Risk Factors of Overweight and Obesity in Primary School Students in Chile: A Gender Perspective

Chile has the highest rates of overweight and obesity among children and adolescents in South America, ranking among the top ten worldwide. Aim: To identify individual, family, and school-related risk factors associated with excess malnutrition among fifth-grade students in Chile, with particular focus on gender differences. Methods: Utilising data from the 2021 Chilean Fifth Primary School Level Survey, the study assessed nutritional status based on WHO Body Mass Index (BMI) z-scores for age. Multivariate logistic regression analyses were conducted by gender to identify predictors, and average marginal effects were analysed to evaluate the likelihood of overweight and obesity. Results: The study included 135,148 children and found a 32.8% overall prevalence of overweight, which was higher in girls, and a 36.3% obesity rate, which was higher in boys. The research confirmed several predictors of excess malnutrition, including male gender, limited physical activity, high birth weight, and lower parental education. It also identified younger age, low self-confidence, insufficient sleep, infrequent reading, dysfunctional family structures, and school schedules as relevant associated factors. Notably, significant gender differences were observed in obesity patterns among fifth-grade students. Conclusions: Interventions aimed at supporting psycho-emotional development, promoting physical, intellectual, and dietary healthy habits, and improving school infrastructure and daily schedules could effectively address the obesogenic environment in schools. Future research should explore the intersection of gender and socioeconomic inequalities, assessing the impact of implemented public policies on childhood obesity with a focus on social efficiency and equity.