Predictors of physical activity and sedentary behaviours among 11-16 year olds: Multilevel analysis of the 2013 Health Behaviour in School-aged Children (HBSC) study in Wales

Background: The present study investigated associations between individual-and school-level predictors and young people's self-reported physical activity (total activity and moderate-to-vigorous activity) and sedentary behaviours. Methods: Individual-level data provided by the 2013/14 cross-sectional survey 'Health Behaviour in School-aged Children (HBSC) study in Wales' were linked to school-level data within the 'HBSC School Environment Questionnaire'. The final sample comprised 7,376 young people aged 11-16 years across 67 schools. Multilevel modelling was used to examine predictors of total physical activity, moderate-to-vigorous physical activity (MVPA) and sedentary behaviours (screen-based behaviours). Results: Taking more physical activity (less than 5 days vs. 5 or more days per week), engaging in higher levels of MVPA (less than 4 hours vs. 4 or more hours per week) and reporting 2 or less hours of sedentary time were predicted by several individual level variables. Active travel to school positively predicted high levels of physical activity, however, gender stratified models revealed active travel as a predictor amongst girls only (OR: 1.25 (95 % CI: 1.05 - 1.49)). No school-level factors were shown to predict physical activity levels, however, a lower school socioeconomic status was associated with a higher level of MVPA (OR: 1.02 (95 % CI: 1.01 - 1.03)) and a lower risk of sedentary behaviour (OR: 0.97 (95 % CI: 0.96 - 0.99)). A shorter lunch break (OR: 1.33 (95 % CI: 1.11 - 1.49)) and greater provision of facilities (OR: 1.02 (95 % CI: 1.00 - 1.05)) were associated with increased sedentary activity. Gender stratified models revealed that PE lesson duration (OR: 1.18 (95 % CI: 1.01 - 1.37)) and the provision of sports facilities (OR: 1.03 (95 % CI: 1.00 - 1.06)) were predictors of boy's sedentary behaviours only. Conclusion: Shorter lunch breaks were associated with increased sedentary time. Therefore, while further research is needed to better understand the causal nature of this association, extending lunch breaks could have a positive impact on sedentary behaviour through the provision of more time for physical activity. The findings also suggest that active travel could offer a mechanism for increasing physical activity levels particularly amongst girls. Particularly, the design and evaluation of interventions to promote physical activity during school hours should employ a comprehensive approach, including a focus on school policies and behaviours both in and out of school hours.