and PCG education level. In fully adjusted models (R² = .034), school night TST (b = ?.04, ?R² = .005, p < .001) was negatively associated with anxiety symptoms, while social jetlag (b = .04, ?R² = .009, p < .001) was positively and independently associated with anxiety symptoms. Findings indicate small associations of school night TST and social jetlag with anxious symptoms. Thus, maintenance of optimal emotional health in adolescents may require both sufficient sleep duration and regularity of sleep timing across the week.     

Social jetlag in school students: evidence to suggest that sleep deprivation during work days is common

The present study investigated social jetlag in school students of the Raipur district of Chhattisgarh. The sample consisted of 919 school students from six different schools, age range 12–19 year, comprising of both males (n = 513) and females (n = 406). Two inventories, the 19-item MEQ and MCTQ (Munich Chronotype Questionnaire) were employed. Data analysis (SPSS) used t-test, Chi-square test, ANOVA, and correlation. The results revealed that 73.9% of the sample had social jetlag. There were significant effects upon social jetlag of chronotype, gender, and the use of an alarm clock. Owls were at a higher risk of having social jetlag. There was a significant positive correlation between the amount of social jetlag and the time spent watching television. From these results, it is concluded that there is prevalence of social jetlag, particularly among boys and those who use an alarm clock. The results also lead to the prediction that those school students with social jetlag will be predisposed to health hazards associated with it in the future. Thus it is recommended that school students must be provided with sleep education so that they understand the role of sleep on health and do not become sleep deprived.     

Optimal Sleep Duration in the Subarctic with Respect to Obesity Risk Is 8–9 Hours

Introduction

Sleep duration, chronotype and social jetlag have been associated with body mass index (BMI) and abdominal obesity. The optimal sleep duration regarding BMI has previously been found to be 7–8 hours, but these studies have not been carried out in the subarctic or have lacked some central variables. The aims of our study were to examine the associations between sleep variables and body composition for people living in the subarctic, taking a range of variables into consideration, including lifestyle variables, health variables and biological factors.

Methods

The cross sectional population Tromsø Study was conducted in northern Norway, above the Arctic Circle. 6413 persons aged 30–65 years completed questionnaires including self-reported sleep times, lifestyle and health. They also measured height, weight, waist and hip circumference, and biological factors (non-fasting serum level of cholesterol, HDL-cholesterol, LDL-cholesterol, triglycerides and glucose). The study period was from 1 October 2007 to 19 December 2008.

Results

The optimal sleep length regarding BMI and waist circumference was found to be 8–9 hours. Short sleepers (<6 h) had about 80% increased risk of being in the BMI≥25 kg/m2 group and male short sleepers had doubled risk of having waist circumference ≥102 cm compared to 8–9 hours sleepers. We found no impact of chronotype or social jetlag on BMI or abdominal obesity after controlling for health, lifestyle, and biological parameters.

Conclusions

In our subarctic population, the optimal sleep duration time regarding risk of overweight and abdominal obesity was 8–9 hours, which is one hour longer compared to findings from other studies. Short sleepers had 80% increased risk of being overweight, and men had a doubled risk of having abdominal obesity. We found no associations between chronotype or social jetlag and BMI or abdominal obesity, when we took a range of life-style, health and biological variables into consideration.     

Chronotype and sleep duration are associated with stimulant consumption and BMI among Chinese undergraduates

The study sought to identify the association between stimulant consumption and social jetlag, chronotype as well as sleep duration among undergraduate students. A cross-sectional survey was conducted in the university town in Chongqing, China. Data were collected on 977 participants, age 20.06 (SD = 1.25) years old, using the Munich Chronotype Questionnaire (MCTQ) to measure social jetlag, chronotype and average sleep duration. A self-reported questionnaire was used to collect the information: BMI, demographic data, outdoor activity time, smoking status, alcohol consumption, coffee consumption and sugar-sweetened beverage consumption. The positive significant association was found between late chronotype and alcohol consumption (OR = 1.26, 95% CI [1.05–1.52]), being a current smoker (OR = 1.62, 95% CI [1.26–2.07]) and sugar-sweetened beverage consumption (OR = 1.42, 95% CI [1.17–1.72]). Average sleep duration was negatively associated with BMI (OR = 0.84, 95% CI [0.71–0.98]). Social jetlag did not find any association between stimulant consumption and BMI in the adjusted model. The results showed that Chinese undergraduate students had a negative significant association between average sleep duration and BMI, and late chronotype might affect the stimulant consumption among the group. This study may provide some implications for health management of obesity among undergraduate students in China.

     

Associations of chronotype with social jetlag and behavioral problems in preschool children

The timing, duration, and intensity of sleep are determined by the interaction between a sleep-wake-dependent homeostatic process and a sleep-wake-independent, intrinsic, clock-like circadian process. Chronotype represents individual differences in diurnal preferences, which are not only genetically determined but also influenced by social and environmental factors. Thus, the discrepancy between biological and social clocks, so-called “social jetlag”, occurs. Chronotype, social jetlag, and the links between chronotype and behavioral problems are well documented in adults and adolescents. However, such studies on young children are limited. We conducted a survey of sleep and health for preschool children attending kindergarten or childcare centers in Wako, Okayama and Kurashiki cities, Japan, between May and July 2012. A total of 654 children aged 4–6 years (342 boys and 312 girls, with an average age of 4.7 years) were assessed using the Children’s ChronoType Questionnaire and the Strength and Difficulties Questionnaire. Morning (M)-type, neither (N)-type and evening (E)-type accounted for 36.2%, 54.0% and 9.8% of the participants, respectively. The weekday-to-weekend differences in midsleep time – originally proposed as the concept of social jetlag – were 11, 25 and 35?min for M-, N- and E-types, respectively. There was a negative correlation between chronotype and sleep period during weekdays (p?<?0.001) and a positive correlation on weekends (p?<?0.001). The weekday-to-weekend difference in sleep period was 0.5?h for E-types, whereas there was no difference for M-types. Binomial logistic regression analyses were used to examine the links between chronotype and behavioral problems, adjusted for participants’ sex, age, childcare programs and locations. Chronotype was significantly associated with hyperactivity/inattention: N-type (adjusted OR?=?1.74, 95% CI?=?1.03–2.95, p?<?0.05) and E-type (adjusted OR?=?2.47, 95% CI?=?1.18–5.20, p?<?0.05). E-type was significantly associated with conduct problems (adjusted OR?=?2.11, 95% CI?=?1.03–4.31, p?<?0.05) and peer problems (adjusted OR?=?2.75, 95% CI?=?1.18–6.44, p?<?0.05). The results suggest that E-type children are vulnerable to higher social jetlag and more behavioral problems. The immature adjustment function of their endogenous circadian pacemakers may not be able to correct a small but significant social jetlag to synchronize with their social clocks. Furthermore, guidance based on chronobiological evidence is required for parents, teachers and health professionals to help children achieve optimal sleep and reduce behavioral problems.     

Interrelationships between distinct circadian manifestations of possible bruxism,perceived stress,chronotype and social jetlag in a population of undergraduate students

ABSTRACT

This study investigates the recently hypothesized association between distinct circadian manifestations of possible bruxism in subjects with different chronotype profiles, social jetlag and levels of perceived stress. A cross-sectional study was performed by surveying dental students’ of Lithuanian University of Health Sciences. A survey instrument was designed and pilot tested for reliability and validity prior to full-scale administration. The instrument consisted of four sections: socio-demographic questions, bruxism-related items, the Perceived Stress Scale and the Munich ChronoType Questionnaire. The study included 228 students (82.5% females; mean age 22.67 ± 2.27). Awake grinding was significantly associated with later chronotype values (p = 0,039). Despite the lack of significance, binary regression models demonstrated that students with later chronotypes report higher rates of possible bruxism, especially as far as awake grinding (p = .170; OR = 1.89) and sleep grinding (p = .140; OR = 1.60) are concerned. There were no significant associations between perceived stress, social jetlag and bruxism. The scores of perceived stress did not correlate with chronotype values, although a high positive correlation was found between chronotype and social jetlag (r = 0.516, p = .000). It can be concluded that later chronotypes increase the odds for self-reported bruxism, and are significantly associated with higher rates of awake grinding and social jetlag. No interrelationships were found between perceived stress, possible bruxism and social jetlag.     

Association between morningness and resilience in Korean college students

Circadian typology and sleep quality may be essential factors associated with the promotion of resilience. However, previous studies investigating the association between circadian typology and resilience did not analyze the effects of sleep quality on resilience. Thus, the present study evaluated the association between circadian typology and resilience in Korean college students after controlling for sleep quality. Additionally, this study investigated several sleep-related variables, including sleep duration, social jetlag and sunlight exposure during the daytime, to examine the modifiable behavioral features of morningness and also investigated whether the findings regarding morningness-related modifiable habits were associated with resilience. This study included 1094 participants (947 males and 147 females) between 19 and 29 years of age (22.8 ± 1.9 years) who completed the 10-item Korean version of the Connor–Davidson Resilience Scale (CD-RISC-10), the Korean version of the Morningness–Eveningness Questionnaire (MEQ), the Pittsburgh Sleep Quality Index (PSQI), the Korean version of the Hospital Anxiety and Depression Scale (HADS) and a survey about social jetlag that determined misalignments between weekday and weekend times of awakening and activity duration under conditions of sunlight between 10:00 and 15:00. A multiple linear regression analysis revealed that sleep duration, mean daily sunlight exposure between 10:00 and 15:00 and age were positive predictors of morningness, whereas social jetlag was a negative predictor of morningness. Of these morningness-related modifiable behavioral features, mean daily sunlight exposure between 10:00 and 15:00 significantly predicted greater resilience. An additional multiple linear regression analysis revealed that morningness was a positive predictor of resilience after controlling for age, sex, depression, anxiety and sleep quality. These results support the idea that morningness and better sleep quality are associated with greater resilience. Morningness was also associated with longer sleep duration, longer sunlight exposure during the daytime and less social jetlag, whereas longer daily sunlight exposure between 10:00 and 15:00 was associated with greater resilience. Future longitudinal studies are needed to examine whether manipulations of morningness-related modifiable behavioral features can rearrange chronotype and promote resilience.     

Evening chronotype,late weekend sleep times and social jetlag as possible causes of sleep curtailment after maintaining perennial DST: ain’t they as black as they are painted?

ABSTRACT

People sleep less in response to setting social clocks earlier relative to the sun clocks. We proposed here a model-based approach for estimating sleep loss as the difference between weekend and weekday risetimes divided on the difference between weekend risetime and weekday bedtime. We compared this approach with a traditional approach to estimating sleep curtailment as the difference in weekly average sleep duration in two conditions. Weekday and weekend sleep times reported for 320 samples provided possibility of testing whether evening types with later weekend sleep times and larger social jetlag differ from morning types with earlier weekend sleep times and smaller social jetlag on amount of sleep lost (1) throughout the week and (2) in response to an advance of weekday wakeups, for instance, after the expected installation of perennial Daylight Saving Time (DST). We found that (1) an amount of sleep lost due to advancing shift of weekday wakeups depends upon neither chronotype nor weekend sleep times nor social jetlag, (2) a very large amount of sleep is usually lost by evening types with later weekend sleep times and larger social jetlag and (3) an essential sleep loss is caused by our usual work/school schedules, even in morning types with early weekend sleep times and small social jetlag. As compared to such permanent sleep losses experienced by any types, an additional loss due to switching from Standard Time (ST) to perennial DST are expected to be relatively small. We also found that the traditional way of calculation of sleep curtailment leads to paradoxical conclusions, such as (1) sleep loss is larger when social jetlag is smaller, not larger, (2) sleep loss is larger when weekend sleep times are earlier, not later, (3) despite 1-h difference between two student samples in weekday wakeups, their sleep losses can be identical.     

Social Jetlag: Misalignment of Biological and Social Time

Humans show large differences in the preferred timing of their sleep and activity. This so‐called “chronotype” is largely regulated by the circadian clock. Both genetic variations in clock genes and environmental influences contribute to the distribution of chronotypes in a given population, ranging from extreme early types to extreme late types with the majority falling between these extremes. Social (e.g., school and work) schedules interfere considerably with individual sleep preferences in the majority of the population. Late chronotypes show the largest differences in sleep timing between work and free days leading to a considerable sleep debt on work days, for which they compensate on free days. The discrepancy between work and free days, between social and biological time, can be described as ‘social jetlag.’ Here, we explore how sleep quality and psychological wellbeing are associated with individual chronotype and/or social jetlag. A total of 501 volunteers filled out the Munich ChronoType Questionnaire (MCTQ) as well as additional questionnaires on: (i) sleep quality (SF‐A), (ii) current psychological wellbeing (Basler Befindlichkeitsbogen), (iii) retrospective psychological wellbeing over the past week (POMS), and (iv) consumption of stimulants (e.g., caffeine, nicotine, and alcohol). Associations of chronotype, wellbeing, and stimulant consumption are strongest in teenagers and young adults up to age 25 yrs. The most striking correlation exists between chronotype and smoking, which is significantly higher in late chronotypes of all ages (except for those in retirement). We show these correlations are most probably a consequence of social jetlag, i.e., the discrepancies between social and biological timing rather than a simple association to different chronotypes. Our results strongly suggest that work (and school) schedules should be adapted to chronotype whenever possible.     

Low Physical Activity and High Screen Time Can Increase the Risks of Mental Health Problems and Poor Sleep Quality among Chinese College Students

Objective

To test the independent and interactive associations of physical activity (PA) and screen time (ST) with self-reported mental health and sleep quality among Chinese college students.

Method

Data were collected in October, 2013. The gender, age, residential background, body mass index (BMI), perceived family economy and perceived study burden were obtained from a total of 4747 college students (41.6% males and 58.4% females). The outcomes were self-reported PA status, ST, anxiety, depression, psychopathological symptoms and sleep quality. Analyses were conducted with logistic regression models.

Results

Overall, 16.3%, 15.9% and 17.3% of the students had psychological problems, such as anxiety, depression and psychopathological symptoms, respectively. The prevalence of poor sleep quality was 9.8%. High ST was significantly positively associated with anxiety (OR=1.38, 95%CI: 1.15-1.65), depression (OR=1.76, 95%CI: 1.47-2.09), psychopathological symptoms (OR=1.69, 95%CI: 1.43-2.01) and poor sleep quality (OR=1.32, 95%CI: 1.06-1.65). High PA was insignificantly negatively associated with anxiety, depression, psychopathological symptoms and poor sleep. Low PA and high ST were independently and interactively associated with increased risks of mental health problems and poor sleep quality (p<0.05 for all).

Conclusion

Interventions are needed to reduce ST and increase PA in the lifestyles of young people. Future research should develop and measure the impacts of interventions and their potential consequences on sleep, health, and well being.     

Later chronotype is associated with higher hemoglobin A1c in prediabetes patients

The circadian system is known to play a role in glucose metabolism. Chronotype reflects the interindividual variability in the phase of entrainment. Those with later chronotype typically prefer later times in the day for different activities such as sleep or meals. Later chronotype has been shown to be associated with metabolic syndrome, increased diabetes risk and poorer glycemic control in type 2 diabetes patients. In addition, “social jetlag”, a form of circadian misalignment due to a mismatch between social rhythms and the circadian clock, has been shown to be associated with insulin resistance. Other sleep disturbances (insufficient sleep, poor sleep quality and sleep apnea) have also been shown to affect glucose metabolism. In this study, we explored whether there was a relationship between chronotype, social jetlag and hemoglobin A1c (HbA1c) levels in prediabetes patients, independent of other sleep disturbances. A cross-sectional study was conducted at the Department of Family Medicine, Ramathibodi Hospital, Bangkok, from October 2014 to March 2016 in 1014 non-shift working adults with prediabetes. Mid-sleep time on free day adjusted for sleep debt (MSFsc) was used as an indicator of chronotype. Social jetlag was calculated based on the absolute difference between mid-sleep time on weekdays and weekends. The most recent HbA1c values and lipid levels were retrieved from clinical laboratory databases. Univariate analyses revealed that later MSFsc (p = 0.028) but not social jetlag (p = 0.48) was significantly associated with higher HbA1c levels. Multivariate linear regression analysis was applied to determine whether an independent association between MSFsc and HbA1c level existed. After adjusting for age, sex, alcohol use, body mass index (BMI), social jetlag, sleep duration, sleep quality and sleep apnea risk, later MSFsc was significantly associated with higher HbA1c level (B = 0.019, 95% CI: 0.00001, 0.038, p = 0.049). The effect size of one hour later MSFsc on HbA1c (standardized coefficient = 0.065) was approximately 74% of that of the effect of one unit (kg/m²) increase in BMI (standardized coefficient = 0.087). In summary, later chronotype is associated with higher HbA1c levels in patients with prediabetes, independent of social jetlag and other sleep disturbances. Further research regarding the potential role of chronotype in diabetes prevention should be explored.     

Perceived morningness–eveningness predicts academic adjustment and substance use across university,but social jetlag is not to blame

Past research has consistently found that evening-types typically report poorer academic adjustment and higher levels of substance use compared to morning-types. An important development within the morningness–eveningness and psychosocial adjustment literature has been the hypothesis that social jetlag (i.e. the asynchrony between an individual’s “biological” and “social” clocks) is one factor that may explain why evening-types are at a greater risk for negative psychosocial adjustment. Yet, only a handful of studies have assessed social jetlag. Furthermore, the few studies that have assessed social jetlag have done so only with concurrent data, and thus have not been able to determine the direction of effects among morningness–eveningness, social jetlag and psychosocial adjustment. To address this important gap in the literature, the present 3-year longitudinal study employed the use of a cross-lagged auto-regressive model to specifically examine the predictive role of perceived morningness–eveningness and social jetlag on two important indices of psychosocial adjustment among university students: academic adjustment and substance use. We also assessed whether there would be an indirect effect between perceived morningness–eveningness and psychosocial adjustment through social jetlag. Participants were 942 (71.5% female; M?=?19 years, SD?=?0.90) undergraduates at a mid-sized university in Southern Ontario, Canada, who completed a survey at three assessments, each one year apart, beginning in first-year university. Measures were demographics (age, gender and parental education), sleep problems, perceived morningness–eveningness, social jetlag, academic adjustment and substance use. As hypothesized, results of path analyses indicated that a greater perceived eveningness preference significantly predicted higher social jetlag, poorer academic adjustment and higher substance use over time. In contrast, we found no support for social jetlag as a predictor of academic adjustment and substance use, indicating that social jetlag did not explain the link between perceived morningness–eveningness and negative psychosocial adjustment. An important finding was the significant predictive effect of higher substance use on social jetlag over time. Results of the present study highlight the importance of employing a longitudinal framework within which to specifically determine the direction of effects among the study variables in order to validate proposed theoretical models that aim to guide our understanding of how perceived morningness–eveningness, social jetlag, academic adjustment and substance use relate to each other.     

Wrist temperature and cortisol awakening response in humans with social jetlag in the North

The discrepancy between biological and social rhythms known as social jetlag (SJL) is common in modern society and has a range of negative consequences for cognitive functioning, well-being and health. Social jetlag is typical for people with late chronotypes. As shown earlier, the prevalence of individuals with a late chronotype is higher among the residents of high latitudes. Therefore, a higher rate of detection of people with SJL should be expected in the North. In this study we assessed the detection rate of SJL among 62 young inhabitants of the European North of Russia (the Komi Republic), and the relationship between SJL, the circadian rhythm of the wrist temperature, and the cortisol awakening response (CAR). The detection rate of SJL was 65% among the people examined. A significant decrease in the amplitude (A) of circadian rhythm of wrist temperature: (β = ?0.34 (CI 95%: ?0.66 to ?0.33); F_1,60 = 10.4; p < 0.0001; η² = 0.31), an increased incidence of depression: No-SJL = 4.5%; SJL = 17.5% (H = 4.84; p < 0.05), and a tendency for an increase in CAR was also observed in the SJL group. There were sex differences in sensitivity to SJL. Females with SJL but not males had higher global seasonality scores (β = 0.51 (CI 95%: 0.21 to 0.81); F_1,33 = 10.9; p < 0.002; η² =0.24), shorter sleep duration (β = ?0.52 (CI 95%: ?0.82 to ?0.22); F_1,33 = 12.9; p < 0.001; η² = 0.28), worse sleep quality (β = 0.39 (CI 95%: 0.07 to 0.72); F_1,33 = 6.31; p < 0.017; η² = 0.16) and lower A of circadian rhythm of wrist temperature (β = ?0.18 (CI 95%: ?0.55 to 0.18); F_1,33 = 4.48; p < 0.043; η² = 0.13) compared with females without SJL. Thus, our data indicate that 40 of 62 participants of investigation had social jetlag. A decrease of the amplitude of the circadian rhythm of the wrist temperature appears to be an objective marker of SJL. Social jetlag had a strong negative impact on females but not on males.     

Chronotype,social jetlag,and time perspective

ABSTRACT

The phase of entrainment (chronotype) is known to be associated with time perspective (TP), suggesting that the state of circadian system is involved in the long-term planning of human life. However, little is known regarding the influence of circadian misalignment on long-term planning ability. The aim of this study was to investigate the association between social jetlag (SJL) and TP. A total of 1064 schoolchildren and university students (mean age ± standard deviation, 19.2 ± 2.9 years; range, 15–25 years; females, 71.7%) from four cities in the Russian Federation located between 56.9 and 61.7 degrees North completed the Munich ChronoType Questionnaire, the Pittsburgh Sleep Quality Index, the Seasonal Pattern Assessment Questionnaire, and Zimbardo Time Perspective Inventory. Study participants also indicated personal data (age, sex, height weight, place of residence, and achievements). A multiple regression analysis with stepwise inclusion of predictors in the model was performed to evaluate associations between time perspective characteristics (dependent variables) and predictor variables. The change in R² was used as the measure of effect size. Chronotype was found to be a moderate predictor of future TP (B = 0.034; ΔR² = 0.037). In addition, sleep quality was found to be a moderate predictor of past negative (B = 0.043; ΔR² = 0.074), present fatalistic (B = 0.021; ΔR² = 0.035), and deviation from balanced TP (B = 0.034; ΔR² = 0.066). Mood seasonality was a moderate predictor of present hedonistic TP (B = 0.016; ΔR² = 0.038), and social jetlag was a weak predictor of present fatalistic (B = 0.052; ΔR² = 0.019), future (B = ?0.033; ΔR² = 0.004), and deviation from balanced TP (B = 0.047; ΔR² = 0.012). In conclusion, this study found a weak but significant association between social jetlag and TP in adolescents and young adults.     

Reliability and Validity of an Interviewer-Administered Adaptation of the Youth Self-Report for Mental Health Screening of Vulnerable Young People in Ethiopia

Objective

Evaluate the reliability and validity of the Youth Self-Report (YSR) as a screening tool for mental health problems among young people vulnerable to HIV in Ethiopia.

Design

A cross-sectional assessment of young people currently receiving social services.

Methods

Young people age 15–18 participated in a study where a translated and adapted version of the YSR was administered by trained nurses, followed by an assessment by Ethiopian psychiatrists. Internal reliability of YSR syndrome scales were assessed using Chronbach''s alpha. Test-retest reliability was assessed through repeating the YSR one month later. To assess validity, analysis of the sensitivity and specificity of the YSR compared to the psychiatrist assessment was conducted.

Results

Across the eight syndrome scales, the YSR best measured the diagnosis of anxiety/depression and social problems among young women, and attention problems among young men. Among individual YSR syndrome scales, internal reliability ranged from unacceptable (Chronback’s alpha = 0.11, rule-breaking behavior among young women) to good (α≥0.71, anxiety/depression among young women). Anxiety/depression scores of ≥8.5 among young women also had good sensitivity (0.833) and specificity (0.754) to predict a true diagnosis. The YSR syndrome scales for social problems among young women and attention problems among young men also had fair consistency and validity measurements. Most YSR scores had significant positive correlations between baseline and post-one month administration. Measures of reliability and validity for most other YSR syndrome scales were fair to poor.

Conclusions

The adapted, personally administered, Amharic version of the YSR has sufficient reliability and validity in identifying young vulnerable women with anxiety/depression and/or social problems, and young men with attention problems; which were the most common mental health disorders observed by psychiatrists among the migrant populations in this study. Further assessment of the applicability of the YSR among vulnerable young people for less common disorders in Ethiopia is needed.     

Pulling the covers in electronic health records for an association study with self-reported sleep behaviors

ABSTRACT

The electronic health record (EHR) contains rich histories of clinical care, but has not traditionally been mined for information related to sleep habits. Here, we performed a retrospective EHR study based on a cohort of 3,652 individuals with self-reported sleep behaviors documented from visits to the sleep clinic. These individuals were obese (mean body mass index 33.6 kg/m²) and had a high prevalence of sleep apnea (60.5%), however we found sleep behaviors largely concordant with prior prospective cohort studies. In our cohort, average wake time was 1 hour later and average sleep duration was 40 minutes longer on weekends than on weekdays (p < 10^?12). Sleep duration varied considerably as a function of age and tended to be longer in females and in whites. Additionally, through phenome-wide association analyses, we found an association of long weekend sleep with depression, and an unexpectedly large number of associations of long weekday sleep with mental health and neurological disorders (q < 0.05). We then sought to replicate previously published genetic associations with morning/evening preference on a subset of our cohort with extant genotyping data (n = 555). While those findings did not replicate in our cohort, a polymorphism (rs3754214) in high linkage disequilibrium with a previously published polymorphism near TARS2 was associated with long sleep duration (p < 0.01). Collectively, our results highlight the potential of the EHR for uncovering the correlates of human sleep in real-world populations.