Genomic African and Native American Ancestry and 15‐Year Cognitive Trajectory: Bambui Study, Brazil. Issue 10 (17th September 2018) - Lima‐Costa, M. Fernanda
Abstract : Objectives: To investigate the association between African and Native American genomic ancestry and long‐term cognitive trajectories in admixed Brazilians. Design: Population‐based longitudinal study. Setting: Bambui‐Epigen (Brazil) cohort study. Participants: Adults aged 60 and older (N=1, 215) Measurements: Participants were followed from January 1997 to December 2011. Cognitive function was assessed annually using the Mini‐Mental State Examination (MMSE), totaling 12, 208 measurements. We used linear mixed‐effects pattern models to assess MMSE score trajectories. Ancestry was assessed using a genome‐wide approach. Results: After adjustments for covariates, the highest quintile of African ancestry was associated with poorer baseline cognitive performance (β=–0.73, 95% confidence interval (CI)=–1.36 to –0.11) but not with cognitive trajectory. Educational level modified the baseline association between highest African ancestry and cognitive performance in that the association was observed only in those with very low (<4 years) education (β=–1.13, 95% CI=–2.02 to –0.23). No association was found between Native American ancestry and baseline cognitive function or its trajectory. Conclusion: Genomic African and Native American ancestry levels had no prognostic value for age‐related cognitive decline in this admixed population.