A 4-SEASON LONGITUDINAL STUDY EXAMINING THE ASSOCIATION BETWEEN SEASONALITY, THE BUILT ENVIRONMENT AND SEDENTARY TIME IN 9-14 YEAR OLD CHILDREN LIVING IN A MID-WESTERN CANADIAN CITY
Background: Canadian youth spend on average 8.6 waking hours of their day in a sedentary state, and consistently exceed recommended leisure hour screen-based sedentary limits of two hours per day. Sedentary behaviour (SB) is associated with an increased risk of overweight, obesity, cardiovascular disease and all-cause mortality. Understanding how the built environment and urban design may influence children’s sedentary time (SED), in different social and physical contexts, addresses a significant gap in the scientific literature and contributes to promoting health in children. Research Aim: This work seeks to examine how seasonal changes affect weekday school hour, leisure hour, total daily and location-specific SED in children and if this relationship is moderated by urban design. The relationship between SED and parental support or children’s perception of this support and seasonality are also explored. Research Questions: (1) How do seasonal changes affect SED accumulation in children? (2) Are seasonal changes in SED moderated by neighbourhood built environment (BE)? and (3) Is parental support or children’s perception of this support associated with activity behaviour outcomes in children? Methodology: Families with children aged 9-14 years were recruited from the prairie city of Saskatoon, Canada. Location-specific, device-based SED was captured in children during three time frames over one year using GPS data loggers and accelerometers. Neighbourhood-level BE features were assessed using multiple audit tools and neighbourhood era design. Using a random intercept model, a multilevel modelling approach was taken to understand the relationship between seasons, demographic factors, BE and SED of children. Multilevel model outcomes were stratified by time- (total daily, leisure hour, school hour) and location-dependent SED (home, school, school park and park area). Results: In multilevel models predicting SED outcomes, older children, those with obesity and children with decreased levels of moderate-to-vigorous physical activity consistently accumulated greater levels of SED. Over a child’s entire day, and while at home or in school, children were significantly less sedentary in fall months but more sedentary in spring (vs winter) months. Neighbourhood-level pedestrian access and traffic safety in a child’s home neighbourhood and safety from crime and traffic and universal accessibility in a child’s school neighbourhood moderated the predicted effect of season on children’s SED. Children who perceived screen time limitations by their parents accumulated significantly lower levels of SED and higher levels of MVPA year round. Similarly, children with parents who reported regulating screen time in their children accumulated significantly lower levels of SED and higher levels of MVPA year round. Project Significance: This study provides greater and more nuanced detail about BE, season and sedentariness/activity in children living in a city with four distinct seasons. This new-found understanding of children’s activity behaviours could shape infill and new urban development projects by providing necessary information to relevant public health policy architects, driving urban transformation and healthier cities year-round.
sedentary behaviour, built environment, season, adolescents, children, physical activity, physical behaviour, sedentary time.
Doctor of Philosophy (Ph.D.)
Community Health and Epidemiology
Community and Population Health Science