title: An epidemiological study of sleep quality in adolescents in South China: a school-based study.
abstract: BACKGROUND
  This study explored the prevalence of disturbed sleep and investigated its distribution characteristics and associated factors in adolescents in South China.
  
  
  METHODS
  Junior middle school and senior high school students (n = 1221) were recruited from schools in Shanghai, China. Students completed a questionnaire using the Pittsburgh Sleep Quality Index and factors associated with disturbed sleep.
  
  
  RESULTS
  The prevalence of a tendency towards poor sleep was 34.32% [95% confidence interval (CI): 31.66-36.98] with no significant difference between genders. This tendency increased with age, yielding a significant group effect (P < 0.01). In middle school and high school, the propensity towards poor sleep was 31.34% (95% CI: 28.29-34.39) and 42.22% (95% CI: 36.92-47.52) respectively. The factors associated with poor sleep were more television viewing during weekdays [odds ratio (OR): 1.56, CI: 1.36-1.71], more frequent computer/Internet use (OR: 1.25, CI: 1.08-1.39), earlier school starting time (OR: 1.12, CI: 1.07-1.28), and more time on homework during weekdays (OR: 1.78, CI: 1.51-1.98) and weekends (OR: 1.35, CI: 1.21-1.52)
  
  
  CONCLUSIONS
  A tendency towards poor sleep is common in adolescents in South China and its incidence increases with age. The factors associated with this phenomenon indicate that poor sleep in adolescents could be improved, at least partly, by reducing the use of visual technologies and by changing school timetables.
authors.affiliation: Department of Gastroenterology, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China. hq.zhou@yahoo.com.cn
authors.forename: H-Q
authors.initials: HQ
authors.lastname: Zhou
authors.forename: W-B
authors.initials: WB
authors.lastname: Shi
authors.forename: X-F
authors.initials: XF
authors.lastname: Wang
authors.forename: M
authors.initials: M
authors.lastname: Yao
authors.forename: G-Y
authors.initials: GY
authors.lastname: Cheng
authors.forename: P-Y
authors.initials: PY
authors.lastname: Chen
authors.forename: D-G
authors.initials: DG
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000367:Age Factors; D002648:Child; D002681:China / Q000453:epidemiology; D004522:Educational Status; D005260:Female; D006801:Humans; D008297:Male; D015995:Prevalence; D011594:Psychometrics; D012307:Risk Factors; D012574:Schools; D012890:Sleep / Q000502:physiology; D012893:Sleep Wake Disorders / Q000453:epidemiology* / Q000209:etiology; D012959:Socioeconomic Factors