Cognitive decline and dementia in older Kerala Americans

Asian Americans (including Indian Americans) comprise 6% of the U.S. population and represent the fastest growing population group. The incidence of mild cognitive impairment and Alzheimer’s disease is higher among racial/ethnic minorities, especially in first-generation immigrants. Immigrant populations spend a greater proportion of their later years with cognitive impairment and dementia than native born U.S. populations. Yet, there are few epidemiological and biological studies of Alzheimer’s disease and related dementias in immigrant populations such as Indian Americans. In this first of its kind study, we propose to clinically and biologically phenotype 400 older first-generation immigrants from the southern Indian state of Kerala residing in the tri-state area (New York, New Jersey, and Connecticut) to better understand risk and protection against Alzheimer’s disease and related dementias in this fast-growing U.S. population segment. We also have an unique opportunity to compare Kerala American first-generation immigrants with a native Kerala based cohort of 800 older adults in our NIH funded Kerala-Einstein study. This cross-national study of a single racial/ethnic group from Kerala in native and immigrant settings using the same protocols will reduce variability and enhance discovery of Alzheimer’s disease and dementia mechanisms. We hypothesize that immigration related sociocultural factors in older Kerala Americans will influence biological/vascular aging, which in turn will impact cognition. Aim 1: Determine role of immigrant/cultural factors and social relationships (networks and support) that contribute to Alzheimer’s disease and dementia risk in older Kerala Americans. Immigrant/cultural factors include age at migration, residency duration, migration reasons, sex, education, acculturation, etc. Primary outcome is global cognition (Addenbrooke’s Cognitive Examination: ACE). Secondary outcomes include individual cognitive domains, mood (depressive symptoms, anxiety) and quality of life. To address the ‘healthy migrant’ effect, we will examine coping and resilience mechanisms that may help preserve cognition. Aim 2: Determine the contribution of immigrant/cultural factors and social relationships to biological aging in older Kerala Americans. Biological aging is quantified using epigenetic clocks. Aim 3: Determine the impact of immigrant/cultural factors and social relationships on vascular aging in older Kerala Americans. Outcomes include cardiovascular (BP/ electrocardiogram) and cerebrovascular disease indices (MRI small vessel disease). We will compare U.S. and Kerala cohorts on vascular aging. Our proposal is very responsive to NOT-HL-23-001, which seek applications to understand health in Asian Americans. Studying Kerala Americans can provide insights into risk and protection of Alzheimer’s disease and related dementias in other immigrant groups with high prevalence of cardiovascular disease.