due to admixture African Americans have elevated levels of the disorder relative to Africans. Some diseases and physiological variables vary depending upon their admixture ratios. Examples include measures of insulin functioning and obesity. Gene interactions The same gene variant, or group of gene variants, may produce different effects in different populations depending on differences in the gene variants, or groups of gene variants, they interact with. One example is the rate of progression to AIDS and death in HIV–infected patients. In Caucasians and Hispanics, HHC haplotypes were associated with disease retardation, particularly a delayed progression to death, while for African Americans, possession of HHC haplotypes was associated with disease acceleration. In contrast, while the disease-retarding effects of the CCR2-641 allele were found in African Americans, they were not found in Caucasians. Theoretical approaches in addressing health and race disparities Public health researchers and policy makers are working to reduce health disparities. Health effects of racism are now a major area of research. In fact, these seem to be the primary research focus in biological and social sciences. Interdisciplinary methods have been used to address how race affects health. according to published studies, many factors combine to affect the health of individuals and communities. Whether people are healthy or not, is determined by their circumstances and environment. Factors that need to be addressed when looking at health and race include income and social status, education, physical environment, social support networks, genetics, health services, targeted instruction, and gender. These determinants are often cited in public health, anthropology, and other social science disciplines. The WHO categorizes these determinants into three broader topics: the social and economic environment, the physical environment, and the person's individual characteristics and behaviors. Due to the diversity of factors that often attribute to health disparities outcomes, interdisciplinary approaches are often implemented. Interdisciplinarity or interdisciplinary studies involves the combining of two or more academic disciplines into one activity (e.g., a research project) The term interdisciplinary is applied within education and training pedagogies to describe studies that use methods and insights of several established disciplines or traditional fields of study. Interdisciplinarity involves researchers, students, and teachers in the goals of connecting and integrating several academic schools of thought, professions, or technologies—along with their specific perspectives—in the pursuit of a common task. Biocultural approach Biocultural evolution was introduced and first used in the 1970s. Biocultural methods focus on the interactions between humans