Body Mass Index and Peer Victimization From Middle Childhood Through Early Adolescence: Disaggregation of Between- and Within-Person Associations and Specificity Across Victimization Types

Abstract

Peer victimization is a prevalent problem, which is often related to high body mass index (BMI). However, prior studies largely overlooked the heterogeneity in this association varying as a function of the victimization type/form (i.e., physical, verbal, and relational). Notably, it also remains unclear how BMI and different types of peer victimization may be related to each other at the within-person level from middle childhood to early adolescence, while controlling for the between-person effects. The current study aims to narrow such gaps. Data were derived from the Early Childhood Longitudinal Studies, Kindergarten Class of 2010 to 2011 (ECLS: 2011). A total of 13,977 children from 2nd to 5th grade (M_age at 2nd grade = 8.12 years, SD = .37; 49.0% females) were included. This study conducted autoregressive latent trajectory with structured residuals models (with the sampling weight in ECLS appropriately considered) to examine the between- and within-person associations between BMI and relational, verbal, and physical peer victimization. Associations between BMI and peer victimization over time varied systematically as a function of the victimization type. Within-person increases in relational victimization at 4th grade were associated with increases in BMI in the subsequent year (i.e., child 4th and 5th grades). Children who experienced higher than their usual level of physical victimization in the 3rd grade had a lower-than-usual level of BMI in the 4th grade, and lower-than-usual BMI in the 4th grade was related negatively to higher-than-usual physical victimization in the subsequent year. Such findings reveal understudied nuance and specificity in the link between BMI and peer victimization, providing more informative insights for the design of more targeted intervention programs.