title: Tracking of TV and video gaming during childhood: Iowa Bone Development Study.
abstract: BACKGROUND
  Tracking studies determine the stability and predictability of specific phenomena. This study examined tracking of TV viewing (TV) and video game use (VG) from middle childhood through early adolescence after adjusting for moderate and vigorous physical activity (MVPA), percentage of body fat (% BF), and maturity.
  
  
  METHODS
  TV viewing and VG use were measured at ages 5, 8, 11, and 13 (n = 434) via parental- and self-report. MVPA was measured using the Actigraph, % BF using dual-energy x-ray absorptiometry, and maturity via Mirwald predictive equations. Generalized Estimating Equations (GEE) were used to assess stability and logistic regression was used to predict children "at risk" for maintaining sedentary behaviors. Additional models examined tracking only in overfat children (boys ≥ 25% BF; girls ≥ 32% BF). Data were collected from 1998 to 2007 and analyzed in 2010.
  
  
  RESULTS
  The adjusted stability coefficients (GEE) for TV viewing were 0.35 (95% CI = 0.26, 0.44) for boys, 0.32 (0.23, 0.40) for girls, and 0.45 (0.27, 0.64) for overfat. For VG use, the adjusted stability coefficients were 0.14 (0.05, 0.24) for boys, 0.24 (0.10, 0.38) for girls, and 0.29 (0.08, 0.50) for overfat. The adjusted odds ratios (OR) for TV viewing were 3.2 (2.0, 5.2) for boys, 2.9 (1.9, 4.6) for girls, and 6.2 (2.2, 17.2) for overfat. For VG use, the OR were 1.8 (1.1, 3.1) for boys, 3.5 (2.1, 5.8) for girls, and 1.9 (0.6, 6.1) for overfat.
  
  
  CONCLUSIONS
  TV viewing and VG use are moderately stable throughout childhood and predictive of later behavior. TV viewing appears to be more stable in younger children than VG use and more predictive of later behavior. Since habitual patterns of sedentarism in young children tend to continue to adolescence, early intervention strategies, particularly to reduce TV viewing, are warranted.
authors.affiliation: Department of Health and Human Physiology, University of Iowa, Iowa City, IA, USA. shelby-francis@uiowa.edu
authors.forename: Shelby L
authors.initials: SL
authors.lastname: Francis
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Stancel
authors.forename: Frances D
authors.initials: FD
authors.lastname: Sernulka-George
authors.forename: Barbara
authors.initials: B
authors.lastname: Broffitt
authors.forename: Steven M
authors.initials: SM
authors.lastname: Levy
authors.forename: Kathleen F
authors.initials: KF
authors.lastname: Janz
mesh_terms: D015502:Absorptiometry, Photon; D056044:Actigraphy; D000293:Adolescent; D000294:Adolescent Behavior; D000367:Age Factors; D001823:Body Composition; D002648:Child; D002652:Child Behavior; D002675:Child, Preschool; D015444:Exercise; D005260:Female; D015438:Health Behavior; D006801:Humans; D007484:Iowa; D008297:Male; D009765:Obesity / Q000517:prevention & control*; D016017:Odds Ratio; D010290:Parents; D012307:Risk Factors; D057185:Sedentary Behavior; D057566:Self Report; D012737:Sex Factors; D013690:Television; D018910:Video Games