Social capital and subjective well-being among older adults: The mediating role of loneliness and the moderating role of optimism

As the demographic trend of population aging accelerates in China, there is a growing need for effective strategies to enhance subjective well-being in older adults. Although social capital is widely recognized as an external resource that contributes to subjective well-being, the underlying mechanisms remain insufficiently understood. Guided by Conservation of Resources (COR) theory, this study proposed a moderated mediation framework to test whether loneliness mediates the relationship between social capital and subjective well-being, and whether optimism moderates this pathway. We employed well-validated scales and conducted a questionnaire survey among older adults aged 60 and above in Guangzhou, Guangdong Province, China. We analyzed 581 valid responses using SPSS. The findings indicated a positive link between social capital and subjective well-being, with loneliness serving as a mediator. Specifically, loneliness accounted for 45.1% of the bonding and 50.5% of the bridging social capital associations with subjective well-being. In addition, optimism negatively moderated the association between social capital and loneliness, meaning that higher optimism diminished the protective association of social capital and corresponded to a weaker reduction in loneliness. The study advances the relevance of COR theory in aging contexts, sheds light on the processes that influence subjective well-being, and supplies theoretical guidance for initiatives seeking to enhance the life quality of older people. It also offers guidance for developing targeted elderly care policies, optimizing community services, and advancing psychological counseling programs.