APOE and dementia: It is notable that most studies examining APOE as a moderator have focused on exercise behaviours and have yielded mixed results.23 68 While some data suggest that the favourable effects of physical activity on cognitive decline and dementia risk might be specific to non-carriers,69 70 other studies report greater cognitive benefits among APOE4 carriers71 72 or find no difference between APOE4 carriers and non-carriers.23 73 74 Demographic and exercise training factors might influence the relationship between APOE status and physical activity, contributing to study heterogeneity.