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

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 aged ≥90.

LifeAfter90 is an ongoing longitudinal study of adults aged ≥90 years 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.

Among 896 participants, non-US-born individuals had lower baseline executive function (EF) (β(95% CI)=-0.38(-0.53,-0.23)) and semantic memory (SM) (β=-0.65(-0.83,-0.47)). Compared to US-born, immigrating at ages 19-29(β_EF=-0.33(-0.53,-0.12);β_SM=-0.47(-0.76,-0.22)) and 30+(β_EF =-0.51(-0.72,-0.29);β_SM =-1.02(-1.29,-0.75)) was associated with lower EF and SM, while immigration ≤18 years was not. Neither nativity nor immigration age was associated with cognitive change.

These findings suggest that despite exceptional longevity, timing of immigration may impact risk for cognitive impairment after age 90.