School-Level Body Mass Index Shapes Children's Weight Trajectories.

BACKGROUND: Embedded within children's weight trajectories are complex environmental contexts that influence obesity risk. As such, the normative environment of body mass index (BMI) within schools may influence children's weight trajectories as they age from kindergarten to fifth grade.

METHODS: I use 5 waves of the ECLS-K-Kindergarten Class 1998-1999 data and a series of multilevel growth models to examine whether attending schools with higher overall BMI influences children's weight status over time.

RESULTS: Results show that, net of child, family, and school sociodemographic characteristics, children who attend schools with higher rates of obesity have increased weight compared to children who attend schools with lower rates of obesity, and this effect increases annually.

CONCLUSIONS: Findings indicate that the overall weight status of schools influence child obesity, and further speak to the importance of school-based intervention programs.