The role of depression and anxiety in the relationship between poor sleep quality and subjective cognitive decline in Chinese elderly: Exploring parallel, serial, and moderated mediation

Poor sleep quality exacerbates subjective cognitive decline (SCD). Mental health may play an important role in the relationship, but the potential underlying mechanisms remain unknown.A cross-sectional study was conducted on older adult residents in Guangdong province, south China from November 2020 to March 2021. A total of 717 adults aged 60 years and over were recruited for a face-to-face investigation on a range of socio-demographic factors, lifestyle behaviors, sleep quality, SCD, depressive and anxiety symptoms. Parallel, serial and moderated mediation models were used to examine whether depression and anxiety mediated in the poor sleep quality-SCD linkage.Both direct and indirect effects of poor sleep quality on SCD symptoms were found. Anxiety and depressive symptoms mediated the relationship between poor sleep quality and SCD symptoms(βAnxiety = 0.123, 95%CI: 0.079 to 0.173; βDepression=0.274, 95%CI: 0.200 to 0.348), respectively. Serial mediation analyses indicated that depressive and anxiety symptoms co-play a serial mediating role in the association of poor sleep quality and SCD symptoms (βa=0.052, 95% CI: 0.026 to 0.084; βb=0.077, 95% CI: 0.033 to 0.128). Moderated mediation model revealed that the mediation of depressive symptoms on the relationship between poor sleep quality and SCD symptoms was moderated by anxiety symptoms(β=0.318, 95% CI: 0.164 to 0.472).The study is the cross-sectional design, which limits the causal inference ability.These findings provided new insights into possible avenues for prevention and intervention on SCD through sleep-based treatments with a multi-faceted approach on psychiatric disorders.