Chronotype and psychological distress among Chinese rural population: A moderated mediation model of sleep quality and age

PURPOSES: Evidence suggests evening-type individuals have a higher risk of reporting psychological distress than morning-type individuals. However, less is known regarding the underlying processes that might mediate or moderate this association among Chinese rural population. This study aimed to evaluate the prevalence of psychological distress, investigate whether sleep quality would mediate the association between chronotype and psychological distress and explore whether age would moderate the direct or indirect effect of the mediation model. METHODS: The cross-sectional study utilized a sample of 884 rural residents from rural regions in Anqing City, Anhui Province, China. Morningness-Eveningness Questionnaire (MEQ), Pittsburgh Sleep Quality Index (PSQI) and 21-item Depression Anxiety Stress Scale (DASS-21) were used to measure chronotype, sleep quality and psychological distress, respectively. MacKinnon’s four-step procedure was employed to examine the mediation effect, while Hayes PROCESS macro (model 59) was used to perform the moderated mediation analysis. RESULTS: The prevalence of psychological distress among Chinese rural population was 33.4%. The association between chronotype and psychological distress was partially mediated by sleep quality (indirect effect = - 0.05, 95% CI = [-0.08, -0.03]). In addition, age moderated the first stage (sleep quality–psychological distress) of the indirect effect, with the indirect effect being attenuated for older rural residents. As suggested by Johnson-Neyman technique, the association between sleep quality and psychological distress was only significant when the age of the participant was lower than 48.59. CONCLUSIONS: The incidence of psychological distress among Chinese rural residents cannot be neglected. Interventions for the enhancement of sleep quality to prevent and reduce psychological distress should be prioritized to rural residents who are prone to eveningness, especially those who are younger.