Building Illness
What could local zoning codes have to do with obesity and asthma? Maybe lots
When Ross Brownson first came to the "boot heel" of Missouri fresh out of grad school, the public health official and tri-athlete was saddened by what he saw. This southeastern tip of Missouri shares a border and a culture with the most hardscrabble rural South. It is bitterly poor, unemployment is high, and economic and educational opportunities are limited. All of this adds up to poor health. The largely African-American population has among the highest rates of heart disease, cancer, obesity, and diabetes in the nation. The people have little or no access to medical care, and few exercise.
Brownson recalls wondering where to start to make a difference in the region's health. His answer was to look not only at lab tests but also at shops, roads, and schools. And what he saw explained a lot. There were no malls, few stores--basically no place to walk to and few sidewalks to walk on. Many studies had clearly shown that walking--the cheapest, easiest, and most common physical activity for most Americans--reduces risk for many of these deadly diseases. Yet residents of the boot heel had no way to take even this simple step.
Rural Missouri is not alone. Research on the health effects of the "built environment" --as roads, buildings, and manmade structures are called--is in its infancy. But a growing number of scientists are looking beyond symptoms and treatments to see how aspects of social planning--zoning, transportation, school siting--contribute to rising rates of obesity, diabetes, asthma, and other diseases. They're also grappling with the big question: What can be done about it? Some disturbing statistics are emerging:
Since 1960, the number of people commuting to work out of the county they live in jumped by 200 percent. Residential "sprawl" has meant a 250 percent increase in vehicle miles traveled. The average driver spends 443 hours yearly behind the wheel, the equivalent of 11 workweeks.
Driving displaces other activities, like exercise. "Being in a car doesn't do anything for you in terms of being thin," says Lawrence Frank of the University of British Columbia. "For every additional hour people spend in the car, there's a 6 percent increase in the likelihood of being obese."
Increased auto traffic is also a key source of ground-level ozone. Asthma rates among children, who are believed to be particularly sensitive to ozone, more than doubled between 1980 and 1995.
Living in the suburbs is linked to eating more higher-calorie fast food. At least 1 in 4 adults now eats fast food on any given day. For children, 1 of every 3 meals is fast food.
Childhood obesity has more than doubled in three decades. But the number of kids who walk or bike to school has dropped from nearly half in 1960 to about 1 in 10 today, largely because schools are far from homes.
School siting is just one example from the built-environment agenda, but it has sparked particularly heated debate. The trend to large, distant schools began in the 1950s, as people moved to the suburbs. School districts sought lower land costs, as well as space for sports fields and modern science labs. One unforeseen consequence of these well-intentioned policies was elimination of the schools that had glued "walkable" neighborhoods together. "If you look at how schools were built in the past, they were these gorgeous civic structures, centrally located, the heart of the community, and students were proud to go to them," says David Salvesen, a professor at the University of North Carolina. "Now we have these buildings that look like shoe factories on the edge of town."
An effort to save older neighborhood schools and to build the new ones smaller is gaining strength. In addition, an international program called Safe Routes to School works in communities to make walking and biking to school easier.
In many ways, focusing on the environment is returning public health to its roots. "If you go back 100 years ago, urban design and public health were integrally related--housing, sanitation, water, disease," says Allen Dearry, associate director of the National Institute of Environmental Health Sciences. But it requires researchers to take their eye off the national picture and look closely at local communities.
Mapmakers and obesity experts at the University of Pennsylvania have joined forces to plot "food opportunities" kids have on their routes to and from school. A local group is encouraging businesses on the routes to sell healthier snacks. "These solutions have got to come from the grass-roots level," says Adam Drewnowski, an epidemiologist at the University of Washington. "We're not going to solve these problems by telling people to eat larger portions of broccoli."
Even before the built environment became the hot topic, Ross Brownson knew any changes in the boot heel would have to originate there. Residents told him they might walk--if they had a place to do it. "But they didn't want more scientists to come in, do a study, and leave." So Brownson began working on a lasting change: a network of walking trails.
A grant from the Centers for Disease Control and Prevention came through in 1990, and since then Brownson has leveraged grants and donations into 30 trails covering about 15 miles. The result? Between 1998 and 2004, the number of people walking the trails has doubled. Among those who had access to the trails, nearly 40 percent reported using them, and more than half of those had increased their walking. What's more, this readily available exercise appeals to all social groups. Says Brownson, now a professor at St. Louis University: "I think walking is becoming the norm here now rather than the oddity." And the rest of the nation, including city dwellers and suburbanites, could very likely learn something by looking to Missouri's boot heel.
This story appears in the June 20, 2005 print edition of U.S. News & World Report.