In the parent R01 to this supplementary proposal, we seek to understand aging and health as an integrative biopsychosocial process, with specific foci on the roles of personality and relationship quality as predictors of health status. In this supplementary proposal, we seek to enhance our current NIH funded efforts by expanding our participant pool to also include a sample of African American twins from a parallel study of aging, and including measures of cognitive health, and thereby establishing relevance to Alzheimer’s disease and/or its related dementias. This will position our research team for future research on health in a more diverse sample and with a focus on Alzheimer’s disease and/or its related dementias. Specifically, personality and relationship quality are known predictors of health status, but underlying reasons for these associations are less well understood. Because of the integrative biopsychosocial focus of our parent NIA-funded R01, this supplement would allow us to begin to tackle major shortcomings of the existing literature. First, variation in personality and the quality of adults' interpersonal resources are rarely examined conjointly so that their associations with health can be studied in terms of their relative magnitude and possible interplay, particularly in diverse samples. Second, the degree to which these associations emerge from environmentally mediated processes amenable to intervention remains largely unknown because existing research cannot rule out the possibility that these associations might reflect the impact of confounds, including especially evocative genetic processes, that produce correlations between personality/interpersonal experiences and health outcomes. Our parent R01 uses an innovative co-twin control design to rule out genetic and family background confounds, thereby identifying environmentally mediated connections linking both personality and interpersonal experiences in advancing age with outcomes. More specifically, with this supplement, we will position ourselves to ultimately study whether relations between individual/interpersonal differences and health are environmentally mediated by augmenting our sample with 100 twin pair participants (200 individuals) in the Carolina African American Twin Study of Aging (CAATSA). These participants will complete assessments parallel to those we are completing with twins in the Minnesota Twin Registry (MTR; 1600 twins in 800 pairs, similar in age).