Abstract INTRODUCTION Associations between television/computer use and dementia in socially inactive older adults remain unclear, and optimal limits are unknown. METHODS We followed 89,671 dementia‐free, socially inactive adults aged ≥55 from UK Biobank for a mean of 12.2 years. Adjusted Cox models assessed associations with incident all‐cause dementia and subtypes. RESULTS Computer use ≤2.4 h/day was associated with lower all‐cause dementia risk (hazard ratio HR 0.88; 95% confidence interval CI 0.82–0.94), whereas higher use increased risk (HR 1.19, 95% CI 1.05–1.34); patterns were similar for Alzheimer's and vascular dementia. Television viewing showed no association below 2.06 h/day but higher risk thereafter (HR 1.17; 95% CI 1.03–1.32), with a roughly linear increase for vascular dementia. Heavy computer use in apolipoprotein E ( APOE ) ‐ε4 homozygotes and higher television viewing in adults < 65 were more harmful. DISCUSSION In socially inactive older adults, moderate computer use may be protective, whereas higher computer use and television viewing are linked to increased dementia risk.
Li et al. (Sun,) studied this question.