title: Senior student smoking at school, student characteristics, and smoking onset among junior students: a multilevel analysis.
abstract: BACKGROUND
  Current research on the etiology of tobacco use has largely focused on identifying the influential psychosocial characteristics of individual students; the influences of characteristics in the school environment are generally ignored. The purpose of this study was to simultaneously examine how school and individual student characteristics were related to smoking onset.
  
  
  METHODS
  Multilevel logistic regression analysis was used to examine how the senior student smoking rate at a school and the psychosocial characteristics of students were able to differentiate tried-once smokers from experimental smokers in a sample of 4850 grade 9, 10, and 11 students from the School Smoking Profile (SSP) project.
  
  
  RESULTS
  Each 1% increase in smoking rate among high school seniors increased the odds that a junior student was an experimental smoker vs. a tried-once smoker (OR 1.07, 95% CI 1.03-1.12). A significant contextual interaction was identified where the senior student smoking rate at a school moderates the negative influence of having close friends who smoke. Influential student characteristics were also identified.
  
  
  CONCLUSIONS
  The smoking prevalence of older students at a school is directly related to smoking onset among younger students at that school. Prevention programs should target schools that put students at-risk.
authors.affiliation: Division of Preventive Oncology, Cancer Care Ontario, 620 University Avenue, Ste 1500, Toronto, ON, Canada M5G 2L7. scott.leatherdale@cancercare.on.ca
authors.forename: Scott T
authors.initials: ST
authors.lastname: Leatherdale
authors.forename: Roy
authors.initials: R
authors.lastname: Cameron
authors.forename: K Stephen
authors.initials: KS
authors.lastname: Brown
authors.forename: Paul W
authors.initials: PW
authors.lastname: McDonald
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D017677:Age Distribution; D001294:Attitude to Health; D002648:Child; D015331:Cohort Studies; D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D016017:Odds Ratio; D009864:Ontario / Q000453:epidemiology; D018570:Risk Assessment; D017678:Sex Distribution; D012907:Smoking / Q000453:epidemiology* / Q000523:psychology*; D013997:Time Factors