An intersectoral structural network intervention to expand social care in-and-with community: Key mechanisms of an intersectoral dementia community investment initiative

Social isolation and loneliness and social connection are recognized social determinants of health and modifiable risk factors for dementia, yet network strategies to address them remain scarce. To evaluate a structural network intervention designed to expand and redistribute social care through an intersectoral partnership. Specifically, we asked: (1) Can arts/culture institutions and community-based/service organizations (CBOs) be engaged in a cross-sector social care network? (2) Can these organizations be empowered to co-design and implement connectivity activities? (3) Can hosting and co-coordination of activities strengthen and sustain the network? Using a participatory approach nested in a mixed-methods ethnography and informed by narrative phenomenology, we administered Partner Network Surveys to engage community-based organizations (CBO) and arts/culture institutions (A/C), envision and co-design activities/events that mattered to them. Network metrics (degree centrality, reciprocity, density) were analyzed using t-tests, Poisson regression, and Stochastic Actor-Oriented Models (SAOM). Engagement increased significantly: individuals reported more organizational ties and out-degree centrality rose for A/C and CBOs. Empowerment was evident in in-degree gains for A/C and CBOs. Sustainability was supported by increased reciprocity and stable density, indicating a decentralized structure. SAOM confirmed that A/C and CBOs sectors became more central while transitivity increased. Three years post-funding, jointly coordinated activities continued across sectors. Leveraging social connection at a structural level, by combining network theory with narrative phenomenology, enabled engagement, empowerment, and sustainability of a decentralized social care network. This model offers a scalable, non-medical approach to addressing social determinants of health. • We created an intersectoral structural network intervention to expand a social care network • A participatory approach, combined with narrative and phenomenological resources, engaged and empowered network partners • Envisioning through prospective network questions fostered sustainability • Our study proposes the mattering of engagement as a mechanism for sustainability