title: Age-related smoking progression among adolescents in China.
abstract: OBJECTIVE
  This study examined the differences in smoking progression between middle and upper school students.
  
  
  METHODS
  The China Seven Cities Study (CSCS) is a longitudinal cohort study. The current sample consists of subjects with both baseline and one-year follow-up measures collected between October 2002 and December 2003. There were 4842 students from 62 middle schools and 5806 students from 83 upper schools. Multilevel random-coefficient modeling techniques were applied.
  
  
  RESULTS
  Among male never or lifetime ever smokers, middle school students were susceptible to transitioning more rapidly than upper school students (never--RR: 1.272, 95% confidence interval [CI]: .985-1.642; lifetime ever--RR: 1.497, 95% CI: .979-2.290). Among female lifetime ever smokers, middle school students were more likely to progress than upper school students (RR: 1.353, 95% CI: 1.038-1.763).
  
  
  CONCLUSIONS
  This longitudinal study is the first to explore differences in smoking progression among adolescents in China. The results revealed that over a one-year interval, there was greater progression across smoking trajectories during early adolescence (corresponding to middle school) than later adolescence (upper school). This is consistent with the neurological development hypothesis, but does not rule out alternative explanations. These findings are important to consider relative to the content and timing of prevention interventions in China where smoking rates approach 70% in adult males and are increasing rapidly in women.
authors.affiliation: Keck School of Medicine, University of Southern California, Los Angeles, California, USA. wsun@usc.edu
authors.forename: Wei
authors.initials: W
authors.lastname: Sun
authors.forename: Valentina A
authors.initials: VA
authors.lastname: Andreeva
authors.forename: Jennifer B
authors.initials: JB
authors.lastname: Unger
authors.forename: David V
authors.initials: DV
authors.lastname: Conti
authors.forename: Chih-Ping
authors.initials: CP
authors.lastname: Chou
authors.forename: Paula H
authors.initials: PH
authors.lastname: Palmer
authors.forename: Ping
authors.initials: P
authors.lastname: Sun
authors.forename: C Anderson
authors.initials: CA
authors.lastname: Johnson
mesh_terms: D000293:Adolescent; D000367:Age Factors; D002648:Child; D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D012574:Schools; D012907:Smoking / Q000453:epidemiology* / Q000639:trends; D011795:Surveys and Questionnaires