Associations between television/computer use and dementia in socially inactive older adults remain unclear, and optimal limits are unknown. We followed 89,671 dementia-free, socially inactive adults a Show more
Associations between television/computer use and dementia in socially inactive older adults remain unclear, and optimal limits are unknown. 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. 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. In socially inactive older adults, moderate computer use may be protective, whereas higher computer use and television viewing are linked to increased dementia risk. Show less