Neighborhood Effects on Health: Exploring the Links and Assessing the Evidence

This article is an extensive review of the relationship between neighborhood and health and methodological challenges. The authors categorize the ways neighborhood might affect health in three ways: direct threats created by the neighborhood's environment; indirect threats through neighborhood influences on health-related behavior; and quality and availability of heath care services. The authors review evidence linking five health outcomes to residence in a neighborhood: 1) low birthweight and infant mortality; 2) physical health of children, discussing cockroach allergen, mites, mold, heating, and asthma, lead and central nervous system damage, and influences on behaviors; 3) physical health of adults, discussing increased risk of death and cardiovascular disease by neighborhood characteristics; 4) differences in health behaviors by neighborhood characteristics; and 5) mental health and neighborhoods, discussing violence and ambient social hazards such as gang activity, drug dealing, and property damage. Four challenges of studying neighborhood effects on health are described. The first is distinguishing between neighborhood and individual effects. Individual characteristics are likely influenced by the neighborhood in which an individual lives. Consequently, to the extent that researchers adjust for these individual characteristics, the importance of neighborhood is underestimated. To the extent that residents self-select into neighborhoods on the basis of individual characteristics (e.g., preference for a healthy environment), the effect of the neighborhood may be overestimated. The second is measuring relevant neighborhood characteristics. These characteristics often do not explain exactly what it is about a neighborhood that affects health. Definitions of neighborhood boundaries (e.g., census tracts) are often imperfect. In addition, many studies measure neighborhood characteristics at a single point and do not consider how long a person has lived in a particular neighborhood. The third challenge is capturing nonlinear effects. Neighborhood effects may exhibit a threshold effect or interact with individual characteristics. The fourth challenge is measuring relevant health outcomes.