During the past 30 years, an increase in published scientific evidence has demonstrated that many chronic and infectious diseases do not occur at random in populations, and genetic predisposition for illness may only minimally explain why some people become sick and others do not.
5–10 Apart from those that are genetically inherited, many diseases and conditions cluster in socially and economically vulnerable populations.
9 Health disparities in diseases may occur by gender, race/ethnicity, education, income, disability, geographic location, and sexual orientation, among many other factors. SDH such as poverty, limited access to health care, lack of education, stigma, and racism are linked to health disparities.
8,11,12Despite prevention efforts, some groups of people are affected by human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS), viral hepatitis, sexually transmitted diseases (STDs), and tuberculosis (TB) more than other groups.
13 In the United States, studies have examined SDH and health outcomes for people with HIV, viral hepatitis, STDs, or TB. Several studies have focused primarily on demographic social determinants, such as age, area of residence, sex, and race/ethnicity. For example, black people are affected by HIV and other STDs at a rate of six to 18 times—and Hispanic individuals, two to four times—the rate of white people.
14,15 TB is a problem among both Hispanic and black populations, with rates eight to nine times that of white populations.
16 Men who have sex with men (MSM) are disproportionately affected by HIV and STDs.
14,15 In 2007, two-thirds of all new HIV/AIDS diagnoses were among men, and half of all new diagnoses overall were among MSM.
15 Similarly, the male-to-female ratio of primary and secondary syphilis in 2007 was 6:1; this may suggest that a large number of primary and secondary syphilis cases may be among MSM.
14 Rates of hepatitis B remain highest among non-Hispanic black populations, and hepatitis C continues to occur in adult age groups, with injection drug use as the most commonly identified risk factor.
17Demographics related to age, race/ethnicity, and gender continue to be critical in identifying disease patterns and health disparities; but studies looking at the socioeconomic determinants of health, such as employment, income, and education level, are revealing equally critical information. For example, studies show that black MSM at lower income levels are more likely to engage in high-risk sexual behaviors that put them at greater risk for acquiring STDs, compared with black MSM with higher income levels.
18,19 Another study shows that although the burden of hepatitis C is greater among some racial/ethnic groups, mortality is largely influenced by the individual's socioeconomic condition.
20 Studies also have shown that HIV-infected people with low literacy levels had less general knowledge of their disease and disease management, and were more likely to be nonadherent to treatment than those with higher literacy levels.
21,22 In addition, a population-based study conducted by Diaz and colleagues found that income was an important predictor of lack of health insurance among people with HIV/AIDS,
23 and, consequently, these people may be less likely to receive treatment.
Environmental social determinants, such as housing conditions, social networks, and social support, are also key drivers for HIV/AIDS, viral hepatitis, STDs, and TB. Kidder et al. conducted a study among housed and homeless individuals with HIV/AIDS and found that homeless people with HIV/AIDS had poorer health status, were less adherent to medication regimens, and were more likely to be uninsured and to have been hospitalized.
24 Social networks also play a role in fueling the spread of HIV and other STDs
25–28 and have been shown to influence adherence to TB drug therapy.
29A recent important focus of public health organizations in the U.S. is the identification of common SDH across subpopulations disproportionately affected by disease so that integrated interventions can be developed. Healthy People (HP) 2010 emphasized the need to collect data that will help drive the elimination of health disparities. Further, HP 2010 stressed the “need for communities, states, and national organizations to take a multidisciplinary approach to achieving health equity—an approach that involves improving health, education, housing, labor, justice, transportation, agriculture, and the environment.”
30 Despite such efforts, some health disparities remain.
31 Because of persistent health disparities, HP 2020's overarching framework explicitly states the importance of achieving health equity through the use of a systematic approach for addressing SDH.
32Concern for addressing SDH is not new to the Centers for Disease Control and Prevention (CDC). Since at least 1993, CDC scientists have worked to include measurement of social determinants in health outcome studies for HIV/AIDS, STDs, and TB,
23,24,29,33 and more recently have expanded evidence-based behavioral interventions to address ecological contexts of risk behaviors.
27,34–36 Responding to disparities in chronic diseases such as diabetes, CDC took up the charge to address SDH by forming a workgroup on SDH
37 and holding a forum in 2003 to discuss root causes of health disparities.
38 In addition, an Office of Health Disparities for CDC's National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention was established in 2003.
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