## 4 Discussion
### Public Health Implications  
The findings of this review have important policy and practice implications in the public health field. The effectiveness of interventions evaluated in school settings affirms that there is a need to include overall health promotion programs in school curricula as a population approach to preventing chronic disease. Schools are an appropriate setting for these interventions because of their broad reach, existing curriculum structure, and potential to intervene with children in formative development stages [12; 13]. The evidence shows that investing in school-based health promotion has high long-term pay-offs in terms of healthcare expenditure savings and improvements in overall population health status.  
The consistency of benefits seen across different demographic groups and geographic locations [40; 41; 43; 44; 45; 46; 47; 50] suggests that these interventions have widespread applicability across different cultural and socioeconomic contexts. However, the variability in effect size seen across different studies reinforces the importance of ensuring high-quality implementation, sufficient intensity of interventions, and context sensitivity. The evidence supports a shift away from independent short-term health education courses toward more integrated and prolonged interventions that include both physical activity and nutrition components within the overall school setting, supported by policy guidelines that prefer multicomponent approaches over single-component approaches. This is further supported by recent Cochrane reviews, showing that combined interventions produce more consistent and larger effects than those with individual components alone [4; 52; 58].  
The early institution of intervention is considered crucial, as supported by significant improvements observed in preschool children [47], which supports the concept of primordial prevention--intervening before risk factors appear. The fact that blood pressure and metabolic parameters can be favorably affected in children as young as 4-5 years old suggests that preventative initiatives must be started as early as possible within the school system. The importance of family involvement, as highlighted in a number of studies [40; 41; 42; 44; 47; 51], indicates that effective interventions must include activities outside of schools to engage parents and caregivers through carefully coordinated school-family partnerships.  
The effectiveness of innovative methods, including gamification [48], highlights the need for public health interventions to become scalable in their approach to meet contemporary youth expectations and desires. The differing results seen between the overall population and individuals in at-risk groups [50] highlight the need for universal as well as targeted intervention methods; while population-wide initiatives reap considerable bene fits, it is appropriate to invest additional resources in already affected children. The targeted approach can potentially maximize resource allocation so that all children get at least a minimum intervention. Health disparities research has shown that well-organized interventions that are conducted in schools can reduce, as opposed to widen, health disparities and make them effective tools for improving equity in healthcare [59; 60].