- Category: HIV/AIDS Epidemiology & Mortality
- Published on Friday, 01 October 2010 18:36
- Written by Liz Highleyman
Nearly 20% of gay and bisexual men in a survey of 21 large U.S. cities are infected with HIV, but more than 40% do not know their status, according to a report in the September 24, 2010 edition of the CDC's Morbidity and Mortality Weekly Report. HIV prevalence varied widely across cities -- from 6% to 38% -- and was highest among black men who have sex with men, at 28%, compared with 18% among Hispanic men and 16% among white men.
A. Smith and colleagues from the Centers for Disease Control and Prevention (CDC) Division of HIV/AIDS Prevention collected data about HIV prevalence rates among men who have sex with men (MSM) from the National HIV Behavioral Surveillance (NHBS) system.
MSM accounted for 57% of all new HIV infections in the U.S. in 2006, the report authors noted as background, despite making up only an estimated 10% or so of the population.
The analysis included more than 800 men in 21 metropolitan statistical areas surveyed during 2008. Anonymous interviews and blood tests were done at venues where MSM gather, such as bars, clubs, and social organizations. Researchers conducted interviews using a handheld computer and asked questions about sex, drug use, HIV testing, and use of HIV prevention services.
Eligible participants were age 18 or older and able to complete the interview in English or Spanish. Participants could self-identify as gay, bisexual, same-gender-loving, straight, or other, but had to have had sex with a man during the past 12 months.
A total of 28,468 men were approached, 12,325 were screened for participation, and 11,074 were found to be eligible for the survey. Of these, 2921 were excluded for various reasons including lack of consent, not having sex with a man within the 1-year time frame, and having an indeterminate HIV test result. This left a total of 8153 men in the final analysis.
- Overall HIV prevalence, or total infections, across all cities in 2008 was 19%.
- The highest prevalence city was Baltimore, at 38%, while the lowest was Atlanta, at 6%.
- Early epicenters of the epidemic had rates in the upper-middle range, including San Francisco (23%), Chicago (19%), and Los Angeles (19%), though New York City remained high at 29%.
- Several higher-prevalence cities were in the south, including Dallas (26%), Houston (26%), Miami (25%), and New Orleans (21%).
- Washington, DC -- often cited as one of the most heavily impacted areas -- had a prevalence rate below the national average, at 14%.
- Prevalence rates for men who said they were homosexual, bisexual, and heterosexual were 19%, 18%, and 8%, respectively.
- HIV prevalence generally rose with age, falling off only in the oldest group:
- 18-19 years: 7%;
- 20-24 years: 12%;
- 25-29 years: 15%;
- 30-39 years: 21%;
- 40-49%: 28%;
- 50 years or older: 25%.
- Prevalence rates varied widely across racial/ethnic groups:
- Black (non-Hispanic): 28%;
- Hispanic/Latino: 18%;
- American Indian/Alaska-Hawaii native/Pacific Islander: 18%;
- White (non-Hispanic): 16%;
- Asian: 8%;
- Other, including mixed race: 21%.
- Prevalence rates fell as education level rose, from 25% for men with less than a high school diploma to 14% for college graduates.
- Prevalence also fell as income increased, from 26% for men with annual household incomes of $19,999 or less to 14% among those with incomes of $75,000 or more.
- Men who had never received an HIV test before the survey had a prevalence of 14%, compared with 13% for those tested within the past year and 32% for those tested more than a year ago.
- Overall, 44% of the men who tested HIV positive in the survey did not know they were infected.
- 39% of homosexual men knew their HIV status, compared with 63% of men who said they were bisexual or heterosexual.
- Lack of knowledge of HIV status was especially high among young men, 75% for those age 18-19, and 68% for those age 20-24 years.
- 59% of black men were unaware they were HIV positive, compared with 46% of Hispanics, 43% of Asians, and 26% of white men.
- Men with more education and higher incomes were more likely to known their HIV status.
- Men with and without health insurance were equally likely to be HIV positive (both 19%), but those without were less likely to know their status (37% vs 57%).
- Looking only at the 5 cities included in the previous NHBS in 2004-2005 (Baltimore, Los Angeles, Miami, New York, and San Francisco), the 2008 prevalence was 27%, similar to the 2004-2005 prevalence of 26%.
"Because MSM represent the only group with increasing HIV incidence and comprise the largest proportion of new infections, it is critical to target resources and prevention strategies to MSM," the study authors wrote. "The National HIV/AIDS Strategy emphasizes the importance of improving the impact of HIV prevention efforts for MSM. "
"The high proportion of MSM unaware of their HIV infection continues to be a serious public health concern, because these MSM account for the majority of estimated new HIV transmissions in the United States," they continued. "Persons aware of their HIV infection often take substantial steps to reduce their risk behaviors, which could reduce HIV transmission."
The CDC recommends that sexually active MSM get tested for HIV at least once per year.
"Many gay and bisexual men do not get tested or retested regularly because they are afraid they may be infected, yet this hinders life-saving treatment and puts their partners at risk," said CDC Division of HIV/AIDS Prevention director Jonathan Mermin. "Stigma, homophobia, and discrimination are real issues that may prevent gay and bisexual men from accessing the prevention and treatment resources they need."
A Smith, I Miles, B Le, and others (Centers for Disease Control and Prevention). Prevalence and Awareness of HIV Infection Among Men Who Have Sex With Men -- 21 Cities, United States, 2008. Morbidity and Mortality Weekly Report 59(37): 1201-1207 (Abstract). September 24, 2010.
J Mermin. September 27, 2010 is National Gay Men's HIV/AIDS Awareness Day. CDC e-HAP Direct Update. September 24, 2010.
Kaiser Family Foundation. CDC: One In Five Gay Men HIV-Positive. Kaiser Daily Health Policy Report. September 24, 2010
D DeNoon. CDC Study Shows Gay/Bisexual African-Americans, Young Adults Least Aware of HIV Status. WebMD. September 23, 2010.
M Smith. HIV Prevalence Remains High Among Gay Men. MedPage Today. September 23, 2010.
D O'Neill. HIV Remains a Gay Disease. Washington Blade. September 23, 2010.