Social characteristics vary systematically across communities along dimensions of socioeconomic status (e.g., poverty, wealth, occupational attainment), cultural context (e.g., normative guidelines), family structure and life cycle (e.g., female-headed households, child density), residential stability (e.g., home ownership and tenure), and racial/ethnic composition (e.g., racial segregation). A long history of research shows that health-related problems also vary systematically by community, often in conjunction with socioeconomic characteristics (Yen and Syme, 1999). As far back as the 1920s, urban neighborhoods characterized by poverty, residential instability, and dilapidated housing were found to suffer disproportionately higher rates of infant mortality, crime, mental illness, low birth weight, tuberculosis, physical abuse, and other factors detrimental to health (see e.g., Shaw and McKay, 1942).
This general empirical finding continues to the present day, as illustrated by the ecological “comorbidity” or spatial clustering of homicide, infant mortality, low birth weight, accidental injury, and suicide. In the period 1995-1996, for example, data from the city of Chicago reveal that census tracts with high homicide rates tend to be spatially contiguous to other tracts high in homicide. Perhaps more interesting, more than 75 percent of such tracts also contain a high level of clustering for low birth weight and infant mortality and more than 50 percent for accidental injuries (Sampson, forthcoming). Suicide is more distinct, although even here the spatial clustering is significant. The ecological concentration of homicide, low birth weight, infant mortality, and injury indicates that there may be geographic “hot spots” for unhealthy outcomes.
Not only do social characteristics vary systematically with health across communities, a growing body of contextually oriented research has linked community social characteristics with variations in individual-level health. Simply put, even when individual attributes and behaviors are taken into account, there is evidence of direct risk factors linked to environmental context (Robert, 1999a). Recent analyses of the longitudinal Alameda County Health study in northern California, for example, found that self-reported fair/poor health was 70 percent higher for residents of concentrated poverty areas than for residents of nonpoverty areas, independent of age, sex, income, education, smoking status, body mass index, and alcohol consumption (Yen and Kaplan, 1999a). In a related study, the age and sex-adjusted odds for mortality were more than 50 percent higher (odds ratio = 1.58) for residents in areas characterized by poverty and deteriorated housing, after adjusting for income, race/ethnicity, smoking, body mass index, alcohol consumption, and perceived health status (Yen and Kaplan, 1999b). Such patterns are not limited to the United States. A multilevel study in