JMIR Publications

ABSTRACT

Background:

With the rise of digital technology, infrastructure development has become vital for social welfare and public health. However, evidence on its effects on depressive symptoms among middle-aged and older adults remains limited.

Objective:

This study evaluates the impact of digital infrastructure development on depressive symptoms among middle-aged and older adults, focusing on underlying mechanisms, heterogeneous effects, and health inequalities.

Methods:

We use longitudinal data from the China Health and Retirement Longitudinal Study (CHARLS), 2011–2020 (N = 56,211). Exploiting the quasi-natural experiment of the “Broadband China” pilot policy, we apply a difference-in-differences (DID) approach to estimate the effect on depressive symptoms. Mediation analysis follows the Baron–Kenny three-step procedure, with bootstrap tests (95% CI) for robustness, and causal interpretation relies on standard assumptions for observational data. Subgroup analyses explore heterogeneity across age, education, and gender groups.

Results:

Our findings indicate that the “Broadband China” pilot significantly reduces depressive symptoms among middle-aged and older adults (p < 0.01). The positive effect is primarily mediated through strengthened social networks, including increased family connection, close social interactions, and greater social participation. Heterogeneity analysis shows that the benefits for depression reduction are more pronounced among women (−0.38, p < 0.01), middle-aged adults (−0.41, p < 0.01), and those with lower levels of education (−0.33, p < 0.01). Moreover, the results suggest that digital infrastructure plays a compensatory role in mitigating health disparities, thereby reducing inequalities in depression outcomes (−0.01, p < 0.01).

Conclusions:

Digital infrastructure reduces depressive symptoms among aging populations mainly by strengthening social networks. Embedding infrastructure into long-term strategies, enhancing digital literacy, and integrating digital health services are key to promoting healthy aging and reducing inequalities. Clinical Trial: The CHARLS project was reviewed and approved by the Institutional Review Board of Peking University (IRB00001052-11015). All participants provided written informed consent prior to the survey. This study relies on de-identified public data; hence no further ethical approval was required.