WASHINGTON — Nearly 6 percent of black gay and bisexual men under age 30 are newly infected with HIV every year in the United States, three times the rate among white men of the same sexuality in the United States, according to the largest study ever to look at infection rates in this population.
The study, conducted in Boston and five other cities, was presented Monday at the 2012 International AIDS Conference. Overall, the infection rate among black gay and bisexual men over 18 was 1½ times the rate for their white counterparts, and the researchers said a lack of HIV testing in this population may be one reason.
“The rates of infection that we’ve documented in this study are higher than the rates of many countries in Africa,” Dr. Kenneth Mayer, medical research director of the Fenway Institute in Boston and a leader of the study, said in an interview before he presented the findings at the Washington meeting.
The study enrolled 1,553 black men who have sex with men, including 237 from the Boston area, between 2009 and 2011. Previous studies have examined only a few hundred participants, and very few have followed black gay and bisexual men for such a long period, AIDS specialists said.
The participants acquired HIV at a rate of 2.8 percent per year. Young men in the study became infected at a rate of 5.9 percent annually. Researchers in Atlanta, Los Angeles, New York, San Francisco, and Washington joined with the Fenway Institute to conduct the study.
The findings reinforce earlier data from the US Centers for Disease Control and Prevention showing that in 2009, black people accounted for 44 percent of new HIV infections in the United States, despite comprising only 12 percent of the general population. CDC data also suggest that young black men who have sex with men are one of the few groups continuing to see rapidly rising rates of new infections in recent years.
“Black men who have sex with men are engulfed in a raging generalized epidemic,” Phill Wilson, founder of the Black AIDS Institute, said during an opening session of the conference Monday. The Black AIDS Institute released its own report last week highlighting persistent HIV disparities for black men who have sex with men.
Researchers have struggled to explain elevated infection rates among this group, when evidence suggests that black gay and bisexual men are not more likely than their white counterparts to engage in risky sexual behaviors.
The new study collected data on a wide range of social, behavioral, economic, and medical factors that could help provide answers.
A large majority of the study population, 88.8 percent, believed they were uninfected or did not know their HIV status. Researchers discovered that 12 percent of these men already carried the virus at the beginning of the study, including three men who showed signs of advanced HIV.
Considering that less than 1 percent of the general US population is estimated to be HIV-positive, low rates of HIV testing may be a critical health risk for black men who have sex with men, the study suggests.
“People are much more likely to practice safer sex if they know that they’re infected,” said Mayer. “So if you have a lot of people who are assuming they’re not infected or unwilling to deal with it, these are people who are much more likely to transmit HIV to their partners.”
The researchers also found higher rates of poverty and unemployment among HIV-positive men. Participants newly diagnosed with HIV upon entering the study were six to seven times more likely to have multiple untreated sexually transmitted infections such as gonorrhea, chlamydia, and syphilis. These diseases can inflame the genital tract and increase a person’s risk of transmitting and acquiring HIV.
“What emerges is a picture of people who are alienated from the health care system,” said Mayer. The team is continuing to analyze the data to understand the social and economic barriers that may discourage black gay and bisexual men from getting tested and treated for HIV and other sexually transmitted infections.
“There’s not a simple narrative that explains why these differences exist,” said Mayer.
Preliminary evidence from the study corroborates previous findings that poverty, lack of education, or unemployment may keep black gay and bisexual men from getting necessary health services.
Some data suggest that these men may also face discrimination or stigma in health care settings. “This study really pulls everything together,’’ said Dr. Kevin Fenton, director of the National Center for HIV/AIDS, viral hepatitis, STD, and TB Prevention at the CDC. “All the things we knew were determinants, they were able to study it and follow them forward in time.’’
The next step, said Fenton, is to continue efforts to test and treat more black gay and bisexual men but to also address socioeconomic issues that may endanger the sexual health of this population.
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