What is the role of the social environment in understanding inequalities in health?

That the social environment is inextricably involved in the health of individuals and populations was recognized long ago, extending back beyond the parallel activities in England, France, and Germany during the mid-1800s that led to the beginnings of the public health movement. 1 Despite the important contributions of early urban sociologists, 2,3 for the next century and a half the discussion of the social environment tended to focus on material living conditions such as housing, sanitation, water quality, and so forth. During the last quarter of a century, the discussion of the social environment broadened with John Cassel’s paper “The Contribution of the Social Environment to Host Resistance” being a sentinel marker of this change. 4 In this paper, Cassel called upon evidence that linked poorer health to social disorganization of counties, social instability and poverty level of census tracts, levels of family competence, acculturation, and life stress and poor social support. More recent papers have shown that characteristics of the areas in which people live, 5 patterns of social connections, 6 social and economic policies, 7 organization of work, 8 and other aspects of the social environment are associated with important variations in health status. The papers presented in this part of the symposium show that this explosion of interest is alive, well, and exciting. But what is the social environment? We can relatively easily define the physical environment, whereas a definition of the social environment is elusive. While it may actually not be important to come up with an exact definition, inspection of F IGURE 1, or other similar representations, 9–12 gives some idea of the magnitude of the terrain that is involved when we speak broadly of the social environment. Thus, we can think of social and economic policies setting the context for the development of particular institutions and regulatory systems related to health care, education, public safety, local and regional development, and working conditions. It is important to remember that these social and economic policies are embedded in history and geography and contain cross-currents related to discrimination and culture. The nature of neighborhoods and communities, living conditions, both material and neomaterial, and patterns of social relationships between individuals and groups set in place processes that facilitate or impede the development of individual risk factors, both behavioral and psychosocial, that may feed back on upstream determinants. Thus, in order to understand the day-to-day experience of individuals and groups and