Project Summary/Abstract: The purpose of this individual National Research Service Award (NRSA) application is to provide the applicant with rigorous research training to develop into an independent investigator focusing on barriers and facilitators to healthy infant feeding practices. This award will ensure the applicant achieves competence in establishing a conceptual understanding of the impact of social determinants of health (SDOH) on infant feeding practices, develops foundational skills needed to launch an independent program of rigorous and ethical research with groups that have been marginalized, and gains professional development skills needed to advance in a research-focused academic setting. This training will occur in a resource-rich academic environment with support from a world-renowned advising team ideally suited to the applicant’s topic and training plan. This intensive research training will extend the applicant’s clinical expertise and facilitate rapid translation of evidence into clinical practice. There exists a racial disparity in breastfeeding rates between U.S. Black and White mother-infant dyads, with Black dyads exhibiting significantly lower rates of exclusive breastfeeding at both three and six months of age. Several factors have been associated with the racial disparity in breastfeeding rates. SDOH, including low socioeconomic status (SES), early maternal return to work, poor feeding support in childcare facilities, housing instability, food insecurity, and low-resource neighborhoods have all been cited as potential barriers to initiating or meeting breastfeeding recommendations. Additionally, the introduction to solid foods before four months of age and poor maternal mental health have both been associated with suboptimal breastfeeding durations. Prior research has focused on the relationship between each risk factor and infant feeding practice in isolation. To date, little is known about the additive effects of multiple adverse SDOH on the impact of infant feeding practices and whether their impact is mediated by maternal mental health status or the timing of introduction to solid foods. This NRSA application proposes to fill this gap through the following aims: 1) identify the impact of select SDOH (SES, employment, food access, housing stability, child care support) on breastfeeding outcomes, 2) examine if the relationship between SDOH and infant feeding practices is mediated by maternal mental health and the timing of introduction to solid foods, and 3) investigate the impact of Black mothers’ experiences with adverse SDOH and their perceived lactation resource availability on infant feeding practices. This multi-methods research project will provide the applicant with training in multivariable regression models (Aim 1), structural equation modeling (Aim 2) and grounded theory qualitative research methods (Aim 3). This study is expected to generate critically important new knowledge about the relationship betwee...