Physical activity and vascular cognitive health: Who may benefit most?

Abstract

AbstractBackgroundThe majority of people with dementia in the population have mixed neurodegenerative and cerebrovascular pathology. Stroke and dementia share many risk factors, and both have potential to impair function and quality of life. Therefore, a comprehensive understanding of vascular brain and cognitive health should integrate stroke and dementia. The association of physical activity (PA) with lower dementia risk suggests PA is a promising strategy to reduce stroke and dementia, and it is critical to understand who may benefit most.MethodsWithin a population‐based cohort study, with up to 10 years of follow‐up, we indexed PA by cumulative weekly minutes walked for exercise. We used survival analysis classification and regression trees (CART) to test which sub‐groups are at greatest risk for a composite outcome of stroke/dementia and to determine optimal PA cutoffs associated with no stroke/dementia in sub‐groups of interest.ResultsOf 1,982 participants recruited from voter rolls, 1,624 were free from stroke and dementia at baseline and had follow‐up visits. 62% were female, 5% Black, 42% had > high school education, 21% were APOE4+, and 65% were hypertensive at baseline. During 9,354 person‐years of follow‐up, N=133 developed stroke/dementia. The median cumulative walking time was 60.0 minutes. Among those with high PA, a group aged 82‐94 + APOE4+ had the highest risk (relative hazard ratio(RHR) of 6.4). In those with low PA, a group aged 82‐99+≥HS education+Black had the greatest risk of dementia/stroke (RHR=4.1). When examining thresholds in women, those APOE4‐, and those with hypertension (HTN), the optimal cutpoint was around 40‐50 minutes across a mean follow‐up time of nearly 6 years. Thresholds could not be determined for men, APOE4+, and those without HTN, likely due to smaller within strata sample sizes; however, the overall population cutpoint of 160 minutes suggests that thresholds in men, APOE4+, and those without HTN may be higher.ConclusionsOur results add evidence that PA can reduce risk of stroke and dementia. Women, those who are APOE4‐, and those with HTN may need fewer minutes of PA than the overall population in order to benefit. These findings are relevant from a personalized medicine perspective.