Overweight during childhood and internalizing symptoms in early adolescence: The mediating role of peer victimization and the desire to be thinner.

Background: Overweight is associated with depression and anxiety among adults. It is unclear whether this association begins in childhood. Overweight among children is associated with a higher risk of peer victimization, and may mediate an association between overweight and internalizing symptoms. No study has tested this hypothesis in a longitudinal population-based sample using developmental trajectories of overweight in middle childhood.

Methods: Data was drawn from the population-based Quebec Longitudinal Study of Child Development. A three-group trajectory model of overweight development (6-12 years) was previously identified using a semi-parametric group-based approach (n=1678): "early-onset" (11.0%), "late-onset" (16.6%) and "never overweight" (72.5%). Mediation models tested the link between overweight status and child-reported depression and anxiety at 13 years via peer victimization and body dissatisfaction.

Results: Children on an early-onset overweight trajectory were at increased risk for both depression (B=.318, 95% CI=.141;.496) and anxiety (B=.262, 95% CI=.09;.44) at 13 years. These direct associations were mediated by peer victimization and subsequent desire to be thinner. Children on a late-onset childhood overweight trajectory were at increased risk for both depression (B=.332, 95% CI=.187;.477) and anxiety (B=.215; 95% CI=.072;.358) at 13 years, mediated by the desire to be thinner.

Limitations: We were unable to control for previous levels of body dissatisfaction. Our measure of peer victimization was not specific to weight-based teasing.

Conclusions: Overweight during middle childhood increases risk of early adolescence internalizing symptoms. Peer victimization and body dissatisfaction are partly responsible for this link.