Associations Between Age-for-Grade, Sex, and Interpersonal Violence Among U.S. High School Students.

The current study examines how atypical age-for-grade (i.e., being old- or young-for-grade) is associated with various types of interpersonal violence (e.g., physical fighting, school-based and electronic bullying victimization, and being threatened or injured with a weapon at school) among a nationally representative sample of U.S. high school students and explores these associations by sex. Data were from 21,892 students in 9th to 11th grades in the 2017 and 2019 National Youth Risk Behavior Survey. Weighted logistic regression models examined associations between age-for-grade categories and various types of interpersonal violence with peers, with stratified models exploring differences by sex. Results showed that, compared to their age-normative peers, students who were young-for-grade were more likely to report physical fighting, being threatened or injured with a weapon at school, and school-based and electronic bullying victimization. Students who were old-for-grade were more likely to report physical fighting than their age-normative peers. These associations differed for boys and girls, where being young-for-grade was more strongly associated with interpersonal violence for boys than for girls. Old-for-grade girls were more likely to report physical fighting than their age-normative peers, whereas young-for-grade girls were more likely to report being threatened or injured with a weapon at school. Findings from the current study may be explained by differences in physical, social, and emotional development in youth who are young-for-grade or old-for-grade compared to their age-normative peers. Results can inform school-level policies when identifying youth for grade retention or acceleration and may have implications for school-based interventions to prevent interpersonal violence between peers.