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.
From the MRC Social, Genetic and Developmental Psychiatry Centre (Baldwin, Arseneault, Matthews, Ambler, Caspi, Moffitt, Danese), Department of Child and Adolescent Psychiatry (Danese), Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK; Center for Child and Family Policy (Odgers), Sanford School of Public Policy (Odgers), Department of Psychology and Neuroscience (Odgers, Caspi, Moffitt), Social Science Research Institute (Belsky), Department of Medicine (Belsky), School of Medicine, and Department of Psychiatry and Behavioral Sciences (Caspi, Moffitt), Duke University, Durham, North Carolina; and National and Specialist Clinic for Child Traumatic Stress and Anxiety Disorders (Danese), South London and Maudsley NHS Foundation Trust, London, UK.
Address correspondence and reprint requests to Andrea Danese, MD, PhD, Social, Genetic and Developmental Psychiatry Centre (MRC), Institute of Psychiatry, Psychology and Neuroscience, De Crespigny Park, Denmark Hill, London, UK, SE5 8AF. E-mail: firstname.lastname@example.org
Received for publication December 14, 2015; revision received July 4, 2016.