Janssen, Ian and Pickett, William (Queen's University)
Freeman, John (Queen's University).
Obesity is a leading health issue in Canadian children and youth. Etiological research is fundamental to the development of informed prevention strategies for obesity and its associated cardiovascular risk. There is an emerging interest in determining the influence of the built environment (e.g., outcomes of community planning, design and implementation) on obesity. However, more research is needed in this area. Specifically, research within populations of Canadian youth need to consider the behavioural mechanisms that link the built environment with obesity, and whether the contributions of built environments to obesity are moderated by other social, behavioural, and geographic contextual factors. Development of a better understanding of the interactive effects of the built environment and these contextual factors to childhood obesity may contribute to the planning of prevention programs and applied health policy.
Objectives and Hypotheses
Our primary (etiological) objective is to use large and representative cross-sectional and longitudinal samples of Canadian youth, with linked data from area-level sources, in order to:
1) Examine how built environments in schools and neighbourhoods are associated with the occurrence of obesity;
2) Determine how associations between built environments and obesity are mediated by individual behaviours;
3) Determine the extent to which associations between built environments with obesity and its behavioural determinants are moderated by social and geographic contextual factors; and
4) Determine the proportion of childhood obesity at the population level that can be attributable to features of the built environment.
We hypothesize that:
1. Built environments will be associated with differential risks for obesity
2. Relationships between built environments and obesity will be mediated by behavioural mechanisms;
3. These same relationships will be moderated by social and geographic contextual factors; and
4. Features of the built environment will collectively account for a significant proportion of obesity.
Secondary objectives are to provide research training opportunities in relevant and growing population health research disciplines (capacity building objective), and to determine the validity of measures that are commonly used to quantify features of the built environment in Canada (methodological objective).
The study will make use of existing (2006; n=9,717) and new (2010; n=90,000) cross-sectional data, and exiting 2006-07 (n=2,050) longitudinal data compiled as part of the nationally representative Canadian Health Behaviour in School-Aged Children Survey. Individual, school-level, and neighbourhood-level data from these surveys will be linked with census-based (e.g., neighbourhood income) and other geographic indicators (e.g., recreational facilities in neighbourhoods) that describe the physical and social contextual features of child environments.
The exposures under study are built features of school and neighbourhood environments. The health outcome is obesity. Key covariates (mediators and moderators) are measures of youth behaviour and social and geographic contextual features. Analyses will involve the development of multi-level regression models that focus on the effects of the built environment on obesity, while simultaneously examining the roles of potential moderators and mediators.
This study is important and practical. Obesity is a leading public health priority in Canada and a key risk factor for cardiovascular disease. There is an identified need for applied research that examines environmental determinants of health in vulnerable populations of Canadians. Our grant builds upon our longstanding efforts to collect national data on the health of Canadian youth. The proposed research will result in numerous research training opportunities in growing health disciplines. It will also lead to methodological improvements in studies of the built environment and health. Study findings should inform the content of prevention initiatives including applied health policy. Our short-term goal is to continue to provide new knowledge to this important area of population health, and our long-term hope is that these analyses will contribute to the optimization of health in populations of young people.