Background: Several studies have found that poor sleep quality appeared to be negatively associated with quality of life in older adults, but the mechanism underlying this association remained unclear. In this study, we aimed to examine whether mental health mediated the association between sleep quality and quality of life among rural elderly and to explore the moderated role of physical activity between mental health and quality of life.
Methods: Data were extracted from the baseline survey of rural elderly household health services in Shandong province, in which 3,243 older adults aged 60 years and above were included. The moderated mediation models were examined using SPSS PROCESS Version 3.4 software, in which the mediation variable was mental health, and the moderation variable was physical activity.
Results: We found that mental health partially mediated the effect of sleep quality on quality of life [indirect effect = -0.158, 95% confidence intervals (CI) = -0.185, -0.133], with the mediating effect accounting for 51% of the total effect. The indirect effect was moderated by physical activity (β = 0.056, p < 0.001), and a greater effect was observed among older adults with lower level of physical activity.
Limitations: We included two mediators in one model, and interpretation of the observed associative direction was limited.
Conclusions: Physical activity moderated the indirect effect of mental health on association between sleep quality and quality of life. Encouraging the rural elderly to increase physical activity appropriately might improve the quality of life for the elderly with poor sleep quality and mental health problems.
Keywords: Mental health; Physical activity; Quality of life; Rural elderly; Sleep quality.
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