Social Class and Mortality
Social Class and Mortality
Racial, ethnic, and class disparities in health outcomes are wide and persistent, and they cut across the full range of indicators of disease prevalence and mortality rates in all nations of the world. Populations understood by social and political convention to constitute distinct “racial” or “ethnic” minorities are, in general, sicker and die sooner than their majority counterparts. These patterns have been evident for as long as researchers have investigated the issue, and even a cursory examination of, say, the health of blacks in the United States and South Africa, or of indigenous people in New Zealand, Canada, or the Commonwealth of Dominica, bears this out. Despite a considerable amount of research in the United States in the early twenty-first century that seeks to understand how “racial” differences—whether in a genetic or, categorical sense—might explain health inequalities, it is clear that these health inequalities reflect the relatively unequal social position that racial and ethnic minorities almost invariably inhabit.
There are a number of reasons why health disparities between and within countries cannot be genetic in nature. “Racial” categories are social and political constructions: They do not reveal much about underlying human variation at the level of the gene. As Richard Lewontin and others have pointed out, there is more genetic variation within the so-called races than between them (see Lewontin 1972). From the standpoint of genetic variation, for example, two“blacks” of sub-Saharan Africa could be further apart from each other genetically than they are from two Swedes selected at random. A second and related point is that, from the standpoint of genetic variability, Africans are more genetically diverse than non-Africans, and thus subsume the genetic diversity found among people in the rest of the world (Marks 2002).Third, the leading causes of death in most countries are not the outcome of single-gene mutations, such as those that produce sickle-cell disease, cystic fibrosis, or Tay-Sachs disease; rather, the leading causes of death reflect a complex interaction between (multiple)genes and thesocial and physical environment (Cooper et al. 2003).
The “social gradient” pattern of morbidity and mortality also argues against agenetic explanation. For more than 150 years, researchers have known that when mortality rates associated with various causes are plotted against measures of class or socioeconomic status—typically income, education, or occupation—a graded pattern emerges, with mortality increasing as socioeconomic status decreases. Figure 1
shows heart disease-related mortality rates among white American women plotted against income.
This graph shows what has been known for some time: that worse health outcomes are not a simple matter of rich and poor, but rather that risk for death (or disease) is continuous along a socioeconomic continuum. Each step up the social ladder corresponds to better health outcomes.
Health related behavior—e.g., smoking, diet, and physical activity—is certainly one fact that explains disparities in health outcomes between populations that differ in terms of socioeconomic status, but two points are worth emphasizing: First, class, or socioeconomic status, predicts health-related behavior; and second, in empirical studies that weigh health behaviors against measures of social status, the results suggest that no more than 30 percent of the variation can be explained by behaviors suchas smoking and physical activity (see Marmot 2004). When statistical analyses weigh the contribution of various factors, socioeconomic status explains more of the disparity than all health-related behaviors combined.
Researchers in public health and other disciplines suggest that social status is undamental to health disparities, but it is also clear that measures of socioeconomic status
might not fully capture these differences. Figure 2 shows heart disease death rates among black American women compared to white American women at the same income points. These bar graphs show a clear gradient in heart disease death rates among white and black women at various points along the income ladder. For both groups, more money means better health. This figure also shows that at comparable points of income, black women have higher mortality rates.
Researchers have found similar patterns in countries around the world. In New Zealand, for example, it is well established that the indigenous people of that country, the Maori, have worse health than non-Maori people. However, in studies that have examined health outcomes in terms of smoking and socioeconomic deprivation, researchers have seen an “independent effect” of ethnicity. Adjusting for smoking and for measures that gauge deprivation (housing, access to a car, and so forth) explains some of the ethnicity health gap, but does not account for all of it (see Blakely et al. 2006).
A study of infant health in Brazil provides additional evidence that health status is a function of racial and class identity. In 2001 Fernando Barros and colleagues conducted a cohort study in Pelotas, southern Brazil, and found that children with one or two black parents had a higher prevalence of poor health indicators—such as low birth weight and infant mortality—than children who had two white parents. Socioeconomic measures and other variables explained a good portion of the inequalities in health indicators, but not all (Barros et al. 2001). This study, and others, lend support to the view that health is a function of social status, but they also point out the need for understanding social status both in terms of race (orethnicity) and social class.
What are the determinants of these social gradients? Access to and quality of health care is certainly part of the story. In the United States, blacks are much more likely than whites to lack health insurance. Studies further suggest that racial and ethnic minoritiesinsurance status, and comorbidity. Around the world, aboriginal health is affected, to varying degrees, by the insufficient/inadequate availability of health services, especially in rural areas. Still, whereas disparities in health care access and treatment are vital with respect to diagnosing and treating chronic conditions, access to health services does not prevent the onset of emany conditions that lead to premature death. In other words, health care matters when an individual gets sick, but it does not determine whether he or she is afflicted in the first place.
A significant body of research suggests that relative inequality “gets under the skin” through a variety of pathways, some material—e.g., exposures that make people sick regardless of perception—and others pyschosocial, such as illness induced by subjective evaluation of one’s social position. In many places worldwide, poor health outcomes reflect deprivation in the form of poor sanitation, more polluted environments, inferior housing, and various features of the social and physical environment. In countries that have passed a certain threshold of development, relative deprivation might impact health through pyschosocial processes: The physiological effects of feeling poor can affect health. Research by Nancy Adler and colleagues in 2000 found, for instance, that subjective evaluations of socioeconomic status predicts levels of stress hormones, patterns of cardiovascular function, incidences of obesity, and other physiological outcomes.
In studies of poor black communities in the American South, the medical anthropologist William Dressler found that, among poor black Americans in a southern community, falling short of the lifestyle that a particular community emphasized (e.g., having certain material items) affected levels of blood pressure. In a 1998 study of subjects from a Brazilian city, Dressler and colleagues (1998) similarly found an inverse relationship between distance from a culturally defined sense of lifestyle and arterial blood pressure, depressive symptoms, and perceived stress.
These and other studies that examine how chronic stress affects health suggest how the material and pyscho-social factors might be linked. Humans may be well equipped to deal with acute stress, but chronic stress clearly increases the risk or severity of a number of diseases, such as Type 2 (adult-onset) diabetes, for example. A broad scientific literature has shown that individuals are at greater risk for stress-sensitive diseases when they (1) feel that they have little control over the source of stress; (2) have no way to predict the duration and intensity of the stress; (3) have few outlets that help deal with the frustration caused by the stress; (4) see the source of stress as evidence that circumstances are getting worse; and (5) lack social support. Moreover, exposure to stress, and the resources that mitigate stress, are not distributed evenly. Moving from high socioeconomic status to low socioeconomic status generally means greater exposure to a variety of stressors—neighborhoods marked by high violence, job and housing insecurity, and so forth—and fewer of the resources that help mitigate them (see Sapolsky 2005).
Many researchers theorize that chronic exposure to racial and ethnic discrimination might affect health in stress-related ways (e.g., Mays et al. 2007). Whereas the overall results have been mixed, a number of studies have found that individual perception of race-based discrimination is associated with higher blood pressure and poorerself-rated health (Kreiger and Sidney 1996). Perceptions of racial discrimination have also been shown to affect birth outcomes (see Kreiger and Sidney 1996, Collins et al. 2000).
These studies suggest, again, that the fundamental sources of health disparities are neither rooted in the genes nor explained by health-related behavior. Morbidity and mortality patterns reflect social status. Inferior status for racial and ethnic minority populations started with slavery and/or colonialism, and in the early twenty-first century it reflects continuing discriminatory practices and unequal access to vital resources that are relevant to health. Health inequalities in terms of race, ethnicity, and class are, therefore, fundamentally rooted in current and past political and economic practices that generate social stratification.
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Dean E. Robinson