Family mHealth Intervention to Improve Health Outcomes in Black Youth with Type 1 Diabetes: A Multi-Center Randomized Controlled Trial - Black adolescents with type 1 diabetes (T1D) face disparities in diabetes-related health outcomes such as higher risk for suboptimal glycemic control, which can lead to diabetes complications. Given the critical protective role played by families in the health of adolescents with T1D, family-based interventions have commonly been used as a strategy to promote optimal adolescent health. However, despite the extensive literature documenting health disparities, few randomized clinical trials, including those testing family-based- interventions, have included adequate samples of Black adolescents with T1D. Moreover, rigorous, adequate powered clinical trials testing behavioral interventions specifically designed and tailored for Black adolescents with T1D and their families are lacking. Primary caregivers of youth with T1D experience elevated levels of stress, depression and anxiety, and caregivers of Black youth are at higher risk for such distress. Family-based interventions for Black adolescents with T1D hold the potential to improve the health not only of the individual youth but of the caregiver as well, as improved family interactions can have spillover effects for caregiver mental health. eHealth interventions have shown promising effects in a number of areas of behavioral health care and may also increase the accessibility of behavioral health interventions to Black families. Our group has developed and tested a culturally tailored, brief eHealth intervention design to promote optimal parenting practices for primary caregivers of Black adolescents with T1D. Results of our recent clinical trial where the intervention was delivered during diabetes clinic visits showed promising results, as adolescents whose caregivers received the intervention had improved glycemic control and families reported reduced diabetes- related family conflict. However, findings also suggested the need for further refinement of the intervention, including the development of additional content to help parents support their adolescent with diabetes management. The proposed study will include an intervention adaptation phase where we will convene community advisory boards to develop new material designed to optimize diabetes-related family interactions that can be integrated into the existing intervention. Subsequently, we will test the efficacy of the new intervention to improve youth glycemic control, improve diabetes-related family relationships and reduce caregiver diabetes-related diabetes distress in a multi-center, randomized controlled trial. The new intervention will be delivered via a mobile health approach to optimize its accessibility. 216 Black adolescents with T1D and their primary caregiver will be recruited from two clinical sites and receive the intervention or an attention control intervention during a six-month window. Additionally, we will evaluate the intervention’s potential to buffer the impact of social and contextual stressors on adolescent and caregiver health. Dose effects and intervention cost-effectiveness will also be evaluated. If successful, the intervention has the potential to improve health outcomes in a vulnerable population of youth and their family members.