Improving Health Literacy Among School-Aged Children on Chronic Disease Prevention: A Systematic Review of Relevant Intervention Studies in the United States and Canada to Inform Efficacious School-Based Strategies in South Florida

Background: Health literacy (HL) is a foundational determinant of child and adolescent health, shaping lifelong trajectories in disease prevention, self-management, and health equity. School-based HL interventions are increasingly recognized as critical public health strategies, particularly in underserved regions such as South Florida. However, intervention studies, which evaluated the domain-specific effectiveness of school HL interventions across multiple health areas in the United States (US) and Canada, have not been systematically reviewed. Methods: To address this, we have conducted a systematic review in accordance with PRISMA 2020 guidelines and registered with PROSPERO (CRD42023456789). Peer-reviewed studies published between 2008 and 2025 were identified via PubMed, ERIC, and CINHAL. Inclusion criteria focused on U.S. and Canada-based school intervention studies targeting HL among students aged 5–18y. Data from the included studies were systematically reviewed across eight predefined health domains, including mental health, nutrition, chronic disease, and media literacy. Findings: From 1,287 screened articles, 42 studies met inclusion, yielding 114 analytic outcome rows. Strongest effects were observed in literacy related to chronic disease and mental health management, with significant post-intervention increases in biological risk factors management, knowledge about depression, stigma reduction, active help-seeking, and asthma self-regulation (p < 0.001-0.01). Nutrition and physical activity programs showed reductions in sugar-sweetened beverage intake and moderate increases in MVPA. Additionally, digital literacy yielded moderate improvements in screen use behavior (ES = 0.45). Across domains, multi-modal delivery, school–home integration, and culturally tailored strategies enhanced the impacts significantly. However, variation in follow-up duration, fidelity reporting, and equity disaggregation limited generalizability. Only X studies could be found on relevant HL interventions in South Florida. Interpretation: In summary, school-based HL interventions are effective, adaptable, and capable of addressing diverse public health priorities in US and Canadian school-aged populations. For high-need settings like South Florida, embedding HL curricula within core education systems—coupled with youth co-design, family engagement, and culturally responsive delivery—offers a promising avenue for scalable, equity-driven health promotion. However, relevant evidence from randomized intervention studies for these HL interventions were very limited from South Florida and highlights a major unmet need. Funding: None.