The Problem: The concept of the Walking School Bus was first introduced abroad in the 1990s. Since then, its popularity has grown in the United States because many see it as a safe, effective way to increase physical activity for children as they walk or bike to and from school under adult supervision.
However, the impact of Walking School Bus programs had never been tested in low-income communities. Would the program's effectiveness hold despite their special socioeconomic challenges? And would the perceived benefits of a Walking School Bus program stand up under rigorous scientific scrutiny?
Grantee Background: The son of a family doctor and a former nurse in Manitowoc, Wis., Jason A. Mendoza, MD, MPH, had an inkling that one day he would be a physician but he had no idea what kind—even while on the pre-med track at the University of Chicago. Finally, a volunteer hospital stint sparked his interest in pediatrics. "It made me realize that working with kids was great and that there was a nice little balancing act to keeping parents informed and involved," he explains. After receiving his medical degree in 2001 from Rush University in Chicago, Mendoza moved to the University of Washington, Seattle, for his pediatric residency.
In Seattle, Mendoza discovered an interest in the overarching role of nutrition and exercise in preventive medicine—especially among disadvantaged children. "Early in my medical training I started to realize that so many kids who were overweight or obese were obviously not getting enough physical activity, and it was disproportionally affecting minority kids," Mendoza recalls. "It became frustrating. There was not a lot that pediatricians could do back then to show that treatment or prevention worked. That's how large-scale prevention—looking at the issue from a macro level—became my focus of interest."
But Mendoza needed more training to pursue his passion. He applied and was accepted to the Robert Wood Johnson Foundation Clinical Scholars program, and from 2004 to 2006 pursued a master's degree in public health at the University of Washington under Dimitri Christakis, MD, MPH, a mentor he still praises today. (See his Grantee Profile.) "That program literally changed my life," Mendoza says. "I had the motivation and basic background from my clinical experience but I didn't have the skill set I needed. As a pediatrician, you're not trained to do public health, but rather one-on-one care…. I was with a cohort of scholars who were fabulous in developing ideas and refining them, and the faculty prepared us very well to become scientists."
At the time, despite the growing popularity of walk-to-school programs in the United States, there had been no long-term controlled studies to document their benefits. The Walking School Bus program—literally, a group of children walking or bicycling to school under adult supervision—had meandered from Australia to Great Britain in the 1990s, and then across the Atlantic to the United States. A few Walking School Bus studies conducted in Great Britain and in the wealthy suburb of Marin County, Calif., reported increases in students commuting to school, but none had tested the program in a socioeconomically disadvantaged neighborhood or against a control group.
As an RWJF Clinical Scholar, Mendoza took up the challenge, impressed by the Walking School Bus program's grassroots beginnings and reach. "Part of the problem in any kind of intervention is acceptance by your target population," he says. "Could we apply it in low-income communities and schools? There are a host of challenges you have with low-income groups that you do not with other populations because there are all kinds of disparities—from access to food to health care—and recruiting people can be more difficult because there are so many demands on their time."
Mendoza conducted a pilot assessment of the effect of a Walking School Bus program on children in three ethnically diverse public elementary schools in a low-income community in Seattle. The main hypothesis was that a Walking School Bus program would increase the proportion of students walking to school and decrease the proportion of students driven to school by car in the short and long term. "We were the first to provide long-term results in the setting of a controlled trial," Mendoza says. "We were able to show significant increases in the proportion of kids walking to school at baseline, six months and one year." The study results were published in BMC Public Health in 2009.
After his RWJF fellowship, Mendoza moved to Houston as an assistant professor of pediatrics at Baylor College of Medicine's Children's Nutrition Research Center and the Section of Academic General Pediatrics. He is pursuing further research at the Children's Nutrition Research Center and practicing at a county clinic a few afternoons a week. A key point he wanted to investigate further was whether more objective measures than questionnaires could be used to document Walking School Bus results using a randomized controlled trial design.
The Project: In 2008, with a Robert Wood Johnson Active Living Research grant, Mendoza undertook a pilot and feasibility evaluation of a Walking School Bus intervention on children attending several ethnically diverse, low-income schools in Houston. For the evaluation, Mendoza used accelerometers—objective measures of physical activity—as well as student and parent surveys in a randomized controlled trial of 149 fourth-graders (where half of the schools—the control group—got no intervention). Mendoza designed the trial to examine the students' active commuting to school (ACS) and its relationship to daily physical activity, using a Walking School Bus based on the model provided by the National Center for Safe Routes to School.
The trial took months of preparation. Training for 20 Walking School Bus staff members was just about to launch in September 2008 when Hurricane Ike struck, devastating the Houston/Galveston area, closing schools and grinding preparations for the study to a sudden halt. The tragedy pushed the study back several months, resulting in the shortening of the intervention period to just five weeks instead of several months. "It was a humbling experience," Mendoza says. "We were thankful that we—and all the kids—were fine. And it taught us that if we were able to survive this, we'll be able to handle other disasters in the future and to be flexible with overall plans."
The Results: Despite the setbacks, Mendoza was satisfied with the project's outcome: The Walking School Bus intervention successfully increased students' active commuting to school and their daily moderate-to-vigorous physical activity. "We are the first to report a group randomized controlled trial examining a walking school bus intervention that successfully increased students' active commuting to school… and daily moderate-to-vigorous physical activity," says Mendoza. "With the funding from Active Living, we were able to do a randomized, controlled trial using an objective measure of activity in a more rigorous way," he adds. "We also used validated instruments to measure student travel through this project." An article on the study's baseline results in the Journal of Applied Research on Children is available online. Two more articles, one with final results on students' active commuting to school and physical activity, and another with results focused on students' pedestrian safety behaviors are under peer review.
Today, Mendoza is planning a larger, randomized controlled trial of a Walking School Bus intervention over an entire year involving children attending Houston elementary schools from all socioeconomic levels. The timing of his project coincides nicely, Mendoza notes, with First Lady Michelle Obama's "Let's Move" anti-obesity campaign, launched in February 2010. "Times have changed even in the brief time I've been doing work in this area," Mendoza says. "When I started, walking to school was not a big deal, but now with Michelle Obama, there is a national shift to childhood obesity prevention."
RWJF Perspective: Launched in 2000, Active Living Research (ALR) is a $19 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 help to inform policy, design of the built environment and other factors necessary to reengineer 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.
Research teams are required to be transdisciplinary. Researchers with grants from the program 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, PhD, RWJF distinguished fellow and senior scientist.
"ALR has had a huge impact in terms of influence," says Celeste Torio, PhD, RWJF program officer for Active Living Research. "The research is very innovative and something policy-makers can use. It's not something you just put on the shelf and forget about."