Characteristics Associated With HIV Infection Among Heterosexuals in Urban Areas With High AIDS Prevalence -- 24 Cities, United States, 2006-2007
August 12, 2011
In the United States, approximately one in three new human immunodeficiency virus (HIV) infections are transmitted via heterosexual contact.1 To monitor HIV risk behaviors and HIV prevalence among heterosexuals and other populations, CDC surveys persons in selected metropolitan statistical areas (MSAs), using the National HIV Behavioral Surveillance System (NHBS). This report summarizes data collected from heterosexuals in 24 MSAs with a high prevalence of acquired immunodeficiency syndrome (AIDS) that participated in NHBS during 2006-2007. Of 14,837 heterosexuals aged 18-50 years who were interviewed and tested, 2.0% were HIV infected. HIV prevalence was higher among those with lower socioeconomic status (SES). For example, HIV prevalence was 2.8% among participants with less than a high school education compared with 1.2% among those with more than a high school education, 2.6% among participants who were unemployed compared with 1.0% among those who were employed, and 2.3% among participants with annual household incomes at or below the poverty level compared with 1.0% among those with incomes above the poverty level. This association between HIV prevalence and SES could not be attributed to factors commonly associated with HIV infection risk in heterosexuals, such as using crack cocaine, exchanging sex for things such as money or drugs, or being diagnosed with a sexually transmitted disease (STD). Based on the association observed between HIV prevalence and SES, HIV prevention activities targeted at heterosexuals in urban areas with high AIDS prevalence should be focused on those with lower SES.
NHBS is an annual cross-sectional survey of three populations at high risk for HIV infection: men who have sex with men (MSM), injection-drug users (IDUs), and heterosexuals at increased risk for HIV infection. Data are collected in annual cycles from one risk group per year, with each population surveyed once every 3 years. This report describes the first NHBS survey among heterosexuals, conducted from September 2006 to October 2007. Twenty-five MSAs with high AIDS prevalence were selected for the survey. In each MSA, NHBS project staff members recruited participants using either respondent-driven sampling (15 MSAs) or venue-based sampling (10 MSAs).2* Recruitment efforts targeted residents of census tracts with high rates of poverty and HIV diagnoses, referred to as high-risk areas. For respondent-driven sampling, a small number of initial participants were recruited by project staff members or referred by community-based organizations. Initial and subsequent participants who lived in high-risk areas were then asked to recruit up to five other persons using a coded coupon to track their referrals. Recruitment continued for multiple waves of peer referral.
For venue-based sampling, project staff members from each MSA selected five to 10 high-risk areas in which they identified venues (e.g., retail businesses, social organizations, restaurants, bars, and parks) attended by local residents, as well as the days and times when the venues were frequented. Project staff members then randomly chose venues where they would recruit participants and the days and times when recruitment would occur. At the venues, persons who entered a designated area were approached and invited to participate in the survey. For both recruitment methods, persons were eligible to participate if they were aged 18-50 years, residents of the MSA, able to complete the survey in English or Spanish, and had sex with an opposite-sex partner during the 12 months before interview. Residency in a high-risk area was not an eligibility criterion. After participants provided informed consent, interviewers administered an anonymous survey using a handheld computer. All participants were offered anonymous HIV testing in accordance with CDC and local testing guidelines. Participants were compensated for their time taking the survey ($20-$30) and, when applicable, for taking the HIV test ($10-$25).
Final data were available from 24 MSAs.† Because outcomes did not differ between respondent-driven and venue-based sampling, data were combined and analyzed as a single sample for this report. Univariable and multivariable regression models§ were used to test associations with HIV prevalence and to calculate prevalence ratios, adjusted prevalence ratios,¶ and 95% confidence intervals.
Of 22,169 persons recruited to participate, 18,377 (83%) were eligible and completed the survey. To limit the analysis to non-IDU heterosexuals, persons were excluded if they acknowledged ever injecting drugs (2,224 persons), having male-male sex (413), both injecting drugs and having male-male sex (309), or if they refused to provide this risk information (five). Persons also were excluded if they did not consent to HIV testing (374), did not have a negative or confirmed positive HIV test result (210), or reported being HIV-positive but, when tested, were HIV-negative (five).
Of the 14,837 survey participants who met the analysis criteria, 57% were women, and 48% were aged ≤29 years (Table). The majority of participants were black (72%) or Hispanic** (18%); the remainder were white (5%) or of other races (4%). SES among participants was low; 31% had less than a high school education, 36% were unemployed, 73% had annual household incomes at or below the poverty level,†† and 19% were homeless. In the 12 months before their interview, 11% had used crack cocaine, 12% had exchanged sex for things such as money or drugs, and 14% had received an STD diagnosis.
Overall, 294 (2.0%) of the 14,387 participants tested positive for HIV infection, and HIV prevalence was similar among men (1.9%) and women (2.1%) (Table). HIV prevalence was higher in the Northeast (3.1%) and South (2.7%) compared with the Midwest (0.9%), West (0.8%), and Territories (0.7%). By race/ethnicity, HIV prevalence was highest among blacks (2.1%), followed by Hispanics (1.8%), persons of other races (1.4%), and whites (1.1%). Only the difference between blacks and whites was statistically significant, but after controlling for all other characteristics in the analysis, this difference was no longer significant. Moreover, among the 10,451 (73%) participants who lived in high-poverty areas (i.e., census tracts in which ≥20% of residents had an annual household income below the U.S. poverty level), no significant differences in HIV prevalence by race/ethnicity were observed: Hispanics (2.4%), persons of other races (2.4%), blacks (2.3%), and whites (1.8%) (chi-square, p=0.89).
HIV prevalence was associated with SES. For example, HIV prevalence was higher among participants with less than a high school education (2.8%) compared with high school graduates (1.9%) and those with more than a high school education (1.2%), higher among participants who were unemployed (2.6%) than those who were employed (1.0%), higher among participants with annual household incomes at or below the poverty level (2.3%) compared with those with incomes above the poverty level (1.0%), and higher among participants who were homeless (3.1%) than those who were not (1.7%) (Table). After controlling for the other characteristics in the analysis, HIV prevalence was significantly higher among persons who had less than a high school education (compared with those who had more than a high school education), were unemployed (compared with those who were employed), and had annual household incomes ≤$9,999 (compared with those with incomes of $10,000-$49,999).
By HIV risk factor, HIV prevalence was higher among participants who used crack cocaine (4.5%) compared with those who did not (1.7%), participants who exchanged sex for things such as money or drugs (3.4%) compared with those who did not (1.8%), and participants who had received an STD diagnosis (4.0%) compared with those who had not (1.7%) (Table). However, among these three common HIV risk factors, only an STD diagnosis was associated with higher HIV prevalence after controlling for the other characteristics in the analysis.
Reported by: Paul H. Denning, M.D., Elizabeth A. DiNenno, Ph.D., Ryan E. Wiegand, M.S., Div of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, CDC. Corresponding contributor: Paul H. Denning, email@example.com, 404-639-2963.
This article was provided by U.S. Centers for Disease Control and Prevention. Visit the CDC's website to find out more about their activities, publications and services.
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