title: Involvement of school students in fights with weapons: prevalence and associated factors in Brazil.
abstract: BACKGROUND
  Violence, as well as other behaviors, is often intensified during adolescence and early adulthood. The objective of this study is estimate the prevalence of Brazilian school students involvement in fights with weapons and to analyze the associated factors.
  
  
  METHODS
  This is a cross-sectional study using data from the National School Student Health Survey conducted in 2012 with 9thgrade elementary school students attending 2842 schools in all 27 Brazilian Federative Units. The outcome studied was involvement in fights with firearms and/or cold weapons in the 30 days prior to the interview. Poisson regression was used to estimate the prevalence ratios and 95 % confidence intervals (95 % CI). The analyses were stratified by sex.
  
  
  RESULTS
  Fifty seven thousand and eighty nine female students and 52,015 male students were included; the prevalence of their involvement in fights with weapons was 7.2 (95 % CI 6.9-7.5) and 13.8 (95 % CI 13.4-14.3), respectively. In the adjusted analysis the factors associated with male student involvement in fights with weapons were: being older, working, having smoked a cigarette, consumed alcoholic beverages and illicit drugs recently, insomnia, not having any close friends, skipping classes without parental supervision, having suffered aggression from a family member, reporting feeling unsafe on the way to or from school and/or at school. The same associated factors were found among female students in addition to not living with their father and/or mother and having suffered bullying. There was no association with type of school in either sex.
  
  
  CONCLUSIONS
  Involvement in fights with weapons was greater among older male students. Health-risk behaviors, mental health characteristics, parental supervision and context of violence also showed association with the outcomes.
authors.affiliation: University of Brasilia, SQN 203, Block C, apart 601. Asa Norte., ZIP: 70833-030, Brasilia, DF, Brazil. acnmedeiros@gmail.com.
authors.forename: Alice Cristina Medeiros
authors.initials: AC
authors.lastname: Melo
authors.affiliation: University of Brasilia and Institute of Applied Economic Research - Ipea, SBS 1, Block J., ZIP: 70076-900, Brasilia, DF, Brazil.
authors.forename: Leila Posenato
authors.initials: LP
authors.lastname: Garcia
keywords: Adolescent behaviour; Cross-sectional studies; Epidemiological surveys; School student health; Violence