title: Screen-based media use clusters are related to other activity behaviours and health indicators in adolescents.
abstract: BACKGROUND
  Screen-based media (SBM) occupy a considerable portion of young peoples' discretionary leisure time. The aim of this paper was to investigate whether distinct clusters of SBM use exist, and if so, to examine the relationship of any identified clusters with other activity/sedentary behaviours and physical and mental health indicators.
  
  
  METHODS
  The data for this study come from 643 adolescents, aged 14 years, who were participating in the longitudinal Western Australian Pregnancy Cohort (Raine) Study through May 2003 to June 2006. Time spent on SBM, phone use and reading was assessed using the Multimedia Activity Recall for Children and Adults. Height, weight, muscle strength were measured at a clinic visit and the adolescents also completed questionnaires on their physical activity and psychosocial health. Latent class analysis (LCA) was used to analyse groupings of SBM use.
  
  
  RESULTS
  Three clusters of SBM use were found; C1 'instrumental computer users' (high email use, general computer use), C2 'multi-modal e-gamers' (both high console and computer game use) and C3 'computer e-gamers' (high computer game use only). Television viewing was moderately high amongst all the clusters. C2 males took fewer steps than their male peers in C1 and C3 (-13,787/week, 95% CI: -4619 to -22957, p = 0.003 and -14,806, 95% CI: -5,306 to -24,305, p = 0.002) and recorded less MVPA than the C1 males (-3.5 h, 95% CI: -1.0 to -5.9, p = 0.005). There was no difference in activity levels between females in clusters C1 and C3.
  
  
  CONCLUSIONS
  SBM use by adolescents did cluster and these clusters related differently to activity/sedentary behaviours and both physical and psychosocial health indicators. It is clear that SBM use is not a single construct and future research needs to take consideration of this if it intends to understand the impact SBM has on health.
authors: School of Physiotherapy, Health Sciences, Curtin University, GPO Box U1987, Perth 6845, WA, Australia. L.Straker@curtin.edu.au.
authors: Leon
authors: L
authors: Straker
authors: Anne
authors: A
authors: Smith
authors: Beth
authors: B
authors: Hands
authors: Tim
authors: T
authors: Olds
authors: Rebecca
authors: R
authors: Abbott
mesh_terms: D000293:Adolescent; D001827:Body Height; D001835:Body Weight; D003201:Computers / Q000706:statistics & numerical data; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008402:Mass Media / Q000706:statistics & numerical data*; D008603:Mental Health; D009043:Motor Activity; D053580:Muscle Strength; D010379:Peer Group; D057185:Sedentary Behavior; D012737:Sex Factors; D011795:Surveys and Questionnaires; D014904:Western Australia / Q000453:epidemiology