Neighborhood effects on posthospitalization mortality: a population-based cohort study of the elderly in Chicago.

Geographic variation in health status, at levels ranging from states to counties to neighborhoods, is well documented (LaVeist 1989; 1992; 1995; Collins and David 1990; 1992; Clarke, Farmer, and Miller 1994; Chang and Christakis 2005). One explanation is that areas differ in health status because residents differ in characteristics such as demographic attributes, socioeconomic status (SES), and health risks (Diez-Roux 2002). However, recent work on neighborhood effects using multilevel statistical methods has pointed to the possible contextual effects of residential areas on health even after controlling for individual characteristics. That is, neighborhood SES and other neighborhood social factors may independently affect individuals' self-rated health, morbidity, or mortality over and above individual sociodemographic backgrounds (Robert 1999; Yen and Syme 1999; Pickett and Pearl 2001). However, there are important gaps in our knowledge about whether neighborhood environment has an impact on mortality among older persons and how such neighborhood effects vary for different social or clinical subgroups in a population. Theoretically, people with different sociodemographic attributes or different illnesses may have different exposure or reactivity to such neighborhood effects. For example, older people may spend more time in their home area or have longer-standing ties to it and therefore be more vulnerable to poor conditions in their local environment. Despite this theoretical expectation, however, evidence is not consistent regarding neighborhood effects on mortality in old life. While some studies have reported a prominent effect of neighborhood SES on mortality in older persons (Waitzman and Smith 1998a; Wen, Cagney, and Christakis forthcoming), others have found insignificant or weaker neighborhood effects among the elderly (Haan, Kaplan, and Camacho 1987; Anderson et al. 1997; Waitzman and Smith 1998b). The effect of neighborhood characteristics, including neighborhood-level SES, may also depend on individual-level SES. For example, the unhealthy consequences of individual poverty could be intensified for those who live in poverty areas (termed the “double jeopardy” hypothesis); on the other hand, poor people living in poor neighborhoods may be less stressed from perceived income inequality and thus suffer less from relative deprivation (termed the “relative deprivation” hypothesis) (Robert and House 2000; Wen, Browning, and Cagney 2003). Only a handful of studies have examined how environmental effects depend on individual characteristics, with mixed findings (Anderson et al. 1997; Collins, Herman, and David 1997; O'Campo, Xue, and Wang 1997; Pearl, Braveman, and Abrams 2001; Merkin, Stevenson, and Powe 2002). This study first documents the effects of neighborhood SES and social environment on posthospitalization mortality and then explores how the effects vary by gender, race, and poverty status. It examines the role of the neighborhood environment in differentially contributing to a higher risk of death in specific diseases. And it emphasizes the way in which neighborhoods might affect the course, as distinct from the onset, of disease. Our sample consists of a complete cohort of Medicare beneficiaries newly diagnosed and hospitalized with one of five serious and common diseases in 1993 throughout the entire city of Chicago (stroke, myocardial infarction, congestive heart failure, hip fracture, and lung cancer). One advantage of this design is that many sources of unobserved neighborhood and individual heterogeneity are implicitly controlled for by the selection of a patient population at the time of their diagnosis with one of the specific five diseases. Here, we take advantage of several data sets with both diagnostic and social information to advance understanding of how neighborhood of residence might affect mortality after the onset of disease. In so doing, we also attempt to advance the evidentiary base regarding the nature of health disparities by social status in our society.