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Most Canadians are accustomed to hearing health care professionals validate the deadly correlation between obesity and the unbridled consumption of fatty and sugary food. It takes a geographer however, to ask the question: If you are what you eat, can the same thing be said about where you live?
In a March 2007 study published in The American Journal of Public Health, Dr. Nancy Ross, Assistant Professor of Geography and her team, concluded that Canadian urban environments play a significant role in shaping the distribution of body mass index (or BMI, the measure of body fat based on an individual's height and weight). "It's a view from 38,000 feet," said Dr. Ross, "It's a very big-scale view of BMI and the incremental influences of neighbourhoods and cities."
Dr. Ross and her team used data from the 2001 Census and Statistics Canada's 2000/2001 Canadian Community Health Survey (CCHS) to explore links between BMI for adults and certain individual characteristics, like income level, diet and stress, as well as immigrant status and the impact of residential neighbourhood characteristics.
The research revealed, for the first time in a Canadian context, that urban sprawl and its characteristic low-density, automobile-reliant suburbs are associated with higher BMI in Canadian men. It's a connection that has been made in recent, less in-depth studies in the United States but that most Canadians, who tend to think of themselves as fitter than Americans, might be surprised to learn.
The study also found that BMI is strongly related to socio-economic factors, like income and education levels, and that a neighbourhood's economic condition is linked to the average BMI of its residents. For men and women, living in a neighbourhood with residents with lower education levels meant that they, too, had a significantly higher BMI, regardless of their own educational background. This finding may reflect norms around diet and physical activity in those neighborhoods, but it might also be related to issues of neighborhood safety, and the availability and quality of recreational opportunities. Living in a neighbourhood with a high proportion of recent immigrants was also associated with lower BMI for men, possibly as a result of newcomer diet or exercise habits that become part of local practice and influence behaviours beyond the immigrant community.
While these findings can significantly help shape tomorrow's urban planning policies, they also offer an important starting point for pursuing more detailed study down the road. "Ideally, what we want to look at now is neighbourhood access to recreation, access to fresh food, access to fast food, how individuals behave in different neighbourhoods and the differences between men and women in their environment interactions and the influence on BMI," explains Dr. Ross.
Instead of focusing solely on changing the individual behaviours that lead to obesity, Dr. Ross points to transforming our urban environments to support healthy behaviour. Historically, successful public health changes, like decreasing opportunities for smoking, have evolved through environmental intervention. "If we can figure out how environments can change to support healthy lifestyle, like how we design our cities, parks and neighbourhoods, then I think we're moving in the right direction in terms of stemming the tide of rising obesity."