title: Sociodemographic, developmental, environmental, and psychological correlates of physical activity and sedentary behavior at age 11 to 12.
abstract: BACKGROUND
  Low levels of physical activity and high levels of sedentary behavior during adolescence are a cause for concern. Sociodemographic, developmental, environmental, and psychological factors may be relevant, but the correlates of these behaviors may differ.
  
  
  OBJECTIVE
  To investigate the multidimensional correlates of physical activity and sedentary behavior in a large sample of 11- to 12-year-old boys and girls.
  
  
  METHODS
  Cross-sectional survey of 2,578 boys and 1,742 girls from 36 schools stratified by socioeconomic background and gender mix of students (84% response rate). Questionnaire assessments and objective measurements of height and weight were obtained.
  
  
  RESULTS
  Days of vigorous physical activity and hours of sedentary behaviors over the past week were uncorrelated. Ethnicity, socioeconomic factors, developmental stage, environmental factors, and psychological variables were associated with physical activity and sedentary behavior in univariate analyses. In multiple regression, sedentary behavior was greater in ethnic minority groups, in students from more deprived backgrounds, and in those with conduct problems. Girls who were more advanced developmentally and who reported emotional symptoms also engaged in more sedentary behaviors. Vigorous physical activity was associated with good self-rated health, prosocial psychological characteristics, and (in boys) with low emotional symptoms.
  
  
  CONCLUSIONS
  A multidimensional approach to understanding the context of physical activity in early adolescence is needed because factors in several domains are relevant. The correlates of physical activity and sedentary behaviors are distinct in this age group, and there are also important gender differences.
authors.affiliation: Health Behaviour Unit, Department of Epidemiology and Public Health, University College London, 2-126 Torrington Place, London WC1E 6BT, UK. N.Brodersen@ucl.ac.uk
authors.forename: Naomi Henning
authors.initials: NH
authors.lastname: Brodersen
authors.forename: Andrew
authors.initials: A
authors.lastname: Steptoe
authors.forename: Sara
authors.initials: S
authors.lastname: Williamson
authors.forename: Jane
authors.initials: J
authors.lastname: Wardle
mesh_terms: D002648:Child; D003710:Demography; D004777:Environment; D005260:Female; D005500:Follow-Up Studies; D015438:Health Behavior; D006801:Humans; D007899:Leisure Activities; D008297:Male; D009043:Motor Activity; D011187:Posture; D011584:Psychology