Interdisciplinary conference discusses effect of man-made environment on health

Mitzi Baker

Gary Schoolnik, Tom Robinson, Lawrence Frank and Marilyn Winkleby discuss the built environment and health.

What do obesity, diminished vision and dengue fever have in common?

These and other maladies can be linked to the man-made environment, whether it is TV, street layout, signage or urban planning. That was the focus of an all-day conference—"The built environment and your health: How buildings, urban form and man-made devices shape health across the lifespan"—held May 11 at the Schwab Center.

Environmentalism no longer means just wild lands, air and water pollution and endangered species. It includes the layouts for neighborhoods, the air in buildings and the way homes are designed and the devices inside them. "It's not just how to protect the environment, but how to protect the health and well-being of the people who live in it and alter it," said Dean of the School of Earth Sciences Pamela Matson, PhD, while kicking off the conference.

The event was organized by the Stanford Prevention Research Center, along with members of the Woods Institute for the Environment at Stanford and the Bill Lane Center for the Study of the North American West at Stanford. Financial support was provided by the James H. Whittam Memorial Lecture Fund of the Stanford Prevention Research Center.

Inspired by Stanford President John Hennessy's drive to encourage interdisciplinary work, the event drew its speakers and an audience of more than 100 from engineering, architecture, history and medicine. The goal was to begin to break down the barriers between these different fields to help get a better grasp on the effect that man-made structures have on health. And what to do about it.

The discussions turned on a question posed by keynote speaker Lawrence Frank, PhD, a professor in the University of British Columbia School of Community and Regional Planning: "Is the built environment a health enabler or health disabler?"

For example, an urban environment can encourage walking. Frank's studies have found that the most active people were those in areas with lots of good sidewalks or trails and lots of different types of stores and restaurants to walk to—a dense urban area. By contrast, many suburban areas lack sidewalks and are not conducive to walking. Frank has also shown that activity levels correspond to rates of obesity, so living in a place that is easy to navigate by foot can mean a healthier heart.

However, Stanford professor of infectious diseases and geographic medicine Gary Schoolnik, MD, underscored the new problems that urban environments have created. The inadequate sanitation of Third World cities, combined with inadequate amounts of water and overcrowding, "coalesce to amplify the transmission of infectious diseases," he said.

And in an age of airline travel and a tightly knit international economy, their problems become our problems. "Urbanization and infectious diseases come together to produce a global problem, not just a local one," said Schoolnik.

He cited as an example the dengue virus, which is carried by a particular mosquito. The insect thrives in cities, taking advantage of the water that collects in bottle caps or used tires to lay its eggs. But city life led it to evolve so that it can only fly at most about 50 yards, Schoolnik said. What this means is that the virus must have a dense human population to carry out its lifecycle.

Other speakers pointed out ways that the built environment affects health:

  • Greg Goodrich, PhD, a research psychologist at the Veterans Affairs Palo Alto Health Care System, described the challenges of navigating through daily life for elderly people with diminishing vision. He recommended better indoor lighting, making signs simple and high contrast and diligent eyesight screening for anyone over age 65.
  • "Urban dwellers use a lot of chemicals inside," said James Leckie, PhD, Stanford professor of civil and environmental engineering, and the chemicals don't break down as fast inside because they are not exposed to ultraviolet light as they are outside. Advice from Leckie: If you use insecticide in your house, clean the surface afterwards.
  • With a particle counter, Lynn Hildemann, PhD, Stanford associate professor of civil and environmental engineering, has documented a dramatic increase in particles in the air when people are walking about their homes. She has yet to determine its health effect, but she offered a tip: Carpets hold five to 10 times more particles than hardwood floors.
  • The conference was a call to action. In his remarks, Tom Robinson, MD, Stanford associate professor of pediatrics and director of the Center for Healthy Weight at Lucile Packard Children's Hospital, said researchers should be discovering answers in their studies, not just identifying causes. He has conducted several clinical trials on altering children's TV-viewing habits and found that reduced time watching TV translates into less obesity and less aggression. Yet more studies on TV's effects are under way, despite experts being "way beyond the hypothesis stage" in linking too much TV with problems for kids, he said. "It is embarrassing that we as scientists spend so much time looking at etiology and reductionist approaches that we're left with little evidence of what works and what doesn't," he added.

    Said Marilyn Winkleby, PhD, associate professor of medicine, who was on the final panel: "It's important to not keep looking at the same study questions, but to build on them. We should be advocates and involved."