PROJECT SUMMARY/ABSTRACT The prevalence of water insecurity, or the lack of stable access to safe and acceptable water, is a growing but overlooked problem in the US. Emerging evidence suggests that water insecurity often co-occurs with food in- security and could be as detrimental as food insecurity, which is well-established as a major public health issue. However, little information exists about the concurrence of water and food insecurity among children and ado- lescents, nor do we understand how water and food insecurity interact to impact key public health nutrition out- comes, i.e., sugar-sweetened beverage intake and cardiometabolic health and well-being. Therefore, the core scientific objective of this R03 application is to understand the concurrent role of water and food insecurity in US child and adolescent health. We will draw on nationally representative data from children and adolescents aged 2-17 years in the National Health and Examination Survey (NHANES) from the 2005-2006 wave to the most current 2017-2020 survey wave (n=19,320). Water insecurity will be assessed using a newly validated proxy for experiential measures of water insecurity in NHANES, i.e., tap water avoidance, as well as other water consumption behaviors. Our central hypothesis is that minoritized children will be more likely to experience water and food insecurity individually and concurrently, and that experiencing both insecurities will compound vulnerabilities to relevant health outcomes. In Aim 1, we will examine disparities in water and food insecurity status by race/ethnicity. In Aim 2, we will test independent and interactive associations between water and food insecurity and the consumption of sugar-sweetened beverages. In Aim 3 we will test independent and interactive associations between water and food insecurity and cardiometabolic health outcomes, including being at risk for type-2 diabetes, weight status, and high body fat percentage. Increasing our knowledge about how water inse- curity shapes health is highly significant because global problems with water quantity (both flooding & short- ages) and quality are occurring with increasing frequency and severity due to climate change, population growth, and crumbling infrastructure. This project is innovative because it is the first examination of the role of water insecurity in the health of US children and adolescents. Further, the concurrent measurement of water and food insecurity will advance public health through insights into their potential for additive or synergistic effects. Ex- pected outcomes include a clearer picture of the epidemiology of water and food insecurity among US children and adolescents, and a more precise understanding of how water insecurity can exacerbate the consumption of sugar-sweetened beverages and poor cardiometabolic health. The examination of compounding vulnerabilities will also advance conceptual understandings of the social and environmental determinants of child h...