PROJECT SUMMARY/ABSTRACT Chronic kidney disease (CKD) and hypertension (HTN) are substantial public health concerns in the US and are important risk factors for other adverse outcomes including acute kidney injury and premature mortality. CKD and HTN are typically diagnosed later in life, yet our understanding of the prenatal and early life environ- mental determinants of reduced kidney function and HTN across childhood and early adulthood remains incipi- ent. This research, however, faces several barriers including lack of assessment of both neighborhood- and individual-level environmental stressors at specific early life stages coupled with long-term follow-up from birth to early adulthood. This project will address these research gaps by leveraging high-quality data from Project Viva, an ongoing longitudinal prospective pre-birth cohort of mother-child pairs followed since pregnancy. The overall goals of the proposed project are to examine the extent to which early-life exposure to disadvantaged neighborhood contexts and nephrotoxicants (i.e., air pollutants and metals) leads to later life kidney dysfunc- tion and higher blood pressure (BP). The investigators will: (Aim 1) examine associations of early-life neighbor- hood environment with kidney function and BP across childhood and early adulthood; (Aim 2) assess associa- tions of individual-level early-life exposure to candidate nephrotoxicants with kidney function and BP from mid- childhood to early adulthood; and (Aim 3) characterize urinary proteomic signatures underlying altered kidney function and BP trajectory from childhood to early adulthood, and examine these signatures as potential mark- ers of toxicant exposure. This innovative proposal will be the first to examine both neighborhood- and individ- ual-level environmental determinants of kidney function and BP trajectories. We will identify actionable risk fac- tors and molecular signatures to identify high-risk individuals and pinpoint when primordial