Longitudinal Effects of Remote Work Frequency on Insomnia Symptoms and Short Sleep Duration Among Japanese Workers.

Remote work has been established as a method of working. However, the impact of remote work on employees' sleep health has not been elucidated. This study aimed to examine the longitudinal association between the frequency of remote work and sleep problems among workers in Japan. A 2-year cohort study analysed 824 workers (male: 57.7%, aged 20s: 33.6%) from five companies in Japan. Surveys were administered at baseline (FY2021) and follow-up (FY2023). The outcomes were being at risk of insomnia using the Athens Insomnia Scale, self-reported short sleep duration (SSD), and being at risk of insomnia with SSD. Generalised estimating equation models were used to analyse the association between the frequency of remote work and outcomes, adjusting for demographic, occupational and health-related variables. The retention rate for the follow-up survey was 29.0%, and the prevalence of sleep problems increased during the study. A U-shaped pattern was observed at baseline, with full onsite and full remote work being associated with a higher prevalence of being at risk of insomnia. However, this phenomenon disappeared at follow-up. High frequency (> 80% remote work monthly; odds ratio = 0.54 [95% confidence interval: 0.35-0.82]) and full remote work (odds ratio = 0.41 [95% confidence interval: 0.27-0.61]) were significantly associated with being at risk of insomnia with SSD compared with full-time onsite work. Thus, high frequency and full remote work may have beneficial effects on sleep duration by allowing employees greater flexibility in aligning their work schedules. Further research is needed to confirm these findings and investigate the mechanisms underlying these associations.