<![CDATA[This study tests the functional alternatives proposition of media system dependency (MSD) theory in the context of a chronic health risk. Social media exposure was positioned as a source of diabetes risk information, and family interpersonal communication as a functional alternative hypothesized to weaken reliance on social media. Survey data from 252 young adults (aged 18–23) in Bandar Lampung, Indonesia, were analyzed using hierarchical moderated regression and simple slope analysis. Social media exposure (β = .632, p < .001) and family interpersonal communication (β = .224, p < .001) both positively predicted diabetes risk health literacy, with social media exposure contributing far more. However, family communication did not moderate the effect of social media exposure (B = 0.002, p = .406, ΔR² = .001), and this effect remained strong across low, average, and high levels of family communication. This pattern of two significant main effects, a null interaction, and a weak positive correlation between the predictors is consistent with channel complementarity rather than MSD substitution. The findings suggest that relational warmth within the family is not equivalent to technical informational capacity about diabetes. As a conceptual refinement, this study proposes measuring functional alternatives in MSD as topic-specific informational capacity rather than general communication climate. Health communication policy should pursue two complementary targets: improving the quality of digital health content and equipping families with diabetes information.]]>
