Childhood Bullying Victimization and Overweight in Young Adulthood: A Cohort Study.

OBJECTIVE: To test whether bullied children have an elevated risk of being overweight in young adulthood and whether this association is: (1) consistent with a dose-response relationship, namely, its strength increases with the chronicity of victimization; (2) consistent across different measures of overweight; (3) specific to bullying and not explained by co-occurring maltreatment; (4) independent of key potential confounders; and (5) consistent with the temporal sequence of bullying preceding overweight.

METHOD: A representative birth cohort of 2,232 children was followed to age 18 years as part of the Environmental Risk Longitudinal Twin Study. Childhood bullying victimization was reported by mothers and children during primary school and early secondary school. At the age-18 follow-up, we assessed a categorical measure of overweight, body mass index, and waist-hip ratio. Indicators of overweight were also collected at ages 10 and 12. Co-twin body mass and birth weight were used to index genetic and fetal liability to overweight, respectively.

RESULTS: Bullied children were more likely to be overweight than non-bullied children at age 18, and this association was (1) strongest in chronically bullied children (odds ratio = 1.69; 95% confidence interval [CI] = 1.21-2.35); (2) consistent across measures of overweight (body mass index: b = 1.12; 95% CI = 0.37-1.87; waist-hip ratio: b = 1.76; 95% CI = 0.84-2.69); (3) specific to bullying and not explained by co-occurring maltreatment; (4) independent of child socioeconomic status, food insecurity, mental health, and cognition, and pubertal development; and (5) not present at the time of bullying victimization, and independent of childhood weight and genetic and fetal liability.

CONCLUSION: Childhood bullying victimization predicts overweight in young adulthood.