Association of social jetlag and eating patterns with sleep quality and daytime sleepiness in Japanese high school students

Longitudinal course and outcome of social jetlag in adolescents: A 1-year follow-up study of the adolescent sleep health epidemiological cohorts

The discrepancy in sleep timing between weekdays and weekends - social jetlag (SJL) - is known to negatively affect student quality of life (QOL). However, the association between social jetlag and physical/mental QOL among adolescents and the precise effect of social jetlag on depressive symptoms and daytime sleepiness remains unknown. This study investigated the longitudinal course, risk factors, and effects of social jetlag, a circadian misalignment, in a school-based cohort. The participants were 427 students (13.3 ± 0.6 years, 45.2% girls) from five junior high schools. We performed a baseline survey in 2019 and a 1-year follow-up survey in 2020. Depressive symptoms, QOL, and daytime sleepiness were assessed using the Birleson Depression Self-Rating Scale for Children, Paediatric Quality of Life Inventory, and Paediatric Daytime Sleepiness Scale. In the baseline survey, 49.6% of the students reported SJL ≥1 h, and 17.1% reported SJL ≥2 h. Among them, 37.2% and 6.8% reported persistent SJL at follow-up, respectively. New incidences of SJL ≥1 h were associated with older age, non-attainment of menarche or voice changes, and longer duration of smartphone use, whereas its persistence was associated with a later chronotype. Persistence of SJL ≥1 h and ≥2 h predicted depressive symptoms and daytime sleepiness at follow-up, whereas new incidences of SJL ≥2 h predicted lower QOL. In conclusion, social jetlag has a persistent course, and daytime functioning can deteriorate as social jetlag becomes chronic. Our findings suggest the need for intensive interventions for social jetlag among adolescents.

Dietary polyphenols and sleep modulation: Current evidence and perspectives

Polyphenols are plant compounds with several biological activities. This review aims to summarize current knowledge on the potential role of polyphenols in modulating sleep. A total of 28 preclinical studies, 12 intervention studies and four observational studies exploring the role of polyphenol intake on sleep were identified. From animal studies, 26 out of the 28 studies found beneficial effects of polyphenols on sleep architecture. Three out of four human observational studies found a beneficial association between polyphenol intake and sleep parameters. And, among clinical intervention studies, eight from a total of 12 studies found some beneficial effect of polyphenol intake on various sleep parameters, although some discrepancies between studies were found. Overall, emerging evidence suggests a benefit of polyphenol intake on sleep. Several mechanisms of action have been suggested, ranging from effects on neurotransmitters to an action through the gut-brain axis. However, more research in this field is needed, emphasizing the use of nutritional doses in mechanistic studies and interventions targeting participants with sleep problems. This would allow to elucidate whether an additional biological effect of polyphenols is modulation of sleep, a behavior associated with adverse health outcomes.

Social jetlag longitudinally predicts internalizing and externalizing behavior for adolescent females, but not males

Biological changes contribute to preferences for later bed and wake times during adolescence, yet the social constraints of school start times necessitate early wake times. This often results in social jetlag (i.e. misalignment between preferred sleep timing on weekends and school days). We examined whether social jetlag predicts adolescent internalizing and externalizing behavior over time and/or whether associations differ based on sex. We used data from the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development Study (n = 767) to test whether social jetlag at 6th grade (ages 12-13 years) predicted internalizing and externalizing behavior at age 15 years and whether child sex moderated associations. Controlling for internalizing and externalizing behavior at 6th grade (ages 12-13 years), results were that social jetlag at 6th grade (ages 12-13 years) predicted more internalizing and externalizing behaviors at age 15 for females, but not males. These findings show that social jetlag during early adolescence confers risk for internalizing and externalizing behavior in females at mid-adolescence. Greater attention should be placed on identifying and addressing social jetlag in adolescent females.

Social jetlag and dietary intake: A systematic review

The objective of the current systematic review was to critically review the available evidence regarding the link between social jetlag and diet among the general population using observational studies. Electronic databases, including PubMed, Scopus, and ISI Web of Sciences were searched systematically. We reviewed 348 references, of which 17 studies met inclusion criteria with a total sample size of 28,905. Qualitative analysis indicated a negative association between social jetlag and adherence to healthy eating habits, including a negative association with empirically-derived healthy dietary patterns, Japanese dietary patterns, Baltic Sea dietary patterns, and the Mediterranean diet, as well as a positive association with Meat and Starchy dietary pattern. On the other hand, the findings on the link of social jetlag with food groups and nutrients were mixed and controversial, except for a more consistent increase in sugar-sweetened beverages, total fat, and saturated fat intake. Our results indicate a possible link between social jetlag and dietary intake. Research suggests that individuals experiencing greater social jetlag exhibit reduced adherence to a healthy eating pattern. However, it is important to note that the reported association lacks consensus, emphasizing the need for additional longitudinal studies to gain further insights into this matter."

Quantifying teenagers' sleep patterns and sex differences in social jetlag using at-home sleep monitoring

Sleep plays an important role in the formative developmental processes occurring during the teenage years. At the same time, teenagers' changing bioregulatory mechanisms and psychosocial factors converge into the so-called social jetlag, a sleep timing misalignment between weekdays and weekends. The aim of this study was to quantify the course of day-to-day changes in sleep/wake patterns and sleep stage distributions, and the sex differences in social jetlag among teenagers. We observed the sleep of 156 teenagers (58.3% girls, 15-16 years) using a novel sleep monitor over the course of up to 10 consecutive days. 1323 nights of data were analyzed using multilevel modeling. On average, participants went to bed at 23:41, woke up at 07:48, slept for 7.7 h and had 85.5% sleep efficiency. Sleep stage distributions were in line with normative data. We found later sleep onset and offset, longer time in bed, sleep duration, and sleep onset latency (p = .001), greater proportion of light sleep and lower proportion of deep sleep, and poorer sleep efficiency (all p < .001) on weekend nights starting on Friday and Saturday. On Friday nights, girls had longer time awake after sleep onset (p = .020) than boys. On Friday and Saturday nights, girls fell asleep earlier (p < .001 and p = .006, respectively). On Saturday nights, girls had shorter sleep latency (p = .024), and better sleep efficiency (p = .019) than boys. In sum, teenagers' sleep patterns reflected healthy, albeit somewhat short sleep. There was convincing evidence of social jetlag, and girls exhibited less severe social jetlag than boys.

Delayed sleep-wake phase disorder and its related sleep behaviors in the young generation

Delayed sleep-wake phase disorder (DSWPD) is a sleep disorder in which the habitual sleep-wake timing is delayed, resulting in difficulty in falling asleep and waking up at the desired time. Patients with DSWPD frequently experience fatigue, impaired concentration, sleep deprivation during weekdays, and problems of absenteeism, which may be further complicated by depressive symptoms. DSWPD is typically prevalent during adolescence and young adulthood. Although there are no studies comparing internationally, the prevalence of DSWPD is estimated to be approximately 3% with little racial differences between Caucasians and Asians. The presence of this disorder is associated with various physiological, genetic and psychological as well as behavioral factors. Furthermore, social factors are also involved in the mechanism of DSWPD. Recently, delayed sleep phase and prolonged sleep duration in the young generation have been reported during the period of COVID-19 pandemic-related behavioral restrictions. This phenomenon raises a concern about the risk of a mismatch between their sleep-wake phase and social life that may lead to the development of DSWPD after the removal of these restrictions. Although the typical feature of DSWPD is a delay in circadian rhythms, individuals with DSWPD without having misalignment of objectively measured circadian rhythm markers account for approximately 40% of the cases, wherein the psychological and behavioral characteristics of young people, such as truancy and academic or social troubles, are largely involved in the mechanism of this disorder. Recent studies have shown that DSWPD is frequently comorbid with psychiatric disorders, particularly mood and neurodevelopmental disorders, both of which have a bidirectional association with the pathophysiology of DSWPD. Additionally, patients with DSWPD have a strong tendency toward neuroticism and anxiety, which may result in the aggravation of insomnia symptoms. Therefore, future studies should address the effectiveness of cognitive-behavioral approaches in addition to chronobiological approaches in the treatment of DSWPD.

Effects of Irregular Mealtimes on Social and Eating Jet Lags among Japanese College Students

College students' social and eating jet lags and chronotypes may be related to irregular eating habits. Therefore, we examined the relationship between social and eating jet lags, chronotypes, variability in first and last mealtimes, and non-eating duration, as well as the effects of snacking between dinner and bedtime on social and eating jet lags, chronotypes, and mealtime variation. A total of 1900 Japanese male college students were recruited in this study. Mean wake-up time, bedtime, sleeping time, first and last mealtimes, snacks between meals, non-eating duration, the midpoint of non-eating duration, social and eating jet lags, and chronotype were calculated. Standard deviations in first and last mealtimes, the midpoint of non-eating duration, and the coefficient of variation in non-eating duration were used to evaluate mealtime variations. Mealtime variations were significantly associated with social and eating jet lags, chronotype, the midpoint of non-eating duration, and the difference in first and last mealtime between school holidays and class days. Chronotype and the midpoint of non-eating duration were significantly delayed with increased snacking after dinner. Mealtime variations were significantly lower in those who avoided snacking than in those who did not. Thus, social and eating jet lags and chronotypes are associated with sleep habits and mealtime irregularities.

Associations of social jetlag and insomnia symptoms with depressive symptoms among Chinese adolescents: A large population-based study

OBJECTIVE

This study aimed to evaluate the associations of social jetlag and insomnia symptoms with depressive symptoms among adolescents.

METHODS

A total of 37,871 junior high students completed an online survey between May 24th and Jun 5th, 2022. Insomnia symptoms were assessed by three items based on the Diagnostic and Statistical Manual of Mental Disorders criteria. Social jetlag and depressive symptoms were evaluated by the Munich Chronotype Questionnaire and the Patient Health Questionnaire, respectively. Restricted cubic splines were used to explore the relationship between social jetlag and depressive symptoms. Joint effects of social jetlag and insomnia symptoms on depressive symptoms were estimated using additive interaction models.

RESULTS

The prevalence of depressive symptoms was 13.1%. Depressive symptoms were more common in adolescents with social jetlag ≥2 h (OR: 1.51, 95% CI: 1.39-1.65) and insomnia symptoms (OR: 6.91, 95% CI: 6.41-7.44). There was a J-shaped relationship between social jetlag and depressive symptoms when we took social jetlag as a continuous variable. Moreover, a positive additive interaction of social jetlag ≥2 h and insomnia symptoms on depressive symptoms was found in female adolescents (RERI: 2.30, 95% CI: 0.11-4.49).

CONCLUSIONS

Our findings suggested that social jetlag ≥2 h and insomnia are related to the occurrence of depressive symptoms in adolescents. Their coexistence additively enhances the strength of the association with depressive symptoms. Early screening and intervention for insomnia, as well as methods to reduce social jetlag, should be comprised as part of preventive strategies for depression in adolescents.

Examination of sleep factors affecting social jetlag in Japanese male college students

We hypothesized that social jetlag would be associated with prolonged sleep duration on weekends and irregularities in wake-up time and/or bedtime on weekdays. In total, 1,200 Japanese male college students were included in this study. Participants completed an eight-day sleep diary in which they recorded their wake-up time, bedtime, and sleep duration every day for a week. Mean wake-up time, bedtime, and sleep duration, standard deviations in wake-up time and bedtime, the coefficient of variation in sleep duration, social jetlag, and chronotype were calculated over seven nights. Multiple regression was used to explore the factors influencing social jetlag. Stepwise selection analysis was performed to analyze the parameters identified on multiple regression analysis. The mean chronotype of the included participants was 5.3 ± 1.5; their mean social jetlag value was 1.1 ± 1.0. The mean wake-up time, bedtime, and sleep duration values were 8.5 ± 1.1, 25.0 ± 1.1, and 7.5 ± 1.1 h, respectively. Multiple regression analysis showed five indicators exerting a statistically significant influence on social jetlag. The standard deviation in wake-up time was adopted as the first factor in the stepwise selection analysis. These results show that social jetlag is associated with not only prolonged sleep duration on weekends but also irregularities in wake-up time during the week.

The associations of chronotype and social jetlag with prosocial behavior problems among Chinese adolescents

Potential relevance between the circadian rhythm and behavioral health has got raising attention in recent years. This study aimed to examine chronotype, social jetlag and their associations with prosocial behavior problems among Chinese adolescents. A total of 4,666 middle school students aged 12-18 years were enrolled in study. Sleep characteristics were collected by the modified Chinese version of Adolescent Sleep Hygiene Scale (M-ASHS); MSFsc and mid-sleep point were calculated to determine chronotypes and social jetlag. Prosocial behavior problems were assessed by the Strength and Difficult Questionnaire (SDQ). Multivariate logistic regression was applied to analyze the relationships between chronotype and social jetlag with prosocial behavior problems. Evening chronotype was associated with higher risk of prosocial behavior problems, whether among male (OR = 1.82, 95%CI:1.27-2.61, P = .001) or female adolescents (OR = 1.83, 95%CI:1.15-2.91, P = .011). Female adolescents with social jetlag of 1-2 hours had 1.60 times the risk of prosocial behavior problems than their peers whose social jetlag was <1 h (P = .028); social jetlag ≥ 2 h was positively associated with prosocial behavior problems in both male and female adolescents (OR = 1.79 and 2.45, respectively, both P < .05). Further, the combination of intermediate chronotype and social jetlag ≥ 2 h was correlated with prosocial behavior problems only in female adolescents (OR = 3.24, 95%CI = 1.40-9.21, P = .004). Evening chronotype and higher social jetlag were risk factors for prosocial behavior problems in adolescents, especially for the female. For the promotion of prosocial behavior in adolescents, the importance of circadian rhythm should be addressed.