derstanding of race and ethnicity by addressing factors that are related to race such as geographic area of ancestry or by providing greater detail about ancestors. In the 2000 Census, less than 3 percent (6.8 million) of the total population reported being of mixed race, and 7 percent of these 6.8 million people reported a heritage that included 3 or more races (Grieco and Cassidy, 2001). However, even those who report one race may have very complex backgrounds in terms of geography. For example, a black American could have origins in East Africa, West Africa, North Africa, or the Caribbean.
NIH has prescribed that all research projects will involve a good faith effort to include minorities when appropriate. By requiring funded research to make appropriate accommodations for minority subject recruitment, NIH has encouraged scientists to begin to consider issues of race, ethnicity, and culture in research as never before. Some of the emphasis on learning more about minority populations arises from the acknowledgement of the stark disparities in health when comparisons are made across racial groups.
Disadvantages in health exist for many groups such as Pacific Islanders, Hispanics, and Native Americans, when compared to Caucasians. Asians on many accounts are found to have more positive health profiles but are not without disadvantages in comparison with Caucasians (Whitfield et al., 2002). Literature on health disparities has documented African American/ Caucasian differences in major causes of death such as hypertension, diabetes, fatal stroke, and heart disease. The gap in health seems to be greatest between the ages of 51 and 63 (Hayward et al., 2000). Despite the 30-year trend toward convergence, the age-adjusted mortality rate from all causes of death for African Americans remains 1.3 times greater than that of Caucasians. This differential produces a life expectancy gap between African Americans and Caucasians of 5.3 years for men and 4.4 years for women (Hoyert et al., 2006). Furthermore, it also appears that African Americans are less likely to survive to middle age, and if they do, they are more likely to have health problems (Hayward et al., 2000).
Health disparities are a major public health concern and are a major emphasis of research across the country and across many disciplines. Genetic, social, and behavioral studies have shown that there are a large number of correlated differences across ethnic groups at the genetic, cultural, and environmental levels. From a methodological point of view, any comparison across ethnic groups from a single disciplinary vantage point will have a tremendous confounding issue. It is only by studying the multiple levels and risk factors simultaneously within subgroups (defined by ethnicity, geography, genetic backgrounds, and exposures to the environment) that we will begin to understand how specific combinations of envi-