title: Addictive internet use among Korean adolescents: a national survey.
abstract: BACKGROUND
  A psychological disorder called 'Internet addiction' has newly emerged along with a dramatic increase of worldwide Internet use. However, few studies have used population-level samples nor taken into account contextual factors on Internet addiction.
  
  
  RESULTS
  We identified 57,857 middle and high school students (13-18 year olds) from a Korean nationally representative survey, which was surveyed in 2009. To identify associated factors with addictive Internet use, two-level multilevel regression models were fitted with individual-level responses (1st level) nested within schools (2nd level) to estimate associations of individual and school characteristics simultaneously. Gender differences of addictive Internet use were estimated with the regression model stratified by gender. Significant associations were found between addictive Internet use and school grade, parental education, alcohol use, tobacco use, and substance use. Female students in girls' schools were more likely to use Internet addictively than those in coeducational schools. Our results also revealed significant gender differences of addictive Internet use in its associated individual- and school-level factors.
  
  
  CONCLUSIONS
  Our results suggest that multilevel risk factors along with gender differences should be considered to protect adolescents from addictive Internet use.
authors: Public Health Joint Doctoral Program, San Diego State University & University of California, San Diego, La Jolla, California, United States of America.
authors: Jongho
authors: J
authors: Heo
authors: Department of Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors: Juhwan
authors: J
authors: Oh
authors: Department of Social and Behavioral Science, Harvard School of Public Health, Boston, Massachusetts, United States of America.
authors: S V
authors: SV
authors: Subramanian
authors: Department of Health Policy and Management, Seoul National University College of Medicine, Seoul, Korea.
authors: Yoon
authors: Y
authors: Kim
authors: Department of Social and Behavioral Science, Harvard School of Public Health, Boston, Massachusetts, United States of America.
authors: Ichiro
authors: I
authors: Kawachi
mesh_terms: D000293:Adolescent; D044466:Asian People; D016739:Behavior, Addictive / Q000453:epidemiology* / Q000523:psychology; D005260:Female; D006801:Humans; D020407:Internet; D008297:Male; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D012737:Sex Factors