Prevalence of nonrestorative sleep before and during the COVID-19 pandemic: based on a nationwide cross-sectional survey among Japanese in 2019 and 2022

Background: Japanese people sleep less compared to other countries around the world. Using a large nationally representative survey in 2019 and 2022, we investigated whether sleep duration and nonrestorative sleep (NRS) among Japanese people have improved or worsened due to the COVID-19 pandemic. Methods: Data were drawn from the Comprehensive Survey of Living Conditions, a nationwide cross-sectional sample based on self-administered questionnaires. We analyzed 426,510 people in 2019 and 375,578 people in 2022 aged ≥20 living in the community. The generalized estimating equations of the multivariable Poisson regression models were used to estimate adjusted prevalence of NRS by survey year. Potential confounders included gender, age, marital status, family size, housing tenure, equivalent household expenditures, education, employment status, illness under treatment, lifestyle behaviors (i.e., smoking, drinking, dietary, and fitness habits), mental health, and sleep duration. Results: Among the study participants, 35.7% slept less than 6 hours and 20.9% had NRS. Regarding sleep duration, the prevalence of sleep duration of less than 6 hours was significantly lower in 2022 than in 2019 for both men and women. By gender and age, the prevalence of short sleep duration (