title: Temporal trends in and relationships between screen time, physical activity, overweight and obesity.
abstract: BACKGROUND
  The aims of this study were to examine temporal trends in the prevalence of sufficient moderate-to-vigorous intensity physical activity (MVPA), high levels of screen time, combined measures of these behaviors and overweight or obesity in Australian adults during the period 2002-2008. Trends over this time period in overweight or obesity within each behavior group (sufficient/insufficient MVPA, high/low screen time and combined behaviors) were also examined.
  
  
  METHODS
  Data were collected via annually conducted cross-sectional computer-assisted-telephone-interviews (CATI) of adults (n=7908) living in Central Queensland, Australia (2002-2008). Self-reported MVPA, screen time (TV viewing and computer use), and BMI were used to create dichotomous classifications of physical activity (Sufficient MVPA (S-MVPA), Insufficient Physical Activity (I-MVPA)), screen time (High Screen Time (HST), Low Screen Time (LST)), combined behavior categories (S-MVPA/LST, I-MVPA/LST, S-MVPA/HST, I-MVPA/HST) and BMI (Overweight or Obese, Healthy Weight) respectively.
  
  
  RESULTS
  The prevalence of S-MVPA, HST, and overweight or obesity increased at approximately the same rate over the study period in the overall sample and females (p≤0.05). In the overall sample and in females, the prevalence of overweight and obesity increased over the study period in those individuals classified as I-MVPA/HST (p≤0.05).
  
  
  CONCLUSIONS
  Results provide evidence that while the prevalence of S-MVPA appears to be modestly increasing, the proportion of the population engaging in HST and classified as overweight or obese are increasing at approximately the same rate. These observations highlight the need to increase levels of total physical activity (including light intensity physical activity) and decrease sedentary behavior including screen time.
authors.affiliation: CQUniversity, Institute for Health and Social Science Research, Centre for Physical Activity Studies, Rockhampton, Bld 18, CQUniversity Australia, Rockhampton, QLD 4702, Australia. m.duncan@cqu.edu.au
authors.forename: Mitch J
authors.initials: MJ
authors.lastname: Duncan
authors.forename: Corneel
authors.initials: C
authors.lastname: Vandelanotte
authors.forename: Cristina
authors.initials: C
authors.lastname: Caperchione
authors.forename: Christine
authors.initials: C
authors.lastname: Hanley
authors.forename: W Kerry
authors.initials: WK
authors.lastname: Mummery
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D015444:Exercise; D005260:Female; D015438:Health Behavior; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D008403:Mass Screening / Q000706:statistics & numerical data* / Q000639:trends; D008875:Middle Aged; D009765:Obesity / Q000175:diagnosis / Q000453:epidemiology*; D050177:Overweight / Q000175:diagnosis / Q000453:epidemiology*; D015995:Prevalence; D011793:Queensland / Q000453:epidemiology; D057185:Sedentary Behavior; D013997:Time Factors