Abstract
Background: Schools offer sustained access to children during critical developmental periods, making them ideal settings for primary health education. Objective: This systematic review synthesizes evidence on SCT-based primary health education interventions in school settings, examining effectiveness, theoretical fidelity, and methodological quality. Methods: A systematic search of nine databases (2000–2025) identified 14 eligible studies employing SCT-based interventions with student-level outcomes and comparison groups. Study selection, data extraction, and quality assessment followed PRISMA 2020 guidelines. Results: Interventions spanned nutrition, physical activity, obesity prevention, hygiene, and mental health. SCT-based interventions consistently improved knowledge and key constructs—particularly self-efficacy, behavioral capability, and social support. However, sustained behavioral and anthropometric changes were more variable. Longer, multicomponent interventions (>12 months) with environmental modifications and parental engagement demonstrated more consistent effects. Peer-led delivery showed superior knowledge gains (adjusted Odd Ratio=6.04, P<0.001). Handwashing interventions were notably successful, with significant improvements in practices (Average Treatment Effect: 0.22, P<0.001). Self-efficacy was the most frequently targeted and improved construct, while outcome expectations showed mixed findings. Study quality varied; common limitations included lack of long-term follow-up, reliance on self-report, and absence of mediation analyses. Conclusions: SCT provides a strong theoretical foundation for school health education, effectively enhancing knowledge and psychosocial determinants of behavior. However, translating knowledge gains into sustained behavior change remains challenging. Effective interventions require addressing multiple SCT constructs, interactive learning, parental engagement, adequate duration (≥12 months), and fidelity monitoring.