The Problem: How does one predict physical activity levels among adolescents? What factors most influence activity patterns: the physical environment, sociodemographics, characteristics of individual teenagers—or a combination of all three? Finding answers to these questions is one of the first steps in identifying intervention strategies designed to promote physical activity and fight rising levels of obesity among adolescents.
RWJF Approach: Robert Wood Johnson Foundation's Active Living Research (ALR) program stimulates and supports research to examine environmental factors and policies that influence physical activity. Funded researchers use a transdisciplinary approach—one that encourages experts from various disciplines to collaborate on identifying environmental factors and policies that are related to physical activity.
Grantee Background: Melissa Nelson, Ph.D., R.D., studies environmental and behavioral factors of excess weight gain and obesity among children, adolescents and young adults. She is an assistant professor, Division of Epidemiology and Community Health at the University of Minnesota in Minneapolis.
With a background in nutrition and epidemiology, Nelson has always been interested in obesity and obesity prevention. But it was not until she began her Ph.D. studies that she started to integrate questions about environmental impact into her obesity research. Through its Active Living Research program, RWJF provided funding for her to explore correlations between adolescent obesity, physical activity and the environment.
"Before, I had been thinking much more about individual-level characteristics and not the environment," says Nelson. "What this research did for me is allow me to gain a better understanding and appreciation of how complex these relationships are between environment and behavior."
The Project: Nelson used her Active Living Research dissertation grant to explore health and community characteristics that influence adolescent activity patterns. She analyzed survey data from more than 20,000 respondents to the 1994-95 National Longitudinal Study of Adolescent Health, a study that explores the causes of health behaviors of adolescents in grades 7-12 and their outcomes in young adulthood. She also analyzed data from a geographic information systems database that characterizes community factors affecting adolescent activity.
Nelson identified patterns of adolescent physical activity and sedentary behavior. She also identified patterns in tangible features of the community environment (e.g., crime, walkability) and examined their impact on activity levels.
"You live in a neighborhood made of many dimensions, where not just one thing like crime or your particular street is important. We tried to understand how these [environmental] factors cluster together in the national landscape," says Nelson.
Results: Nelson and her colleagues found that:
- Physical activity was notably low among adolescents whose parents limited their access to television. Therefore, simply restricting adolescent TV viewing may not be effective in increasing physical activity.
- By young adulthood, the activity levels of both active and sedentary adolescents declined. Nelson suggested that it is important to identify and address barriers to continued activity in order to sustain activity into adulthood.
- Different types of neighborhoods are associated with adolescent overweight and physical activity. For instance, Nelson found that adolescents living in suburban communities with more walkable street networks and greater access to community resources for physical activity were more physically active overall, as compared with those adolescents living in suburban communities that lacked these assets.
"The environment has important influence over behaviors, but it doesn't operate in straightforward mechanisms," says Nelson. As an individual "I function within the context of my neighborhood, my family—all of these spheres of influence. In the field, we talk a lot about theoretical frameworks for those different spheres." But what challenges Nelson are answers to the questions: "How do I operationalize these theories that are influenced by all of these factors? How do I draw something meaningful from trying to understand these factors?"
"This is a really exciting field to be in," Nelson says. "Urban planners are working with public health professionals and architects are working with public health disciplines. But I think we need to enhance those networks and do more transdisciplinary work.
"Active Living has done such a good job of linking people from different disciplines and pushing ahead with transdisciplinary research," she says. "It's one of the few organizations I know of that has 'walked the walk and talked the talk' about transdisciplinary research."
RWJF Perspective: Launched in 2000, Active Living Research (ALR) is a $31-million national program that supports research to examine how physical and built environments and policies influence the amount of physical activity Americans get as part of everyday life. Findings from the research are used to help inform policy, design of the built environment, and other factors necessary to re-engineer healthy levels of physical activity into everyday lifestyles for all Americans. Over the past few years, the program has focused increasingly on reversing the rise in childhood obesity, particularly in the low-income and racial/ethnic minority communities where childhood obesity levels are highest and rising fastest.
ALR research teams are required to be transdisciplinary, involving investigators from multiple disciplines and backgrounds who work together across traditional disciplinary boundaries. ALR researchers represent more than 20 different disciplines (e.g., public health, urban planning, architecture, behavioral science, exercise science, transportation, sociology, political science).
"In addition to building an evidence base for physical activity, Active Living Research is developing a vibrant, new transdisciplinary field and a diverse network of active living researchers," says C. Tracy Orleans, Ph.D., RWJF distinguished fellow and senior scientist.
ALR seeks to translate research findings rapidly into policy and practice change. Says Orleans: "For instance, if we find out that adding bike paths and sidewalks, or walk-to-school programs significantly increases physical activity, we want to get this information out to key decision- and policy-makers as quickly and effectively as possible, so they can start using it.
"The Active Living Research program has sparked new awareness among policy-makers and community leaders in many sectors that how active we are depends greatly on the presence or absence of environmental and policy supports for physical activity," says Orleans. "Increasing numbers of urban planners now recognize that community design is critical for population health."