Prevalence and influencing factors of insomnia among adults in centralized quarantine: A cross-sectional study

Large-scale quarantine is critical for controlling coronavirus disease 2019 transmission but may adversely affect sleep. Although many global reports have examined mental health and sleep problems in individuals under quarantine or restricted conditions, most studies were conducted in hospital settings or during home quarantine in high-income countries, with research involving individuals quarantined in centralized quarantine hotels being limited. This study assessed the prevalence of insomnia and its risk factors among residents of centralized quarantine hotels. In this retrospective observational study (April 2020-January 2022), 34,253 quarantined individuals completed the patient health questionnaire-9, generalized anxiety disorder-7, and insomnia severity index questionnaires. Insomnia was defined as an insomnia severity index score ≥ 8. Multivariable logistic regression and restricted cubic spline analyses were performed to examine risk factors and the relationship between age and insomnia. The prevalence of insomnia was 17.81%. Significant risk factors included female sex (odds ratio [OR] = 1.17, 95% confidence interval [CI]: 1.09-1.26), middle economic status (OR = 1.16; 95% CI: 1.02-1.31), anxiety symptoms (OR = 4.91; 95% CI: 4.48-5.37), and depressive symptoms (OR = 7.84; 95% CI: 7.16-8.58). Restricted cubic spline analyses revealed a nonlinear association between age and insomnia (P-overall < .001, P-nonlinear = .005), driven by a U-shaped pattern in females (lowest risk at 48.3 years), with no significant association in males. These findings indicate that adults in quarantine experience a substantial degree of insomnia, with sex-specific age effects and strong associations with mental health. Targeted interventions for high-risk subgroups (e.g., women at age extremes and individuals with psychological symptoms) are urgently needed.