Prosocial helping behaviors attenuate accelerated cognitive decline driven by APOE ε4.

INTRODUCTION: The apolipoprotein E (APOE) ε4 allele accelerates cognitive decline through multiple biological pathways-including neuroinflammatory, vascular, and stress-regulatory mechanisms-yet few modifiable behaviors counter this genetic vulnerability. Prosocial helping engages these same systems in opposing directions, suggesting it may attenuate APOE ε4-related cognitive decline. METHODS: We analyzed more than two decades of longitudinal data from a large, multiethnic US sample (N = 17,972). Multilevel models that isolate within-person change tested whether transitions in formal volunteering and informal helping moderate APOE ε4-related cognitive decline, while addressing key sources of endogeneity. RESULTS: Adopting and sustaining formal volunteering attenuated the accelerated cognitive decline typically observed among ε4 carriers, with protective associations evident at modest engagement levels (≤ 4 hours/week). Informal helping was uniquely protective among Hispanic older adults, highlighting the role of cultural context in prosocial engagement. DISCUSSION: Prosocial helping may be a feasible, scalable strategy for slowing APOE ε4-driven cognitive decline.