Two determinants of bullying behavior among adolescents in 40 countries: physical fighting and national homicide rates

Objectives: Adolescent bullying may result from a combination of traits, such as delinquency, and sociocultural influences, such as a culture of violence. This study examined whether physical fighting and national homicide rates were associated with adolescent bullying using a multinational sample. Methods: Data were sourced from the 2017/2018 Health Behaviour in School-Aged Children study and linked to the 2018 World Health Organization national homicide rates. After we excluded incomplete survey responses (n = 21,695) and six countries for which data on adolescent bullying behavior or alcohol use were unavailable, we obtained a final sample involving 179,097 adolescents from 40 countries/regions. Data on bullying behaviors and physical fighting were dichotomized (0 = never, 1 = at least once) for ease of interpretation. Multilevel logistic regressions were also conducted. Results: Bullying prevalence varied significantly across countries (6.62%–51.70%). The null model revealed country-level differences in adolescent bullying behaviors (intraclass correlation coefficient = 0.11). The random intercept model indicated that adolescents who reported physical fighting had a higher likelihood of engaging in bullying behaviors (adjusted odds ratio [AOR] = 2.96, 95% confidence interval [CI] = 2.88–3.04). Living in countries with higher homicide rates was associated with an increased likelihood of engaging in bullying behaviors (AOR = 1.22, 95% CI = 1.12–1.34). Conclusions: Physical fighting and national homicide rates are risk factors for adolescent bullying. These findings highlight the requirement for intervention programs targeting both individual behaviors and broader social contexts to prevent bullying and promote safer environments.