PROJECT SUMMARY AND ABSTRACT Chronic low back pain (LBP) is extremely common worldwide yet poorly understood due to its multidimensional complexity of biological, psychological, and sociological factors. Social determinants of health are non-medical factors that influence health outcomes and can be measured partly by sociodemographic factors and social health factors (i.e., social isolation, social participation, and social roles). An individual’s social factors may interact with that individual’s biology during an acute LBP episode by influencing specific immune responses, which may provide two pathways for interventions to prevent the development of chronic LBP. The goal of this proposed project is to elucidate the relationship between social and biological factors’ influence on the transition from acute to chronic LBP. To achieve this goal, we will use extant data on participants experiencing an episode of acute LBP and determine if sociodemographic and social health factors influence the transition to chronic LBP at three months. Then we will begin exploring the role of the immune system in this model by cross-sectionally examining the association between social factors and the immune system during an acute episode of LBP. The overall hypothesis of this proposal is that social factors are directly associated with the transition from acute to chronic LBP and may influence biological pathways initiated during an acute episode of LBP. This proposal will achieve the goals of the proposed study in three specific aims: first, by determining if race or racial identity is associated with the transition from acute to chronic LBP; second, by determining if social health factors are associated with the transition from acute to chronic LBP, as well as examining the potential moderating effect of race on this relationship; third, by identifying the relationships between social factors and the immune system during acute LBP. These aims will advance our knowledge of risk factors for developing chronic LBP. The proposed work will have broad clinical implications for treating, managing, and/or preventing chronic LBP through potential targeted treatments of social health risk factors (i.e., isolation, roles, or participation) or potential immunotherapy treatments for sub-groups (i.e., race) at high risk for transition to chronic LBP.