Distinct patterns of social media use in later life: Digitally mediated social environments and a dual-association pattern of human vulnerability

Abstract

As digitally mediated social environments increasingly structure everyday interaction, understanding how such artificial environments relate to human vulnerability has become a critical challenge. This study examines how distinct patterns of social media engagement, active/expressive versus informational-communicative use, are associated with frailty among older adults, and whether psychological well-being and lifestyle behaviors operate as intervening associations rather than causal pathways. Survey data were collected from 963 community-dwelling Japanese adults aged 65–89. Exploratory factor analysis identified two dimensions of social media use. Logistic regression using a quartile-based frailty definition showed that informational-communicative social media use was associated with a higher likelihood of frailty, whereas active/expressive use was not. However, this direct association was not robust in sensitivity analyses using the established clinical Kihon Checklist cutoff; under this clinical criterion, informational-communicative use was no longer significantly associated with frailty and the odds ratio changed direction. In contrast, psychological well-being and healthy lifestyle behaviors were consistently associated with lower frailty across operationalizations. Mediation analyses conducted within a structural equation modeling framework suggested a modest indirect protective association through psychological well-being and healthier lifestyle behaviors. Taken together, the findings indicate a definition-sensitive and dual-association pattern, rather than a robust direct association between informational-communicative use and clinically defined frailty. Cluster analysis further demonstrated substantial heterogeneity in digital engagement, with high-use individuals exhibiting the highest frailty prevalence under the quartile-based frailty classification. These findings should be interpreted as a pattern of associations rather than causal pathways, as the cross-sectional design does not permit temporal inference; alternative explanations, including reverse causality, remain plausible. Nevertheless, the results suggest that artificially mediated social environments may be linked to heterogeneous patterns of human vulnerability in later life, particularly at the level of relative or subclinical vulnerability rather than clinically defined frailty. This nuanced association pattern underscores the importance of age-sensitive design and governance of digital social systems.