City structure, obesity, and environmental justice: An integrated analysis of physical and social barriers to walkable streets and park access Bethany B. Cutts a, * , Kate J. Darby b , Christopher G. Boone b , Alexandra Brewis b a School of Life Sciences, Arizona State University, Tempe, AZ, United States b School of Human Evolution and Social Change, Arizona State University, United States article info Article history: Available online 12 September 2009 Keywords: Physical activity Walkability Park access Environmental justice Children Geographic information systems (GIS) Neighborhoods USA Obesity abstract Local parks and walkable neighborhoods are commonly cited as elements of the urban environment that promote physical activity and reduce obesity risk. When those vulnerable to obesity-related diseases live in neighborhoods without these qualities, it works against environmental justice goals that aim for a fair distribution of amenities. We use geographic information systems (GIS) to evaluate the relationship between the distribution of populations vulnerable to obesity and proximity to parks and walkable street networks in Phoenix, Arizona, USA. Though previous studies have used GIS to assess the distribution of access to opportunities for physical activity, none have analyzed access to both parks and walkable resources at once. Neither have they included data that reflects findings on a smaller scale indicating that perceptions of resource quality, safety, and cultural relevance also affect physical activity levels. We include these safety and quality factors in our study through statistical data on traffic fatalities, crime rates and park size. We find that, counter to predictions, subpopulations generally considered vulnerable to obesity (and environmental injustices more generally) are more likely to live in walkable neighbor- hoods and have better walking access to neighborhood parks than other groups in Phoenix. However, crime is highest in walkable neighborhoods with large Latino/a and African-American populations and parks are smaller in areas populated by Latino/as. Given the higher prevalence of obesity and related diseases in lower income and minority populations in Phoenix, the results suggest that benefits of built environments may be offset by social characteristics. Our most consistent finding indicates a strong negative relationship between the percentage of the population under 18 years of age living in an area and the likelihood that the structure of the built environment supports physical activity. Children under 18 are significantly underrepresented in regions deemed highly walkable and those with access to parks. Ó 2009 Elsevier Ltd. All rights reserved. Introduction The built environment shapes both behavior and health outcomes: more walkable neighborhoods and access to parks correlate with higher levels of physical activity and lower body mass index (BMI) (Giles-Corti & Donovan, 2002a,b; Saelens, Sallis, Black, & Chen, 2003). Recent research suggests that these neigh- borhood characteristics are at least as significant as individual characteristics in determining likelihood of obesity (Harrington & Elliott, 2009; Santana, Santos, & Nogueira, 2009). A neighborhood becomes ‘obesogenic’ when its layout prevents or discourages physical activity. Recent research has explored the specific attri- butes of the built environment that encourage physical activity. Previous built environment studies tend to focus on either walk- ability or park access. Walkability studies examine the suitability of neighborhood form and function for walking as a means of recre- ation and transportation. In the United States, 84% of the population walks for recreation, making it the most common form of leisure- time exercise (USDA Forest Service, 2006), and neighborhood streets are the most frequently used physical activity space (Giles- Corti & Donovan, 2002a). Studies that focus on walking at the city- wide or ‘macro-level’ scale frequently use destinations, distance, density, and route to determine the walkability of a neighborhood (Lee & Moudon, 2006; Leslie et al., 2007; Sallis et al., 2009). That is, dense neighborhoods with diverse land use and many destinations within a safe and short distance of people’s homes are deemed most walkable (Frank & Engelke, 2001; King et al., 2006). Neigh- borhood parks also encourage exercise (Bedimo-Rung, Gustat, Tompkins, Rice, & Thomson, 2005; Roemmich et al., 2006; Sallis, Bauman, & Pratt, 1998). People who live within walking distance of urban parks are reported to be nearly three times more likely to get * Corresponding author. School of Life Sciences, Arizona State University, PO Box 4601, Tempe, AZ 85287-4601, United States. Tel.: þ1 508 265 5514. E-mail address: bcutts@asu.edu (B.B. Cutts). Contents lists available at ScienceDirect Social Science & Medicine journal homepage: www.elsevier.com/locate/socscimed 0277-9536/$ – see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.socscimed.2009.08.020 Social Science & Medicine 69 (2009) 1314–1322