Abstract INTRODUCTION The relationship between biological sex, considered a risk factor for Alzheimer's disease (AD), and bilingualism, a resilience factor, is unclear. We assessed this relationship in 335 individuals with mild cognitive impairment (MCI) in a Canadian cohort. METHODS We used univariate analysis and structural equation modelling to study the relationship between female sex and bilingualism. We created a resilience index (RI) for each participant using the residual approach. Logistic and linear regressions predicted cognitive and brain health in relation to RI. RESULTS Overall, bilingual males had increased RI. Higher RI was associated with less risk of AD and less neuropathology and glial activation as indexed by plasma p‐tau181, neurofilament light, and glial fibrillary acidic protein. DISCUSSION In MCI, the combination of elevated estradiol levels due to aromatization and bilingualism may provide synergistic protection for verbal memory, making old bilingual males more resilient. Highlights Sex steroids influence verbal memory In a structural equation modeling (SEM) model, verbal memory mediates cognitive decline Elevated estradiol from aromatization makes old bilinguals more resilient
Calvo et al. (2026) studied this question.