Social jetlag as a predictor of depressive symptoms among Japanese adolescents: Evidence from the Adolescent Sleep Health Epidemiological Cohort

Association between social jetlag and anxiety symptoms: Findings from a nationally representative sample of the Korean working population

OBJECTIVES

Social jetlag (SJL), which arises from the misalignment of biological and social rhythms, is associated with adverse health outcomes. We explored the association between SJL and anxiety symptoms in Korean workers.

METHODS

This cross-sectional study included a nationally representative sample, consisting of 2731 adult workers. SJL was calculated as the absolute difference in the midpoint between sleep onset and offset times on workdays and free days. The Generalized Anxiety Disorder-7 scale was used to assess anxiety symptoms. Logistic regressions were used to estimate the odds ratios (ORs) and 95 % confidence intervals (CIs).

RESULTS

Among the sample, 66.5 % individuals had 0-59 min of SJL, 22.6 % had 60-119 min of SJL, and 10.9 % had ≥120 min of SJL. The prevalence of anxiety symptoms was 3.4 % for those with 0-59 min of SJL, 3.2 % for those with 60-119 min of SJL, and 7.7 % for those with ≥120 min of SJL. Workers with ≥120 min of SJL, compared with those with 0-59 min of SJL, were associated with an increase in the odds of having anxiety symptoms (OR:2.04, 95 % CI:1.10-3.78). A 1-h increase in SJL is associated with a 1.35-fold increase in the odds of anxiety symptoms (95 % CI:1.04-1.75). This positive association remained robust after adjusting for the effect of sleep deprivation using a sleep-corrected formula.

CONCLUSION

≥2 h of SJL is associated with anxiety symptoms in Korean workers. Policy measures are required to mitigate excess SJL and monitor the mental health of workers with high SJL levels.

Association of Social Jetlag with the Dietary Quality Among Korean Workers: Findings from a Nationwide Survey

Background/Objectives: Social jetlag, which refers to the misalignment between biological rhythms and social schedule, is linked to an increased risk of metabolic diseases. This cross-sectional study investigated the relationship between social jetlag and workers' dietary quality. Methods: This secondary data analysis included a sample of workers from the Korea National Health and Nutrition Examination Survey (n = 11,430). Social jetlag was determined by calculating the difference in the sleep midpoint between free days and workdays, based on sleep onset and offset times. The Korean Health Eating Index (KHEI) was calculated based on 24-h recalls, with higher scores indicating superior dietary qualities (range: 0-100). Poor dietary quality was defined as a KHEI below the lowest quartile (<51.6). Linear or logistic regressions were utilized to estimate β or odds ratio (OR), respectively. Results: Among study participants, 12.1% of workers experienced ≥120 min of social jetlag. ≥120 min of social jetlag was associated with a reduced KHEI score compared with 0-59 min (β: -1.23, 95% confidence interval [CI]: -2.16, -0.30). Those with ≥120 min of social jetlag were more likely to have poor dietary quality than those with 0-59 min (OR: 1.27, 95% CI: 1.08, 1.50). Conclusions: Workers experiencing ≥120 min of social jetlag had poorer dietary quality compared with workers with 0-59 min of social jetlag. Therefore, this study suggests that policy efforts are needed to reduce social jetlag among workers in Korea.

Association between screen time, homework and reading duration, sleep duration, social jetlag and mental health among Chinese children and adolescents

OBJECTIVES

To examine the associations of screen time, homework and reading duration, sleep duration, social jetlag with mental health in children and adolescents, as well as its gender differences.

METHODS

From December 2023 to April 2024, a total of 62 395 children and adolescents were selected from 51 schools in 17 cities of China by stratified cluster sampling. Screen time, homework and reading duration, sleep duration, and social jetlag were calculated by answering the questions about watching TV time, playing smartphones time, doing homework time, reading extracurricular books time, bedtime, wake-up time, and nap time during weekdays and weekends. Mental health was assessed by the Revised Mental Health Inventory-5 (MHI-5). The generalized linear model was used to determine the association between screen time, homework and reading duration, sleep duration, social jetlag, and mental health in children and adolescents.

RESULTS

The generalized linear model results showed that longer watching TV time, longer playing smartphones time, longer homework time, and greater social jetlag were correlated with poorer mental health in children and adolescents, while longer nighttime sleep duration, and longer daytime nap duration were correlated with better mental health. Moreover, in primary school and junior high school, we found that this association was stronger during the weekdays. However, in senior high school, this association was stronger during the weekends. After according to gender stratified, we found that the strength of this association was different in boys and girls at different study phases. Furthermore, our findings also revealed a significant quadratic relationship, indicating the association of better mental health with an optimal amount of sleep duration.

CONCLUSIONS

There was a significant association between screen time, homework and reading duration, sleep duration, social jetlag, and mental health in children and adolescents. This study has the potential to offer useful insights for the prevention and control of mental health issues in children and adolescents.

Sex differences in the association between social jetlag and hazardous alcohol consumption in Korean workers: A nationwide cross-sectional study

BACKGROUND

Social jetlag, the misalignment between biological and social rhythms, can lead to adverse health outcomes. This study explored the association between social jetlag and hazardous alcohol consumption, as well as the sex differences in this association.

METHODS

This study included a nationally representative sample of Korean workers consisting of 11,462 individuals (5479 women). Social jetlag was calculated as the difference in the mid-point between sleep onset and offset on free days and workdays. Hazardous alcohol consumption was determined using the Alcohol Use Disorder Identification Test-Consumption (range 0-12), with a cutoff of ≥6 for men, ≥5 for women, and ≥3 for those aged ≥65. Logistic regression analysis was used to estimate the odds ratios (ORs) and 95 % confidence intervals (CIs).

RESULTS

Among men, 599 out of 5983 individuals (10.0 %) had ≥120 min of social jetlag. Among women, 550 out of 5479 individuals (10.0 %) had ≥120 min of social jetlag. The prevalence of hazardous alcohol use was 56.2 % for men and 27.3 % for women. In the regression analysis, there was a significant sex interaction, where social jetlag ≥120 min was associated with hazardous alcohol consumption in female workers (OR: 1.52, 95 % CI: 1.18-1.96), but not in male workers (OR: 1.04, 95 % CI: 0.84-1.29).

CONCLUSION

High social jetlag was associated with an increased likelihood of hazardous alcohol consumption among women. Our findings underscore the importance of considering sex differences in future research and policy interventions regarding social jetlag and its associated behavior outcomes.

Prevalence, correlates, and mental health outcomes of social jetlag in Chinese school-age adolescents: A large-scale population-based study

BACKGROUND

This cross-sectional study aimed to examine the prevalence and correlates of social jetlag (SJL) in Chinese adolescents, as well as to test the relationships between SJL and mental health problems.

METHODS

A total of 106979 students (Mage = 13.0 ± 1.8 years; Nmale = 58296 [54.5 %]) from Shenzhen, China completed an online survey from May 24th to June 5th, 2022. Information on sociodemographics, lifestyles, sleep characteristics, anxiety symptoms, and depressive symptoms was collected by a self-administered questionnaire. Multivariate and binary logistic regression were adopted for data analysis.

RESULTS

17.8 % of participants experienced SJL ≥ 2 h. To adjust the accumulated sleep debt, sleep-corrected SJL (SJLsc) was calculated and 8.3 % of individuals self-reported SJLsc ≥ 2 h. Both SJL and SJLsc show an increasing trend with age. Risk factors of SJL included females, poor parental marital status, being overweight, physically inactive, smoking, drinking, and having a late chronotype. Moreover, males, having siblings, boarding at school, short sleep duration, experiencing insomnia, and frequent nightmares were significantly associated with an increased risk of SJLsc. After adjusting for all covariates, adolescents with SJLsc ≥ 2 h were more likely to have anxiety symptoms (OR: 1.35, 95 % CI: 1.24-1.48) and depressive symptoms (OR: 1.35, 95 % CI: 1.25-1.46) than those with SJLsc < 1 h.

CONCLUSIONS

SJL is common among Chinese school-age adolescents. This study is valuable for the development of prevention and intervention strategies for SJL in adolescents at the population level. Additionally, the strong links between SJLsc and emotional problems underscore the critical significance of addressing SJL as a key aspect of adolescent well-being.

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.

Stability of social jetlag and sleep timing into the second year of the Covid-19 pandemic: Results from a longitudinal study of a nationally representative adult sample in Ireland

The early phase of the COVID-19 pandemic has previously been associated with marked changes in sleep/wake timing arising from the imposition of society-wide infection mitigation measures. Such observations are considered of broader significance as they reveal the social pressures that sleep timing normally operates under. In order to assess how persistent such changes were as the COVID-19 pandemic developed, we assessed sleep timing and quality in a longitudinal study of a nationally-representative sample of Irish adults with data collected at two time-points (December 2021 and March 2021). Data on social jetlag and chronotype was derived from the micro Munich Chronotype Questionnaire from 830 and 843 participants who provided data in December 2020 and March 2021 respectively, of which 338 contributed data to both timepoints. Demographics and measures of insomnia symptoms, anxiety, depression and loneliness were also collected, and data was analysed both within-subjects and cross-sectionally within data waves. Social jetlag (the mismatch between sleep timing on "work" and "free" days) and other measures of sleep timing were stable across the two time-points, although insomnia symptoms improved slightly from December 2020 to March 2021. The mean social jetlag at both timepoints was ~ 30 minutes, considerably lesser than reported pre-pandemic levels in similar populations. Multiple regression analysis of cross-sectional data reveals that the timing of midsleep on "free" days was only a weak-to-moderate predictor of social jetlag, whilst hours worked per week was the strongest predictor of social jetlag. Requirement for "face-to-face" contact with the public at work and urban location of residence also emerged as predictors of social jetlag, although insomnia, anxiety and depression symptoms and loneliness rating did not. We conclude that sleep timing changes that occurred during the initial phase of the COVID-19 pandemic persisted into the second year of the pandemic, and these results further illustrate the key roles working practices and other social factors have in shaping social jetlag.