Defining Relationships of Early Mediators and Moderators of Sleep (DREAMS) - Major causes of sleep deficiency affect around 40% of children at some point and 11% through adulthood. Causes of pediatric sleep deficiency are defined by adverse dimensions of sleep health. If untreated, early sleep deficiency can contribute to health, behavior, and learning problems at kindergarten entry that may persist into adulthood. Yet, early causes of sleep deficiency are grossly underdiagnosed in primary care, and few receive validated treatment. Evidence also suggests that sleep deficiency and downstream outcomes are significantly worse for children with family risk factors such as low income, education, and parent psychological health. Yet, limited research defines early childhood sleep health and missing from this work is the examination of the effects of psychosocial stress, housing instability, peak levels of screen media use, and physiological toxic stress on child sleep health. Our long-term goal is to design and test strategies and health guidelines to prevent and remedy early sleep health. Our objective in this proposal is to empirically test the ecological sleep health framework to define how comprehensive multi-level ecological factors predict early childhood sleep health. We propose testing 3 specific aims: (1) Evaluate the effect of understudied factors (psychosocial stress, housing insecurity, screen media, toxic stress) on pediatric sleep health; (2) Evaluate the effect of comprehensive multilevel ecological factors on pediatric sleep health; (3) Evaluate child level stress as a moderator of comprehensive multilevel ecological factors on pediatric sleep health. Our central hypothesis is that factors within the macro and neighborhood level influence factors within the family level, which then influence the child’s sleeping environment and consequently the child’s pediatric sleep health. We will test these aims and central hypothesis in a micro longitudinal study (three time points over six months) of 550 socially and economically varied families of young children (20-48 months of age, when sleep health differences likely develop) in two geographic sites of the Midwest with rigorous multi-level measures (e.g., Geographic Information Systems [GIS], self-report, ecological momentary assessment [EMA], actigraphy, and physiological biomarkers) using structural equation mediation modeling. The project will provide a critical next step to reduce young child sleep health problems and their downstream effects. It will also provide the opportunity for an early-stage investigator to change research directions. The proposal aligns with NHLBI’s strategic plan to identify factors accounting for differences in population health and individual biology.