Can a city make you fat?

Jan. 27, 2006. 01:00 AM
MEGAN OGILVIE
SPECIAL TO THE STAR

New York City—At the south-east corner of Thompson and West 3rd in Greenwich Village, Andrew Rundle stops and turns around.
"Look," he says, pointing in all directions. "There's a grocery store on every corner."
Small corner groceries packed tight with food squat at each corner of the intersection, their bright awnings protecting rows of fresh fruit and vegetables neatly arranged on sidewalk racks.
The busy intersection also boasts a handful of restaurants, several shops, a laundromat and a drab-looking cantina. People are bustling along the sidewalks and weaving in and out of doorways, ignoring the grey afternoon drizzle.
This is the kind of neighbourhood Rundle likes to see in New York City. An assistant professor of clinical epidemiology at Columbia University's Mailman School of Public Health, Rundle is studying the links between the urban environment and body size. He wants to know whether neighbourhood amenities, such as corner stores, parks, decent sidewalks, and access to public transit, affect a person's diet and activity levels.
In other words, does your environment make you fat?
During a one-hour walking tour of a small section of New York City — by Gramercy Park, across Union Square and through Greenwich Village — Rundle points out different environmental features that may influence obesity.
A farmer's market in Union Square that sells fresh greens and organic meats three days a week is likely a positive feature in this neighbourhood; it may encourage people to make healthy food choices.
A park with a large, safe jungle gym may get families off of the couch and outside to play, increasing their daily quota of physical activity.
A desolate stretch of New York University faculty housing along West 3rd St. has no street-level shops or restaurants. Residents are not likely to go out for an afternoon walk, says Rundle.
"This space is a dis-amenity," he says, gesturing towards the grey block building. "It's a boring street to walk down. Look, there's no one out."
Right now, many of Rundle's hypotheses are untested. But four years from now, he expects to have a large base of evidence linking the built environment to body size. And the implications of his findings, he says, will have wide-reaching applications.
Rundle and his research team are one of 14 groups across the United States to receive funding from the National Institute of Environmental Health Sciences (NIEHS) to study the links between body size and the built environment. Rundle's work is also supported by a philanthropic organization called the Robert Wood Johnson Foundation.
This is a new field of study in obesity research, says Allen Dearry, associate director for research co-ordination, planning and translation at NIEHS.
Much of the last 30 years of obesity research has focused on ways to change individual behaviour and to educate people about diet, exercise and the importance of leading a healthy lifestyle, says Dearry.
But many of these approaches have met with little success in the real world, he says, pointing out the obesity rates in North America continue to climb.
That's why researchers are now turning their efforts to studying how the built environment might contribute to the etiology — the cause or origins — of obesity and how environment-based interventions might be effective in reducing it.
Until recently, there has been no formal push to fund these kinds of studies in Canada. Instead, researchers have been extrapolating data from U.S. studies and fitting them into a Canadian context.
While this methodology is adequate, it's hardly ideal, says Stephen Samis, director of health policy at the Heart and Stroke Foundation of Canada.
There are significant differences between major cities in Canada and the U.S., he says.
Major metropolitan areas in Canada have, for example, fewer segregated neighbourhoods, less neighbourhood fragmentation and better inner-city health than in the U.S., says Samis.
`The more mixed an area, the skinnier people are.'
Andrew Rundle,
New York City epidemiologist
To address these research gaps, the Heart and Stroke Foundation of Canada, in partnership with the Canadian Institutes of Health Research (CIHR), led a think tank in Toronto last fall to help focus obesity research efforts in Canada. They determined that studying the links between obesity and the built environment should be a priority.
The two groups plan to fund research in this area as soon as this spring. Next week, in fact, a group of experts will meet in Vancouver to develop the basis for requests for proposals.
"The ball is starting to roll in Canada," says Samis, as it should. Almost 60 per cent of Canadians are overweight or obese.
"We need to try and curb the obesity epidemic," says Samis. "It's responsible for serious health issues, including hypertension, heart disease and type 2 diabetes, in Canada."
Rising rates of obesity across North America drive Rundle and his research team. And they're tackling the problem on a massive scale.
The research area comprises New York City — more than 700 square kilometres of cramped streets, highrises and bustling neighbourhoods. The research variables are smaller in scale, but no less difficult to compile.
Rundle is collecting what he calls exquisite data. Working with various city departments, he and his research team are gathering data sets on neighbourhood features such as land use, density of bus and subway stops, the location and quality of parks and recreation facilities — even the number of trees on a street and the number of buildings with elevators.
"We've mapped, for example, every single farmer's market, grocery store, bodega, Korean supermarket, fast food joint and restaurant in this city and sorted them by zip codes," he says. "One of the things we want to get is a measure of helpful and less helpful food options throughout the city."
All of these data on the built environment will then be linked to health data for three different groups: 14,000 men and women; 4,000 women (half black, half white) and 500 children (aged 4,5 and six). Rundle knows each of the participant's height and weight, demographics and general location within a neighbourhood.
Keeping track of this vast amount of data — much of which is still streaming in and will be for the next four years — is a monumental task. But Rundle has already crunched some of the numbers.
He's found that people who live in neighbourhoods that are about 50 per cent residential and about 50 per cent commercial have lower levels of obesity than people who live in neighbourhoods that are closer to being 100 per cent residential.
"The more mixed an area, the skinnier people are," he says. "Mixing supports walking, it supports incidental activity and it makes you independent of an automobile."
Rundle has also shown that as the density of bus and subway stops increases in a neighbourhood, the body size of residents goes down.
"None of this is, like, rocket science," laughs Rundle. "None of this is, like, some grand esoteric formula. A lot of it has a `that-kind-of-makes-sense' quality to it. But nobody has looked at these (kinds of) data and nobody has analyzed these (kinds of) data to see if it's true."
At the close of his four-year study, Rundle hopes his research findings will bring a discussion of health to urban planning decisions in New York City — and across North America.
"If we can influence zoning so that neighbourhoods 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.
Rundle believes that subtle changes in lifestyle, such as walking to the corner store for a litre of milk, repeated over and over can have a tremendous influence on a person's body size.
North Americans have been in the grip of an obesity epidemic since 1975.
If our environment shapes our behaviour, says Rundle, then perhaps understanding the built environment will provide the plan to fight the epidemic.
"The epidemic of obesity is like an epidemic of a thousand paper cuts," he says.
"There are all these 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, says Rundle, is why it's so hard to fight the epidemic. You don't have one target to hit, you've got one thousand targets to strike to win.