Inequality in health related to race/ethnicity, income and education continues to characterize the U.S. population. One important manifestation of inequality is the substantial racial and ethnic differences in prevalence of chronic disease risk factors, morbidity and mortality. Despite extensive research on such differentials, it still is not fully understood why gaps persist, and are in some cases widening. This application proposes to study this issue by focusing attention on overweight and patterns of physical activity and inactivity in U.S. youths as they make the transition from adolescence to adulthood, using data from the three waves of the National Longitudinal Study of Adolescent Health (Add Health). The application proposes to study overweight and activity because overweight and activity are two of the top modifiable risk factors for cardiovascular disease and diabetes. Add Health data are well suited for this research because they come from a longitudinal, population-based survey that includes large minority samples and provides in-depth SES and contextual data. The main goal is to identify specific factors that account for the disparity of health outcomes in minority populations by looking at how socioeconomic, demographic, community, family and individual factors act or interact to affect overweight and activity patterns. After fully documenting patterns of prevalence of overweight and activity/inactivity over the transition from adolescence to young adulthood, the proposed project will focus on an analysis of the patterns and determinants of the dynamics of activity/inactivity and overweight. It also will examine the extent to which patterns established in early adolescence persist into adulthood. This will include an analysis of initial status and factors that operate during the transition period (i.e. between waves two and three) to influence change in status, including an examination of how such factors interact with initial characteristics to affect change. Finally, taking advantage of the Add Health special sample of sibling pairs, the proposed project will identify socioeconomic and contextual factors that account for sibling differences in overweight and patterns of activity. This work will provide important insights in the relative importance of genetic and environmental determinants of overweight and activity.