Researchers are working to understand the troubling presence of health disparities-the higher incidence of certain diseases and conditions, including heart disease, high blood pressure, and infant mortality-in low-income communities and communities of color. Some studies have looked at health care access and quality-related issues, others have focused on how socioeconomic status, race, and ethnicity affect health. A relatively new development in the field is studying how community conditions affect health. Researchers are finding differences in health outcomes between neighborhoods even after adjusting for individual risk factors-suggesting that neighborhood effects on health extend beyond just the characteristics of the individuals who live there. Given the highly segregated nature-by race and socioeconomic status-of many communities in the United States , it is important to consider how community factors may influence health disparities.

In 2002, PolicyLink received a grant from The California Endowment to help develop frameworks and strategies that will help to reduce health disparities in California. A primary focus of the work was to better understand how environments in low-income communities of color contribute to health disparities. PolicyLink produced Reducing Health Disparities Through a Focus on Communities, which presents a framework for understanding the effects of community factors on health, discusses research findings from interviews and a literature review, and examines implications for programs and policies to strengthen community factors and improve health.

As part of this work, PolicyLink staff and consultants produced an annotated bibliography based on a review of literature that addressed connections between community factors and health. That version of the bibliography has been updated to include more than 150 entries. The information included here is not an exhaustive list of articles in each category, but it does include much of the key literature on community factors and health. Articles and reports were identified through journal database searches, Internet searches of relevant reports and book chapters, and recommendations from expert advisors. To limit the scope of the document, only literature that makes explicit links between community factors and health, and addresses factors present at the community level, is included. The large bodies of work on health services and on broad structural issues that influence communities, such as political economy and income inequality, are not explored in depth, even though these factors certainly influence conditions at the neighborhood level. In addition, only articles that were published before March 2004, when the final phase of research was completed, are included.

This document provides insight into the ways that researchers have investigated community effects on health, their findings, and the program and policy implications that researchers have drawn from their work. The work focuses on the role of social structures, social relationships, and peer influences; the role of institutions and services (e.g., schools, police, and health care institutions); the role of direct environmental factors (e.g., exposure to toxins) and indirect environmental factors that influence behavior (e.g., access to healthy foods); the role of structural factors (e.g., race relations and public policies that affect the neighborhood and local residents); and the changing nature of all of these factors over the life-course. Evidence on these community influences on health is accumulating rapidly. Public health professionals can benefit from a better understanding of the community influences that affect health and the ways that interventions and policies addressing community factors could influence health. Practitioners in areas like urban planning, social welfare, public policy, and the like can benefit from understanding how policies and programs that are not explicitly about health can actually have important health impacts.

The first section, "Neighborhood Influences on Health," includes research on how living in a particular neighborhood or area affects health. Overall, the studies in this section show a clear connection between neighborhood factors (such as housing access and quality, exposure to environmental toxins, access to grocery stores and recreation centers, and community social relationships) and health outcomes (such as asthma, heart disease, depression, self-reported health, and mortality). The articles in this section also address conceptual frameworks for understanding these connections as well as measurement challenges.

The second section, "Communities Not Defined by Neighborhood," focuses on how communities that are defined by shared characteristics or experiences, rather than by a shared neighborhood, can influence health. For example, immigrants entering neighborhoods in the United States demonstrate the effects of place as they move from one community to another. For parts of the year, migrant farmworkers do not live in a single neighborhood, but they do have a mobile community that is characterized by common demographic characteristics and shared experiences related to their jobs. Rural areas and urban Indians may have communities that share particular experiences, even though they do not live in close proximity to others who are part of their community.