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Background: Medical mistrust is a barrier to engaging in HIV prevention and treatment, including testing and adherence to antiretroviral therapy. Research often focuses on how race and experiences of discrimination relate to medical mistrust, overlooking the role that other characteristics may play (e.g., history of physical abuse, diagnosis of mental illness). Furthermore, studies are often restricted to samples of men who have sex with men and findings may not generalize to other at-risk groups. Aims: The current study explores a range of demographic, cognitive, behavioral, and social network correlates of medical mistrust. Method: This study employed an egocentric network design among a racially diverse sample of at-risk women and women in their social networks (n = 165). Results: Results from multivariable linear regressions stratified by race (Black vs. others) indicate that medical mistrust is associated with both individual-level and network-level characteristics. Across both groups, age and experiences of racial discrimination were associated with higher medical mistrust. Having a regular sex partner and having a higher proportion of network members who are family was significantly associated with medical mistrust among non-Black women. Discussion: Individual-level and network-level variables were significantly associated with medical mistrust. Therefore, interventions that attempt to mitigate medical mistrust as a barrier to HIV prevention and treatment should consider how mistrust may be related to characteristics of individuals and broader contexts. Conclusion: Health interventions may benefit from conceiving of medical mistrust as a complex, rational response to cumulative discriminatory life experiences and a reflection of the networks within which individuals are embedded.

BackgroundOpioid overdose deaths have increased exponentially in the United States. Bystander response to opioid overdose ideally involves administering naloxone, providing rescue breathing, and calling 911 to summon emergency medical assistance. Recently in the US, public health and public safety agencies have begun seeking to use 911 calls as a method to identify and deliver post-overdose interventions to opioid overdose patients. Little is known about the opinions of PWUDs about the barriers, benefits, or potential harms of post-overdose interventions linked to the 911 system. We sought to understand the perspectives of PWUDs about a method for using 911 data to identify opioid overdose cases and trigger a post-overdose intervention.Methods and findingsWe conducted three focus groups with 11 PWUDs in 2018. Results are organized into 4 categories: willingness to call 911 (benefits and risks of calling), thoughts about a technique to identify opioid overdoses in 911 data (benefits and concerns), thoughts about the proposed post-overdose intervention (benefits and concerns), and recommendations for developing an ideal post-overdose intervention. For most participants, calling 911 was synonymous with "calling the police" and law enforcement-related fears were pervasive, limiting willingness to engage with the 911 system. The technique to identify opioid overdoses and the proposed post-overdose intervention were identified as potentially lifesaving, but the benefits were balanced by concerns related to law enforcement involvement, intervention timing, and risks to privacy/reputation. Nearly universally, participants wished for a way to summon emergency medical assistance without triggering a law enforcement response.ConclusionsThe fact that the 911 system in the US inextricably links emergency medical assistance with law enforcement response inherently problematizes calling 911 for PWUDs, and has implications for surveillance and intervention. It is imperative to center the perspectives of PWUDs when designing and implementing interventions that rely on the 911 system for activation.

We develop a practical and computationally efficient penalised estimation approach for partially linear additive models to zero-inflated binary outcome data. To facilitate estimation, B-splines are employed to approximate unknown nonparametric components. A two-stage iterative expectation-maximisation (EM) algorithm is proposed to calculate penalised spline estimates. The large-sample properties such as the uniform convergence and the optimal rate of convergence for functional estimators, and the asymptotic normality and efficiency for regression coefficient estimators are established. Further, two variance-covariance estimation approaches are proposed to provide reliable Wald-type inference for regression coefficients. We conducted an extensive Monte Carlo study to evaluate the numerical properties of the proposed penalised methodology and compare it to the competing spline method [Li and Lu. 'Semiparametric Zero-Inflated Bernoulli Regression with Applications', Journal of Applied Statistics, 49, 2845–2869]. The methodology is further illustrated by an egocentric network study. [ABSTRACT FROM AUTHOR]

Background: Co-use of stimulants and opioids is often deliberate. However, the possibility remains that some people are unintentionally consuming fentanyl. To advance understanding of overdose risk, we examined the rate of concordance between self-reported fentanyl use and corresponding urine toxicology screen results. Methods: Between August 2022–August 2023, 411 participants (adults who reported any non-medical drug use in the past three months) in Nevada and New Mexico completed a cross-sectional survey, of whom 64% (n = 270; the analytical sample) also completed a urine toxicology screen, which detects fentanyl use in the past three days. Positive predictive value, negative predictive value, sensitivity, and specificity were calculated using self-reported past three-day fentanyl use (yes/no) and urine toxicology screen results for the presence of fentanyl (positive/negative). Results: Of the 270 participants who provided a urine sample, 268 are included in the descriptive statistics (two with inconclusive urine toxicology screen results were excluded). Of the 268 participants, 146 (54.5%) had a fentanyl-positive urine toxicology screen result, 122 (45.5%) had a fentanyl-negative urine toxicology screen result, 137 (51.1%) reported past three-day fentanyl use, and 130 (48.5%) reported no past three-day fentanyl use. Only 6.9% of those with a fentanyl-positive urine toxicology screen did not report recent fentanyl use. The sensitivity of self-reported fentanyl use was 93%, specificity was 97%, positive predictive value was 97%, and negative predictive value was 92%. Discussion: The rate of unanticipated exposure to fentanyl (that is, positive urine screen and negative self-report) in this sample was low, at 6.9%. This runs counter to the national narrative that there is widespread unknown contamination of fentanyl in the drug supply. Conclusion: Future research is needed to further explore how people who use multiple substances interpret their overdose risk and what harm reduction methods they employ. [ABSTRACT FROM AUTHOR]

Female sex workers (FSWs) are at risk for multiple health harms, including HIV. This article describes a mixed methods study of the social support networks of 19 FSWs and their primary male sex partners in Tijuana, Mexico. We collected quantitative and qualitative social network data, including quantitative network measures, qualitative narratives, and network visualizations. Methodologically, we illustrate how a convergent mixed methods approach to studying personal social support networks of female sex workers can yield a more holistic understanding of network composition and role. From a health-related perspective, we show how migration/deportation and stigma shape social networks and might be leveraged to support HIV prevention interventions. We believe others can benefit from a mixed methods approach to studying social networks.

BackgroundNorth Tijuana, Mexico is home to many individuals at high risk for transmitting and acquiring human immunodeficiency virus (HIV). Recently, policy shifts by local government impacted how these individuals were handled by authorities. Here we examined how this affected regional HIV transmission dynamics.MethodsHIV pol sequences and associated demographic information were collected from 8 research studies enrolling persons in Tijuana and were used to infer viral transmission patterns. To evaluate the impact of recent policy changes on HIV transmission dynamics, qualitative interviews were performed on a subset of recently infected individuals.ResultsBetween 2004 and 2016, 288 unique HIV pol sequences were obtained from individuals in Tijuana, including 46.4% from men who have sex with men, 42.1% from individuals reporting transactional sex, and 27.8% from persons who inject drugs (some individuals had >1 risk factor). Forty-two percent of sequences linked to at least 1 other sequence, forming 37 transmission clusters. Thirty-two individuals seroconverted during the observation period, including 8 between April and July 2016. Three of these individuals were putatively linked together. Qualitative interviews suggested changes in policing led individuals to shift locations of residence and injection drug use, leading to increased risk taking (eg, sharing needles).ConclusionsNear real-time molecular epidemiologic analyses identified a cluster of linked transmissions temporally associated with policy shifts. Interviews suggested these shifts may have led to increased risk taking among individuals at high risk for HIV acquisition. With all public policy shifts, downstream impacts need to be carefully considered, as even well-intentioned policies can have major public health consequences.

BackgroundThe prevalence of HIV and Hepatitis C Virus (HCV) are significantly lower among people who inject drugs (PWID) in San Diego, CA, USA compared with PWID in Tijuana, Mexico, located directly across the border. We investigated associations between cross-border injection drug use (IDU), HIV and HCV seroprevalence and engagement in injecting risk behaviours while on each side of the border.MethodsUsing baseline interviews and serologic testing data from STAHR II, a longitudinal cohort study of PWID in San Diego, bivariate and multivariable logistic regression analyses examined associations between recent (past six months) cross-border IDU and HIV and HCV antibody seropositivity, socio-demographics, drug use characteristics, and participants' connections to, and perceptions about Mexico. Chi-squared tests and McNemar tests examined associations between cross-border IDU and injecting risk behaviours.ResultsOf the 567 participants (93% U.S.-born, 73% male, median age 45 years), 86 (15%) reported recent cross-border IDU. Cross-border IDU was not associated with HIV (OR: 0.85, 95% CI: 0.37-1.95) or HCV seropositivity (OR: 1.01, 95% CI: 0.62-1.65). Age, identifying as Hispanic or Latino/a, and being concerned about risk of violence when travelling to Mexico were independently associated with decreased odds of recent cross-border IDU. Injecting cocaine at least weekly, having ever lived in Mexico and knowing PWID who reside in Mexico were associated with increased odds of recent cross-border IDU. PWID who reported cross-border IDU were significantly less likely to engage in receptive needle sharing, equipment sharing, and public injection while in Mexico compared with in San Diego (all p

BackgroundBlack tar heroin is typically prepared for injection with heat which decreases the risk of HIV transmission by inactivating the virus. We received reports that persons who inject drugs (PWID) in Tijuana, Baja California, Mexico, a black tar heroin market, were using only water to dissolve heroin.ObjectivesBecause Tijuana abuts San Diego County, CA, United States, we undertook the present analyses to determine the prevalence of this practice among PWID in San Diego, California.MethodsPWID completed quarterly behavioral assessments and serological testing for blood-borne viruses. Bivariate and multivariable logistic regression models were constructed to assess for individual, social, and structural correlates of preparing heroin without heat within the preceding 6 months.ResultsNearly half of black tar heroin users (149/305) reported they had prepared heroin without heat within 6 months. In multivariable analysis, cold preparation was independently associated with younger age (10 year decrease; AOR = 1.25; 95% CI 1.03, 1.53), more drug injecting acquaintances (per 5 acquaintance increase; AOR = 1.05; 95% CI 1.01, 1.09) and prefilled syringe use (injecting drugs from syringes that are already filled with drugs before purchase; AOR = 1.86; 95% CI 1.14, 3.02). Conclusions/Importance: To our knowledge, this is the first paper to report that PWID living in a black tar heroin market are preparing heroin without heat. Additional research is needed to determine whether this is an endemic practice or PWID are engaging in new forms of drug preparation in response to changes in the environment.

BackgroundResearch among people who inject drugs (PWIDs) in the USA and Mexico has identified a range of adverse health impacts associated with policing of PWIDs. We employed a mixed methods design to investigate how PWIDs from San Diego and Mexico experienced policing in Tijuana, and how these interactions affect PWIDs behavior, stratifying by country of origin.MethodsIn 2012-2014, 575 PWIDs in San Diego, 102 of whom had used drugs in Mexico in the past six months, were enrolled in the STAHR-II study, with qualitative interviews conducted with a subsample of 20 who had recently injected drugs in Mexico. During this period, 735 PWIDs in Tijuana were also enrolled in the El Cuete-IV study, with qualitative interviews conducted with a subsample of 20 recently stopped by police. We calculated descriptive statistics for quantitative variables and conducted thematic analysis of qualitative transcripts. Integration of these data involved comparing frequencies across cohorts and using qualitative themes to explain and explore findings.ResultsSixty-one percent of San Diego-based participants had been recently stopped by law enforcement officers (LEOs) in Mexico; 53% reported it was somewhat or very likely that they would be arrested while in Mexico because they look like a drug user. Ninety percent of Tijuana-based participants had been recently stopped by LEOs; 84% reported it was somewhat or very likely they could get arrested because they look like a drug user. Participants in both cohorts described bribery and targeting by LEOs in Mexico. However, most San Diego-based participants described compliance with bribery as a safeguard against arrest and detention, with mistreatment being rare. Tijuana-based participants described being routinely targeted by LEOs, were frequently detained, and reported instances of sexual and physical violence. Tijuana-based participants described modifying how, where, and with whom they injected drugs in response; and experienced feelings of stress, anxiety, and powerlessness. This was less common among San Diego-based participants, who mostly attempted to avoid contact with LEOs in Mexico while engaging in risky injection behavior.ConclusionExperiences of discrimination and stigma were reported by a larger proportion of PWIDs living in Mexico, suggesting that they may be subject to greater health harms related to policing practices compared with those residing in the USA. Our findings reinforce the importance of efforts to curb abuse and align policing practices with public health goals in both the US and Mexico.

In 2009, Mexico decriminalized small-scale drug possession, instituting drug treatment diversion in lieu of incarceration. To assess initial reform impact, our mixed methods study integrated a structured questionnaire with in-depth interviews assessing legal knowledge, police encounters, and risk behaviors among people who inject drugs (PWID) in Tijuana. Between 2010 and 2013, we recruited 737 adults; 32 participated in qualitative interviews. Only 11% reported being aware of the reform; virtually none experienced its operational components. Narratives underscored the law’s irrelevance to PWID; 699 (98%) saw police practice as generally inconsistent with formal law. Instead of treatment diversion, police encounters were associated with risk behaviors, including syringe sharing (odds ratio [OR] = 1.26; 95% confidence interval [CI] = 1.09-1.46) and polydrug use (OR = 2.11; 95% CI = 1.38-3.22). As drug policy reforms gain global momentum, ancillary structural interventions are needed to improve their public health benefit.

BackgroundIllegal drug markets are shaped by multiple forces, including local actors and broader economic, political, social, and criminal justice systems that intertwine to impact health and social wellbeing. Ethnographic analyses that interrogate multiple dimensions of drug markets may offer both applied and theoretical insights into drug use, particularly in developing nations where new markets and local patterns of use traditionally have not been well understood. This paper explores the emergent drug market in Kisumu, western Kenya, where our research team recently documented evidence of injection drug use.MethodsOur exploratory study of injection drug use was conducted in Kisumu from 2013 to 2014. We draw on 151 surveys, 29 in-depth interviews, and 8 months of ethnographic fieldwork to describe the drug market from the perspective of injectors, focusing on their perceptions of the market and reports of drug use therein.ResultsInjectors described a dynamic market in which the availability of drugs and proliferation of injection drug use have taken on growing importance in Kisumu. In addition to reports of white and brown forms of heroin and concerns about drug adulteration in the market, we unexpectedly documented widespread perceptions of cocaine availability and injection in Kisumu. Examining price data and socio-pharmacological experiences of cocaine injection left us with unconfirmed evidence of its existence, but opened further possibilities about how the chaos of new drug markets and diffusion of injection-related beliefs and practices may lend insight into the sociopolitical context of western Kenya.ConclusionsWe suggest a need for expanded drug surveillance, education and programming responsive to local conditions, and further ethnographic inquiry into the social meanings of emergent drug markets in Kenya and across sub-Saharan Africa.

Persons who inject drugs (PWID) are at increased risk for blood-borne virus (BBV) infections and overdose resulting from high-risk injecting practices. Studies of prefilled syringe use ([PFSU] using a syringe that already contained drug solution when it was obtained by the user), an injection practice previously described in Eastern Europe, suggest that it increases susceptibility to BBV. However, little is known about this practice in the USA. Data were obtained from an ongoing cohort study of PWID to determine the prevalence and assess correlates of PFSU in San Diego, CA. Baseline interviews assessed socio-demographics and drug use behaviors. Logistic regression was used to identify factors independently associated with ever using a prefilled syringe (yes/no). Participants (n = 574) were predominately males (73.9%) and white (50.9%) with a mean age of 43.4 years (range 18-80); 33.3% reported ever using prefilled syringes, although only 4.9% reported use in the past 6 months. In multivariable analyses, PFSU was independently associated with ever having a rushed injection due to police presence [adjusted odds ratio (AOR) = 2.51, 95% CI 1.66, 3.79], ever being in prison (AOR = 1.80, 95% CI 1.23, 2.63), injecting most often in public versus private places in the past 6 months (AOR = 1.66, 95% CI 1.11, 2.48), and injecting drugs in Mexico (AOR = 1.70, 95% CI 1.16, 2.49). Results indicate that a history of PFSU is common and associated with environmental factors that may also increase risk for adverse health outcomes. Studies are needed to better understand PFSU in order to develop interventions to prevent adverse outcomes associated with their use.

© 2015 Australasian Professional Society on Alcohol and other Drugs. Introduction and Aims: Injecting drugs in the neck has been related to adverse health conditions such as jugular vein thrombosis, deep neck infections, aneurysm, haematomas, airway obstruction, vocal cord paralysis and wound botulism, among others. We identified prevalence and correlates of neck injection among people who inject drugs (PWID) in Tijuana, Mexico. Design and Methods: Beginning in 2011, PWID aged ≥18 years who injected drugs within the last month were recruited into a prospective cohort. At baseline and semi-annually, PWID completed interviewer-administered surveys soliciting data on drug-injecting practices. Logistic regression was used to identify predictors of injecting in the neck as the most frequent injection site at a single visit. Results: Of 380 PWID, 35.3% injected in the neck at least once in the past 6 months, among whom 71.6% reported it as their most common injection site, the most common injecting site after the arms (47%). Controlling for age, years injecting and injecting frequency, injecting heroin and methamphetamine two or more times per day and having sought injection assistance were associated with injecting in the neck [adjusted odds ratios (AOR): 2.12; 95% confidence intervals (CI): 1.27-3.53 and AOR: 2.65; 95% CI: 1.52-4.53 respectively]. Discussion and Conclusions: Injecting in the neck was very common among PWID in Tijuana and was associated with polydrug use and seeking injection assistance. Tailoring harm reduction education interventions for individuals who provide injection assistance ('hit doctors') may allow for the dissemination of safe injecting knowledge to reduce injection-related morbidity and mortality. [Rafful C, Wagner KD, Werb D, González-Zúñiga PE, Verdugo S, Rangel G, Strathdee SA. Prevalence and correlates of neck injection among people who inject drugs in Tijuana, Mexico.

© 2015 Australasian Professional Society on Alcohol and other Drugs. Introduction and Aims: Injecting drugs in the neck has been related to adverse health conditions such as jugular vein thrombosis, deep neck infections, aneurysm, haematomas, airway obstruction, vocal cord paralysis and wound botulism, among others. We identified prevalence and correlates of neck injection among people who inject drugs (PWID) in Tijuana, Mexico. Design and Methods: Beginning in 2011, PWID aged ≥18 years who injected drugs within the last month were recruited into a prospective cohort. At baseline and semi-annually, PWID completed interviewer-administered surveys soliciting data on drug-injecting practices. Logistic regression was used to identify predictors of injecting in the neck as the most frequent injection site at a single visit. Results: Of 380 PWID, 35.3% injected in the neck at least once in the past 6 months, among whom 71.6% reported it as their most common injection site, the most common injecting site after the arms (47%). Controlling for age, years injecting and injecting frequency, injecting heroin and methamphetamine two or more times per day and having sought injection assistance were associated with injecting in the neck [adjusted odds ratios (AOR): 2.12; 95% confidence intervals (CI): 1.27-3.53 and AOR: 2.65; 95% CI: 1.52-4.53 respectively]. Discussion and Conclusions: Injecting in the neck was very common among PWID in Tijuana and was associated with polydrug use and seeking injection assistance. Tailoring harm reduction education interventions for individuals who provide injection assistance ('hit doctors') may allow for the dissemination of safe injecting knowledge to reduce injection-related morbidity and mortality. [Rafful C, Wagner KD, Werb D, González-Zúñiga PE, Verdugo S, Rangel G, Strathdee SA. Prevalence and correlates of neck injection among people who inject drugs in Tijuana, Mexico.

BackgroundHIV sequence data can be used to reconstruct local transmission networks. Along international borders, like the San Diego-Tijuana region, understanding the dynamics of HIV transmission across reported risks, racial/ethnic groups, and geography can help direct effective prevention efforts on both sides of the border.MethodsWe gathered sociodemographic, geographic, clinical, and viral sequence data from HIV infected individuals participating in ten studies in the San Diego-Tijuana border region. Phylogenetic and network analysis was performed to infer putative relationships between HIV sequences. Correlates of identified clusters were evaluated and spatiotemporal relationships were explored using Bayesian phylogeographic analysis.FindingsAfter quality filtering, 843 HIV sequences with associated demographic data and 263 background sequences from the region were analyzed, and 138 clusters were inferred (2-23 individuals). Overall, the rate of clustering did not differ by ethnicity, residence, or sex, but bisexuals were less likely to cluster than heterosexuals or men who have sex with men (p = 0.043), and individuals identifying as white (p ≤ 0.01) were more likely to cluster than other races. Clustering individuals were also 3.5 years younger than non-clustering individuals (p < 0.001). Although the sampled San Diego and Tijuana epidemics were phylogenetically compartmentalized, five clusters contained individuals residing on both sides of the border.InterpretationThis study sampled ~ 7% of HIV infected individuals in the border region, and although the sampled networks on each side of the border were largely separate, there was evidence of persistent bidirectional cross-border transmissions that linked risk groups, thus highlighting the importance of the border region as a "melting pot" of risk groups.FundingNIH, VA, and Pendleton Foundation.

BackgroundAccidental overdose, driven largely by opioids, is a leading cause of death among people who inject drugs (PWIDs). We conducted secondary analysis of data from a cohort of PWIDs to identify venues where high-risk PWID could be targeted by overdose education/naloxone distribution (OEND) programs.Methods573 PWIDs completed a quantitative survey between June, 2012 and January, 2014, which was analyzed using multivariable logistic regression. The dependent variable was a dichotomous indicator of experiencing a heroin/opioid-related overdose in the past six months. Independent variables included: demographics, drug use behavior, and encounters with two venues - the health care and criminal justice systems - that could serve as potential venues for OEND programs.ResultsAlmost half (41.5%) reported ever experiencing a heroin/opioid overdose, and 45 (7.9%) reported experiencing at least one heroin/opioid overdose in the past six months. In the final multivariable model, receiving care in a hospital in the past six months (Adjusted Odds Ratio [AdjOR] 4.08, 95% Confidence Interval [C.I.] 2.07, 8.04, p

Injection drug-using men from the US and Mexico who purchase sex in Tijuana, Mexico are at risk for transmitting HIV to their contacts in both countries via syringe sharing. We used social network methods to understand whether place of residence (US vs. Mexico) moderated the effect of emotional closeness on syringe sharing. We interviewed 199 drug-using men who reported paying/trading for sex in Tijuana, Mexico using an epidemiological and social network survey and collected samples for HIV/STI testing. Seventy-two men reported using injection drugs with 272 network contacts. Emotional closeness was strongly associated with syringe sharing in relationship where the partner lives in the US, while the relationship between emotional closeness and syringe sharing was considerably less strong in dyads where the partner lives in Mexico. Efforts to reduce HIV risk behaviors in emotionally close relationships are needed, and could benefit from tailoring to the environmental context of the relationship.

BackgroundInjection drug use is increasingly contributing to the HIV epidemic across sub-Saharan Africa. This paper provides the first descriptive analysis of injection drug use in western Kenya, where HIV prevalence is already highest in the nation at 15.1%.MethodsWe draw on quantitative data from a study of injection drug use in Kisumu, Kenya. We generated descriptive statistics on socio-demographics, sexual characteristics, and drug-related behaviors. Logistic regression models were adjusted for sex to identify correlates of self-reported HIV positive status.ResultsOf 151 participants, mean age was 28.8 years, 84% (n = 127) were male, and overall self-reported HIV prevalence reached 19.4%. Women had greater than four times the odds of being HIV positive relative to men (Odds Ratio [OR] 4.5, CI: 1.7, 11.8, p = .003). Controlling for sex, ever experiencing STI symptoms (Adjusted Odds ratio [AOR] 4.6, 95% CI 1.7, 12.0, p = .002) and sharing needles or syringes due to lack of access (AOR 3.6, 95% CI 1.2, 10.5, p = .02) were significantly associated with HIV positive status. Lower education (AOR 2.3, 95% CI 0.9, 5.6, p=.08), trading sex for drugs (AOR 2.8, 95% CI 0.9, 8.8, p = .08), being injected by a peddler (AOR 2.9, 95% CI 1.0, 8.5, p = .05), and injecting heroin (AOR 2.3, 95% CI 1.0, 5.7, p = .06), were marginally associated with HIV.ConclusionsThis exploratory study identified patterns of unsafe drug injection and concurrent sexual risk in western Kenya, yet few resources are currently available to address addiction or injection-related harm. Expanded research, surveillance, and gender sensitive programming are needed.

HIV prevention efforts must be comprehensive in their understanding of the factors involved in HIV risk. Male clients, who have received less research attention than female sex workers (FSWs), may experience stigma as a function of purchasing sex. Perceived stigma may be related to poor psychological outcomes, risky psychosexual characteristics, and higher drug and sexual risk behavior among male clients of FSWs. However, perceived stigma of purchasing sex may differ between clients of different ethnic groups. In the present study, we examine the correlates of perceived stigma of purchasing sex among Latino versus non-Latino male clients of FSWs in Tijuana, Mexico. Using time-location sampling, we recruited 375 male clients (323 Latino, 52 non-Latino) in Tijuana who completed a computerized survey on various measures. We measured perceived stigma of purchasing sex using three items we developed for this study. Using linear regression analyses we found that perceived stigma was associated with greater guilt, a greater feeling of escape from everyday life, and more negative condom attitudes among Latino clients. This was not found among non-Latino clients. Features of Latino culture, like machismo, and how they may relate to stigma of purchasing sex are discussed.

BackgroundAmong persons who inject drugs (PWID), polydrug use (the practice of mixing multiple drugs/alcohol sequentially or simultaneously) increases risk for HIV transmission and unintentional overdose deaths. Research has shown local drug markets influence drug use practices. However, little is known about the impact of drug mixing in markets dominated by black tar heroin and methamphetamine, such as the western United States.MethodsData were collected through an ongoing longitudinal study examining drug use, risk behavior, and health status among PWID. Latent class analysis (LCA) was used to identify patterns of substance use (heroin, methamphetamine, prescription drugs, alcohol, and marijuana) via multiple administration routes (injecting, smoking, and swallowing). Logistic regression was used to identify behaviors and health indicators associated with drug use class.ResultsThe sample included 511 mostly white (51.5%) males (73.8%), with mean age of 43.5 years. Two distinct classes of drug users predominated: methamphetamine by multiple routes (51%) and heroin by injection (49%). In multivariable logistic regression, class membership was associated with age, race, and housing status. PWID who were HIV-seropositive and reported prior sexually transmitted infections had increased odds of belonging to the methamphetamine class. Those who were HCV positive and reported previous opioid overdose had an increased odds of being in the primarily heroin injection class (all P-values

BackgroundPolicymakers and researchers seek answers to how liberalized drug policies affect people who inject drugs (PWID). In response to concerns about the failing "war on drugs," Mexico recently implemented drug policy reforms that partially decriminalized possession of small amounts of drugs for personal use while promoting drug treatment. Recognizing important epidemiologic, policy, and socioeconomic differences between the United States-where possession of any psychoactive drugs without a prescription remains illegal-and Mexico-where possession of small quantities for personal use was partially decriminalized, we sought to assess changes over time in knowledge, attitudes, behaviors, and infectious disease profiles among PWID in the adjacent border cities of San Diego, CA, USA, and Tijuana, Baja California, Mexico.MethodsBased on extensive binational experience and collaboration, from 2012-2014 we initiated two parallel, prospective, mixed methods studies: Proyecto El Cuete IV in Tijuana (n = 785) and the STAHR II Study in San Diego (n = 575). Methods for sampling, recruitment, and data collection were designed to be compatible in both studies. All participants completed quantitative behavioral and geographic assessments and serological testing (HIV in both studies; hepatitis C virus and tuberculosis in STAHR II) at baseline and four semi-annual follow-up visits. Between follow-up assessment visits, subsets of participants completed qualitative interviews to explore contextual factors relating to study aims and other emergent phenomena. Planned analyses include descriptive and inferential statistics for quantitative data, content analysis and other mixed-methods approaches for qualitative data, and phylogenetic analysis of HIV-positive samples to understand cross-border transmission dynamics.ResultsInvestigators and research staff shared preliminary findings across studies to provide feedback on instruments and insights regarding local phenomena. As a result, recruitment and data collection procedures have been implemented successfully, demonstrating the importance of binational collaboration in evaluating the impact of structural-level drug policy reforms on the behaviors, health, and wellbeing of PWID across an international border.ConclusionsOur prospective, mixed methods approach allows each study to be responsive to emerging phenomena within local contexts while regular collaboration promotes sharing insights across studies. The strengths and limitations of this approach may serve as a guide for other evaluations of harm reduction policies internationally.

BackgroundDrug use and partner violence affect older women, yet few studies highlight age-specific HIV risks and prevention strategies. This study compares sexual risk behaviors, condom use attitudes, and HIV knowledge between midlife/older women (ages 45+) and younger women (ages 18-44) reporting methamphetamine use and partner violence in San Diego, California.MethodsOur mixed methods study used themes from a qualitative substudy (n = 18) to inform logistic regression analysis of baseline data from an HIV behavioral intervention trial (n = 154).FindingsAge-related qualitative themes included physiologic determinants, HIV knowledge, and "dodging the bullet," referring to a lifetime of uncertainty surrounding HIV serostatus after engaging in unsafe drug and sex practices. Midlife/older age was associated with never being married (24.2% vs. 51.2; p = .03), having less than a high school education/GED (12.1% vs. 34.7%; p = .04), lower condom use self-efficacy (2.87 vs. 3.19; p = .03), lower positive outcome expectancies (1.9 vs. 2.1; p = .04), and lower HIV knowledge (85.3% vs. 89.7%; p = .04); however, sexual risk behaviors were not associated with age group. In the multivariate analysis, midlife/older age remained independently associated with lower condom use self-efficacy (adjusted odds ratio, 0.49; 95% CI, 0.27-0.87) and lower HIV knowledge (adjusted odds ratio, 0.96; 95% CI, 0.93-0.99).ConclusionsMidlife/older methamphetamine-using women with experiences of partner violence present similar sexual risk profiles, but possess different HIV-related knowledge and attitudes toward prevention methods compared with their younger counterparts. Clinicians and public health practitioners can have a positive impact on this overlooked population by assessing HIV risks during routine screenings, encouraging HIV testing, and providing age-appropriate HIV prevention education.

BackgroundStudies of injection drug-using couples suggest a gendered performance of risk in which men exert greater control over drug use and render their female partners vulnerable to HIV infection and other negative health outcomes. This study assesses gender roles in injection drug use as practiced among female sex workers and their intimate male partners within a risk environment marked by rapid socioeconomic changes.MethodsWe draw on quantitative surveys, semi-structured interviews, and ethnographic fieldwork conducted as part of cohort study of HIV/STI risk among female sex workers and their intimate, non-commercial partners along the Mexico-U.S. border. This study employed descriptive statistics and inductive analyses of transcripts and field notes to examine practices related to drug procurement, syringe sharing, and injection assistance among couples in which both partners reported injecting drugs in the past 6 months.ResultsAmong 156 couples in which both partners injected drugs (n=312), our analyses revealed that women's roles in drug use were active and multidimensional, and both partners' injection risk practices represented embodied forms of cooperation and compassion. Women often earned money to purchase drugs and procured drugs to protect their partners from the police. Sharing drugs and syringes and seeking injection assistance were common among couples due to drug market characteristics (e.g., the use of "black tar" heroin that clogs syringes and damages veins). Both women and men provided and received injection assistance, which was typically framed as caring for the partner in need of help.ConclusionOur mixed methods study suggests that in certain risk environments, women are more active participants in injection-related practices than has often been revealed. This participation is shaped by dynamic relationship and structural factors. Our suggestion to consider gendered injection risk as a nuanced and relational process has direct implications for future research and interventions.

Background and objectivesMale clients of female sex workers (FSWs) are at high risk for HIV. Whereas the HIV risks of alcohol use are well understood, less is known about hazardous alcohol use among male clients of FSWs, particularly in Mexico. We sought to identify risk factors for hazardous alcohol use and test associations between hazardous alcohol use and HIV risk behavior among male clients in Tijuana.MethodMale clients of FSWs in Tijuana (n = 400) completed a quantitative interview in 2008. The AUDIT was used to characterize hazardous alcohol use. Multivariate logistic regression was used to determine independent associations of demographic and HIV risk variables with hazardous alcohol use (vs. non-hazardous).ResultsForty percent of our sample met criteria for hazardous alcohol use. Variables independently associated with hazardous drinking were reporting any sexually transmitted infection (STI), having sex with a FSW while under the influence of alcohol, being younger than 36 years of age, living in Tijuana, and ever having been jailed. Hazardous drinkers were less likely ever to have been deported or to have shared injection drugs.Discussion and conclusionsHazardous alcohol use is associated with HIV risk, including engaging in sex with FSWs while intoxicated and having an STI among male clients of FSWs in Tijuana.Scientific significanceWe systematically described patterns and correlates of hazardous alcohol use among male clients of FSWs in Tijuana, Mexico. The results suggest that HIV/STI risk reduction interventions must target hazardous alcohol users, and be tailored to address alcohol use.

BackgroundUse of synthetic cathinones (SC) and cannabimimetics (i.e., "THC homologues" [TH]) is associated with adverse health effects. We investigated the epidemiology of synthetic drug use among a cohort of injection drug users (IDUs) in San Diego, California.MethodsWe used logistic regression analysis to identify correlates of SC and TH use among 485 IDUs enrolled from June 2012 to September 2013.ResultsSeven percent of participants reported ever using SC and 30% reported ever using TH. In multivariate logistic regression, age and recent hospitalization were significantly associated with odds of SC use (Adjusted Odds Ratio [AOR] 0.93, 95% Confidence Interval [C.I.] 0.90, 0.97; and AOR 2.34 95% C.I. 1.00, 5.49, respectively) and TH use (AOR 0.96, 95% C.I. 0.94, 0.98; and AOR 2.62, 95% C.I. 1.47, 4.68, respectively). Use of methamphetamine (AOR 9.35, 95% C.I. 1.20, 72.79) and club drugs in the past six months (AOR 3.38, 95% C.I. 1.17, 9.76) were significantly associated with SC use. Being on probation/parole (AOR 2.42, 95% C.I. 1.44, 4.07), initiating injection drug use with stimulants (AOR 1.89 95% C.I. 1.13, 3.16), and past six-month marijuana (AOR 9.22, 95% C.I. 4.49, 18.96) and prescription drug use (AOR 1.98, 95% C.I. 1.20, 3.27) were significantly associated with TH use.ConclusionsA considerable proportion of IDU use synthetic drugs and may experience harms associated with their use. Findings have implications for criminal justice system management. Prevention efforts should emphasize the risks associated with rapidly changing synthetic formulations, and the potential harms associated with polydrug use.

BackgroundResearch has focused on male clients of female sex workers (FSWs) and their risk for HIV/sexually transmitted infections (STIs). However, it is unclear whether the commercial sex behaviors of these men are limited to paying for sex or whether they may also be paid for sex themselves.MethodsWe analyzed the interview data and HIV/STI test results from 170 drug-using male clients of FSWs in Tijuana, Mexico, to determine the extent to which these men report being paid for sex and the association with positive HIV/STI results.ResultsMore than one quarter of men reported having been paid for sex in the past 4 months. In a multivariate logistic regression model, reporting having been paid for sex was significantly associated with testing positive for any HIV/STI (adjusted odds ratio [AdjOR], 3.53; 95% confidence interval [CI], 1.33-9.35), being bisexual (AdjOR, 15.59; 95% CI, 4.81-50.53), injection drug use in the past 4 months (AdjOR, 2.65; 95% CI, 1.16-6.03), and cocaine use in the past 4 months (AdjOR, 2.93; 95% CI, 1.22-7.01).ConclusionsFindings suggest that drug-using male clients of FSWs may be characterized by unique risk profiles that require tailored HIV prevention interventions.

We examined correlates of ever injecting drugs in Mexico among residents of San Diego, California. From 2007 to 2010, injecting drug users (IDUs) in San Diego underwent an interviewer-administered survey. Logistic regression identified correlates of injection drug use in Mexico. Of 302 IDUs, 38% were Hispanic, 72% male and median age was 37; 27% ever injected in Mexico; 43% reported distributive syringe sharing there. Factors independently associated with ever injecting drugs in Mexico included being younger at first injection, injecting heroin, distributive syringe sharing at least half of the time, and transporting drugs over the last 6 months. One-quarter of IDUs reported ever injecting drugs in Mexico, among whom syringe sharing was common, suggesting possible mixing between IDUs in the Mexico-US border region. Prospective studies should monitor trends in cross-border drug use in light of recent Mexican drug policy reforms partially decriminalizing drug possession.