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The Mutlilevel Influences on HIV and Substanc eUse in YMSM Cohort (RADAR) seeks to identify and understand the connections between sexually transmitted infections, substance use, and romantic relationship patterns over time among young men who have sex with men.


  • Understand how syndemics of substance use, HIV, STIs, mental disorders, and violence develop among YMSM using an accelerated longitudinal design.We will assess youth every 6 months during the transition from late adolescence to early adulthood, to describe the trajectories of syndemic development (including substance use) and use innovative statistical modeling to characterize different trajectories of syndemic development to predict youth most at risk of HIV acquisition.
  • Determine how dyadic processes influence HIV risk behaviors and transmission among YMSM by enrolling their serious sexual partners into the cohort. We will utilize dyadic data to identify which sexual partner and relationship factors are longitudinally related to unprotected sex and HIV/STI transmission across development. Phylogenetic analyses will link HIV transmissions within dyads to determine what behavioral, partner and dyadic factors predict such transmission.
  • Describe network and structural influences on syndemic development among YMSM. We will examine how sexual and drug use network structures explain racial disparities in HIV transmission, including network size, density, concurrency, and homophily. We will conduct ecological resource mapping to understand how access to resources impacts the HIV epidemic in YMSM, and how neighborhood resources and HIV prevalence impact HIV incidence.
  • Determine if, and how, substance use increases HIV acquisition risk and viral set point. We hypothesized that substance use is associated with (a) acquiring HIV, (b) elevating viremia set point, and (c) evading host defenses early during incident HIV infections (HIV adaptation). We will build arepository of specimens/data before, during, and after incident HIV to facilitate collaborative studies.

Current Research

  • Focus on PrEP (pre-exposure prophylasis) uptake and discontinuation
  • Biomarkers of inflammation related to HIV and substance use
  • Study of the APOBEC3G enzyme
  • Utilizing multiple cohort accelerated longitudinal design to study developmental and historical changes in HIV risk behaviors and substance use

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