Public Transit Systems Contribute to Weight Loss and Improved Health

New Study of Light-Rail System Users in the American Journal of Preventive Medicine

San Diego, CA, June 29, 2010 -- Increasing the availability of public transit systems is one among a number of modifications to the built environment that offers opportunities for increasing physical activity and reducing the prevalence of obesity and its associated problems. In a study published in the August issue of the American Journal of Preventive Medicine, researchers from the University of Pennsylvania, Drexel University and the RAND Corporation found that construction of a light-rail system (LRT) resulted in increased physical activity (walking) and subsequent weight loss by people served by the LRT. These findings suggest that improving neighborhood environments and increasing the public's use of LRT systems could improve health outcomes and potentially impact millions of individuals

Public policy implications of the study are significant. “The built environment can constrain or facilitate physical activity. Understanding ways to encourage greater use of local environments for physical activity offers some hope for reducing the growth in the prevalence of obesity,” commented lead investigator John M. MacDonald, PhD, University of Pennsylvania. “Given that perceptions of neighborhood environments are independently associated with improved health outcomes, and that individuals who choose to use LRT obtain some relative weight reduction, it would be prudent to encourage public policies that improve the safety and attractiveness of pedestrian environments that link home, work and transit stops to increase use of public transit for commuting to work. Public policy investments in transit should consider potential increases in physical activity as part of the broader set of cost–benefit calculations of transit systems. Land- use planning and travel choice have a clear impact on health outcomes. Public transit systems can generate positive health impacts by encouraging greater numbers of users to walk to station stops and maintain more physically active lives. An added benefit of public policy investments in LRT, on top of the general transportation benefits accrued, is the potential reductions in obesity in the population.”

Using two surveys, one collecting data prior to the completion of an LRT in Charlotte, North Carolina, the second after completion, investigators found that using light rail for commuting was associated with reductions in body mass index (BMI) over time. Specifically, LRT reduced BMI by an average of 1.18 kg/m2 compared to non-LRT users in the same area over a 12-18 month follow-up period. This is equivalent to a relative weight loss of 6.45 lbs for a person who is 5’5. LRT users were also 81% less likely to become obese over time.

Survey questions assessed level of physical activity, BMI, perception of the neighborhood environment, public transit use before and after LRT construction, any plans to use LRT when available, and actual LRT usage.

There are currently 32 LRT systems operating in major U.S. metropolitan areas, generating over 200 million passenger trips a year.

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Note to Editors
The article is “The Effect of Light Rail Transit on Body Mass Index and Physical Activity” by John M. MacDonald, PhD, Robert J. Stokes, PhD, Deborah A. Cohen, MD, MPH, Aaron Kofner, MS, and Greg K. Ridgeway, PhD. It appears in the American Journal of Preventive Medicine, Volume 39, Issue 2 (August 2010) published by Elsevier.

Full text of the article is available to journalists upon request; contact eAJPM@ucsd.edu. To schedule an interview with the authors, please contact John M. MacDonald, University of Pennsylvania, at johmm@sas.upenn.edu or 215-746-3623.

A video pubcast featuring a discussion of the article by lead author John M. MacDonald, PhD, will become available (after the embargo lifts) at  http://www.ajpm-online.net/content/video_pubcasts_collection. Please check the website periodically for availability.

Study authors are:
John M. MacDonald, PhD
Department of Criminology, University of Pennsylvania, Philadelphia, PA

Robert J. Stokes, PhD
Department of Culture and Communication, Drexel University, Philadelphia, PA

Deborah A. Cohen, MD, MPH

Aaron Kofner, MS

Greg K. Ridgeway, PhD

RAND Corporation, Los Angeles, CA

About The American Journal of Preventive Medicine
The American Journal of Preventive Medicine (www.ajpm-online.net) is the official journal of The American College of Preventive Medicine and the Association for Prevention Teaching and Research. It publishes articles in the areas of prevention research, teaching, practice and policy. Original research is published on interventions aimed at the prevention of chronic and acute disease and the promotion of individual and community health. The journal features papers that address the primary and secondary prevention of important clinical, behavioral and public health issues such as injury and violence, infectious disease, women's health, smoking, sedentary behaviors and physical activity, nutrition, diabetes, obesity, and alcohol and drug abuse. Papers also address educational initiatives aimed at improving the ability of health professionals to provide effective clinical prevention and public health services. The journal also publishes official policy statements from the two co-sponsoring organizations, health services research pertinent to prevention and public health, review articles, media reviews, and editorials.

The American Journal of Preventive Medicine, with an Impact Factor of 4.235, is ranked 11th out of 122 Public, Environmental & Occupational Health titles and 16th out of 132 General and Internal Medicine titles according to the 2010 Journal Citation Reports© published by Thomson Reuters.

About Elsevier

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