Internet adoption and health trajectories in older adults during COVID-19: a longitudinal study.

BACKGROUND: Population aging highlights the need to understand whether late-life internet use is associated with cognitive and mental health trajectories. Using the COVID-19 period as a unique social context, we examined whether first-time internet adoption was associated with changes in cognitive function and depressive symptoms among older Chinese adults. METHODS: Using the 2018 and 2020 waves of CHARLS, we first compared three digital-social profiles in 2018: Inactive, Offline-only, and Dual-mode participants (n = 10,935). We then conducted a longitudinal change-score analysis among 3,346 baseline offline-only participants, of whom 1,699 became new internet adopters by 2020. Cognitive function was measured using a 10-point Minimum Mental State Examination (MMSE)-derived cognitive function score, and depressive symptoms were assessed using the 10-item Center for Epidemiologic Studies Depression Scale. RESULTS: Cross-sectionally, Dual-mode participants, who combined internet use with offline social participation, showed the most favorable cognitive and depressive symptom profiles. Longitudinally, new internet adoption was associated with a greater increase in the 10-point MMSE-derived cognitive function score compared with consistent non-use (β = 0.28, 95% CI: 0.11 to 0.44, p < .001). This association remained consistent in propensity-score-weighted and baseline-adjusted sensitivity analyses. In contrast, internet adoption was not significantly associated with depressive symptom change in the primary model (β = -0.18, 95% CI: -0.59 to 0.22, p = .40). CONCLUSION: Internet adoption was associated with more favorable cognitive change, whereas evidence for depressive symptoms was weaker and less consistent. Digital inclusion may be relevant to cognitive health promotion, but should be complemented by offline social and community support.