Associations of social jetlag with mental health, somatic symptoms, and work functioning in a nationwide Japanese survey: A population-based cross-sectional study.

BACKGROUND

Social jetlag (SJL), reflecting misalignment between biological circadian rhythms and socially imposed sleep schedules, has been linked to adverse health outcomes. However, population-based studies examining mental health, somatic symptoms, and work functioning simultaneously are limited. This study aimed to investigate the associations of SJL with these outcomes in a nationwide Japanese general population.

METHODS

We analyzed cross-sectional data from 12,372 individuals participating in the 2025 Japan Society and New Tobacco Internet Survey; 48.6% of the participants were male. SJL was calculated as the absolute difference in mid-sleep timing between workdays and non-workdays and categorized as <1 h, 1-<2 h, and ≥2 h. Psychological distress, somatic symptoms, and work functioning were assessed using validated questionnaires. Survey-weighted regression models incorporating inverse probability weighting were applied to estimate associations, with adjustments for sociodemographic characteristics, lifestyle factors, categorical sleep duration, and health-related variables.

RESULTS

In crude models, SJL ≥2 h was associated with higher psychological distress, somatic symptom burden, and work functioning impairment. After full adjustment including categorical sleep duration, SJL ≥2 h remained independently associated only with psychological distress.

CONCLUSIONS

SJL was independently associated with psychological distress but not with somatic symptoms or work functioning after comprehensive adjustment including sleep duration. These findings indicate that circadian misalignment reflected by SJL may be particularly relevant for mental health in the general population.