A NEW meta-analysis has found that prolonged television watching is associated with an increased risk of cognitive decline in adults and older adults, strengthening concerns over the impact of sedentary behaviours on brain health.
Researchers conducted a systematic review across six major databases, identifying 35 studies involving 1,292,052 participants, of whom 8,572 developed cognitive impairment. Twenty-eight studies were eligible for meta-analysis. Risk of bias was assessed using the Newcastle–Ottawa Scale, and dose–response and conventional meta-analyses were applied to evaluate associations between television viewing time and cognitive outcomes. This comprehensive approach sought to address longstanding inconsistencies in the literature regarding screen-based sedentary activity and cognitive decline.
The dose–response analysis revealed a nonlinear relationship between television viewing and cognitive impairment (Wald test p=0.04). Adults watching ≥4 hours of television per day had a significantly higher risk of cognitive decline, while viewing durations of ≥6 hours daily were associated with a measurable reduction in cognitive test scores (standardised beta coefficient: -0.09; 95% CI: -0.17 to -0.003; I²=71.8%). Similarly, pooled data from six studies demonstrated that longer viewing times correlated with lower cognitive scores overall (standardised mean difference: -0.02; 95% CI: -0.03 to -0.003; I²=66.45%). These findings suggest that excessive television watching, particularly beyond 4 hours daily, may be detrimental to cognitive performance in later life.
This study adds weight to growing evidence that lifestyle factors play a central role in cognitive ageing. Daily screen habits should be considered as part of strategies to preserve brain health in older populations. Further research will be needed to confirm causality and explore the biological mechanisms underpinning the association.
Reference
Dejakaisaya H et al. Television watching and cognitive outcomes in adults and older adults: a systematic review and dose-response meta-analysis of observational studies. PLoS One. 2025;20(9):e0323863.
