To explore the mediating effect of quality of sleep and cognitive reserve in the association of depression and cognitive function among the community-dwelling older adults.

A total of 492 community-dwelling elderly in the Pudong New Area of Shanghai were selected by convenience sampling method and investigated with the general information questionnaire, 15-item Geriatric Depression Scale (GDS-15), Pittsburgh Sleep Quality Index(PSQI), Cognitive Reserve Index Questionnaire(CRIq), and Beijing version of the Montreal Cognitive Assessment(MoCA). SPSS 25.0 software was used to explore the mediating role of sleep quality and cognitive reserve.

Pearson’s partial correlation analysis showed the cognitive function of elderly was significantly positively correlated with the cognitive reserve scores (r=0.189,P<0.001), and negatively correlated with the depression scores and sleep quality scores (r=0.179 and -0.362, both P<0.001); depression scores were significantly negatively correlated with cognitive reserve scores (r=-0.152, P<0.01), and significantly positively correlated with sleep quality scores (r=0.185, P<0.001), after adjusting for significant covariates including age, marital status, economic income and BMI, the mediating analysis showed depression had a significantly negative directly effect oncognitive function (β=-0.297, P<0.001); depression also had an indirectly negative effect on cognitive function through the pathways: reducing sleep quality and diminishing cognitive reserve, with medication effect values (β=-0.019, P<0.001) both accounted for 5.69%.

Community-dwelling elderly with depression, sleep disorders, and lower cognitive reserve have poorer cognitive function. Depression may directly affect cognitive function, and may also have indirect effects on cognitive function in elderly by decreasing sleep quality and cognitive reserve.