DRUG ABUSE, HIV, AND SEXUAL RISK BEHAVIORS
Behavioral Risk and HIV-1 Molecular Diversity: Making the Connections
Chris C. Beyrer, M.D., M.P.H., Sodsai Tovanabutra, Ph.D., Gustavo Kijak, Ph.D., Teerada Sripaipan, M.H.S., Eric Sanders-Buell, Ph.D., Kittipong Rungruengthanakit, M.A., Jaroon Jittiwutikarn, M.D., David D. Celentano, Sc.D., M.H.S, and Francine E. McCutchan, Ph.D.
HIV-1 is a highly, genetically diverse pathogen, and its genetic diversity is increasing. Advances in epidemiologic understanding and in the full-length genetic sequencing of HIV-1 suggest that risk behaviors may play critical roles in the genetic diversity of the pandemic and may have important implications for HIV prevention, vaccine research, and eventual epidemic control. Individual-level risk behaviors and network-level interactions may play critical roles in the risk of dual-infection, super-infection, and HIV-1 intersubtype recombination. We investigated these interactions in the opiate users research (OUR) cohort in northern Thailand where CRF01_AE, subtype B, as well as unique and circulating recombinant forms (CRFs) have been detected. Recent work among sexual risk populations in East Africa and analyses linking Thai, Chinese, and Burmese epidemics suggest that risk dynamics may play similar roles in HIV-1 genetic complexity in epidemics driven by sexual, as well as injection drug use, risks.
The OUR study was conducted among 2,231 volunteers in Chiang Mai, Thailand, between 1999 and 2001. Serum samples from 347 participants who were HIV-1 seropositive at baseline were analyzed by the RT-PCR amplification of HIV-1 genome fragments and subtyping in 6–8 genome regions per strain with the Multiregion Hybridization Assay MHAbce v.2. The assay distinguishes subtypes from recombinant forms and detects dual infections. Social and demographic variables and risk behavior were assessed using a structured questionnaire administered in a confidential, face-to-face interview.
Among the 336 (96.8 percent) samples that were typed, 81.8 percent were CRF01_AE; 3.9 percent were subtype B; and 9.2 percent were recombinants, most combining CRF01_AE and subtype B. Dual infections were detected in 5.1 percent of subjects. Subtype B was more frequent among participants 30 years or older (OR=6.92, 95-percent confidence interval [CI]: 1.51–31.73). Dual infections were more frequent among those with a lower education level (OR=5, 95-percent CI: 1.39–17.51) and among those who had initiated injecting in the past 3 years (OR=3.41, 95-percent CI: 1.19–9.79). Recombinant strains and dual infections were more frequent among those who reported frequent needle-sharing in the past 3 months (OR=4.08, 95-percent CI: 1.42–11.73).
Dual infections were associated with those possessing longer injection histories and among injection drug users (IDUs) reporting more frequent and recent needle-sharing. Early intervention aimed at a reduction in needle-sharing, especially among new IDUs, might help limit the increasing complexity of HIV-1 strains. Data from the region, and from East Africa, suggest that these risk dynamic and genetic interactions may have regional implications.
Alcohol and HIV Risk Behaviors
Michael D. Stein, M.D.
Worldwide, alcohol is the most commonly used psychoactive substance. Since the early 1900s, alcohol use has been associated with sexual behavior that places people at risk for sexually transmitted infections. This implied causal association can now be rigorously investigated across a variety of populations. This presentation (1) discusses the pertinent methodological issues in alcohol use and sexual risk research, (2) describes the approaches to investigating the connection of alcohol and sexual risk, (3) presents event-level data from one Daily Diary study in South Africa, (4) provides a conceptual model of alcohol use in sexual situations, and (5) examines the intervention strategies that may offer future directions in research and clinical care.
Methamphetamine Use and HIV
Grant N. Colfax, M.D.
Methamphetamine use is a driving force in the HIV epidemic. Methamphetamine is associated with increased unprotected sex acts, increased numbers of partners, and increased risk for HIV infection. Among men who have sex with men (MSM), methamphetamine use is at least 10 times more prevalent than among the general population. Most methamphetamine-using MSM are infrequent users (< weekly), and the majority do not inject. Methamphetamine use doubles to triples the risk of HIV infection. Longitudinal cohort studies report that methamphetamine is independently associated with HIV seroconversion, even after controlling for other behavioral risk factors, including the numbers of sexual partners and unprotected sex acts. Although the direct effects of methamphetamine on HIV disease progression remain to be determined, methamphetamine users on antiretroviral therapy have higher viral loads compared to nonmethamphetamine users, after controlling for medication adherence. Among persons with recent HIV infection, methamphetamine has been associated with primary drug resistance. Entering drug treatment and participating in methamphetamine-specific treatment interventions are associated with decreases in sexual risk and methamphetamine use. However, most programs have been tested among treatment-seeking, frequent methamphetamine users. The majority of methamphetamine-using MSM have not been in drug treatment, indicating a continued need to develop new interventions and to expand on those already shown to be efficacious in reducing both methamphetamine use and HIV risk.