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Across the disparate fields of psychology, sociology, and neuroscience, work is converging on “candidate” variables (e.g., social processes, functional neuroscience, contextual effects) that might be essential to understanding underlying processes associated with racial discrimination and negative health outcomes in African Americans. The challenge, at this point, is to cleave together the literatures examining the upstream side of discrimination and health with its focus on behavioral, social, and psychological factors to those studying the downstream biological pathways and molecular events that are proximal causes of the high rates of disease and disability (Kaplan 1999Schillinger et al. 2005). In the past decade, particularly, the number of models proposed to account for the relation-ship between race-based experiences and poor physical and mental health have exploded (Clark 2003Clark et al. 1999Everson-Rose & Lewis 2005Hertzman 2000House 2002House & Williams 2000Kuh & Ben-Sholmo 1997Massey 2004McEwen 2000Morenoff & Lynch 2004Smedley et al. 2003). Several of the race-discrimination-health pathway models posit connections among environmental stimuli including conditions of violence, poor education, and negative social connectedness or early childhood exposure to these conditions, and resulting changes in brain functioning and bodily psychophysiological responses (Clark 2003Clark et al. 1999Everson-Rose & Lewis 2005Hertzman 2000House 2002House & Williams 2000Kuh & Ben-Sholmo 1997Massey 2004McEwen 2000Morenoff & Lynch 2004Smedley et al. 2003). Across these many models, three elements consistently emerge: (a) an emphasis on the importance of unhealthy social spaces in which racial stratification (particularly in the form of residential segregation) serves as a structural lattice for maintaining discrimination; (b) intergenerational and life-span effects of race discrimination that result in pernicious effects on health despite increasingly better opportunities and better environments; and (c) chronicity and magnitude of race-based discrimination (e.g., major life events, everyday hassles, and reduced opportunities) as an allostatic load factor in negative health outcomes. We discuss below three emerging areas where contributions to elucidating the candidate variables in the race-discrimination-health pathway arise in the context of new methodologies.

Social Place, Unhealthy Environments, Racial Stratification, and Health Outcomes

In recent years, the concept of place, particularly social place (e.g., geographic location, local context, neighborhood), has emerged as an important construct in understanding the contributions of discrimination in fostering ill health and health risks (Diez Roux 2002Ellen et al. 2001Morenoff & Lynch 2004). Traditionally, research on the health of African Americans focused on individual-level risk factors, with ownership for change residing in individual-level strategies. But the newer work argues for casting a broader net that will capture more complex and multilevel factors in the environment. These are hypothesized to play a significant role in the health status and health outcomes of individuals (Acevedo-Garcia et al. 2003Diez Roux 200120022003Diez Roux et al. 1997Krieger 1999O’Campo et al. 1997Pickett & Pearl 2001Williams & Harris-Reid 1999). For example, a number of sociologists and epidemiologists have made the case that neighborhood is a critical variable in mediating access to economic opportunities, social connections, and social capital (Diez Roux 2003Massey 2000O’Campo et al. 1997Oliver & Shapiro 1995Wilson 1987), all of which are components that mediate health status. Integrating neighborhood level effects into models of individual risk represents an intriguing new methodology for psychologists.

When neighborhoods work well, they are a place where individuals derive many social benefits. However, when neighborhoods are characterized by persistently low SES and residential segregation, often linked to ethnic/racial minority population concentrations (Acevedo-Garcia 20002001Lester 2000O’Campo et al. 1997Peterson & Krivo 1999), then African Americans living in those neighborhoods have higher rates of morbidity and mortality. Residential segregation that creates concentrated neighborhoods where residents are predominantly poor, racial/ethnic minority, or of immigrant status are social spaces with concentrated social problems. This increases the chances that residents, whatever their individual backgrounds, will experience greater exposure to stressful environments while also having fewer resources with which to cope with these exposures (Boardman 2004Roberts 19971999Macintyre et al. 2002).

Roberts (19971999) presents three different pathways by which poor and often racial/ethnic minority–inhabited neighborhoods can have an effect on individual health. First, poorer communities are less likely to have adequate health and social services, creating a problem of access and timely use. Also, the physical environments are more likely to expose the residents to health hazards (e.g., air pollution, lead, dust, dirt, smog, and other hazardous conditions). Finally, the concentration of poverty and its related characteristics (e.g., exposure to drugs, crime, gangs, and violence; unemployment, stress, and anxiety; substandard housing and schools; and lack of green space or fresh fruits and vegetables) often creates social environments that lessen social connectedness and provide fewer social benefits for residents.

Although the perspective that some neighborhoods are less fostering of health than others is not new, researchers who are linking this idea to biological responses that might arise from chronic neighborhood stressors are gaining new insights. In Figure 1, we depict sociologist Douglas Massey’s (2004) model of the upstream/downstream process of risk for specific disease states for African Americans. The pathway begins with two correlated factors: residential segregation and social economic inequality. These factors work to concentrate social stressors, which in turn set into motion high allostatic loads that are associated with increased risk for coronary heart disease, chronic inflammation, and cognitive impairment. In racially segregated, poor neighborhoods, both chronic and acute daily stressors (e.g., violence, unemployment, personal safety concerns) repeatedly invoke a biological challenge similar to the flight/fight response. According to Massey, an African American living in this unhealthy environment responds at a biological level with persistently elevated levels of cortisol and other glucocorticoid hormones. The effect of the chronic stress response is a premature wearing down of the body and a greater tendency to develop specific disease processes.

 
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Massey’s (2004) biosocial model of racial stratification. Reprinted from Massey 2004.

One of the issues in current work in the area is identifying the core elements in an unhealthy environment that activate a sense of danger or, conversely, protect against harmful effects of chronic neighborhood stressors. Some of the pertinent work has examined the consequences of negative social interactions and has discovered positive associations between perceptions of being treated badly, lacking social support, and an absence of emotional warmth and closeness and patterns of physiological arousal associated with cardiovascular, sympathetic nervous system reactivity (Repetti et al. 2002Seeman et al. 19931995Ursa et al. 2003). For example, Kiecolt-Glaser and colleagues found that 30 minutes of conflict between a married couple was associated with changes in norepinephrine, cortisol, and adrenocorticotropic (ACTH) levels, with both husbands and wives showing decreased immunologic responsiveness during the conflictual communication (Kiecolt-Glaser et al. 1997Robles & Kiecolt-Glaser 2003).

Intergenerational and Developmental Perspectives

Researchers are also making a strong empirical case for the importance of positive emotions and positive relationships as critical ingredients in healthy children and healthy adults. Seeman and her colleagues investigated the relationship between social environments and the activation of biological responses (Repetti et al. 2002Seeman et al. 1993). Their findings show that when children are exposed to environments characterized by conflict and low levels of nurturance, they are more likely to present dysregulated cortisol activity and show greater cardiovascular and sympathetic nervous system reactivity in the face of stress-related challenges. Similarly, Taylor and colleagues, working with Seeman in reviewing the literature in this area, identified three characteristics of children and young adults’ family social environments that contribute to negative mental and physical health in later adult years (Taylor et al. 1997). These are (a) social environments that are conflictual, angry, violent, or abusive; (b) parenting styles that are highly domineering or controlling; and (c) parent-child relationships that are unresponsive and lack the characteristics of warmth, social cohesiveness, and emotional support. Furthermore, a growing number of studies indicate that positive social interactions, positive expectations in the form of optimism, positive illusions, and hopeful outlooks are associated with physiological arousal patterns and biological responses (e.g., lower ambulatory blood pressures) to stress challenges that are consistent with long-term positive physical and mental health outcomes (Fredrickson 2000Ryff & Singer 20002001Seeman & McEwen 1996Taylor & Brown 1994Taylor et al. 1997).

Identification of candidate psychosocial variables that strongly influence health disparities in this country offers the possibility of developing more highly tailored and efficacious interventions, particularly if these interventions began in childhood. In the United States, one in five children grow up in neighborhoods characterized as poor, and for racial/ethnic minorities, particularly African Americans, the rates are even higher (Mather & Rivers 2006). Children who grow up in these poor neighborhoods are at higher risk than their counterparts in more affluent neighborhoods for a number of health challenges, including teen pregnancy, substance abuse, obesity, smoking, limited exercise, and poor dietary habits, as well as early departure from formal education activities, all of which are risk factors for premature mortality, morbidity, or disability (Mather & River 2006Messer et al. 2005). Unfortunately, there is also strong evidence that individuals who live in poor neighborhoods as children are more likely to end up as adults living in poor neighborhoods with extended families that also live in similar neighborhoods (Mather & River 2006). Concentrations of families within higher-risk neighborhoods increase individual burden, especially when there is a local catastrophe, as occurred during Hurricane Katrina.

Efforts such as those of Seeman, Repetti, Taylor, Ryff, and others move beyond descriptive epidemiology into the realm of elucidating possible social psychological processes that mediate connections between the conditions in poor neighborhoods and the experience of the individual. This work is important to identifying the ways in which social context influences health disparities in African Americans. Nevertheless, little of the literature cited above examined the specific experiences of African Americans. Some studies have shown a negative health impact of repeated experiences with race discrimination in African Americans, particularly when the response is one of a passive coping style (Krieger 1990Krieger & Sidney 1996). These results suggest that repeated experiences with race-based discrimination are associated with higher resting systolic blood pressure levels (Armstead et al. 1989Clark 1992Clark et al. 1999Harrell et al. 2003James et al. 1984McNeilly et al. 1996) and more frequent reports of being diagnosed with hypertension (Krieger 1990Krieger & Sidney 1996). Drawing from a larger body of work in this area, one can hypothesize that living in neighborhoods characterized by concentrations of poverty and violence may have harmful effects on both the immune system and neuroendocrine responses. But further study is needed to quantify the nature of these effects.

Allostatic Load: A Physiological Approach to Understanding the Effects of Race-Based Discrimination

Another model developed by neuroscientist Bruce McEwen to explain the effects of stress on the human body is allostatic load. This model can also be used to conceptualize the possible deleterious effects of race-based discrimination. In McEwen’s model, the emphasis is on the interaction between cognitive processes and physiologic response (see Figure 2). In this model, race-based discrimination could be viewed as creating a chronic biological challenge to the human regulatory systems. According to this model, homeostasis is the internal processes of the body that regulate its response to challenges and demands. Allostasis, on the other hand, is the process of the body’s response to those challenges (McEwen 199820042005McEwen & Stellar 1993). The simplest example of the allostasis process is the flight/fight response that occurs when one experiences a challenge, demand, or perceived danger. This response operates through the engagement of the sympathetic nervous system, the HPA axis, and the immune system. McEwen argues that when chronic and/or excessive demands are placed on the body’s regulatory systems, these systems over time will exhibit “wear and tear,” losing their ability to efficiently and effectively respond to demands (McEwen 20042005). One possible consequence is overt disease pathology. Invoking McEwen’s model extends the scope of stressors (challenges) in Massey’s model to include environmental stressors of work, home, social relationships, major life events, traumas, and abuses (McEwen 2000). McEwen’s model could include racially discriminatory behavior in social interactions as stressors that send the body into allostasis (Brondolo et al. 2005Mays & Cochran 1998Mays et al. 1996).

 
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McEwen’s (1998) model of stress response and development of allostatic load. Reprinted from McEwen (1998).

Although increased physiological and psychological arousal during an acute stress response is temporarily and evolutionarily advantageous, continuous bouts of stress such as those daily hassles of race-based discrimination along with frequency of exposure to stressful life events (Jackson 2004Kessler et al. 1999) could significantly alter physiological responses of African Americans (Benschop & Schedlowski 1999.) Indeed, McEwen finds that moderate challenges to the cardiovascular system actually mobilize energy through the activation of the sympathetic nervous system and enhance immune response. This can be seen in the positive role of exercise in maintaining health. However, when the stress challenge to the cardiovascular system is prolonged and excessive to the point of allostasis, immunity is suppressed, blood pressure increases, and, over time, atherosclerosis can develop (McEwen 2002), resulting in coronary vascular disease.

Although McEwen’s model is not specific to African Americans, like Massey’s model (2004), it identifies a number of downstream health effects that are expected to result from race-based discriminatory stress challenges that Massey has identified as more prevalent among African Americans. Together, these two models offer perspectives on the ways in which chronic experiences with racial discrimination might exert harmful effects on African Americans’ health. Recent studies have shown, for example, that the experience of stressful racial discrimination places African Americans at an increased risk of developing hypertension (Din-Dzietham et al. 2004) and carotid plaque (Troxel et al. 2003), both of which are related to the development of atherosclerosis and other cardiovascular diseases

These models might also facilitate an understanding of one of the important health paradoxes among African Americans: African American women, regardless of socioeconomic status, consistently exhibit the highest rates of preterm birth, and their offspring have the lowest birth weights of any group of American women (Dole et al. 2004MMWR 19992002). Furthermore, African American women as compared with White women have a threefold higher rate of very-low-birth-weight babies, secondary to preterm births (Carmichael & Iyasu 1998). The extent to which experiences with discrimination underlie this health disparity is not fully known, but in one study, African American mothers who scored high on a measure of perceived racial discrimination were twice as likely to deliver low-birth-weight infants (Ellen 2000). In a second longitudinal study of 6000 pregnant women, blood samples were taken through the first and second trimesters of pregnancy. Results suggest a correlation between high placental levels of the stress hormone corticotrophin-releasing hormone and preterm delivery (Rich-Edwards et al. 2001). Finally, in a third study, abnormally high levels of corticotrophin-releasing hormone were shown to have a strong correlation with long-term stress (Pike 2005). Although the evidence is still being accumulated, it points to a plausible set of links in a pathway model connecting race-based discrimination, stress, and negative preterm birth outcomes in African American women. In his model of racism and negative health effects, Hertzman (2000) makes the further distinction that the negative health outcomes occur not only at the time of preterm birth, but also in later life because preterm birth increases the risk of eventual coronary heart disease, high blood pressure, diabetes and other chronic diseases in offspring.

Problems with preterm and low-birth-weight babies do not disappear with improving socioeconomic conditions. College-educated African American women as compared with college-educated White American women still are more likely to deliver infants with low birth weight (Schoendorf et al. 1992). Indeed, in comparison with White American women, second-generation high-SES African American women continue to be at higher risk for low-birth-weight deliveries (Foster et al. 2000). A study of second-generation high-SES African American female college graduates and their mothers was compared with a similar cohort at Yale on rates of low birth weight and preterm delivery. Results from this study found that despite two generations of increasing SES in the African American college students, they still had the higher rates of low-birth-weight and preterm delivery, with only modest improvement over the generations (Foster et al. 2000). Furthermore, African American women born in the United States and Caribbean-born women in the United States differ in their risk for low-birth-weight deliveries, with African American women being more likely to give birth to lower-birth-weight babies (Cabral et al. 1990Fuentes-Afflick et al. 1998, Guendelman & English 1996, Hummer et al. 1999Pallotto et al. 2000).

ncbi.nlm.nih.gov

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