Bilingualism as a protective factor of ADRD in American Indian adults: the Strong Heart Study - PROJECT SUMMARY/ABSTRACT American Indian populations have greater burden of cerebrovascular and Alzheimer’s disease and Related Dementias (ADRD) comorbidities compared with non-Hispanic White U.S. populations and may also have greater burden of cognitive decline and dementia. Bilingualism—common in American Indian communities— may enhance working memory capacity, attentional control, and cognitive reserve, thus reducing cognitive risk. However, bilingualism is a highly individual experience, and the context of use can modify its cognitive effects. Factors that may influence this association include age, sex, vocabulary, physical and mental status, socioeconomic status, culture, and social activity. Comprehensively assessing the relationship between bilingualism and cognitive performance may be critical to fully understanding ADRD in American Indian adults. Although the link between bilingualism and cognitive reserve has been studied in many populations, bilingualism research in American Indian populations has been limited, due in part to critical cofactors related to their experiences, perspectives, and standardized assessments. Unjust United States (U.S.) federal policies affecting American Indian people included forced attendance at English-speaking boarding schools where use of Native languages was punished, and cultural assimilation was prioritized over quality of education. As a result, bilingualism in American Indian adults who attended such schools may present differently than for other populations. Indeed, NIA (RFA-AG-23-001) defines bilingualism as “proficiency in two or more languages”, however no validated, detailed assessment of proficiency exists for U.S. Native languages, or for American Indian speakers of those languages. Our proposed study will be the first to culturally adapt a language use and history instrument in a large, heterogeneous American Indian population. In response to RFA-AG-23-001, we will leverage the Strong Heart Study, a large, longitudinal, heterogeneous, population-based study of aging in American Indian adults over 3 geographic regions (N=2,500). In this proposed work, we will build on this study, as well as our prior work, to assess the continuum of bilingualism in American Indian peoples by culturally adapting the Language History Questionnaire, evaluate bilingualism in American Indians of multiple generations in association with a detailed cognitive performance battery, and construct conceptual models to assess intervariable relationships including effect modification and moderation by crystallized cognition. This project will illuminate questions of public health significance in a vulnerable population that remains underrepresented in ADRD research, with potential implications for future prevention and treatment strategies.
