- Category: HIV/AIDS Epidemiology & Mortality
- Published on Tuesday, 07 August 2012 00:00
- Written by Liz Highleyman
African-American gay and bisexual men in U.S. cities have a significantly higher likelihood of becoming infected with HIV despite the fact that they do not engage in more high-risk sex or drug use, according to studies presented at the recent XIX International AIDS Conference (AIDS 2012) in Washington, DC, and in an HIV-theme issue of The Lancet.
For several years epidemiological studies have shown that rates of HIV prevalence (total cases) and incidence (new infections) are higher among African Americans compared with other racial/ethnic groups in the U.S. According to the Centers for Disease Control and Prevention (CDC), young black MSM saw a 48% increase in new HIV infections between 2006 and 2009.
A set of studies presented at the conference shed further light on this disparity, which is particularly evident among young black men who have sex with men (MSM).
HIV Prevention Trials Network (HPTN) Study 061 was the largest-ever longitudinal study of black MSM in the U.S. Kenneth Mayer from the Fenway Institute in Boston and Beryl Koblin from the New York Blood Center Laboratory of Infectious Disease Prevention presented results from HPTN 061 at an oral abstract session, and Koblin and study co-chair Darrell Wheeler from Loyola University in Chicago discussed the findings at a press conference on July 23.
HPTN followed 1553 self-identified black MSM in 6 cities (Atlanta, Boston, New York City, Los Angeles, San Francisco, and Washington, DC) between 2009 and 2011. They received HIV and sexually transmitted infection (STI) testing and completed in-person and computer interviews. Those found to be HIV negative were followed up at 6 and 12 months, and those testing positive were linked to care.
Participants were considered at risk for HIV infection, reporting unprotected anal sex with a man during the past 6 months. About one-third were 30 years of age or younger, most were low-income, about 30% were employed, just under half had some college education, one-fifth were currently students, and 60% had a history of incarceration. About 40% self-identified as gay/homosexual and a similar percentage as bisexual, while about 10% said they were straight/heterosexual; 2% identified as transgender.
- About 10% of participants reported a prior HIV diagnosis.
- 12.4% of men who thought they were HIV negative or had never been tested were newly diagnosed with HIV at study entry.
- Overall, 2.8% of black gay and bisexual men were infected with HIV annually during follow-up -- nearly 50% higher than the rate for white MSM.
- Among young MSM age 18-30, the incidence rate was higher at 5.9% -- 3 times higher than the rate for white MSM.
- Men who identified as gay or said they had sex only with men had a higher infection risk than men said they were bisexual or reported sex both with men and women (about 4% vs 1.5%, respectively).
- Newly diagnosed men were younger, less likely to use marijuana and other drugs, more likely to have certain STIs, and reported less religious affiliation and less internalized homophobia than men who already knew they were HIV positive.
- Factors associated with becoming HIV infected, relative to men who remained negative, included unprotected anal intercourse (HIV incidence rate of 4.9%), having another sexually transmitted infection, and unemployment.
- Substance use, however, was not an independent risk factor for HIV infection.
"Given the high rates of HIV infection among black MSM, culturally-tailored programs that encourage repeated HIV/[STI] testing, engagement in care, and innovative prevention strategies addressing current risks are urgently needed to decrease further spread," the researchers concluded.
Wheeler explained that biological, behavioral, and social-environmental factors come together to influence high rates of HIV among black gay and bisexual men, and effective interventions must address all 3 areas.
Previous or current STIs are a key biological factor, he said; 14% of study participants were found to have an STI at baseline. Social and economic factors he cited included poverty, less education, lack of employment, poorer health care, incarceration, stress, internalized homophobia, "fewer systemic resources," and higher community viral load.
Eli Rosenberg from Emory University's Rollins School of Public Health and colleagues sought to learn more about the apparently paradoxical finding that differences in individual risk behavior do not explain the large disparities in HIV prevalence and incidence between black and white MSM in the U.S.
The InvolveMENt study is an ongoing cohort study of more than 700 sexually active black and white gay and bisexual men in Atlanta, age 18-40, looking at individual, dyadic (couple- or partner-level), and community-level factors that might help explain these disparities. Participants were recruited from community venues, underwent HIV testing, and completed surveys.
The researchers developed an index dubbed "transmission potential prevalence" (TPP), representing the proportion of individuals in a community with viral load presumed to be high enough to allow HIV transmission (which they set at 400 copies/mL).
- Black MSM had a 3-fold higher HIV prevalence than white men, 42% vs 14%, respectively.
- 25% of black men were HIV positive with a viral load > 400 copies/mL, compared with 8% of white men.
- Black and white men both reported the same number of anal sex partners -- a median of 2 -- during the past year.
- Looking at TPP, the researchers estimated that the average annual probability of having at least 1 sex partner with transmission potential was 39% for black MSM compared with 18% for white MSM, a significant difference.
- They further estimated that black MSM would have to engage in unprotected anal sex with 3 men to have a 50% chance of encountering a partner with transmission potential, while the corresponding number for white MSM was 7 partners.
- To reach a 90% risk of encountering a partner with transmission potential, the numbers would be 10 for black men versus 25 for white men.
"HIV negative black MSM have comparable risk behaviors, but have a substantially higher likelihood of encountering a [unprotected anal intercourse] partner with viral load > 500 copies/mL," the investigators concluded. "Our results suggest a limited ability of behavioral interventions to eliminate racial disparities, and support the need to increase HIV testing with linkage to care and antiretroviral treatment of all HIV positive MSM to reduce the risk of HIV transmission from sex partners."
As described in the July 28, 2012, issue of The Lancet, Gregorio Millett from the CDC and Office of National AIDS Policyand colleagues performed a meta-analysis of nearly 200 studies to assess factors associated with disparities in HIV infection among black MSM in the U.S., Canada, and the U.K.
The researchers searched Embase, Medline, Google Scholar, and online conference proceedings from January 1, 1981, through December 31, 2011, selecting racial comparison studies with quantitative outcomes associated with HIV risk or infection.
They identified 174 studies from the U.S., 13 from the U.K., and 7 from Canada. Summary odds ratios (OR) were calculated for a total of 106,148 black MSM and a comparison population of 581,577 MSM of other racial/ethnic groups.
- Black MSM in the U.K. were nearly twice as likely to be HIV positive as non-black MSM (OR 1.86), and in the U.S. they were 3 times more likely (OR 3.00).
- Young black men (under age 30) were about 5 times more likely to have HIV than non-black men, but were more likely to be undiagnosed.
- Overall, black MSM were more likely to have been tested for HIV, as well as more likely to have had more than 1 test.
- In each country, black MSM were somewhat less likely to engage in any unprotected anal intercourse thannon-black MSM, while both groups were similarly likely to engage in unprotected sex with serodiscordant partners.
- Black MSM were less likely to have a high number of sex partners, either in total or during the past year.
- Young black men, however, were more likely than young white men to have sex with older partners.
- Black men were about 1.5 times more likely to report transactional sex.
- They were nearly twice as likely as white men to report childhood sexual abuse.
- Black and white MSM were equally likely to be circumcised.
- Black MSM were significantly more likely to have an STI than non-black men.
- U.S. black MSM were more likely to report taking preventive measures against HIV infection (OR 1.39), and black men were twice as likely to report using condoms.
- Black men in the U.S. and Canada were about half as likely than non-black men to have a history of substance use, including alcohol, marijuana, and injection drugs (OR 0.67 for the U.S., 0.53 for Canada).
- HIV positive black MSM in each country were less likely to start combination antiretroviral therapy than non-black MSM.
- HIV positive black MSM in the U.S. were half as likely to have health insurance and saw healthcare providers less often than non-black MSM.
- Black men also more likely to have a low CD4 T-cell count (< 200 cells/mm3), less likely to achieve good adherence to antiretroviral treatment, and less likely to have undetectable viral load.
- Black MSM were twice as likely as non-black MSM in the U.S. to face structural barriers that increase HIV risk, such as unemployment, low income, previous incarceration, and less education.
"Similar racial disparities in HIV and sexually transmitted infections and combination ART initiation are seen in MSM in the U.K. and the U.S.A.," the study authors concluded. "Elimination of disparities in HIV infection in black MSM cannot be accomplished without addressing structural barriers or differences in HIV clinical care access and outcomes."
"The HPTN 061 study results are part of an HIV prevention narrative that consistently continues to show that Black MSM are exceedingly vulnerable," said Ben Perkins, HPTN 061 project director at the Fenway Institute in Boston, in a Fenway press release.
"The truth is that these troubling HIV infection rates are associated with underlying issues of stigma, discrimination, joblessness, homelessness, incarceration, and trauma," he continued. "Any attempts to address the HIV problem will, therefore, by necessity, need to tackle these issues in order to make a real and lasting impact in the epidemic."
"We found that the men had many unmet medical and social service needs," added Mayer. "There is an urgent need to focus resources to address these high rates of HIV infection as part of the larger national strategy to combat the AIDS epidemic."
"The HPTN 061 study findings are a sobering wake-up call," said HPTN co-principal investigator Wafaa El-Sadr from Columbia University's Mailman School of Public Health in an HPTN press release. "These results, and others to be garnered from further analysis of the study, highlight the enormity of the challenges ahead and offer important insights into how to design research studies and programs for prevention of HIV among black MSM."
The HPTN backgrounder noted that the overall infection rate among black MSM in HPTN 061 is "comparable to the rate seen in the general populations of countries in sub-Saharan Africa hardest hit by the HIV epidemic."
Coinciding with the conference, the Black AIDS Institute released a new report on HIV/AIDS in black MSM entitled, Back of the Line: The State of AIDS Among Black Gay Men in America 2012.
"No population in the entire developed world has been more heavily affected by HIV/AIDS than Black MSM, who represent among the most heavily affected group in the entire world," according to the report. "HIV represents a lifelong challenge for Black MSM, with a 40-year-old Black gay man facing roughly 60% odds of being HIV-infected."
"Today, there is greater hope than ever for progress against AIDS, as antiretroviral therapy reduces the odds of HIV transmission by 96%," the report continues. "Indeed, with recent biomedical breakthroughs, we now have the means to end the AIDS pandemic -- for all populations and in all settings, including among Black MSM here in the U.S."
"Without a major change of direction, however, Black MSM will not benefit from recent research breakthroughs," the report concludes. "A high-priority, multi-faceted, multi-stakeholder national plan is urgently needed to address the spiraling HIV crisis among Black MSM. This plan needs to ensure Black MSM’s full and equitable access to essential services, correct imbalances in resource allocation, and combat homophobia and other social and economic issues that increase vulnerability and reduce health care access."
Analysis of HPTN 061 and its implications by Kenyon Farrow for the Black AIDS Institute
[Interview with Gregorio Millett, CDC and Office of National AIDS Policy]
[Interview with Sheldon Fields, College of Nursing and Health Sciences, Florida International University]
K Mayer, L Wang, B Koblin, D Wheeler et al (HPTN 061 Study Team). An evolving concentrated epidemic: comparison of socioeconomic, behavioural and biological factors among newly diagnosed, previously diagnosed and HIV-negative black men who have sex with men in six US cities (HPTN 061). XIX International AIDS Conference (AIDS 2012). Washington, DC, July 22-27, 2012. Abstract MOAC0105.
B Koblin, K Mayer, S Eshelman, D Wheeler, et al (HPTN 061 Study Team).Correlates of HIV incidence among black men who have sex with men in 6 U.S. cities (HPTN 061). XIX International AIDS Conference (AIDS 2012). Washington, DC, July 22-27, 2012. Abstract MOAC0106.
E Rosenberg, C Kelley, B O'Hara, et al. Equal behaviors, unequal risks: the role of partner transmission potential in racial HIV disparities among men who have sex with men (MSM) in the US. XIX International AIDS Conference (AIDS 2012). Washington, DC, July 22-27, 2012.Abstract MOAC0101.
GA Millett, JL Peterson, SA Flores, et al. Comparisons of disparities and risks of HIV infection in black and other men who have sex with men in Canada, UK, and USA: a meta-analysis. The Lancet 380(9839):341-348. July 28, 2012 (Epub July 20, 2012).
Black AIDS Institute. Back of the Line: The State of AIDS Among Black Gay Men in America 2012.
HIV Prevention Trials Network. New Study Finds Greatly Elevated HIV Infection Rates among Young Black Gay and Bisexual Men in the U.S. Press release. July 23, 2012.
National Institutes of Health. NIH-Funded Study Finds High HIV Infection Rates among Gay and Bisexual Black Men in the U.S. Press release. July 23, 2012.
National Black Gay Men’s Advocacy Coalition. Pivotal Prevention Trial Highlights Critical Challenges for Black Gay Men. Press release. July 23, 2012.