title: Patterns of substance use initiation among young adolescents in a Northern Plains American Indian tribe.
abstract: BACKGROUND
  Substantial evidence documents problematic substance use in Northern Plains American Indian communities. Studies suggest that disparities can be traced to disproportionate rates of early substance use, but most evidence comes from the retrospective reports of adults or older adolescents.
  
  
  OBJECTIVE
  To use a prospective longitudinal design to examine substance use initiation patterns as they emerge among young American Indian adolescents.
  
  
  METHODS
  Four waves of data were collected across three consecutive school years from middle school students on a Northern Plains reservation (N = 450). Discrete-time survival analyses were used to estimate risks of initiation of cigarettes, alcohol, and marijuana from age 10 to 13.
  
  
  RESULTS
  Risk for cigarette initiation was relatively high at age 10 and stable until age 13. Marijuana risk was low at age 10 but increased sharply by age 12. Alcohol initiation lagged, not surpassing risk for cigarette initiation until age 13 and remaining below risk for marijuana initiation throughout middle school. Hazards for girls trended higher than those for boys across all substances, but differences did not reach significance.
  
  
  CONCLUSIONS
  Initiation patterns among these American Indian adolescents differed from patterns reported in other US groups, particularly with respect to deviation from the sequence characterized the initiation of marijuana before alcohol that is predicted by the gateway theory.
  
  
  CONCLUSIONS
  Findings suggest that prevention efforts with youth in this community should begin early with a primary focus on marijuana use. They also suggest the importance of examining sequences of substance initiation among youth in other American Indian communities.
authors.affiliation: Department of Community and Behavioral Health, Centers for American Indian and Alaska Native Health, Colorado School of Public Health, University of Colorado Anschutz Medical Campus , Aurora, CO 80045, USA. nancy.whitesell@ucdenver.edu
authors.forename: Nancy Rumbaugh
authors.initials: NR
authors.lastname: Whitesell
authors.forename: Carol E
authors.initials: CE
authors.lastname: Kaufman
authors.forename: Ellen M
authors.initials: EM
authors.lastname: Keane
authors.forename: Cecelia Big
authors.initials: CB
authors.lastname: Crow
authors.forename: Carly
authors.initials: C
authors.lastname: Shangreau
authors.forename: Christina M
authors.initials: CM
authors.lastname: Mitchell
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000428:Alcohol Drinking / Q000453:epidemiology* / Q000208:ethnology; D002648:Child; D003625:Data Collection; D005260:Female; D006801:Humans; D007198:Indians, North American / Q000706:statistics & numerical data*; D008137:Longitudinal Studies; D008297:Male; D008385:Marijuana Smoking / Q000453:epidemiology / Q000208:ethnology; D011446:Prospective Studies; D012737:Sex Factors; D012907:Smoking / Q000453:epidemiology* / Q000208:ethnology; D019966:Substance-Related Disorders / Q000453:epidemiology* / Q000208:ethnology; D014481:United States / Q000453:epidemiology