Commuting time, working time, and their link to insomnia symptoms among Korean employees: A cross-sectional study

Objective: Although commuting time is an extension of working hours, few studies have examined the relationship between commuting time and insomnia symptoms in relation to working time. Thus, this study investigated the relationship between commuting time and working time and their link to sleep disturbance. Methods: This study included employees with >= 35 weekly working hours (n = 30,458) using data from the Sixth Korean Working Conditions Survey conducted in Korea between October 2020 and April 2021. The association between commuting time (<= 60, 61-120, and >120 minutes) and insomnia symptoms based on working hours (35-40, 41-52, and >52 h/wk) or shift work was investigated using survey-weighted logistic regression analysis. Results: Long commuting time (>120 min/d) combined with >52 working hours/week (OR: 7.88, 95% CI: 2.51-24.71) or combined with 41-52 h/wk (OR: 3.64, 95% CI: 2.15-6.14) was associated with a higher risk of insomnia symptoms compared with the reference group (working hours: 35-40 h/wk; daily commuting time: <= 60 minutes), after controlling for sex, age, socioeconomic factors, and work-related factors. Among shift workers, those with daily commuting time <= 60 minutes (OR: 1.71, 95% CI: 1.39-2.09), 61-120 minutes (OR: 2.63, 95% CI: 1.21-5.74), and >120 minutes (OR: 5.16, 95% CI: 2.14-12.44) had higher odds of insomnia symptoms than nonshift workers with <= 60 minutes daily commuting time. Conclusion: Long working hours and shift work are associated with greater risk of insomnia symptoms. (c) 2024 The Author(s). Published by Elsevier Inc. on behalf of National Sleep Foundation. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).