We examined how drugs, high-risk sexual behaviors, and socio-demographic variables are associated with recent HIV infection among men who have sex with men (MSM) in a case-control study. Interviewers collected risk factor data among 111 cases with recent HIV infection, and 333 HIV-negative controls from Chicago and Los Angeles. Compared with controls, cases had more unprotected anal intercourse (UAI) with both HIV-positive and HIV-negative partners. MSM with lower income or prior sexually transmitted infections (STI) were more likely to be recently HIV infected. Substances associated with UAI included amyl nitrate ("poppers"), methamphetamine, Viagra (or similar PDE-5 inhibitors), ketamine, and gamma hydroxybutyrate (GHB). Cases more frequently used Viagra, poppers, and methamphetamine during UAI compared with controls. In multivariate analysis, income, UAI with HIV-positive partners, Viagra, and poppers remained associated with recent HIV seroconversion. Better methods are needed to prevent HIV among MSM who engage in high-risk sex with concurrent drug use.

People who inject drugs (PWID) are at high risk for blood-borne pathogens transmitted during the sharing of contaminated injection equipment, particularly hepatitis C virus (HCV). HCV prevalence is influenced by a complex interplay of drug-use behaviors, social networks, and geography, as well as the availability of interventions, such as needle exchange programs. To adequately address this complexity in HCV epidemic forecasting, we have developed a computational model, the Agent-based Pathogen Kinetics model (APK). APK simulates the PWID population in metropolitan Chicago, including the social interactions that result in HCV infection. We used multiple empirical data sources on Chicago PWID to build a spatial distribution of an in silico PWID population and modeled networks among the PWID by considering the geography of the city and its suburbs. APK was validated against 2012 empirical data (the latest available) and shown to agree with network and epidemiological surveys to within 1%. For the period 2010–2020, APK forecasts a decline in HCV prevalence of 0.8% per year from 44(±2)% to 36(±5)%, although some sub-populations would continue to have relatively high prevalence, including Non-Hispanic Blacks, 48(±5)%. The rate of decline will be lowest in Non-Hispanic Whites and we find, in a reversal of historical trends, that incidence among non-Hispanic Whites would exceed incidence among Non-Hispanic Blacks (0.66 per 100 per years vs 0.17 per 100 person years). APK also forecasts an increase in PWID mean age from 35(±1) to 40(±2) with a corresponding increase from 59(±2)% to 80(±6)% in the proportion of the population >30 years old. Our studies highlight the importance of analyzing subpopulations in disease predictions, the utility of computer simulation for analyzing demographic and health trends among PWID and serve as a tool for guiding intervention and prevention strategies in Chicago, and other major cities.

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HIV-related risk behaviors, prevalence, and estimated incidence density for adolescent SMM were high, especially for minority SMM. Our findings suggest that initiating intervention efforts early may be helpful in combating these trends.

Young men who have sex with men (YMSM) are disproportionately impacted by HIV/AIDS and have elevated rates of substance use. Parenting practices, such as knowledge of child whereabouts and monitoring of behavioral rules, protect against these outcomes among heterosexual youth. This article examined the relationship between these parenting practices and substance use and HIV risk behaviors among YMSM. Data are reported from three similar studies of YMSM: ChiGuys (ages 14-18), Crew 450 (ages 16-22), and RADAR (ages 16-29). The ChiGuys and RADAR studies report cross-sectional analyses, whereas Crew 450 reports latent growth curve analyses. In ChiGuys and Crew 450, participants reported significantly higher scores for parental knowledge of general activities than parental knowledge of gay-specific activities. Parental knowledge of general activities was significantly associated with less binge drinking in both samples and with condomless sex in the ChiGuys sample. Parental monitoring was significantly associated with less marijuana use and condomless sex in younger RADAR participants (16-18 years) and with less drug use in older participants (>18 years). Findings support the need for further research on the influences of parents on YMSM health risk behaviors and the value of exploring family- and parent-interventions to address YMSM health.