title: Nonalcoholic fatty liver disease in Japanese junior high school students: its prevalence and relationship to lifestyle habits.
abstract: BACKGROUND
  Despite the increase in nonalcoholic fatty liver disease (NAFLD) in Japanese adults, its prevalence in adolescents remains unclear. This prompted us to evaluate the incidence and clinical characteristics of NAFLD among junior high school students.
  
  
  METHODS
  A population-based cross-sectional study was conducted among students in a single junior high school in Nagano prefecture. Serum alanine aminotransferase (ALT) and gamma-glutamyltransferase (gammaGT) measurements and abdominal ultrasonography were performed in 249 and 288 students in 2004 and 2007, respectively. In the latter survey, student lifestyle habits were also assessed, using questionnaires.
  
  
  RESULTS
  The prevalence of NAFLD was 4.4% and 4.5% in 2004 and 2007, respectively, which was lower than that of obesity (10.0% and 5.9%). Body mass index and ALT and gammaGT levels increased significantly with hepatic steatosis severity. Multivariate logistic regression analysis demonstrated that the presence of obesity and an ALT level of 30 U/L or more were independent predictors of NAFLD (odds ratio 16.9, P<0.001 and odds ratio 16.6, P=0.001, respectively). The ratios of students commuting to and from school by car and not doing sports outside of school were higher in NAFLD students compared with non-NAFLD ones. Such tendencies were observed independently of the presence of obesity. Additionally, one obese student with severe steatosis and liver dysfunction was diagnosed as having nonalcoholic steatohepatitis (NASH).
  
  
  CONCLUSIONS
  Approximately 4% of junior high school students had NAFLD that was primarily associated with obesity and reduced daily physical activity. Serum ALT measurement during school check-ups is recommended for the early detection of young adolescent NAFLD/NASH.
authors.affiliation: Department of Pediatrics, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Goro
authors.initials: G
authors.lastname: Tsuruta
authors.forename: Naoki
authors.initials: N
authors.lastname: Tanaka
authors.forename: Minoru
authors.initials: M
authors.lastname: Hongo
authors.forename: Michiharu
authors.initials: M
authors.lastname: Komatsu
authors.forename: Akira
authors.initials: A
authors.lastname: Horiuchi
authors.forename: Kaeko
authors.initials: K
authors.lastname: Hamamoto
authors.forename: Chieko
authors.initials: C
authors.lastname: Iguchi
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Nakayama
authors.forename: Takeji
authors.initials: T
authors.lastname: Umemura
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Ichijo
authors.forename: Akihiro
authors.initials: A
authors.lastname: Matsumoto
authors.forename: Kaname
authors.initials: K
authors.lastname: Yoshizawa
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Aoyama
authors.forename: Eiji
authors.initials: E
authors.lastname: Tanaka
mesh_terms: D000293:Adolescent; D000410:Alanine Transaminase / Q000097:blood; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005234:Fatty Liver / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008019:Life Style; D008111:Liver Function Tests; D016015:Logistic Models; D008297:Male; D008403:Mass Screening / Q000379:methods*; D015999:Multivariate Analysis; D009765:Obesity / Q000150:complications* / Q000453:epidemiology; D015995:Prevalence; D013334:Students / Q000706:statistics & numerical data
chemical_list: D000410:Alanine Transaminase