Principal Investigator: Barnett, Tracie A. (Sainte-Justine Hospital)
Co-Investigators: Apparicio, Philippe (Institut national de la recherche scientifique); Brice, Stéphane (Ville de Montréal); Daniel, Mark (Université de Montréal); Gauvin, Lise (Université de Montréal); Kestens, Yan (Université de Montréal); Koushik, Anita (Centre de recherche du CHUM); Lambert, Marie (Sainte-Justine Hospital); McGrath, Jennifer J. (Concordia University); Mongeau, Lyne (Ministère de la Santé et des services); Valois, Pascale (CQPP).
This project is funded by the Heart and Stroke Foundation of Canada (HSFC) and the Canadian Institutes of Health Research (CIHR).
1. The research question
Obesity in children has tripled in the last 15 years. Although obesity has many causes, including genetic, biological, social, and behavioural facctors, the very steep and sudden increase in obesity suggests that the cause of this obesity epidemic is largely due to changes in people's environments. Prevention or early intervention is important because overweight and obese in children tend to become obese adults, and because obesity in childhood is related to many illnesses in adulthood, over and above adult obesity. Unfortunately, our knowledge base for developing prevention programs is very limited, in large part because of a lack of understanding of the natural history and determinants of overweight and obesity in youth.
2. The objectives
The overarching aim is to identify those characteristics of children's residential environments that are most strongly associated with indicators of adiposity (BMI, % body fat), fitness (VO2max), and weight related behaviours (physical activity, sedentary behaviour, dietary behaviour) at baseline (when children are 8-10 years of age), as well as with changes in these outcomes between baseline and 2-year follow-up. We will also examine how these relationships are influenced by other factors inlcuding child's gender, attitudes, and beliefs; parents modeling and support of healthy behaviours; and neighbourhood safety and socio-economic status. Because the neighbourhood boundaries that are relevant to children of different ages are unknown, associations will be examined for varying neighbourhood definitions.
Focusing specifically on active commuting, another objective is to identify features of the built environment that influence walking and cycling to school, including school proximity and how 'connected' the home-school path is. Finally, because the specific neighbourhood attributes that relate to children in general and obesity in particular are unknown, and because ways of measuring this are still being developed, we will compare different sources of information and ways of measuring neighbourhood characteristics: child/parent perceptions, geocoded databases, and neighbourhood observations.
3. The approach
Our project is complementary to the Québec Adipose and Lifestyle Investigation in Youth (QUALITY) cohort study, a longitudinal study of Québec youth at risk for overweight/obesity because of parental obesity. Children aged 8-10 years and their parents are recruited through schools; recruitment is ongoing and is scheduled to end in December 2008. Close to 300 families have already been enrolled.
Participating children and their parents attend a full day clinic visit at the Clinical Research Unit of Hôpital Sainte Justine in Montréal. During the clinic visit, factors like biological (e.g. body fat distribution, aerobic fitness), metabolic (e.g. insulin sensitivity), genetic/familial (e.g. family history, parental characteristics) and behavioral (e.g. dietary behaviours, self reported physical activity, television watching and computer use) will be assessed. A follow up is scheduled to occur two years after baseline.
By adding detailed assessments of residential environments using the best available sources and methods, including geocoded databases and observations of neighbourhood characteristics by trained assistants, we will be able to see how these characteristics inflence the development of excess weight, as well as related behaviours such as physical activity and food choices.
4. The unique factors
A unique aspect of our project is the link between sedentary behaviours and characteristics of residential areas.
Another is the use of multiple methods for measuring influences in the residential environments of children. Valuable information about relevant boundaries for children will be obtained because we are will be defining neighbourhoods according to several incremental network distances.
Other unique aspects include the vulnerable status of the population, which ensures that a high proportion will present with or develop overweight/obesity within the time frame of the study; the prospective design, which allows us to examine how the built environment influences change in obesity-related outcomes; and the use of state of the art outcomes not previously examined in the context of influences from the built environment, including fitness, percent body fat, and central adiposity.
5. How the project is relevant to the objectives of the initiative
We are addressing several of the initiatives objectives. These include, but are not limited to:
1) Advancing knowledge on how the location and nature of recreational resources and food establishments, land use policies, and transportation infrastructure impact on obesity, physical activity levels, and nutrition;
2) Exploring what standard measures and indicators of the built environment (i.e. child and parent perceptions, geo-coded data, trained observers) are required to more effectively demonstrate the relationship between obesity and the built environment;
3) Enhancing our understanding of the causality between the built environment and physical activity, nutrition and obesity by using a prospective design, and in particular contrasting cross-sectional associations with analyses linking the built environment to longitudinal change in weight status and behavioural outcomes;
4) Building research capacity in Canada on obesity, nutrition, physical activity and the built environment by encouraging horizontal networks and collaboration among urban planners, researchers, government, and non-governmental organizations.