Background: Although the effect of social relationships on sarcopenia has been explored, the underlying pathways remains to be elucidated. This study aimed to examine whether loneliness and social isolation influenced new-onset sarcopenia through depressive symptoms and cognitive function.
Methods: A total of 5003 participants aged ≥60years from 2011 (Wave 1), 2013 (Wave 2) and 2015 (Wave 3) of China Health and Retirement Longitudinal Study (CHARLS) were included. Of these, 49.1 % were females, and mean age was 67.1 years at Wave 1. Generalized linear model and Cox proportional hazard regression model were carried out to test the associations among loneliness (Wave 1), social isolation (Wave 1), depressive symptoms (Wave 2), cognitive function (Wave 2), and new-onset sarcopenia (Wave 3). A four-way decomposition was applied with depressive symptoms and cognitive function as mediators to explore their mediation and interaction effects on social relationships and sarcopenia.
Results: Loneliness (HR = 1.309, 95%CI = 1.073-1.596) and social isolation (HR = 1.115, 95%CI = 1.013-1.228) were associated with new-onset sarcopenia. Depressive symptoms (coefficient = 0.036, 95%CI = 0.030-0.042, attributable ratio = 23.5 %) and cognitive function (coefficient = 0.015, 95%CI = 0.010-0.019, attributable ratio = 9.8 %) mediated the association between loneliness and new-onset sarcopenia, while only cognitive function (coefficient = 0.015, 95%CI = 0.013-0.018, attributable ratio = 9.8 %) mediated the association between social isolation and sarcopenia.
Limitations: Although various confounding factors were adjusted for, we cannot rule out the possibility of residual confounders.
Conclusion: The pathways through which social relationships impact sarcopenia vary by the attributes of social relationships. Healthcare providers may address the mental and cognitive health issues to prevent and manage sarcopenia among lonely and socially isolated older adults.
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