title: [Relationships between prevalence of youth risk behaviors and sleep duration among Japanese high school students].
abstract: OBJECTIVE
  This study aimed to clarify relationships between prevalence of risk behaviors and sleep duration among Japanese high school students.
  
  
  METHODS
  Data from a national survey, the Japan Youth Risk Behavior Survey 2011 (the subjects were 9,778 students: 5,027 males, 4,751 females, in the first grade to the third grade of 102 schools randomly selected among high schools throughout Japan) was used for this analysis. We focused on nine items of risk behavior in JYRBS: "lack of vigorous physical activity," "skipping breakfast," "current cigarette use," "current alcohol use," "lifetime thinner use," "ever had sexual intercourse," "rarely or never wore seatbelts," "in a physical fight," and "seriously considered attempting suicide."
  
  
  RESULTS
  Students with less than six hours of sleep duration accounted for approximately 40% of males and females. The odds ratios of prevalence of each of the nine risk behaviors were calculated on the basis of the group "six hours or more and less than eight hours" of sleep, whose prevalence of risk behaviors was the lowest. In the group with "four hours or more and less than six hours," the odds ratios of "lack of vigorous physical activity" and "skipping breakfast" for both males and females were significantly high. Furthermore, in the group with shorter sleep duration of "less than four hours," the odds ratios of all nine risk behaviors for males (odds ratios: 1.47-3.28) and eight risk behaviors (except for "rarely or never wore seatbelts") for females (1.54-4.68) were significantly high. On the other hand, in the group with long sleep duration of "10 hours or more," the odds ratios of "current cigarette use" and "lifetime thinner use" for both males and females were significantly high.
  
  
  CONCLUSIONS
  It was shown that short sleep duration of less than six hours and long sleep duration of 10 hours or more related to the prevalence of youth risk behaviors among Japanese high school students. It was suggested that sleep duration should be considered as an important category of youth risk behaviors.
authors.affiliation: Faculty of Health and Sport Sciences, University of Tsukuba.
authors.forename: Chie
authors.initials: C
authors.lastname: Kataoka
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nozu
authors.forename: Masako
authors.initials: M
authors.lastname: Kudo
authors.forename: Yuki
authors.initials: Y
authors.lastname: Sato
authors.forename: Motoyoshi
authors.initials: M
authors.lastname: Kubo
authors.forename: Naoko
authors.initials: N
authors.lastname: Nakayama
authors.forename: Hideki
authors.initials: H
authors.lastname: Iwata
authors.forename: Motoi
authors.initials: M
authors.lastname: Watanabe
mesh_terms: D000293:Adolescent; D005260:Female; D015438:Health Behavior; D006801:Humans; D008297:Male; D015995:Prevalence; D012309:Risk-Taking; D012890:Sleep; D012907:Smoking / Q000453:epidemiology; D013177:Sports; D019966:Substance-Related Disorders / Q000453:epidemiology