The Impact of Smart Elderly Care Technology Application on Social Isolation Among Urban Elderly Living Alone: Based on a Quasi-Natural Experiment in the Yangtze River Delta Urban Agglomeration From 2018 to 2023.

Amidst accelerated urbanisation and population ageing in China, urban solo-dwelling elders face escalating social isolation-manifested through diminished physical networks and profound psychological loneliness-severely compromising their well-being. To address gaps in existing studies (such as short-term evaluations and insufficient heterogeneity exploration), this research employs a quasi-natural experiment leveraging regional disparities in smart elderly care policy implementation within the Yangtze River Delta urban agglomeration. By constructing treatment and control groups through multi-level matching of individual behavioural data and city-level indicators across technology-advanced and technology-lagging regions, we assess the technology's sustained impact. Findings reveal that smart elderly care interventions significantly alleviate social isolation, yet effects exhibit pronounced regional stratification and age-based differentials. Elders residing in areas with strong infrastructure and policy enforcement, alongside younger cohorts (exemplified by the 65-75 age group), gain substantially greater benefits. The technology operates via dual mechanisms: intensifying community participation and optimising health self-management behaviours. Crucially, individual education attainment, family support networks, and regional resource allocation efficiency emerge as key moderators of impact magnitude. This study not only deciphers the dynamic process of technology-facilitated social capital accumulation but also warns that unevenly distributed technological dividends may deepen marginalisation of vulnerable subgroups (such as the oldest-old or low-literacy elders). These insights provide theoretical grounding for designing inclusive age-friendly technologies and formulating spatially calibrated health resource allocation policies in ageing societies.