PROJECT SUMMARY This career development award will establish the candidate, Dr. Katherine Arlinghaus, as an independent investigator with expertise in the development, implementation, and evaluation of community-based, interventions that are strategically designed to address the interconnection between physical and mental health to optimize the reduction of risk for cardiovascular disease development among underserved youth. Cardiovascular disease is the leading cause of death worldwide. Most pediatric prevention programs focus on key modifiable physical health behaviors like physical activity, diet, and more recently sleep. While important components for prevention, the physical health focus can overlook the importance of mental health and wellbeing as a preventative factor for cardiovascular disease development. The omittance of intervention explicitly aimed at preventing depression has been highlighted by the recent substantial increases in rates of youth depression symptoms. To reduce the number of youth at high risk for developing CVD, we need to create accessible and appealing prevention interventions that synergistically address youth mental and physical health needs and have realistic pathways to large-scale dissemination. To address this critical need, Dr. Arlinghaus designed an afterschool program that uses a mentorship model to simultaneously address mental and physical health among youth. While well-liked, challenges regarding intervention reach encountered during the proof-of-concept study require further revision and augmentation. Dr. Arlinghaus’s K01 project will return to the design phase of intervention optimization and work with current and new school sites to augment and revise the intervention to increase its reach and impact. Preliminary testing of the intervention will be conducted at the new school sites to identify needs for further revisions and harmonize research methodologies to prepare for a future fully-powered, real-world efficacy trial. Specifically, Dr. Arlinghaus will use informative qualitative methods to collaboratively identify intervention augmentations and revision with stakeholders to improve intervention reach and impact (Aim 1), and will then conduct a two year quasi- experimental crossover pilot trial to characterize the feasibility, acceptability and preliminary impact on physical activity and depression outcomes among adolescents and young adult mentors (aim 2). These research aims will provide hands-on-experience for Dr. Arlinghaus to apply didactic training in qualitative methods skills, content area knowledge of the connection between mental health and physical activity, accelerometry skills, and community-based intervention study design and implementation. She will be supported by a multidisciplinary team of mentors with expertise in each of these areas. This proposal addresses NHLBI priorities to optimize novel cardiovascular disease prevention strategies and implementation research and identify ho...