title: [Analysis on sleep duration of 6-12 years old school children in school-day in 8 provinces, China].
abstract: OBJECTIVE
  To analyze the influencing factors for sleep duration of school children aged 6-12 years in school-day in 8 provinces in China.
  
  
  METHODS
  The cross sectional study was conducted among 20,603 children aged 6-12 years and selected through stratified random cluster sampling in 8 provinces (municipality and autonomous region) with different geographic characteristics and economic development level in China from September to November, 2010 to understand their sleep duration in school-day and related habits. t test and χ2 test were used to compare the sleep duration of the children. Multivariate stepwise logistic regression analysis was conducted to identify the influencing factors.
  
  
  RESULTS
  The survey indicated that the daily average sleep duration of the children in school days was 9.11 hours. The proportions of the children with serious insufficient sleep, insufficient sleep and sufficient sleep were 32.82% (7,672/20,603), 39.70% (8,179/20,603) and 27.48% (5,662/20,603), the children's sleep duration declined with age, so did proportion of children with serious insufficient sleep. There were no sex, urban or rural area and household income level specific significant differences in sleep duration among the children surveyed, and there were no sex specific differences in the proportion of children with serious insufficient sleep, insufficient sleep and sufficient sleep, however, these proportions were statistically different between urban area and rural area and among the regions with different economic level. The proportions of children with serious insufficient sleep and sufficient sleep was higher in rural area than in urban area (χ2=59.96, χ2=45.47, P<0.05), while the proportion of children with insufficient sleep was lower in rural area than in urban area. In the economy developed region, the proportion of children with insufficient sleep was lowest, the difference was statistical significant. After adjusting for sex, weight, diet and exercise time, multivariate logistic regression analysis showed that the factors benefiting children to have 10 hours sleep every day included having high protein diet, exercise, high household economic status and living in urban area.
  
  
  CONCLUSIONS
  The problem of school children having insufficient sleep was serious in China, especially in the rural area.
authors.affiliation: Office for Chronic and Non-communicable Disease Control and Community Health, Chinese Center for Disease Control and Prevention, Beijing 102206, China.
authors.forename: Wenhui
authors.initials: W
authors.lastname: Shi
authors.affiliation: Office for Chronic and Non-communicable Disease Control and Community Health, Chinese Center for Disease Control and Prevention, Beijing 102206, China; Email: zhaiiahz@163.com.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhai
authors.affiliation: Office of Statistics, Beijing Friendship Hospital.
authors.forename: Weirong
authors.initials: W
authors.lastname: Li
authors.affiliation: School of Public Health, Nanjing Medical University.
authors.forename: Chong
authors.initials: C
authors.lastname: Shen
authors.affiliation: Office for Chronic and Non-communicable Disease Control and Community Health, Chinese Center for Disease Control and Prevention, Beijing 102206, China.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Shi
mesh_terms: D001835:Body Weight; D002648:Child; D002681:China; D003430:Cross-Sectional Studies; D015444:Exercise; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D008297:Male; D012574:Schools; D012890:Sleep / Q000502:physiology*; D012959:Socioeconomic Factors; D013997:Time Factors