• Higher activity was linked to slower precuneus atrophy in older women with APOE ε4. • Activity was associated with a preserved default mode network in high-risk women. • MVPA may contribute to maintaining cognitive function in high-risk women. The apolipoprotein E ε4 (APOE ε4) allele, a major genetic risk factor for Alzheimer's disease, is associated with early atrophy in the precuneus and posterior cingulate cortex. Whether physical activity can mitigate this atrophy in high-risk APOE ε4 carriers remains unclear. This study aimed to determine whether physical activity can reduce such neurodegenerative changes in older adults carrying this allele. This 10-year longitudinal study included 295 community-dwelling older adults (154 men and 141 women; age ≥65 years). Baseline physical activity was measured using accelerometers and analyzed according to activity intensity. Participants were categorized as APOE ε4 carriers or non-carriers. Volumes of the precuneus and posterior cingulate cortex were assessed using longitudinal magnetic resonance imaging. Sex-stratified linear mixed models examined the interaction between physical activity and APOE ε4 status on brain volume changes, adjusting for relevant covariates. The moderate-to-vigorous physical activity (MVPA) × APOE ε4 × year effect in women’s left precuneus was significant unadjusted but not after false discovery rate (FDR; 16 models) and exploratory. Left precuneus volume declined significantly over 10 years regardless of MVPA level or APOE ε4 genotype (each p < 0.0001). However, among APOE ε4 carriers, greater time spent in MVPA slowed the rate of volume decline. No similar effect was observed in men. Higher habitual MVPA may be associated with slower left precuneus decline in APOE ε4–positive women. As this exploratory three‑way effect was FDR‑nonsignificant, targeted replication is needed to clarify the role of everyday activity in genetically vulnerable groups.
Yuki et al. (Sun,) studied this question.