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."