Too many communities, particularly in suburbia, may be contributing to obesity and other health problems of modern America by discouraging activities such as walking and biking in favor of driving, new research has found.

Several studies, including one based in Pittsburgh, being published in scientific journals today are providing new evidence of how what's called the "built environment" can affect health.

In the Pittsburgh study, appearing in the American Journal of Health Promotion, researchers found that older women who thought of their neighborhoods as safe and "walkable" were twice as active as their peers who didn't, suggesting that the creation of such environments would be a step in a healthier direction.

And in another study that appears today in the American Journal of Public Health, researchers at Rutgers University examined the effects of urban sprawl, comparing the health of adults in "compact" counties with those in "sprawling" counties.

Although the differences were small, the risk from sprawl equaled certain other risk factors for obesity and high blood pressure, such as eating few fruits and vegetables. People from the most sprawling areas weighed an average of six pounds more residents of compact areas.

"Certain things need to be done to the built environment to create a norm in our society that embraces physical activity as opposed to accepts a lifestyle that is largely built upon sedentary living," said Richard Killingsworth, director of Active Living By Design, a national program of the Robert Wood Johnson Foundation.

In the Pittsburgh study, researchers from the University of Pittsburgh, the Robert Wood Johnson Foundation and the University of North Carolina found that women who could stroll to a biking trail or a department store took around 2,000 more steps per day than those who didn't have walkable routes to those facilities.

And women who rated the walkability of their neighborhoods as excellent took about 3,000 more steps daily than those from areas where walkability was described as poor.

"This is one of the first papers where we've looked at whether you can walk to destinations in your community and whether that influences your walking level," said lead investigator Wendy King, an epidemiology student at the Pitt Graduate School of Public Health.

King recruited about 150 Pittsburgh women who had an average age of 74. They completed surveys that asked if their neighborhood had facilities, such as parks, shops and businesses, that were within a 20-minute walk of home. The participants also wore pedometers to count how many steps they took during the course of a typical week.

Women who could walk to a biking or walking trail took an average of 6,797 steps per day, while those who couldn't averaged 4,908 steps. Women who could walk to a department, discount or hardware store took 6,808 steps daily and those who couldn't took 5,015 steps. And women who could walk to a park averaged 6,075 daily steps while those who couldn't averaged 4,802 steps.

Appealing destinations "need to be put in place," said Killingsworth, who helped develop the study survey. "They need to be clean, they need to be safe and they need to be inviting."

Studies have shown that moderate activity such as regular walking can protect people from high blood pressure, heart disease and osteoporosis. During the next five years, the $70 million Active Living by Design program directed by Killings-worth will closely examine 25 communities to identify approaches that create opportunities for people to be more physically active and healthier. Pittsburgh is not one of the sites.

Killingsworth also participated in the study of urban sprawl published today that was led by urban planner Reid Ewing of Rutgers University.

Ewing collected data on more than 200,000 people living in 448 counties in metropolitan areas. In the Pittsburgh region, Allegheny, Beaver, Fayette, Westmoreland and Washington counties were found to have about average sprawl. San Francisco, Philadelphia and four New York boroughs, including Manhattan and Brooklyn, were the most compact. Counties around Cleveland, Richmond, Va., and Lansing, Mich., were the most sprawling.

The researchers found that in the 25 most compact counties, 22.8 percent of adults had high blood pressure and 19.2 percent were obese. In the 25 most sprawling counties, those rates were 25.3 percent and 21.2 percent.

More attention needs to be paid to health concerns as new communities are built in rapidly growing areas, they concluded.

"Look at many new suburbs -- there are not any sidewalks at all. ... The result is, we just don't walk," said Rutgers' John Pucher.