A hybrid implementation-effectiveness study of a school-based intervention for promoting health and well-being in low-resource settings: the ISOBAR study protocol.

Introduction: School-based interventions can improve adolescent health outcomes and tackle the growing burden of non-communicable diseases (NCDs) in low-and-middle-income countries (LMICs). Results to date are variable, partly due to lack of cultural adaptation of Westernised models and limited focus on implementation processes. The aim of the ISOBAR project is to develop, implement, and test a school-based intervention to address the emergence of mental and physical (i.e., nutritional, physical inactivity) health problems in LMICs. The three-stage intervention comprises (1) assessment for mental and physical health problems, (2) universal health literacy, and (3) indicated counselling. Methods and analysis: The ISOBAR multi-site project comprises three phases: (1) pre-intervention (co-development and cultural adaptation of the intervention); (2) implementation of the intervention; and (3) post-intervention evaluation. The intervention will be delivered using a staggered roll-out design to introduce the intervention sequentially to three schools per site (nine in total) in Chennai, Gujarat (India), and Ibadan (Nigeria). Each school will receive the intervention by the end of the study period. Local teams will recruit 200 adolescents per school (Total n=1, 800). All adolescents (in intervention and control conditions) will be assessed for mental health/behavioural problems and nutritional/weight problems at baseline. Adolescents in the intervention school will receive the universal health literacy intervention (main cohort), and those adolescents reaching pre-determined thresholds on mental health and/or nutritional indices (sub-cohort) will be referred to school-based counselling support. A suite of assessments will be conducted throughout the study period including: (1) intervention effectiveness (e.g., impact on help-seeking, weight, and mental health and behavioural outcomes); (2) implementation processes (e.g., facilitators and barriers) and outcomes (e.g., acceptability, appropriateness, sustainability); and (3) cost-effectiveness. Ethics and dissemination: The study was approved by the University of Warwick's Biomedical and Scientific Research Ethics Committee (BSREC 36/23-24) and the institutional ethics committees of all participating sites. Research findings will be disseminated through peer reviewed scientific publications, public announcements in local communities, policy briefings, print and online media, and institutional and professional social media accounts and websites.