Social factors play a role in U.S. HIV/AIDS epidemic among black women

April 2008

At the end of 2005, an estimated 23% of the 421,873 people living with HIV in the United States were women. Sixty percent of the women in the United States with AIDS have been black.

A number of factors are involved in driving the HIV/AIDS epidemic among black women in the United States, and Adaora A. Adimora, MD, MPH, a professor at the University of North Carolina, Chapel Hill, discussed those factors at the 15th Conference on Retroviruses and Opportunistic Infections, held recently in Boston.

“The racial disparity in HIV infection rates and other health indicators in this country is truly extraordinary,” Adimora said at the meeting. “It is nothing less than a national disgrace and reflects a failure of the civil rights and human rights agendas within the United States. As researchers and as citizens, we can change this.”

HIV prevalence

Although the overall number of AIDS cases among women in the United States has risen substantially since 1995, minorities are disproportionately affected. The researchers of one study that covered almost 10,000 cases in 33 states found that although Hispanics had more than a five times higher case rate than non-Hispanic whites (15.8/100,000 people vs. 3.0/100,000), black individuals had a rate more than 20 times higher (60.2/100,000). Adimora said that the rates are particularly high among black women in the southeastern part of the country.

The transmission methods in the United States are similar to the rest of the world. Heterosexual transmission accounts for an estimated 71% for American women, and injection drug use accounts for 27%. The higher seroprevalence among blacks overall is also reflected among adolescents and young adults. Among the more than 13,000 youth in the National Longitudinal Study of Adolescent Health (Add Health) study, which explores the causes of health-related behaviors of adolescents, seroprevalence among white individuals was 0.022% vs. 0.492% among blacks.

Data from the NHANES study showed high seroprevalence rates among black men and women compared with whites.

Higher infection risk

Results of one case-control study indicated that although most newly HIV-positive patients reported high-risk characteristics such as low education, crack use, crack-using partners or injection drug-using partners, 27% denied having high-risk behaviors or partners. Among the lower-risk cases, there were several independent risk factors for HIV; these included less than high school education, food insecurity and nonmonogamous sex partners.

This theme of increased risk in minorities despite similar behaviors has been found elsewhere as well. The results of the NHANES study indicated that blacks had greater risk than whites across all demographic and risk variables, and the results of the Add Health study suggested that black adolescents and young adults with low-risk behavior had a 25-fold greater risk for HIV or other STDs than white people.

STDs may play a role in increased HIV prevalence among black individuals. “STDs increase the probability of HIV transmission, so the high probability of STDs among African-Americans likely increases the probability of HIV transmission per contact,” Adimora said. For example, the ratio of black patients to white patients for infection with chlamydia is eight-to-one, and the ratio for gonorrhea is 18-to-1.

Sexual network patterns

Sexual network patterns are also important determinants influencing transmission of HIV. Adimora said that concurrent partnerships, or partnerships that overlap in time, can spread HIV and other STDs through a population substantially faster than the same number of relationships held sequentially. Results of a 1995 study of more than 10,000 women indicated that the five-year prevalence of concurrent partnerships was 12% for the general population and 21% for black women. After controlling for concurrency correlates such as marital status, age and age at first sex, however, the black to white concurrency odds ratio fell to 1.3.

Another part of sexual network patterns are sexual mixing patterns. Assortative mixing, or partnerships between people at similar risk for infection, tends to keep infection within that risk subpopulation. According to Adimora, most social and sexual networks are relatively assortative. Dissortative mixing, or sexual partnerships between people of differing risk status, can disseminate infection throughout a population much more widely.

In a study of sexual mixing among black people in North Carolina, Adimora said that researchers found that there was more frequent contact between people with many partners than those with few partners. This form of dissortative mixing, along with the fact that the sexual networks are relatively segregated by race, can increase transmission among the population.

Poverty and incarceration

Given this sexual transmission context among black men and women, Adimora discussed the social and economic context that could lead to these higher risk patterns. Blacks living in rural North Carolina reported pervasive economic and racial oppression, lack of community recreation and resultant substance abuse and widespread sexual concurrency among unmarried people.

There is also a low sex ratio among blacks in the United States because of increased mortality among black men and the disproportionate incarceration of black men.

“Incarceration is a big part of the context of life for African-Americans,” Adimora said. “The United States has the highest incarceration rates in the world, and blacks are disproportionately incarcerated. … A black man born in the United States today has about a 29% chance of being incarcerated in his lifetime.” One of every eight black men aged 25 to 29 years is currently incarcerated, and varying reports suggested that the likelihood of incarceration is between seven and 44 times greater for black men than white men given the same crime.

This problem has widespread effects on sexual networks and HIV transmission. First, it directly affects sexual networks by physically removing people from partnerships. The partner who enters prison may have sex while there with high-risk individuals, and the partner who is left behind loses the social support of the incarcerated partner; this may result in a search for other partners. Adimora said it is believed that women whose partner has been incarcerated are more likely to have concurrent sexual partnerships.

As inmates return to the community, resumption of old partnerships and/or starting new partnerships will increase the likelihood of concurrency further. “While in prison, inmates may join gangs and thus forge long-term links with antisocial networks,” Adimora said. “This can affect sexual networks by connecting previously low-risk people, such as the girlfriend back home, with new high-risk subgroups.”

Incarceration also reduces employment prospects, thereby increasing the risk for poverty and destabilizing long-term sexual partnerships. On the community level, this can shrink not only the absolute number of men but also the proportion of financially viable men.

From individual to community

The apparent importance of sexual network patterns and economic and racial disparities in the HIV epidemic among black women calls into questions some of the thinking on how HIV is spread. “The interrelatedness of these factors underscores the fact that social and contextual factors are not ‘distal’ determinants in the way that we usually use the word distal, but instead they directly impact behavior and the risk for infection,” Adimora said.

Thus, the current research efforts need to be expanded outside of individual risk behaviors and into a community-level social and economic context. “We need to broaden the public health research paradigm to include research to develop structural interventions: programs, laws and policies that alter the context of life to improve health behaviors and health outcomes,” Adimora said.

For more information:

• Adimora A. What’s driving the US epidemic among women. #54. Presented at: the 15th Conference on Retroviruses and Opportunistic Infections; Feb. 3-6, 2008; Boston.