Neighborhood differences, including race, ethnicity, and socioeconomic factors, may contribute to health inequalities and have public health and policy relevance.
Space—as defined by place, neighborhood, or environment—is a key dimension across which health is patterned. For example, there is a fivefold difference in diabetes prevalence rates across New York City neighborhoods, according to calculations by the New York City Department of Health & Mental Hygiene, the U.S. Centers for Disease Control and Prevention, and the World Health Organization. These differences could occur because residents are segregated by factors that research has shown are health-related (such as income, race, or ethnic group), but the features of the places themselves may contribute to the problem. However, Diez Roux emphasized that environmental constraints and reinforcements, such as local food availability and affordability, are just some of many factors that affect health.
As discussed by the previous panel, researchers have used many different databases and instruments to understand local food environments. Two important points emerged: (1) the local food environment is patterned by areas of socioeconomic, race, and ethnic composition; and (2) features of the local food environment have been cross-sectionally associated with the diet of residents and with related health outcomes. In an ancillary study of the Multiethnic Study of Atherosclerosis (MESA), in which Diez Roux was the principal investigator, supermarkets were less common in low-income areas, and liquor stores and small grocery stores were more common (Moore and Diez Roux, 2006). The smaller stores did not stock many healthy foods. Moreover, even supermarket offerings can vary by location. A comparison of two supermarkets—one in predominantly African-American Baltimore City and one in predominantly Caucasian Baltimore County—showed that the inner-city store offered far fewer healthy options (see Table 3-1).
How do these differences in food availability relate to health outcomes? Studies show that respondents living in neighborhoods with the lowest availability of healthy food, as indicated by surveys of residents or lower density of supermarkets, were 32 to 55 percent less likely to have a good-quality diet than those with greater availability (Moore et al., 2008). In addition, measures of the availability of healthy food in stores are also related to the diet of residents (Franco et al., 2009). Diez Roux stressed that