ABSTRACT The United States (US) is currently experiencing among the highest rates of sexually transmitted infections (STIs) on record, and women who use drugs are disproportionately affected. Drug use contributes to sexual risk behaviors, but there has been little examination of the role of drug treatment in preventing STIs among women who use drugs. The “drug treatment as disease prevention” paradigm has been applied to viral infections primarily transmitted via blood (i.e., HIV, HCV), and studies conducted mostly among men who inject drugs have found that drug treatment reduces HIV/HCV risk likely by reducing drug use and unsterile injection. However, the relationship between drug treatment and risk of STIs among the broader population of women who use drugs (e.g., those who do and do not inject) is underexplored. The mechanisms through which drug treatment may affect STI risk are unknown and elucidating them could identify novel intervention approaches. Finally, a range of individual, social, and structural factors drive inequities in access to drug treatment and STI risk, independently and together with race/ethnicity, and may lead to heightened vulnerability within specific groups of women. In the proposed secondary data analysis study, we will create an analytic sample of women who use drugs (n=842) using data from Project AWARE (NIDA-CTN-AWARE), which was a prospective study of men and women seeking care at US STD clinics. We will evaluate whether baseline drug treatment is associated with cumulative STI incidence measured at six months follow up (Aim 1). Using causal mediation analyses, we will evaluate mediation of the link between drug treatment and STI incidence by substance use, sexual behavior, and STI/HIV testing uptake among women who use drugs (Aim 2). We will identify potential differences in associations between drug treatment and STI incidence and the mediating pathways by individual (e.g., age, mental health), social (e.g., marital status), and structural (e.g., housing instability, healthcare access) factors (Aim 3). Across aims, we will explore differences in the associations and potential mediating pathways by race/ethnicity among women who use drugs, and compare effects observed among women to effects observed among men who use drugs. Research on intersections among drug treatment and sexual and reproductive health among women is scarce, but represents a critical aspect of addressing the specific needs of women who use drugs. The proposed study is highly responsive to NIH’s special interest in advancing research specific to women and will directly address the topics that cut across NIDA’s goals, including identifying approaches to reduce health inequities and understand interactions between drug use and co-occurring medical consequences.

PROJECT NARRATIVE Women who use drugs have a high risk of sexually transmitted infections (STIs) and related adverse sexual and reproductive health outcomes, and treating drug use could reduce substance use and sexual risk behavior while also increasing STI/HIV testing uptake, which in turn may ultimately reduce STI risk. The goal of the proposed research is to measure the associations between drug treatment and STI incidence among women who use drugs, evaluate the potential mediating pathways, and examine whether individual, social, and structural factors may modify these associations. Results of this research will inform targets for actionable interventions to improve women’s health, reduce morbidity and mortality, and address inequities in drug treatment and sexual and reproductive health.