title: Co-occurrence of health-risk behaviors among adolescents in the United States.
abstract: OBJECTIVE
  Although it is common for adolescents to experiment with several health-risk behaviors before reaching adulthood, little is known about the co-occurrence of these behaviors. The purposes of this study were to determine the co-occurrence of specific health-risk behaviors among a nationally representative sample of adolescents, and to examine whether the distribution of multiple risk behaviors varies by age, sex, and school enrollment status.
  
  
  METHODS
  This study analyzed survey data from a United States national probability sample (n = 10,645) of youth aged 12-21 years. Survey items measuring current seat belt use, weapon carrying, tobacco, alcohol, and other drug use, and sexual behavior were included in the analysis.
  
  
  RESULTS
  The majority of adolescents aged 12-17 years did not engage in multiple health-risk behaviors. However, the prevalence of multiple risk behaviors increased dramatically with age. While only 1 in 12 adolescents aged 12-13 years engaged in two or more of these behaviors, one-third of those aged 14-17 years and half of the college-aged youth (18-21 years) did so. Male respondents and out-of-school youth aged 14-17 years were more likely to engage in multiple health-risk behaviors than were other respondents.
  
  
  CONCLUSIONS
  These results suggest that the likelihood that adolescents engage in multiple health-risk behaviors is related to age and that many adolescents engage in these behaviors serially rather than at the same time.
authors.affiliation: Division of Adolescent and School Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, USA.
authors.forename: N D
authors.initials: ND
authors.lastname: Brener
authors.forename: J L
authors.initials: JL
authors.lastname: Collins
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D000328:Adult; D000367:Age Factors; D002648:Child; D005260:Female; D015438:Health Behavior; D006801:Humans; D008297:Male; D012309:Risk-Taking; D012737:Sex Factors; D014481:United States