The Health Cost of Irregular Sleep Timing: Age Differences in Social Jet Lag and Health Outcomes Among Middle-Aged and Older Adults (Brief Report)

Background Social jet lag, a misalignment between circadian rhythms and societal schedules, has been reported to pose significant health risks. However, evidence of social jet lag's implications on health outcomes among middle-aged and older adults, and the moderating role of age on these associations is limited. We investigated the cross-sectional associations of social jet lag with key health outcomes and considered the moderating role of age. Methods This study included 661 participants aged 50-83 drawn from the 2018 wave of the U.S.-based Health and Retirement Study. We computed multiple linear regressions to estimate the associations between social jet lag—calculated from self-reported sleep timing as the difference between weekday and weekend sleep midpoints—and depressive symptoms, cognitive functioning, and body mass index. Results Unadjusted regressions indicated that higher levels of social jet lag were associated with higher depressive symptoms and higher body mass index. No association was found between social jet lag and cognitive functioning. In adjusted regressions, higher levels of social jet lag remained positively associated with higher depressive symptoms, and this association was moderated by age. Specifically, higher levels of social jet lag were linked to higher depressive symptoms only among adults over age 61.24, whereas no such association was observed in participants aged 50-61.24. Conclusion The findings suggest that greater social jet lag is associated with higher depressive symptoms, particularly among older adults. Future research should explore causal links between social jet lag and health outcomes to inform interventions aimed at improving mental health in this population.