PROJECT SUMMARY The purpose of this supplement is to examine associations between community-level effects of structural racism, circadian rhythm patterns, and indicators of health among women caring for young children living in underserved communities. Circadian rhythm disruption is associated with poor health outcomes including cardiovascular disease, diabetes, obesity, cancer, and depression, as well as maternal morbidities and poor birth outcomes including gestational diabetes, preeclampsia, low birth weight, and preterm birth. Women living in underserved communities are at high-risk for circadian rhythm disruption due to the community-level effects of structural racism, such as noise pollution, light pollution, and community violence. Women caregivers of young children are also at increased risk for disrupted circadian rhythm due to gendered caregiving responsibilities, including nighttime caregiving tasks. However, structural and social determinants of circadian rhythm patterns among women living in underserved communities have not been examined. In this supplement, we leverage data from the Principal Investigator’s Parent R00 study, a cross-sectional study of maternal-child dyads that seeks to examine biological, behavioral, and genetic mechanisms underlying the intergenerational transmission of toxic stress. In the proposed supplement, we will use measures of women’s circadian rhythm patterns (rest-activity rhythms via actigraphy) and health (stress biomarkers, anthropometrics, physical/mental health) that are collected in the Parent R00 as key outcome variables. In collaboration with experts from the University of Connecticut Department of Geography and the Connecticut Children’s Medical Center (CCMC) Geographic Information Systems (GIS) laboratory, we will use GIS and spatial analysis to construct innovative, objective measures of community-level effects of structural racism. Based on the National Institute on Minority Health and Health Disparities (NIMHD) Research Framework, community-level variables will include indicators of the physical/built environment (light pollution, noise pollution) and the sociocultural environment (gun violence, social vulnerability). By leveraging data collected with women in the Parent R00 and developing new, objective community-level variables using secondary analyses, this supplement offers an innovative, efficient approach to addressing new research questions pertinent to women’s health while also generating valuable data to inform the parent study. The proposed supplement is aligned with priorities of the National Institutes of Health, including goals outlined in the Trans-NIH Strategic Plan for Women’s Health Research and the 2021 NIH Sleep Research Plan. We expect results of this study will provide critical, novel insights into the structural factors that may contribute to health and health inequities among women caregivers of young children living in underserved communities.