Bilingualism and cognitive aging in ethnically diverse older adults: cross-sectional and longitudinal evidence from Health and Aging Brain Study-Health Disparities.

OBJECTIVES

Identifying modifiable factors that shape cognitive aging trajectories is a central goal in aging research. This study examined whether bilingualism is associated with dementia status and longitudinal cognitive decline, and whether associations vary by ethnicity or gender.

METHODS

We analyzed Wave 7 data from the Health and Aging Brain Study-Health Disparities (HABS-HD), a longitudinal U.S. cohort of adults aged ≥50 years. Bilingualism was defined by self-reported use of a second language. Cross-sectional analyses included 4,140 participants (1,013 bilinguals); longitudinal analyses included 1,760 participants (522 bilinguals) followed for up to 4 visits at approximately 2-year intervals. Outcomes were baseline dementia status and latent factor scores for executive function and episodic memory derived from 11 neuropsychological tests. Regression and linear mixed-effects models assessed associations, adjusting for age, education, gender, ethnicity, and practice effects.

RESULTS

Bilingualism was not associated with baseline dementia status or conversion to probable dementia. Cross-sectionally, associations varied by ethnicity: Hispanic bilinguals showed higher executive function and episodic memory scores. No advantage was observed in White participants; conversely, Black bilinguals had lower episodic memory scores. Longitudinally, bilingualism was associated with slower episodic memory decline independent of sociodemographic factors; no longitudinal association was observed for executive function.

DISCUSSION: These findings suggest that bilingualism may confer domain-specific benefits for memory trajectories in later life, while cross-sectional differences appear shaped by sociocultural context. The results underscore the importance of considering ethnic diversity and language history when evaluating experiential influences on cognitive aging.