Insomnia during coronavirus disease 2019 pandemic in Korea: a National sleep survey

Coronavirus disease 2019 (COVID-19) pandemic has caused widespread increase in stress and affected sleep quality and quantity, with up to 30% prevalence of sleep disorders being reported after the declaration of the pandemic. This study aimed to assess perceived changes due to the pandemic in the prevalence of insomnia and excessive daytime sleepiness (EDS) in Korea, and identify the associated factors. An online survey was conducted among 4000 participants (2035 men and 1965 women) aged 20-69 years enrolled using stratified multistage random sampling according to age, sex, and residential area, between January, 2021 and February, 2022. The questionnaire included various items, such as socio-demographics, Insomnia Severity Index, and Epworth Sleepiness Scale (ESS). Insomnia was defined as difficulty falling asleep and difficulty maintaining sleep more than twice a week. EDS was classified as an ESS score >= 11. Insomnia was reported by 32.9% (n = 1316) of the participants (37.3% among women and 28.6% among men). Multivariate logistic regression revealed that insomnia was associated with female sex [odds ratio (OR) = 1.526, 95% confidence interval (CI) = 1.297-1.796], night workers (OR 1.561, 95% CI 1.160-2.101), and being unmarried (OR 1.256, 95% CI 1.007-1.566). EDS was reported by 12.8% (n = 510) of the participants (14.7% among men and 10.7% among women). EDS was associated with male sex (OR 1.333, 95% CI 1.062-1.674), and being employed (OR 1.292, 95% CI 1.017-1.641). During the COVID-19 pandemic, the prevalence of insomnia increased in Korea, while there was no significant change in EDS compared with pre-pandemic evidence.