Tom Tiemann, professor of economics, Paul Miller, associate professor of exercise science, and economics student Erika Lamanna recently co-authored a paper that was presented at the 2nd International Congress on Physical Activity and Public Health (April 13-16, 2008) in Amsterdam, the Netherlands.
The paper was titled “The Impact of Journey to Work on Body Mass Index in Metropolitan Areas.”
The abstract reads;
Physical inactivity has been described as a significant threat to health and contributory to the development of chronic disease risk factors. Interestingly, many individuals do not currently participate in the recommended volume of physical activity identified as being health promoting. Obesity continues to be a health concern with its primary cause stemming from physical inactivity. Previous studies have described the relationship between urban form and utilitarian exercise. Other studies have detailed the relationship between urban form and obesity. However, none have linked together the chain of causation from urban form through utilitarian exercise to obesity. Consequently, the potential role utilitarian exercise may play in promoting health remains to be elucidated. PURPOSE: To examine the links between urban form, utilitarian exercise, and obesity. METHODS: Data was gathered for 174 metropolitan counties from the Behavioral Risk Factor Surveillance System from 2002, 2003 and 2004 and the 2000 U.S. Census. These data were analyzed using a two stage least squares regression analysis. The first stage estimates utilitarian exercise (measured by the percentage of the work force which walks, bikes, or uses public transport for the journey to work) as a function of urban form. The second stage estimates obesity and overweight (measured by the percentage of the county’s adult population with a Body Mass Index > 25) as a function of the endogenous utilitarian exercise variable from the first stage and a number of control variables. RESULTS: The coefficient on the endogenous variable is negative with z = -2.35 (p = 0.019). The first stage F-score is 17.62 (p < 0.0001) and the second stage F is 15.68 (p < 0.0001). There are no indications of over- or under identification. Other variables have expected signs. CONCLUSIONS: Areas that had higher population density and less urban sprawl experienced greater rates of utilitarian exercise and lower incidence of overweight and obesity. This finding was independent of participation in formal exercise. Public policies that affect urban form, at least those that reduce the cost of walking, biking or using public transport for the journey to work in metropolitan areas, may have compelling public health benefits.