Health-Related Behaviors and BMI Across Three School Years: Annual Bayesian Network Patterns During the PETICA Childhood Obesity Prevention Program

Background/Objectives: This study examined annual probabilistic network structures among dietary habits, health-related attitudes, lifestyle behaviors, and body mass index (BMI) during implementation of the PETICA school-based program.

Methods

This was a three-year prospective, uncontrolled school-based intervention with repeated measurements of the same cohort in Grades 2–4. The BMI analytic samples comprised 915 pupils in Grade 2 (461 boys, 454 girls; mean age 7.9 ± 0.4), 840 in Grade 3 (429 boys, 411 girls; mean age 8.9 ± 0.5), and 684 in Grade 4 (341 boys, 343 girls; mean age 9.9 ± 0.4). BMI was recalculated from measured body mass and height and used as the continuous network outcome. BMI-for-age percentiles were retained for age- and sex-specific descriptive classification and sensitivity analysis. Separate score-based Bayesian networks were estimated for each grade. Network stability was assessed using 200 nonparametric bootstrap samples, with stable adjacency defined as a bootstrap frequency of at least 50%.