Abstract
BACKGROUND: Social isolation and digital exclusion are significant public health concerns, particularly among older adults, with potential links to mental, cognitive, and physical health. This study aims to quantify the associations of social isolation and digital exclusion with depression, cognitive decline, and physical functioning in community-dwelling older adults. METHODS: We conducted a systematic review and meta-analysis of 11 primary studies (9 observational, 2 randomized controlled trials) published since the year 2000. These studies included over 3,50,000 participants from North America, Europe, and Asia. We performed meta-analysis using random-effects models to calculate pooled odds ratios (ORs) with 95% confidence intervals (CIs) for depression and cognitive decline. Physical function outcomes were analyzed qualitatively due to insufficient data for quantitative pooling. We assessed heterogeneity using the I2 statistic and performed subgroup and sensitivity analyses to explore potential biases. RESULTS: For depression risk, the pooled OR from analyses of approximately 1,11,784 participants was 1.60 (95% CI: 1.39-1.84, P < .001). This indicates a 60% higher likelihood of depressive symptoms among socially or digitally disconnected seniors. Cognitive decline, assessed in 3 longitudinal cohorts, showed a nonsignificant pooled OR of 1.03 (95% CI: 0.92-1.15). Physical function outcomes, including reductions in short physical performance battery scores and increased activities of daily living disability, were consistently worse among isolated or digitally excluded individuals. We found moderate heterogeneity for depression (I2 = 43%) and cognition (I2 = 55%), with no evidence of small-study bias. CONCLUSION: Our findings suggest that both social isolation and digital exclusion are independently and significantly associated with an elevated risk of depression in older adults. Furthermore, these factors correlate with poorer physical functioning. Digital exclusion may be a critical "super-social determinant" of health, underscoring the need for integrated interventions that address both social connectivity and digital literacy to improve the well-being of the elderly.