Project Summary/Abstract Prevalence of physical and cognitive functioning problems increases dramatically with age. These conditions are associated with mobility challenges, decline in quality of life, increase in falls and bone fractures, loss of independence and increased healthcare costs. Important disparities in these outcomes by socioeconomic status (SES) and race/ethnicity exist. This application seeks to improve knowledge about physical and cognitive functioning and their decline over time in the context of the neighborhood environment, with special emphasis on social and physical aspects of neighborhoods. Additionally, this proposal seeks to further understand how neighborhood environments contribute to race/ethnic and SES disparities in function. This proposed study involves separate secondary analyses of two datasets, including the ongoing MESA (Multi-Ethnic Study of Atherosclerosis) study of 6,000 mid-aged and older men and women nationwide, and SWAN (Study of Women's Health Across the Nation), an ongoing annual study of 3,302 multi-ethnic midlife women. We hypothesize that neighborhoods with lower SES, fewer resources for physical engagement, fewer resources for intellectual engagement and less favorable social environments (fewer resources for social engagement and higher stress levels) will predispose to poorer physical and cognitive function. Aim 1 proposes cross-sectional investigation of how the neighborhood environment is associated with physical and cognitive function after adjusting for individual-level factors, and how neighborhood factors contribute to cross-sectional health disparities in function. Aim 2 will investigate whether neighborhood factors and changes in neighborhood factors are related to changes in physical and cognitive function over time as well as the contribution of neighborhoods to differential changes in function over time by SES and race/ethnicity. A variety of analytical methods will be used to address the causal inference challenges present in neighborhood health effects research. The analyses are embedded in a training and mentoring plan including training in substantive areas related to cognition, function, and aging as well as methodologic training in longitudinal data analyses, propensity scores, econometric techniques and causal inference generally. This application will provide preliminary data and the mentoring necessary to establish the applicant as an independent investigator and promote the development of a successful R01 application.