How digital and social isolation drive frailty transitions in middle-aged and elderly adults populations: a seven-year multicohort study

The rapid expansion of the internet has introduced digital isolation as a new dimension of social isolation, increasingly impacting frailty among the elderly people. We systematically integrated cohort studies from multiple databases spanning up to 7 years across four countries, enrolling 32,973 participants aged 50 years and older who reported social and digital isolation status at baseline and underwent at least two frailty assessments which used The Frailty Index (FI) to evaluate. Using multi-state transition models to analyze bidirectional frailty transitions and Generalized Estimating Equations (GEE) for average FI effects, we found that social isolation bidirectionally influenced transitions: it increased deterioration risk (robust→pre-frail: HR = 1.11, 95 %CI 1.06–1.15; pre-frail→frail: HR = 1.16, 1.11–1.22; frail→death: HR = 1.29, 1.20–1.40) and reduced recovery likelihood (pre-frail→robust: HR = 0.92, 0.87–0.98; frail→pre-frail: HR = 0.87, 0.81–0.94), with intensifying effects in poorer health states. In contrast, digital isolation primarily accelerated frailty progression, especially in healthier and younger-old adults (robust→pre-frail: HR = 1.50, 1.42–1.59; pre-frail→frail: HR = 1.23, 1.16–1.30; frail→death: HR = 1.38, 1.26–1.52). Concurrent digital and social isolation significantly elevated mortality risk. These results demonstrate different characteristics by which two types of isolation impact transitions necessitating targeted, health-status-specific interventions supported by family-community collaboration to mitigate risks.