Age at immigration and cognitive aging in those with exceptional longevity; does timing matter? The LifeAfter90 Study

INTRODUCTION The role of immigration on brain health in the oldest‐old is not well understood. We evaluated how nativity and age at immigration were associated with cognition in a diverse cohort ≥90 years of age. METHODS LifeAfter90 is an ongoing longitudinal study of adults ≥90 years of age with domain‐specific cognition assessed every 6 months. Linear regression and linear mixed models examined associations of nativity and age at immigration, pooled across countries, with cognitive function and change adjusted for demographic variables. RESULTS Among 896 participants, non–U.S.‐born individuals had lower baseline executive function (EF = −0.38, −0.53 to −0.23) and semantic memory (SM = −0.65, 95% CI −0.83 to −0.47). Compared to U.S.‐born individuals, participants immigrating at ages 19–29 ( = −0.33, 95% CI −0.53 to −0.12; = −0.47, 95% CI −0.76 to −0.22) and 30+ (= −0.51, 95% CI −0.72 to −0.29; = −1.02, 95% CI −1.29 to −0.75) was associated with lower EF and SM, whereas immigration 18 years was not. Neither nativity nor immigration age was associated with cognitive change. CONCLUSION These findings suggest that, despite exceptional longevity, the timing of immigration may impact the risk for cognitive impairment in individuals 90 years of age or older.