Association between body size and the built environment

Researchers at the Mailman School of Public Health are studying the link between the urban environment and how it might contribute to the cause or origins of obesity.

In a study that will have wide-reaching applications, the Mailman School is one of 14 groups across the United States to receive funding from the National Institute of Environmental Health Sciences (NIEHS) to study the association between body size and the built environment.

Up until now, obesity research has focused on ways to change individual behavior but with obesity rates continuing to climb, researchers are now turning their efforts to the built environment and the interventions that might be effective in fighting the epidemic. Working with various city departments, Andrew Rundle, DrPH, assistant professor in the Department of Epidemiology at the Mailman School, and his research team, are gathering data on neighborhood features such as land use, density of bus and subway stops, availability of nutritious food, the location and quality of parks and recreation facilities -- even the number of trees on a street and the number of buildings with elevators -- that affect a person's diet and activity levels. Upon completion of the research, Dr. Rundle expects to have a large base of evidence linking the built environment to body size.

In some preliminary results, Dr. Rundle found that people who live in neighborhoods that have a mixture of residential and commercial uses have lower levels of obesity than people who live in neighborhoods that are closer to being 100 percent residential. "The more mixed an area, the skinnier people are," according to Dr. Rundle. "Mixing supports walking, it supports incidental activity and it makes you independent of an automobile." The data also indicates that as the density of bus and subway stops increases in a neighborhood, the body size of residents goes down. Again, it is thought that public transit allows residents to be private automobile independent and promotes walking.

With Americans in the grip of an obesity epidemic since 1975, Dr. Rundle hopes his research findings will bring a discussion of health to urban planning decisions in New York City -- and across North America, at the close of his four-year study. "If we can influence zoning so that neighborhoods are not 100 per cent residential, so you can walk to a corner store -- because you have a corner store -- that's huge, that has real public health significance," he says.

Dr. Rundle believes that subtle changes in lifestyle repeated over and over can have a tremendous influence on a person's body size. He observes, "The epidemic of obesity is like an epidemic of a thousand paper cuts. There are many subtle little pokes and prods and they all accumulate toward us getting fat. There is no magic bullet that will curb the rise in obesity. And that is why it's so hard to fight the epidemic. You don't have one target to hit, you have one thousand targets to strike to win."