Continuing racial differences in HIV prevalence in US

October 6, 2009

HIV prevalence among African Americans is ten times greater than the prevalence among whites. This racial disparity in HIV prevalence has persisted in the face of both governmental and private actions, involving many billions of dollars, to combat HIV. In the November 2009 issue of the American Journal of Preventive Medicine, researchers from the University of North Carolina at Chapel Hill examine factors responsible for the stark racial disparities in HIV infection in the U.S. and the now concentrated epidemic among African Americans.

The Centers for Disease Control and Prevention (CDC) estimates that 45% of new HIV infections in the U.S. in 2006 occurred among non-Hispanic blacks. Among the 13,184 adolescents and young adults in The National Longitudinal Study of Adolescent Health, a nationally representative study, HIV seroprevalence was almost 0.5% among blacks - 20 times that of whites.

While individual-level sexual behaviors can contribute to the disparity in HIV prevalence, these observed differences in individual behaviors do not fully explain the marked racial differences in HIV infection prevalence. Even when comparisons are stratified by education, poverty index, marital status, age at first sexual intercourse, lifetime number of sex partners, history of male homosexual activity, illicit drug use, injection drug use, and HSV-2 antibody positivity, HIV prevalence among African Americans exceeds that of whites, typically substantially.

The authors suggest a number of social factors that may contribute to the difference in infection rates. Because of racially segregated mixing patterns and the much higher HIV seroprevalence in African Americans, exposure to the virus is more likely among blacks than among whites for any given number of partners or frequency of sexual contacts. The prevalence of concurrent sexual partnerships (relationships that overlap in time) is higher among U.S. blacks than whites and this can spread infection through a sexual network faster than the same number of new, sequential relationships. Poverty, a reality of life for a disproportionately large number of African Americans, is strongly associated with HIV infection. The population gender ratio (number of men:women) is a major determinant of the structure of sexual networks and both high male mortality and disproportionate incarceration of black men reduce the gender ratio among African Americans. This likely influences not only marriage rates, but also participation in sexual risk behaviors and sexual mixing and other network patterns.

According to the authors, the overall impact of these factors constitutes structural violence; a social system characterized by inequalities in power and life chances of sufficient magnitude to restrict a group of people from realizing their full potential and put them "in harm's way." Although the link between social context and disease is increasingly recognized, with a few notable exceptions, the specific role of structural violence in the HIV epidemic among African Americans has received considerably less research attention.

Writing in the article, Adaora A. Adimora, MD, MPH, University of North Carolina at Chapel Hill, School of Medicine, states, "Continuing racial disparities in HIV infection more than 2 decades after the identification of the virus and availability of an accurate test are an indictment of the U.S. response to the epidemic. Existing interventions have failed to control the epidemic in African Americans in part because critical features of the socioeconomic context promote behaviors that transmit HIV and increase the risk of HIV infection even among those who do not have high-risk behaviors.

Failure to address these structural determinants has allowed the epidemic to continue in the black community. There is a need for research and interventions that are informed by expertise in public health, medicine, basic science, and social sciences - along with expertise in economics, business and finance, education, criminal justice, political science, and other disciplines…Governments should be held accountable for progress or lack thereof in eliminating inequities."

More information: The article is "Ending the Epidemic of Heterosexual HIV Transmission Among African Americans" by Adaora A. Adimora, MD, MPH, Victor J. Schoenbach, PhD, and Michelle A. Floris-Moore, MD. It appears in the American Journal of Preventive Medicine, Volume 37, Issue 5 (November 2009) published by Elsevier.

Source: Elsevier Health Sciences