remaining). The multiple jeopardy hypothesis, for example, holds that negative environmental, social, and economic conditions during the early years of life for African Americans detrimentally affect social, psychological, and biological conditions in late life (Jackson, 1989). Although this hypothesis attempts to explain health differentials experienced by African Americans relative to Caucasians, it is critical to remember that there is considerable individual variability in these conditions within the African American population and within other minority populations.

In the search for the environmental origins of health differentials among ethnic groups, much of the earlier research focused on behaviors and social structures (NRC, 2001). The complexity of variables within racial groups presents challenges to identifying single, simple causes for poor health among racial/ethnic minorities. For example, environmental and behavioral variability among Hispanics evinces similarities and differences among its subgroups. This racial/ethnic (Hispanic) category consists of people from more than 20 different origins, but the people share a common language. Conversely, the groups within the Hispanic category significantly differ in their regional concentrations in the United States (e.g., Mexicans in the Southwest, Puerto Ricans in the Northeast, and Cubans in the Southeast) (NRC, 2001). In the United States, a significant relationship between race/ ethnicity and foreign birth status also is found (NRC, 2001). Contrasts between immigrants and their U.S.-born peers suggest an advantage in health status to those who are foreign born (Singh and Yu, 1996; Hummer et al., 1999), at least until they become oriented to American culture. Then the advantage decreases (Vega and Amaro, 1994).

Perhaps the most studied social variable in the search for environmental origins of health differentials is socioeconomic status (SES) (see Chapter 2). For example, substantial differences exist between African Americans and Caucasian Americans with regard to their socioeconomic position. Thus, according to the U.S. Census Bureau’s Current Population Survey (DeNavas et al., 2005), the median income for African American households was $30,134 in 2004 (the latest year for which data are available), compared to $48,977 among non-Hispanic Caucasian Americans. Poverty rates among African American households are nearly three times as high (24.7 percent in 2004), compared to Caucasian households (8.6 percent). Comparing households reporting similar levels of income, African American households report substantially lower levels of net wealth compared to Caucasian Americans (Conley, 1999). These differences in income and wealth are partly attributable to differences in average educational attainment when comparing African Americans (17.6 percent of whom reported having bachelor’s degree or higher in 2004) to Caucasian Americans (30.6 percent of whom had a bachelor’s degree or higher) (U.S. Census Bureau, 2005). Racial differences in intergenerational transfers of wealth, the growth of home equity over time,



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