Prevalence of HIV/STIs and correlates with municipal characteristics among female sex workers in 13 Mexican cities.

OBJECTIVE: To identify correlates of HIV/STI prevalence among 13 cities with varying sizes of female sex worker (FSW) populations and municipal characteristics in Mexico. MATERIALS AND METHODS: FSWs underwent interviews and testing for HIV, syphilis, gonorrhea and chlamydia. Logistic regression explored variations in HIV/STI prevalence. RESULTS: Among FSWs (n=1 092), prevalence across 13 sites was: HIV: 0.4% (range: 0%-1.4%): syphilis: 7.8% (range: 0%-17.2%); chlamydia: 15.3% (range: 5.7%-32.2%); gonorrhea:2.9% (range 0%-13.8%), and any HIV/STI: 23% (range: 9.9%- 46%). Municipalities with high human development scores and a lower municipal marginalization index had higher odds of combined HIV/STI prevalence. After controlling for sitespecific variability in municipal characteristics, greater risk of HIV/STIs was associated with lower education, having a spouse diagnosed or treated for an STI, unaffordability of condoms, and having non-Mexican clients. CONCLUSIONS: Prevalence of HIV/STIs varies across Mexican municipalities indicating the need for surveillance to identify hotspots for targeted resource allocation.

OBJETIVO: Identificar correlaciones de la prevalencia de VIH / ITS entre 13 ciudades con diferentes tamaños de población de trabajadoras sexuales y características municipales en México. MATERIAL Y MÉTODOS: Las trabajadoras sexuales fueron entrevistadas y recibieron pruebas de VIH, sífilis, gonorrea y clamidia. La regresión logística exploró las variaciones en la prevalencia del VIH/ITS. RESULTADOS: Entre las trabajadoras sexuales (n = 1 092), la prevalencia en 13 sitios fue: VIH: 0.4% (rango: 0-1.4%): sífilis: 7.8% (rango: 0-17.2%); clamidia: 15.3% (rango: 5.7-32.2%); gonorrea: 2.9% (rango 0-13.8%) y cualquier VIH/ITS: 23% (rango: 9.9-46%). Los municipios con altos puntajes de desarrollo humano y menor índice de marginación municipal tuvieron una mayor probabilidad de prevalencia combinada de VIH/ITS. Después de controlar la variabilidad específica del sitio en las características municipales, el mayor riesgo de VIH / ITS se asoció con menor educación, tener un cónyuge diagnosticado o tratado para una ITS, imposibilidad de conseguir condones y tener clientes no mexicanos. CONCLUSIONES: La prevalencia de VIH/ITS varía entre losmunicipios mexicanos, lo que indica la necesidad de una vigilancia para identificar hotspots para la asignación selectiva.

Prevalence of HIV/STIs and correlates with municipal characteristics among female sex workers in 13 Mexican cities / Prevalencia de VIH/ITS y correlaciones con carácterísticas municipales entre trabajadoras sexuales en 13 ciudades mexicanas

Abstract: Objective: To identify correlates of HIV/STI prevalence among 13 cities with varying sizes of female sex worker (FSW) populations and municipal characteristics in Mexico. Materials and methods: FSWs underwent interviews and testing for HIV, syphilis, gonorrhea and chlamydia. Logistic regression explored variations in HIV/STI prevalence. Results: Among FSWs (n=1 092), prevalence across 13 sites was: HIV: 0.4% (range: 0%-1.4%): syphilis: 7.8% (range: 0%-17.2%); chlamydia: 15.3% (range: 5.7%-32.2%); gonorrhea: 2.9% (range 0%-13.8%), and any HIV/STI: 23% (range: 9.9%-46%). Municipalities with high human development scores and a lower municipal marginalization index had higher odds of combined HIV/STI prevalence. After controlling for site-specific variability in municipal characteristics, greater risk of HIV/STIs was associated with lower education, having a spouse diagnosed or treated for an STI, unaffordability of condoms, and having non-Mexican clients. Conclusions: Prevalence of HIV/STIs varies across Mexican municipalities indicating the need for surveillance to identify hotspots for targeted resource allocation.

Resumen: Objetivo: Identificar correlaciones de la prevalencia de VIH / ITS entre 13 ciudades con diferentes tamaños de población de trabajadoras sexuales y características municipales en México. Material y métodos: Las trabajadoras sexuales fueron entrevistadas y recibieron pruebas de VIH, sífilis, gonorrea y clamidia. La regresión logística exploró las variaciones en la prevalencia del VIH/ITS. Resultados: Entre las trabajadoras sexuales (n = 1 092), la prevalencia en 13 sitios fue: VIH: 0.4% (rango: 0-1.4%): sífilis: 7.8% (rango: 0-17.2%); clamidia: 15.3% (rango: 5.7-32.2%); gonorrea: 2.9% (rango 0-13.8%) y cualquier VIH/ITS: 23% (rango: 9.9-46%). Los municipios con altos puntajes de desarrollo humano y menor índice de marginación municipal tuvieron una mayor probabilidad de prevalencia combinada de VIH/ITS. Después de controlar la variabilidad específica del sitio en las características municipales, el mayor riesgo de VIH / ITS se asoció con menor educación, tener un cónyuge diagnosticado o tratado para una ITS, imposibilidad de conseguir condones y tener clientes no mexicanos. Conclusiones: La prevalencia de VIH/ITS varía entre los municipios mexicanos, lo que indica la necesidad de una vigilancia para identificar hotspots para la asignación selectiva.

Factors associated with extrajudicial arrest for syringe possession: results of a department-wide survey of municipal police in Tijuana, Mexico.

BACKGROUND: Mexican law permits syringe purchase and possession without prescription. Nonetheless, people who inject drugs (PWID) frequently report arrest for syringe possession. Extrajudicial arrests not only violate human rights, but also significantly increase the risk of blood-borne infection transmission and other health harms among PWID and police personnel. To better understand how police practices contribute to the PWID risk environment, prior research has primarily examined drug user perspectives and experiences. This study focuses on municipal police officers (MPOs) in Tijuana, Mexico to identify factors associated with self-reported arrests for syringe possession. METHODS: Participants were active police officers aged ≥18 years, who completed a self-administered questionnaire on knowledge, attitudes and behaviors related to occupational safety, drug laws, and harm reduction strategies. Univariable and multivariable logistic regression was used to identify correlates of recent syringe possession arrest. RESULTS: Among 1044 MPOs, nearly half (47.9%) reported always/sometimes making arrests for syringe possession (previous 6mo). Factors independently associated with more frequent arrest included being male (Adjusted Odds Ratio [AOR] = 1.62; 95% Confidence Interval [95% CI] =1.04-2.52; working in a district along Tijuana River Canal (where PWID congregate) (AOR = 2.85; 95%CI = 2.16-3.77); having recently experienced a physical altercation with PWID (AOR = 2.83; 95% CI = 2.15-3.74); and having recently referred PWID to social and health services (AOR = 1.97; 95% CI = 1.48-2.61). Conversely, odds were significantly lower among officers reporting knowing that syringe possession is legal (AOR = 0.61; 95% CI = 0.46-0.82). CONCLUSIONS: Police and related criminal justice stakeholders (e.g., municipal judges, prosecutors) play a key role in shaping PWID risk environment. Findings highlight the urgent need for structural interventions to reduce extra-judicial syringe possession arrests. Police training, increasing gender and other forms of diversity, and policy reforms at various governmental and institutional levels are necessary to reduce police occupational risks, improve knowledge of drug laws, and facilitate harm reduction strategies that promote human rights and community health.

Predictors of injecting cessation among a cohort of people who inject drugs in Tijuana, Mexico.

INTRODUCTION: Little is known about the cessation of injecting drug use (IDU) among people who inject drugs (PWID) in low and middle-income settings, where access to effective interventions for reducing drug use (e.g., opioid substitution treatment; OST), may be limited. We measured the incidence and identified predictors of IDU cessation among a cohort of PWID in Tijuana, Mexico. METHODS: Data were drawn from 621 participants in Proyecto El Cuete IV, a prospective cohort of PWID recruited in 2011 and interviewed biannually to 2016. A multivariable Extended Cox model was constructed to identify socio-demographic, drug use, risk environment and health-related predictors of IDU cessation (no IDU for ≥six months). RESULTS: 141 participants (23%) reported at least one IDU cessation event during follow-up. The crude IDU cessation rate was 7.3 per 100 person-years (95% Confidence Interval [CI]: 6.2-8.7). IDU cessation was negatively associated with injecting at least daily on average and heroin/methamphetamine co-injection in the past six months, and positively associated with testing HIV positive at baseline, being on methadone maintenance therapy in the past six months, and recent arrest. Concern for personal safety was also independently associated with IDU cessation. CONCLUSIONS: The rate of IDU cessation among PWID in Tijuana was low. These findings underscore the importance of expansion of services including OST to help reduce drug use and facilitate IDU cessation for those who wish to do so. In this setting, interventions addressing individual-level economic barriers as well as broader social and structural barriers to harm reduction services are integral.

Perceived Treatment Need and Latent Transitions in Heroin and Methamphetamine Polydrug Use among People who Inject Drugs in Tijuana, Mexico.

People who inject drugs (PWID) in Tijuana, Mexico, use heroin and/or methamphetamine. While polydrug use is associated with HIV risk behavior, less is known about the stability of polydrug use patterns over time and how polydrug use is related to perceived treatment need. Within a cohort of PWID in Tijuana (N = 735) we sought to (1) characterize subgroups of polydrug and polyroute use from baseline to six months; (2) determine the probabilities of transitioning between subgroups; and (3) examine whether self-reported need for help for drug use modified these transition probabilities. Latent transition analysis (LTA) identified four latent statuses: heroin-only injection (38% at both baseline and follow-up); co-injection of heroin with methamphetamine (3% baseline, 15% follow-up); injection of heroin and methamphetamine (37% baseline, 32% follow-up); and polydrug and polyroute users who injected heroin and both smoked and injected methamphetamine (22% baseline, 14% follow-up). Heroin-only injectors had the highest probability of remaining in the same latent status at follow-up. The majority reported great or urgent need for treatment (51%) and these PWID had greater odds of transitioning to a higher-risk status at follow-up, emphasizing the need for evidence-based drug treatment options for PWID.

Latent classes of polydrug and polyroute use and associations with human immunodeficiency virus risk behaviours and overdose among people who inject drugs in Tijuana, Baja California, Mexico.

INTRODUCTION AND AIMS: Patterns of polydrug use among people who inject drugs (PWID) may be differentially associated with overdose and unique human immunodeficiency virus (HIV) risk factors. Subgroups of PWID in Tijuana, Mexico, were identified based on substances used, route of administration, frequency of use and co-injection indicators. DESIGN AND METHODS: Participants were PWID residing in Tijuana age ≥18 years sampled from 2011 to 2012 who reported injecting an illicit substance in the past month (n = 735). Latent class analysis identified discrete classes of polydrug use characterised by 11 indicators of past 6 months substance use. Multinomial logistic regression examined class membership association with HIV risk behaviours, overdose and other covariates using an automated three-step procedure in mplus to account for classification error. RESULTS: Participants were classified into five subgroups. Two polydrug and polyroute classes were defined by use of multiple substances through several routes of administration and were primarily distinguished from each other by cocaine use (class 1: 5%) or no cocaine use (class 2: 29%). The other classes consisted primarily of injectors: cocaine, methamphetamine and heroin injection (class 3: 4%); methamphetamine and heroin injection (class 4: 10%); and heroin injection (class 5: 52%). Compared with the heroin-only injection class, memberships in the two polydrug and polyroute use classes were independently associated with both HIV injection and sexual risk behaviours. DISCUSSION AND CONCLUSIONS: Substance use patterns among PWID in Tijuana are highly heterogeneous, and polydrug and polyroute users are a high-risk subgroup who may require more tailored prevention and treatment interventions. [Meacham MC, Roesch SC, Strathdee SA, Lindsay S, Gonzalez-Zuniga P, Gaines TL. Latent classes of polydrug and polyroute use and associations with human immunodeficiency virus risk behaviours and overdose among people who inject drugs in Tijuana, Baja California, Mexico. Drug Alcohol Rev 2018;37:128-136].

Impact of Public Safety Policies on Human Immunodeficiency Virus Transmission Dynamics in Tijuana, Mexico.

Background: North 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. Methods: HIV 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. Results: Between 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). Conclusions: Near 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.

Structural factors associated with methamphetamine smoking among female sex workers in Tijuana, Mexico.

INTRODUCTION AND AIMS: Smoking methamphetamine is associated with increased risk of HIV among female sex workers (FSW). The structural context of substance use is an important shaper of individual behaviour; however, structural determinants of methamphetamine use among FSWs are largely unknown. We identified individual, structural and neighbourhood factors associated with smoking methamphetamine among FSWs in the border city of Tijuana, Baja California, Mexico. DESIGN AND METHODS: A prospective cohort of 301 FSWs sampled from indoor and outdoor sex work venues throughout Tijuana participated in quantitative surveys on behaviours and mapping of home and work neighbourhoods across three visits. Multinomial logistic regression using generalised estimating equations identified individual, structural and neighbourhood variables associated with smoking methamphetamine. RESULTS: Methamphetamine use, particularly smoking, was highly prevalent among FSWs. Over half (61%) of FSWs had ever used methamphetamine in their lifetime and at baseline, 38% currently smoked methamphetamine. Smoking methamphetamine daily was associated with living in the red light district [adjusted odds ratio (AOR) = 2.72, 95% confidence interval (CI) = 1.23-6.02] and with perceived homelessness, but only among women in a good financial situation (AOR = 4.08, 95% CI = 1.58-10.50). Smoking methamphetamine less than daily was associated with older age (AOR = 1.06, 95% CI = 1.02-1.10). DISCUSSION AND CONCLUSIONS: Our findings point to the important dynamic between the residential environment and more severe methamphetamine use. FSWs may prioritise the purchase of methamphetamine over stable housing if they have the financial means. Given the high prevalence of smoking methamphetamine among FSWs in Tijuana, drug treatment options, especially for women living in the red light district, are needed.

The Spatial-Temporal Pattern of Policing Following a Drug Policy Reform: Triangulating Self-Reported Arrests With Official Crime Statistics.

BACKGROUND: In 2009, Mexico enacted a drug policy reform (Narcomenudeo) designed to divert persons possessing small amounts of illicit drugs to treatment rather than incarceration. To assess reform impact, this study examines the spatial-temporal trends of drug-related policing in Tijuana, Mexico post-enactment. METHOD: Location of self-reported arrests (N = 1,160) among a prospective, community-recruited cohort of people who inject drugs (PWID) in Tijuana (N = 552) was mapped across city neighborhoods. Official police reports detailing drug-related arrests was triangulated with PWID self-reported arrests. Exploratory spatial data analysis examined the distribution of arrests and spatial association between both datasets across three successive years, 2011-2013. RESULTS: In 2011, over half of PWID reported being detained but not officially charged with a criminal offense; in 2013, 90% of arrests led to criminal charges. Official drug-related arrests increased by 67.8% (p <.01) from 2011 to 2013 despite overall arrest rates remaining stable throughout Tijuana. For each successive year, we identified a high degree of spatial association between the location of self-reported and official arrests (p <.05). CONCLUSION: Two independent data sources suggest that intensity of drug law enforcement had risen in Tijuana despite the promulgation of a public health-oriented drug policy reform. The highest concentrations of arrests were in areas traditionally characterized by higher rates of drug crime. High correlation between self-reported and official arrest data underscores opportunities for future research on the role of policing as a structural determinant of public health.

Prevalence and Correlates of Heroin-Methamphetamine Co-Injection Among Persons Who Inject Drugs in San Diego, California, and Tijuana, Baja California, Mexico.

OBJECTIVE: Although persons who inject drugs (PWID) in the western United States-Mexico border region are known to inject both heroin and methamphetamine, little is known about the prevalence and risks associated with co-injection of this depressant-stimulant combination (also known as "goofball" and "Mexican speedball"). METHOD: Baseline data from parallel cohort studies of PWID conducted concurrently in San Diego, CA, and Tijuana, Mexico, were used to estimate the prevalence and identify correlates of heroin-methamphetamine co-injection. PWID older than 18 years of age who reported injecting illicit drugs in the past month (N = 1,311; 32.7% female) were recruited in San Diego (n = 576) and Tijuana (n = 735) and completed interviewer-administered questionnaires. Bivariate and multivariable logistic regression analyses were used to identify correlates of heroin-meth-amphetamine co-injection. RESULTS: The prevalence of co-injection in the past 6 months was 39.9% overall and was higher in Tijuana (55.8%) than in San Diego (19.8%). In multivariable analyses adjusting for study cohort, distributive syringe sharing, purchasing syringes prefilled with drugs, finding it hard to get new syringes, reporting great or urgent need for treatment, and younger age were independently associated with co-injection. Past-6-month overdose was significantly associated with higher odds of co-injection in San Diego than in Tijuana. CONCLUSIONS: These findings indicate that heroin-methamphetamine co-injection is more common in Tijuana than in San Diego, yet this practice was only associated with overdose in San Diego. Heroin-methamphetamine coinjection was also independently associated with HIV-associated injection risk behaviors. Overdose-prevention interventions should address co-injection of depressants and stimulants.

Utilization of Google enterprise tools to georeference survey data among hard-to-reach groups: strategic application in international settings.

BACKGROUND: As geospatial data have become increasingly integral to health and human rights research, their collection using formal address designations or paper maps has been complicated by numerous factors, including poor cartographic literacy, nomenclature imprecision, and human error. As part of a longitudinal study of people who inject drugs in Tijuana, Mexico, respondents were prompted to georeference specific experiences. RESULTS: At baseline, only about one third of the 737 participants were native to Tijuana, underscoring prevalence of migration/deportation experience. Areas frequented typically represented locations with no street address (e.g. informal encampments). Through web-based cartographic technology and participatory mapping, this study was able to overcome the use of vernacular names and difficulties mapping liminal spaces in generating georeferenced data points that were subsequently analyzed in other research. CONCLUSION: Integrating low-threshold virtual navigation as part of data collection can enhance investigations of mobile populations, informal settlements, and other locations in research into structural production of health at low- or no cost. However, further research into user experience is warranted.

Short-term cessation of sex work and injection drug use: evidence from a recurrent event survival analysis.

OBJECTIVE: This study quantitatively examined the prevalence and correlates of short-term sex work cessation among female sex workers who inject drugs (FSW-IDUs) and determined whether injection drug use was independently associated with cessation. METHODS: We used data from FSW-IDUs (n=467) enrolled into an intervention designed to increase condom use and decrease sharing of injection equipment but was not designed to promote sex work cessation. We applied a survival analysis that accounted for quit-re-entry patterns of sex work over 1-year stratified by city, Tijuana and Ciudad Juarez, Mexico. RESULTS: Overall, 55% of participants stopped sex work at least once during follow-up. Controlling for other characteristics and intervention assignment, injection drug use was inversely associated with short-term sex work cessation in both cities. In Ciudad Juarez, women receiving drug treatment during follow-up had a 2-fold increase in the hazard of stopping sex work. In both cities, income from sources other than sex work, police interactions and healthcare access were independently and significantly associated with shorter-term cessation. CONCLUSIONS: Short-term sex work cessation was significantly affected by injection drug use. Expanded drug treatment and counseling coupled with supportive services such as relapse prevention, job training, and provision of alternate employment opportunities may promote longer-term cessation among women motivated to leave the sex industry.

Examining the spatial distribution of law enforcement encounters among people who inject drugs after implementation of Mexico's drug policy reform.

In 2009, Mexico decriminalized the possession of small amounts of illicit drugs for personal use in order to refocus law enforcement resources on drug dealers and traffickers. This study examines the spatial distribution of law enforcement encounters reported by people who inject drugs (PWID) in Tijuana, Mexico to identify concentrated areas of policing activity after implementation of the new drug policy. Mapping the physical location of law enforcement encounters provided by PWID (n = 461) recruited through targeted sampling, we identified hotspots of extra-judicial encounters (e.g., physical/sexual abuse, syringe confiscation, and money extortion by law enforcement) and routine authorized encounters (e.g., being arrested or stopped but not arrested) using point density maps and the Getis-Ord Gi* statistic calculated at the neighborhood-level. Approximately half of the participants encountered law enforcement more than once in a calendar year and nearly one third of these encounters did not result in arrest but involved harassment or abuse by law enforcement. Statistically significant hotspots of law enforcement encounters were identified in a limited number of neighborhoods located in areas with known drug markets. At the local-level, law enforcement activities continue to target drug users despite a national drug policy that emphasizes drug treatment diversion rather than punitive enforcement. There is a need for law enforcement training and improved monitoring of policing tactics to better align policing with public health goals.

Evaluating outcome-correlated recruitment and geographic recruitment bias in a respondent-driven sample of people who inject drugs in Tijuana, Mexico.

Respondent-driven sampling's (RDS) widespread use and reliance on untested assumptions suggests a need for new exploratory/diagnostic tests. We assessed geographic recruitment bias and outcome-correlated recruitment among 1,048 RDS-recruited people who inject drugs (Tijuana, Mexico). Surveys gathered demographics, drug/sex behaviors, activity locations, and recruiter-recruit pairs. Simulations assessed geographic and network clustering of active syphilis (RPR titers ≥1:8). Gender-specific predicted probabilities were estimated using logistic regression with GEE and robust standard errors. Active syphilis prevalence was 7 % (crude: men = 5.7 % and women = 16.6 %; RDS-adjusted: men = 6.7 % and women = 7.6 %). Syphilis clustered in the Zona Norte, a neighborhood known for drug and sex markets. Network simulations revealed geographic recruitment bias and non-random recruitment by syphilis status. Gender-specific prevalence estimates accounting for clustering were highest among those living/working/injecting/buying drugs in the Zona Norte and directly/indirectly connected to syphilis cases (men: 15.9 %, women: 25.6 %) and lowest among those with neither exposure (men: 3.0 %, women: 6.1 %). Future RDS analyses should assess/account for network and spatial dependencies.

Venue-level correlates of female sex worker registration status: a multilevel analysis of bars in Tijuana, Mexico.

In Tijuana, Mexico, sex work is regulated by the municipal government, through registration cards issued to female sex workers (FSWs) for an annual fee. Registration has been associated with decreased drug use and increase condom use and HIV testing. Previously, it was demonstrated that FSWs operating in bars were more likely than street-based FSWs to be registered. This implies that certain venues may be more accessible to local authorities for the enforcement of this type of programme. Taking a novel multilevel approach, we examined whether venue characteristics of bars reflecting greater organised management and visibility affect registration status of FSWs. In an analysis of venue-level characteristics, predictors of being registered were availability of free condoms at work and distance to the main sex strip; however, these were not independently associated after inclusion of FSWs' income, illicit drug use and history of HIV testing. Our findings suggest that sex work regulations may inadvertently exclude venues in which the more vulnerable and less visible FSWs, such as injection drug users and those with limited financial resources, are situated. Efforts to revise or reconsider sex work regulations to ensure that they best promote FSWs' health, human and labour rights are recommended.