Relationship between Violent Behavior and Repeated Weight-Loss Dieting among Female Adolescents in Japan

PURPOSE To examine whether interpersonal violence perpetration and violence toward objects are associated with body mass index (BMI), body weight perception (BWP), and repeated weight-loss dieting in female adolescents. METHODS A cross-sectional survey using a self-report questionnaire was performed evaluating interpersonal violence perpetration, violence toward objects, the number of diets, BMI, BWP, the 12-item General Health Questionnaire (GHQ-12), victimization, substance use, and other psychosocial variables among 9,112 Japanese females aged between 12-18 years. Logistic regression analysis was conducted to analyze the contribution of BMI, BWP, and weight-control behavior to the incidence of violent behavior, while controlling for potential confounding factors. RESULTS The number of diets was associated with both interpersonal violence perpetration (OR = 1.18, 95% CI 1.08-1.29, p<0.001) and violence toward objects (OR = 1.34, 95% CI 1.24-1.45, p<0.001), after adjusting for age, BMI, BWP, the GHQ-12 total score, victimization, and substance use. In terms of BMI and BWP, the "overweight" BWP was associated with violence toward objects (OR = 1.29, 95% CI 1.07-1.54, p<0.05). On the other hand, the "Underweight" and "Slightly underweight" BMI were related to violence toward objects [(OR = 1.28, 95% CI 1.01-1.62, p<0.05) and (OR = 1.27, 95% CI 1.07-1.51, p<0.05), respectively]. The "Underweight" BWP was related to interpersonal violence perpetration (OR = 2.30, 95% CI 1.38-3.84, p<0.05). CONCLUSIONS The cumulative number of diets is associated with violent behavior in female adolescents. In addition, underweight BMI and extreme BWP are associated with violent behavior.