Sexually Transmitted Diseases:
HIV and African Americans in the Southern United States: Sexual Networks and Social Context
Adimora, Adaora A. MD, MPH*†; Schoenbach, Victor J. PhD†; Doherty, Irene A. PhD*
From the *Department of Medicine, School of Medicine, and the †Department of Epidemiology, School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
The authors thank Drs. Peter Leone and Sonia Naprovnik for their insightful comments.
This work was supported by National Institute of Allergy and Infectious Diseases Award 1K02 AI01867-01 (to AAA)
Correspondence: Adaora A. Adimora, MD, MPH, Division of Infectious Diseases, 130 Mason Farm Road, CB #7030, Bioinformatics Building, UNC School of Medicine, Chapel Hill, NC 27599-7030. E-mail: email@example.com.
Received for publication February 10, 2005, and accepted April 29, 2005.
Background: Heterosexual HIV transmission among African Americans in the rural southern United States has climbed in recent years. Concurrent partnerships and bridge populations have emerged as key elements in the spread of sexually transmitted infections (STIs).
Goal: The goal of this study was to examine published empiric data and other literature concerning the extent of these network patterns and their relationship to the socioeconomic context among African Americans in the rural South.
Study Design: The authors conducted a review of public health, medical, and social sciences literature.
Results: In areas of the rural South with high STI rates, there is extensive concurrency with evidence of dense sexual networks and bridging among the general population, core group members, and other high-risk subpopulations. Qualitative research reveals socioeconomic factors that support these network patterns: low ratio of men to women, economic oppression, racial discrimination, and high incarceration rates of black men.
Conclusion: Concurrency and bridging likely contribute to increased heterosexual HIV transmission among blacks in the South; contextual factors promote these network patterns in this population.
HETEROSEXUAL HIV TRANSMISSION HAS ESCALATED in the southern United States with marked racial disparities and high rates among African Americans, especially black women.1,2 Reasons for the racial disparity in HIV infection rates are multifactorial and may include healthcare access and differences in the prevalence of herpes simplex virus,3 bacterial vaginosis,4,5 and other sexually transmitted infections (STIs) that facilitate HIV transmission.6–8 Recently, STI epidemiology has begun to emphasize the importance of networks and population parameters such as concurrent partnerships and sexual interactions (“bridging”) among the general population, core group members with numerous partners, and high-prevalence subpopulations. Relatively few empiric data have been published concerning the extent of these network components among African Americans in the South, but they are likely of key importance in this region's high STI rates. This article reviews quantitative and qualitative data concerning these critical network components among blacks in the South and the evidence for the influence of socioeconomic context in formation and maintenance of network patterns that help sustain the observed disparity in HIV rates.
New Paradigm of Sexually Transmitted Infection Epidemiology: The Importance of Population-Level Factors
Patterns of population exposure—not simply individual-level behaviors—help determine the population's health.9 Therefore, sexual network patterns are critical in transmission of HIV and other STIs throughout a population.10–16 Aral has described an emerging paradigm of STI epidemiology that shifts the discipline's emphasis from individual-level behaviors to a broader perspective that includes sexual network and population-level parameters.11 Among its important features are the extent of concurrent partnerships, absolute and relative size of the core group (persons with large numbers of sexual contacts), average level of risk engaged in by the core, and the extent of sexual interaction or “bridging” between members of the core group and the general population and between the core group and other high-risk subpopulations.
Concurrent partnerships are multiple simultaneous sexual relationships or sexual relationships that overlap in time.17 Once a concurrent partner acquires infection, transmission to a third person can occur without the delay involved with ending the first relationship and beginning the next. In addition, because relationships overlap in time, early partners are no more protected from infection than those acquired later.17 Thus, concurrency permits faster transmission of infection through a network than do sequential partnerships acquired at the same rate17 and has emerged as a particularly important factor in population HIV transmission.18,19 The prevalence of concurrent partnerships influences both the rate of the epidemic's spread in its initial phase and the number of persons who are infected at a later time period.20 Concurrency particularly enhances population spread of HIV because of the virus' long duration of infectiousness.19
Bridge populations influence transmission of HIV and other STIs from the core group into other population subgroups. The extent of sexual bridging between these high-risk subpopulations and the general population and the size of this bridge group affect the potential rate of spread of STIs beyond the core and into the general population, as do disease prevalence and the types of mixing patterns within the bridged populations.11 For example, bridging between groups of similar prevalence is unlikely to substantially change overall population transmission. Similarly, bridging to a group with very low rates of partner change will have minimal impact on overall population prevalence.
Empiric data support the importance of concurrency (Table 1) and mixing (Table 2) in STI transmission, but there are few data concerning the extent of bridging and concurrency among African Americans in the South.
Differences in Sexual Network Patterns Between African Americans and Whites
Recent studies suggest that there are differences between blacks and whites in types of sexual network mixing patterns and prevalence of concurrency. The National Health and Social Life Survey found more dissortative mixing (partnerships between people of differential risk) among blacks than among whites. Specifically, African Americans with only one partner in the past year are 5 times as likely as whites to choose sexual partners from the core (persons who have had at least 4 partners in the past year). Moreover, the analysis indicated that STIs tend to remain within the black population because their partner choices are more segregated; blacks more often than other ethnic/racial groups tend to choose African Americans as partners.21 Concurrency also appears to be more frequent among African Americans, although published national-level data pertain only to women.22,23 The 5-year prevalence of concurrency among U.S. women between the ages of 15 and 44 years surveyed in the National Survey of Family Growth was 21% among blacks compared with 11% among whites and 8% among Hispanics. However, these differences appeared to be mainly the result of extremely low marriage rates among blacks. Racial differences markedly decreased after adjustment for marital status, age at time of interview, and age at first sexual intercourse.22
Concurrency and Bridging Among African Americans in North Carolina's General Population
We examined the prevalence of concurrency among African Americans from the general population in selected counties in eastern North Carolina, a predominantly rural region of the state.24 These counties were chosen because of their high prevalence of HIV and other STIs and relatively high proportion of African Americans. Respondents were interviewed between 1997 and 2000; those who reported a history of male same-sex behavior or injection drug use were excluded from the analyses.
The study's population, although less affluent than that of the overall North Carolina general population, was demographically similar to blacks in that region (Table 3). Almost one fourth of the men and more than one third of the women reported annual household income less than $16,000. Marriage rates were low (below 50%) and incarceration rates were high, a harsh reality for African Americans in the South and nationally.25–27 More than half of the women from this sample of the general population reported that at least one of their last 3 sex partners had been in jail or prison for more than 24 hours.24
Women reported substantially fewer partners during their lifetime than did men.24 Nevertheless, more than one fourth of women (and 42% of men) had multiple partnerships during the preceding year. These partnerships were often concurrent: 26% and 38% of respondents had concurrent partnerships during the preceding 1 and 5 years, respectively. Networks appeared dense; most respondents believed that at least one of their last 3 partners had sex with others while in a sexual relationship with the respondent, and women were more likely to report this than men.24 Almost all respondents had unprotected sex with at least one of their last 3 partners on numerous occasions, and a substantial proportion had been diagnosed with a sexually transmitted disease (STD) during their lifetime.28
The data highlight the potential for bridging between high-risk subgroups and the general population. Although the prevalence of substance abuse and sexual contact with injection drug users in this sample of the general population was relatively low, crack had clearly made significant inroads into the community; 15% of respondents believed it very likely that at least one of their last 3 partners had used the drug. A smaller proportion (7%) reported having exchanged sex for drugs, money, or a place to stay and 10% believed that a partner had done so.24
Individuals who either had high-risk characteristics themselves or had potentially high-risk sex partners were more likely to have concurrent partnerships (Table 4). For example, respondents who smoked crack, had been incarcerated themselves, who had a recent partner who had been incarcerated, or who believed that at least one of their last 3 partners had an STD were all more likely to have had concurrent partnerships during the past 5 years. Moreover, respondents who had concurrent partnerships were more likely to report that their sex partners also had other concurrent partnerships.24
Concurrency and Bridging Among African Americans With Recently Reported Heterosexually Transmitted HIV Infection
In a related population-based study, we surveyed approximately half of African Americans with recently reported heterosexually transmitted HIV infection in a number of North Carolina counties.29 These respondents (also interviewed between 1997 and 2000) differed from those surveyed in the general population in their lower educational attainment, lower marriage rates, and considerably higher prevalence of poverty and incarceration (Table 3). The HIV-infected study population experienced substantially higher rates of concurrency than did the general population sample; more than one third of the HIV-infected group had concurrent partnerships in the past year and more than half experienced them in the preceding 5 years.
Many respondents with heterosexually transmitted HIV infection likely represented the core group. Approximately one fourth of the women reported at least 3 partners during the preceding year and just over one fourth of the men reported at least 4 partners. A substantial proportion of respondents had recently received an STD diagnosis, many traded sex, and crack use was common. More than one fourth of cases, however, had no history of drug use or high-risk sexual behaviors, including sexual contact with persons they believed had used crack.28 In this lower-risk group, HIV infection was associated with having very low income, low education, and nonmonogamous partners.28
There were sexual bridges between the HIV-infected respondents and high-risk subpopulations.29 For example, although the respondents themselves had not used injection drugs, a substantial minority reported a partner who had done so. Almost half of respondents reported that at least one of their last 3 partners had very likely smoked crack, and 12% of women had a male partner whom they believed had sex with other men. As was found in the general population, individuals who had been incarcerated, reported incarceration of a recent partner, or smoked crack were more likely to have had concurrent partnerships during the past year.
In summary, a population-based survey of African Americans from the general population in North Carolina counties with high rates of STIs and heterosexually transmitted HIV infection revealed high concurrency rates. Concurrency was even more extensive among African Americans with heterosexually reported HIV infection. Sexual networks were dense, and there was evidence of connections to high-risk subgroups from both the general population and from HIV-infected persons who were otherwise not high risk. Such network patterns likely contribute to the high rates of STIs and heterosexual HIV transmission observed in this region.
Social Forces and Sexually Transmitted Infections in the South
Qualitative research further elucidates the social context and social forces that drive formation and maintenance of these networks. In preparation for the research described here, we conducted a series of focus groups in 1996 among 93 African American men and women between the ages of 18 and 59 in the study area to explore the study population's perceptions of societal forces on individuals' sexual behavior.30 Focus group participants, stratified by age group and sex, were roughly representative of eastern North Carolina's young and middle-aged African American residents in geographic residence, age, sex, income, and education. The views reported subsequently were unanimous among participants except when stated otherwise. The respondents reported extensive economic injustice and racial discrimination that constrained educational and employment opportunities, job advancement, and other aspects of their lives. Opinion varied about the role of education in their difficulties finding work. Although some respondents felt lack of a college education to be a major hindrance in their search for employment, others believed the effects of racial discrimination to be so overwhelming that no amount of education would afford blacks an opportunity for good employment in their community, and several noted the tendency of employment agencies to refer blacks for factory work and steer them away from white collar jobs.
Most respondents described community race relations as poor and reported residential and social segregation. They focused their concerns on their perceptions of institutional racism such as preferential hiring and job advancement of whites, blacks' inability to obtain mortgages, and academic tracking of black youth in schools. Respondents universally reported a scarcity of recreational outlets and cultural activities. Some attributed STI-related risk behaviors such as community substance abuse to boredom and absence of recreational outlets.
Respondents perceived a dramatic disparity in the ratio of available black men to women because of male attrition resulting from incarceration, drug addiction, or death. Some women noted gender inequality and women's perception (especially those who are poor or had low educational attainment) that they are dependent on men. Respondents described concurrent partnerships as widespread among unmarried men and indicated that the relative paucity of black men and the adverse socioeconomic plight of both black women and men profoundly affect partner selection, participation in sexual risk behavior, and the types of male sexual behavior women believe they must tolerate. Thus, their comments are consistent with the argument that racism, discrimination, and resultant economic and social inequity promote concurrency and possibly other mixing patterns such as bridging with high-risk subgroups that, in turn, promote HIV transmission.
Social sciences and public health literature support these observations. The social and economic context of life in the United States differs markedly for blacks and whites and affects individual sexual behaviors, community sexual networks, and resultant population transmission of HIV and other STIs.31 Eighteen of the 20 U.S. counties with the largest proportional increases in incidence rates of AIDS were in the southeastern United States. These counties, compared with those with smaller proportional increases in AIDS, had lower levels of income, education, and literacy as well as higher income inequality, concentration of ill health, and proportions of African Americans.32 Thomas et al examined social forces and outlined mechanisms through which they promote STIs in the southern United States.33,34 Several community features distinguished counties with high syphilis rates from those with lower than expected rates.34 Counties with high rates tended to have worse race relations with exclusion of minorities from positions of influence such as the county commission or board of health, lack of employment opportunities for minorities, lack of minority-owned businesses, and in some cases, evidence of systematic economic oppression.34
A detailed study of a rural North Carolina county with high STD rates revealed a number of social forces and contextual features that contributed to the county's dramatic racial disparity in STD rates. For example, changes in the national economy and agricultural trends had disproportionately affected black farmers with resultant migration of this population. Thomas et al documented substantial residential segregation with a quantitative residential black isolation index that was 15 standard errors above the state mean and significant income inequality between blacks and whites; the index of black–white income dualism was almost 2 standard errors above the state mean. Emigration (in addition to well-known causes of increased black male mortality) profoundly depressed the ratio of black men to women (sex ratio) in the county compared with the rest of the state. The authors interpreted these findings as indications that the county consisted of “two separate and unequal communities residing within the same political boundaries.”34
Pathways Between Contextual Forces and Sexual Networks
Pathways have been described through which these contextual forces influence individual sexual behaviors, sexual networks, and STI rates.35 Poverty depresses the pool of marriageable black men36 and is also associated with marital instability.37 As described by the focus group respondents, the low sex ratio places women at a disadvantage in negotiating and maintaining mutually monogamous relationships, because men can easily find another relationship if they perceive their primary one as problematic. Moreover, men who maintain concurrent partnerships may be confident that their primary partner will not end the relationship because primary relationships are relatively difficult for women to attain.33 Thus, a low sex ratio likely promotes concurrency31 and may also increase the likelihood of bridging between low-risk women and men from high-risk subpopulations. The high proportion of women from the general population with a recent partner who smoked crack supports this theory.
Residential segregation by race, a prominent feature of racial discrimination in the United States, effectively concentrates poverty and other adverse social and economic influences within the segregated group, thereby increasing its risk of socioeconomic failure through exposure to violence, poverty, and drugs.38 Residential segregation is an important factor in the structure of sexual networks because many people choose partners from their neighborhoods.39
The high rates of imprisonment of black men and women in the United States25,40,41 have dramatic effects on sexual networks among African Americans,35 and community incarceration rates strongly correlate with gonorrhea and chlamydia rates.42 Incarceration disrupts existing partnerships. The partner who remains behind in the community may pursue other partnerships to satisfy the social and sexual companionship lost by incarceration of the partner. Gorbach et al described “separational concurrency” as common among people whose partners are frequently incarcerated.43 In multivariate analysis of the general population sample, incarceration of a recent partner increased the odds of concurrency. In addition, the partner entering prison may join gangs, develop new long-term links with high-risk antisocial networks, and form new sexual connections in prison, where the HIV prevalence is estimated to be 8- to 10-fold higher than that of the general U.S. population.40 If inmates resume old sexual partnerships (as many do) on release, they may bridge lower-risk community partners to higher-risk contacts developed in prison.
In an area of the southern United States with high HIV rates, survey data revealed extensive concurrency, evidence of dense sexual networks, and sexual bridging between the general population and high-risk, high-prevalence subgroups—mixing patterns that efficiently transmit HIV throughout a population. Qualitative research revealed socioeconomic forces such as racial discrimination, low ratios of men to women, and deprivation of economic opportunities that inhibit stable sexual partnering and increase the likelihood of concurrent partnerships and other network patterns that increase the spread of HIV and other STIs. Taken together, these findings help explain the persistent and marked racial disparity in HIV/STI rates as well as the inability of individual-level interventions by themselves to resolve this disparity among African Americans in the South as well as elsewhere in the United States.
Pathways through which discrimination and inequality harm health have become increasingly clear.35,44 Future research should examine these pathways to further define their mechanisms and develop effective interventions, some of which may require societal changes. In recent years, incorporation of a human rights dimension to HIV prevention has been advocated, including acknowledgment of the right to nondiscrimination.45 Elimination of racial disparity in rates of HIV and other diseases in the South and throughout the United States will require redressing basic issues of human rights among African Americans.
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