CORE C: LIFE COURSE CORE PROJECT SUMMARY The Adult Changes in Thought (ACT) U19 Research Program’s overarching goal is to use a life course approach to investigate modifiable and other factors that influence cognition and Alzheimer’s disease and related dementia, including better understanding of underlying mechanisms. The Life Course Core provides data and theoretical support for this goal. The Core leverages existing Kaiser Permanente Washington (KPWA) electronic data files and medical records, existing ACT data, new survey instruments, and data in the public domain. By efficiently building on the extensive resources of ACT as a long-standing longitudinal cohort set in a health care delivery system, the Life Course Core will support scientific inquiry to enhance our understanding of aging, especially brain aging and dementia and Alzheimer’s disease. The interdisciplinary Core team with expertise in life course epidemiology, the built environment, neuroscience, and health policy and econometrics will support the life course framework in all Projects and Core activities. The Life Course Core’s Specific Aims are: Aim 1) To aggregate data from disparate sources (including administration of a questionnaire and linkage to external data sources) to characterize socioeconomic status over the life course; Aim 2) To test the hypothesis that specific crucial times in brain development and function determine the timing of the relevance of individual and area level socioeconomic status indicators to cognitive trajectories in late life; and Aim 3) To assist the Projects in identifying relevant life course parameters from newly collected and existing variables and partner with Cores to integrate the most influential variables into their analyses to understand the spectrum of robust cognitive function to dementia. Integrating new social and health data over the life course will allow this Core to work with other cores to support aims across the three Projects and broader scientific endeavors. We will work particularly closely with the Clinical Core and the Data and Analysis Core to collect and share data, respectively. The Life Course Core serves a central role in the U19 by providing thematic unification that will transform the future value of ACT U19 Program science.