Health-Related Quality of Life and Mediterranean Diet Adherence in Chilean Schoolchildren: A Cross-Sectional Study from Southern Chile

Background/Objectives: Childhood obesity in Chile, particularly in southern regions, is driven by unhealthy eating habits, physical inactivity, and socioeconomic inequali-ties. Adherence to the Mediterranean diet has been linked to metabolic, cardiovascular, and psychosocial benefits in children, while Health-Related Quality of Life (HRQoL) is a key indicator of well-being. This study aimed to describe and analyze adherence to the Mediterranean diet and HRQoL in Chilean schoolchildren, and to assess the psy-chometric performance of the KIDSCREEN-27 in this context. Methods: A cross-sectional study was conducted with 356 schoolchildren (52% boys; 7–14 years) from municipal, subsidized, and private schools in Valdivia, Los Ríos Region. Adher-ence was assessed using the KIDMED questionnaire, and HRQoL with the KID-SCREEN-27. Exploratory and confirmatory factor analyses produced an adapted 20-item version (KIDSCREEN-20). Reliability was estimated with Cronbach’s alpha, and associations with sociodemographic variables were analyzed using Kendall’s Tau-C, Goodman–Kruskal’s Gamma, and Chi-square tests. Results: The KID-SCREEN-20 showed high internal consistency (α=0.876) and excellent fit indices (χ²/df=1.15, RMSEA=0.021, CFI=0.998). No significant associations were found between HRQoL or KIDMED scores and age, grade, type of school, or area of residence. A weak, non-practically relevant association was observed between HRQoL and sex (p=0.023). Conclusions: Adherence to the Mediterranean diet and HRQoL in this sample were not influenced by sociodemographic factors, suggesting that equitable access to re-sources and inclusive school programs may reduce disparities. The adapted KID-SCREEN-20, derived from factor analyses, showed high reliability and strong psycho-metric properties, supporting its potential use in future research in similar contexts.