Correlates of perceived risk of HIV infection among persons who inject drugs in Tijuana, Baja California, Mexico.

OBJECTIVE: We identified correlates of perceived risk of HIV infection among persons who inject drugs (PWID) in Tijuana. MATERIALS AND METHODS: PWID ≥18 years of age who injected drugs in the past month were recruited between 2006-2007 and completed risk assessment interviews and serologic testing for HIV, syphilis, and tuberculosis. Logistic regression was used to determine factors associated with high-perceived risk of HIV infection. RESULTS: Among 974 PWID, HIV prevalence was 4.4%; 45.0% of participants perceived themselves to be more likely to become HIV infected relative to other PWID in Tijuana. Participants who reported high-perceived risk of HIV infection participated in high-risk behaviors such as injecting with used syringes, transactional sex, and were less likely to have had an HIV test. CONCLUSIONS: Recognition of HIV infection risk was associated with high risk behaviors and markers of vulnerability. Findings support efforts to encourage HIV testing and access to health care for this vulnerable population.

Correlates of perceived risk of HIV infection among persons who inject drugs in Tijuana, Baja California, Mexico / Correlaciones de percepción de riesgo de infección con VIH entre personas que se inyectan droga en Tijuana, Baja California, México

Objective. We identified correlates of perceived risk of HIV infection among persons who inject drugs (PWID) in Tijuana. Materials and methods. PWID ≥18 years of age who injected drugs in the past month were recruited between 2006-2007 and completed risk assessment interviews and serologic testing for HIV, syphilis, and tuberculosis. Logistic regression was used to determine factors associated with high-perceived risk of HIV infection. Results. Among 974 PWID, HIV prevalence was 4.4%; 45.0% of participants perceived themselves to be more likely to become HIV infected relative to other PWID in Tijuana. Participants who reported high-perceived risk of HIV infection participated in high-risk behaviors such as injecting with used syringes, transactional sex, and were less likely to have had an HIV test. Conclusions. Recognition of HIV infection risk was associated with high risk behaviors and markers of vulnerability. Findings support efforts to encourage HIV testing and access to health care for this vulnerable population.

Objetivo. Identificar factores correlacionados con el riesgo percibido de contraer VIH entre personas que se inyectan drogas (PID) en Tijuana. Material y métodos. Entre 2006-2007 se reclutaron PID ≥18 años de edad que se inyectaron drogas en el último año previo al estudio y completaron entrevistas para evaluación de riesgos y pruebas serológicas para VIH, sífilis y tuberculosis. Se utilizó regresión logística para determinar factores asociados con alto-riesgo percibido para la infección del VIH. Resultados. En los 974 PID la prevalencia de VIH fue 4.4%; 45.0% se consideró con mayor probabilidad de infectarse con VIH en relación con otros PID en Tijuana. Los participantes que reportaron alto riesgo percibido participaron en comportamientos de alto riesgo como inyectarse con jeringas usadas y transacción sexual, y tenían menos probabilidades de haber tenido una prueba de VIH. Conclusiones. Reconocer el riesgo del VIH se asoció con comportamientos de alto riesgo y marcadores de vulnerabilidad. Los resultados apoyan los esfuerzos para fomentar las pruebas para VIH y acceso a servicios de salud para esta población vulnerable.

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.

Over-the-counter but out of reach: a pharmacy-based survey of OTC syringe sales in Tijuana, Mexico.

Sterile syringe access is critical to HIV prevention efforts targeting injection drug users (IDUs) but some pharmacies do not sell syringes over-the-counter (OTC) even where such sales are legal. We conducted a pharmacy survey in Tijuana, Mexico (where OTC sales are legal) to characterize attitudes toward syringe sales and to explore support for expanding pharmacy-based HIV prevention efforts. Of 203 respondents, 28% supported OTC syringe sales to IDUs and 74% said their pharmacy required a prescription for at least some syringe sales. Support for OTC syringe sales was independently associated with selling OTC syringes, understanding the role of sterile syringes in HIV prevention, and recognizing pharmacies as an important health resource for IDUs. Most respondents supported an expanded role for pharmacies in HIV prevention, exclusive of OTC syringe sales. Our study provides information for developing interventions to promote OTC syringe sales and expanding pharmacy-based distribution of HIV-related information and resources.

Prevalence and correlates of client-perpetrated abuse among female sex workers in two Mexico-U.S. border cities.

History of abuse has been associated with greater HIV risk among women. This study examined client-perpetrated abuse among female sex workers (FSWs) in two Mexico-U.S. border cities where HIV prevalence is rising. Among 924 FSWs, prevalence of client-perpetrated abuse was 31%. In multivariate logistic regression models, intimate partner violence (IPV), psychological distress, and having drug-using clients were associated with experiencing client-perpetrated abuse. FSWs along the Mexico-U.S. border report frequently experiencing abuse from both clients and intimate partners, which may have serious mental health consequences. Our findings suggest the need for screening and gender-based violence prevention services for Mexican FSWs.

Perceived risk of HIV infection among deported male injection drug users in Tijuana, Mexico.

Deported injection drug users (IDUs) in Mexico may be vulnerable to HIV infection following expulsion from the USA. We examined factors associated with HIV risk perception among a sample of deportees in Tijuana. From January to April 2010, 313 male IDUs who reported ever being deported from the USA completed a questionnaire. Overall, 35% (N=110) of deportees perceived HIV risk. In multivariate logistic regression analyses, factors independently associated with HIV risk perception included ever having a steady female partner in Tijuana post-deportation (adjusted odds ratio [AOR]: 2.26; 95% confidence interval [CI]: 1.01-5.07) and years spent in a US prison (AOR: 1.29 per year; 95% CI: 1.13-1.48). Conversely, years of drug injection use (AOR: 0.95 per year; 95% CI: 0.91-0.99), ever witnessing family members use drugs prior to first migration trip (AOR: 0.24; 95% CI: 0.09-0.65), years of residence in the USA (AOR: 0.91 per year; 95% CI: 0.84-0.98) and being a Tijuana native (AOR: 0.40; 95% CI: 0.16-0.99) were negatively associated with HIV risk perception. US-Mexico border cities that receive deported migrants should target HIV prevention interventions to specific subgroups, including drug-using male deportees. Interventions should consider migrant's time in the USA, the role of their social networks, and reducing missed opportunities for HIV testing/education.

Correlates of injecting in an HIV incidence hotspot among substance users in Tijuana, Mexico.

BACKGROUND: Substance use and HIV are growing problems in the Mexico-U.S. border city of Tijuana, a sex tourism destination situated on a northbound drug trafficking route. In a previous longitudinal study of injection drug users (IDUs), we found that >90% of incident HIV cases occurred within an 'HIV incidence hotspot,' consisting of 2.5-blocks. This study examines behavioral, social, and environmental correlates associated with injecting in this HIV hotspot. METHODS: From 4/06 to 6/07, IDUs aged ≥18 years were recruited using respondent-driven sampling. Participants underwent antibody testing for HIV and syphilis and interviewer-administered surveys eliciting information on demographics, drug use, sexual behaviors, and socio-environmental influences. Participants were defined as injecting in the hotspot if they most frequently injected within a 3 standard deviational ellipse of the cohort's incident HIV cases. Logistic regression was used to identify individual and structural factors associated with the HIV 'hotspot'. RESULTS: Of 1031 IDUs, the median age was 36 years; 85% were male; HIV prevalence was 4%. As bivariate analysis indicated different correlates for males and females, models were stratified by sex. Factors independently associated with injecting in the HIV hotspot for male IDUs included homelessness (AOR 1.72; 95%CI 1.14-2.6), greater intra-urban mobility (AOR 3.26; 95%CI 1.67-6.38), deportation (AOR 1.58; 95%CI 1.18-2.12), active syphilis (AOR 3.03; 95%CI 1.63-5.62), needle sharing (AOR 0.57; 95%CI 0.42-0.78), various police interactions, perceived HIV infection risk (AOR 1.52; 95%CI 1.13-2.03), and health insurance status (AOR 0.53; 95%CI 0.33-0.87). For female IDUs, significant factors included sex work (AOR 8.2; 95%CI 2.2-30.59), lifetime syphilis exposure (AOR 2.73; 95%CI 1.08-6.93), injecting inside (AOR 5.26; 95%CI 1.54-17.92), arrests for sterile syringe possession (AOR 4.87; 95%I 1.56-15.15), prior HIV testing (AOR 2.45; 95%CI 1.04-5.81), and health insurance status (AOR 0.12; 95%CI 0.03-0.59). CONCLUSION: While drug and sex risks were common among IDUs overall, policing practices, STIs, mobility, and lack of healthcare access were correlated with injecting in this HIV transmission hotspot. Although participants in the hotspot were more aware of HIV risks and less likely to report needle sharing, interventions addressing STIs and structural vulnerabilities may be needed to effectively address HIV risk.

Establishing a binational student-run free-clinic in Tijuana, Mexico: a model for US-Mexico border states.

In 2011, a bi-national student-run free clinic for the underserved, known as "Health Frontiers in Tijuana" (HFiT), was created in Tijuana, Mexico. Students and faculty from one Mexican and one US medical school staff the clinic and attend patients on Saturdays. Students from both medical schools enroll in a didactic course during the quarter/semester that they attend the free clinic. The course addresses clinical, ethical, cultural, population-specific issues and the structure, financing and delivery of medical care in Mexico. The clinic implements an electronic medical record and is developing telemedicine for consulting on complex cases. Despite challenges related to sustaining adequate funding, this program may be replicated in other border communities.

Prevalence and characteristics of abuse experiences and depression symptoms among injection drug-using female sex workers in Mexico.

This mixed methods study examined the prevalence and characteristics of physical and sexual abuse and depression symptoms among 624 injection drug-using female sex workers (FSW-IDUs) in Tijuana and Ciudad Juarez, Mexico; a subset of 47 from Tijuana also underwent qualitative interviews. Linear regressions identified correlates of current depression symptoms. In the interviews, FSW-IDUs identified drug use as a method of coping with the trauma they experienced from abuse that occurred before and after age 18 and during the course of sex work. In a multivariate linear regression model, two factors-ever experiencing forced sex and forced sex in the context of sex work-were significantly associated with higher levels of depression symptoms. Our findings suggest the need for integrated mental health and drug abuse services for FSW-IDUs addressing history of trauma as well as for further research on violence revictimization in the context of sex work in Mexico.

Reductions in HIV/STI incidence and sharing of injection equipment among female sex workers who inject drugs: results from a randomized controlled trial.

BACKGROUND: We evaluated brief combination interventions to simultaneously reduce sexual and injection risks among female sex workers who inject drugs (FSW-IDUs) in Tijuana and Ciudad Juarez, Mexico during 2008-2010, when harm reduction coverage was expanding rapidly in Tijuana, but less so in Juarez. METHODS: FSW-IDUs ≥18 years reporting sharing injection equipment and unprotected sex with clients within the last month participated in a randomized factorial trial comparing four brief, single-session conditions combining either an interactive or didactic version of a sexual risk intervention to promote safer sex in the context of drug use, and an injection risk intervention to reduce sharing of needles/injection paraphernalia. Women underwent quarterly interviews and testing for HIV, syphilis, gonorrhea, Chlamydia and Trichomonas, blinding interviewers and assessors to assignment. Poisson regression with robust variance estimation and repeated measures ordinal logistic regression examined effects on combined HIV/STI incidence and receptive needle sharing frequency. FINDINGS: Of 584 initially HIV-negative FSW-IDUs, retention was ≥90%. After 12 months, HIV/STI incidence decreased >50% in the interactive vs. didactic sex intervention (Tijuana:AdjRR:0.38,95% CI:0.16-0.89; Juarez: AdjRR:0.44,95% CI:0.19-0.99). In Juarez, women receiving interactive vs. didactic injection risk interventions decreased receptive needle-sharing by 85% vs. 71%, respectively (p = 0.04); in Tijuana, receptive needle sharing declined by 95%, but was similar in active versus didactic groups. Tijuana women reported significant increases in access to syringes and condoms, but Juarez women did not. INTERPRETATION: After 12 months in both cities, the interactive sexual risk intervention significantly reduced HIV/STI incidence. Expanding free access to sterile syringes coupled with brief, didactic education on safer injection was necessary and sufficient for achieving robust, sustained injection risk reductions in Tijuana. In the absence of expanding syringe access in Juarez, the injection risk intervention achieved significant, albeit more modest reductions, suggesting that community-level interventions incorporating harm reduction are more powerful than individual-level interventions. TRIAL REGISTRATION: clinicaltrials.gov NCT00840658.

Individual, interpersonal, and social-structural correlates of involuntary sex exchange among female sex workers in two Mexico-U.S. border cities.

BACKGROUND: To investigate individual, interpersonal, and social-structural factors associated with involuntary sex exchange among female sex workers (FSWs) along the Mexico-U.S. border. METHODS: In 2010 to 2011, 214 FSWs from Tijuana (n = 106) and Ciudad Juarez (n = 108) aged ≥ 18 years who reported lifetime use of heroin, cocaine, crack, or methamphetamine, having a stable partner, and having sold/traded sex in the past month completed quantitative surveys and HIV/sexually transmitted infection testing. Logistic regression was used to identify correlates of involuntary sex exchange among FSWs. RESULTS: Of 214 FSWs, 31 (14.5%) reported involuntary sex exchange These women were younger at sex industry entry [adjusted odds ratio (AOR): 0.84/1-year increase, 95% confidence interval (CI): 0.72 to 0.97] and were significantly more likely to service clients whom they perceived to be HIV/sexually transmitted infection-infected (AOR: 12.41, 95% CI: 3.15 to 48.91). In addition, they were more likely to have clients who used drugs (AOR: 7.88, 95% CI: 1.52 to 41.00), report poor working conditions (AOR: 3.27, 95% CI: 1.03 to 10.31), and report a history of rape (AOR: 4.46, 95% CI: 1.43 to 13.91). CONCLUSIONS: Involuntary sex exchange is disproportionate among FSWs who begin to exchange sex at a younger age, and these women experience elevated risk of violence and HIV/STIs related to their clients' behaviors and their working conditions. These data suggest the critical need for evidence-based approaches to preventing sexual exploitation of women and girls and to reducing harm among current sex workers. Multilevel interventions for all females who exchange sex and their clients that target interpersonal and social-structural risks (eg, measures to improve safety and reduce exploitation within the workplace) are needed.

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.

Social support and recovery among Mexican female sex workers who inject drugs.

This qualitative study describes social support that female sex workers who inject drugs (FSW-IDUs) receive and recovery efforts in the context of relationships with family and intimate partners. We conducted thematic analysis of in-depth interviews with 47 FSW-IDUs enrolled in an intervention study to reduce injection/sexual risk behaviors in Tijuana, Mexico. FSW-IDUs received instrumental and emotional social support, which positively and negatively influenced recovery efforts. Participants reported how some intimate partners provided conflicting positive and negative support during recovery attempts. Problematic support (i.e., well-intended support with unintended consequences) occurred in strained family relationships, limiting the positive effects of support. Mexican drug treatment programs should consider addressing social support in recovery curricula through evidence-based interventions that engage intimate partners, children and family to better reflect socio-cultural and contextual determinants of substance abuse.

Syringe confiscation as an HIV risk factor: the public health implications of arbitrary policing in Tijuana and Ciudad Juarez, Mexico.

Female sex workers who inject drugs (FSW-IDUs) face elevated risk for HIV/STIs and constitute a key population for public health prevention. Through direct and indirect pathways including human rights violations, policing practices like syringe confiscation can compound FSW-IDU health risk and facilitate the spread of disease. We studied correlates of experiencing syringe confiscation among FSW-IDUs in northern Mexico, where formal policy allows for syringes to be available over the counter without a prescription, but police practices are often at odds with the law. FSW-IDUs reporting recent syringe sharing and unprotected sex with clients in Tijuana and Ciudad Juarez were administered surveys and HIV/STI testing. Logistic regression was used to identify correlates of syringe confiscation. Among 624 respondent FSW-IDUs, prevalence of syringe confiscation in the last 6 months was 48%. The following factors were positively associated with syringe confiscation: testing positive for HIV (adjusted odds ratio [aOR] = 2.54, 95% confidence interval [CI] = 1.11-5.80), reporting sexual abuse by police (aOR = 12.76, 95% CI = 6.58-24.72), engaging in groin injection (aOR = 1.84, 95% CI = 1.15-2.93), injecting in public (aOR = 1.64; 95% CI = 1.14-2.36), and obtaining syringes from pharmacies (aOR = 1.54; 95% CI = 1.06-2.23). Higher education level was negatively associated with syringe confiscation (aOR = 0.92, 95% CI = 0.87-0.98) as was frequent injection with clients within the last month (aOR = 0.64, 95% CI = 0.44-0.94). This analysis adds to the body of evidence linking unauthorized law enforcement actions targeting high-risk groups with HIV and other adverse health outcomes. Using a public health lens to conceptualize abuse as a structural risk factor, we advocate for multi-prong prevention, systematic monitoring, and evidence-based intervention response to deleterious police practices.

Factors associated with pathways toward concurrent sex work and injection drug use among female sex workers who inject drugs in northern Mexico.

AIMS: To identify factors associated with time to initiation of (i) sex work prior to injecting drugs initiation; (ii) injection drug use prior to sex work initiation; and (iii) concurrent sex work and injection drug use (i.e. initiated at the same age) among female sex workers who currently inject drugs (FSW-IDU). DESIGN: Parametric survival analysis of baseline data for time to initiation event. SETTING: Tijuana and Ciudad Juarez situated on the Mexico-US border. PARTICIPANTS: A total of 557 FSW-IDUs aged ≥18 years. MEASUREMENTS: Interview-administered surveys assessing context of sex work and injection drug use initiation. FINDINGS: Nearly half (n = 258) initiated sex work prior to beginning to inject, a third (n = 163) initiated injection first and a quarter (n = 136) initiated both sex work and injection drug use concurrently. Low education and living in Ciudad Juarez accelerated time to sex work initiation. Being from a southern Mexican state and initiating drug use with inhalants delayed the time to first injection drug use. Having an intimate partner encourage entry into sex work and first injecting drugs to deal with depression accelerated time to initiating sex work and injection concurrently. Early physical abuse accelerated time to initiating sex work and injection, and substantially accelerated time to initiation of both behaviors concurrently. CONCLUSIONS: Among female sex workers who currently inject drugs in two Mexican-US border cities, nearly half appear to initiate sex work prior to beginning to inject, nearly one-third initiate injection drug use before beginning sex work and one-quarter initiate both behaviors concurrently. Predictors of these three trajectories differ, and this provides possible modifiable targets for prevention.

Reducing harm from HIV/AIDS misconceptions among female sex workers in Tijuana and Ciudad Juarez, Mexico: A cross sectional analysis.

BACKGROUND: HIV prevalence is increasing among female sex workers (FSWs) in Mexico's Northern border region, who experience multiple occupational risks. Improving vulnerable populations' education, empowerment, and access to preventive services are important components of harm reduction strategies. Given the increasing interest in adapting harm reduction principles from drug use to sex work and other public health responses to the HIV epidemic, we used a sex work harm reduction framework to guide our investigation of FSWs' HIV knowledge. METHODS: From 2004-2006, FSWs aged ≥18 years in Tijuana and Ciudad Juarez participated in a behavioral intervention study and completed structured interviews. Measures included HIV knowledge assessment and factors within each domain of our theoretical framework for sex work harms: (1) socio-demographic factors that may lead to sex work, (2) sex work characteristics and behaviors that may lead to harm, and (3) mutually reinforcing harms that lead to sex work and result from it (e.g., drug abuse). Negative binomial regression identified factors independently associated with suboptimal HIV knowledge (i.e., incorrect responses during the HIV knowledge assessment). RESULTS: Among 924 FSWs, the median proportion of incorrect responses was nearly one third (28% incorrect). Examination of item responses revealed misconceptions regarding specific transmission and prevention mechanisms, including prevention of mother to child transmission. Suboptimal HIV knowledge was independently associated with older age, lower education, living in Tijuana (vs. Ciudad Juarez), inconsistent condom use for vaginal sex with male clients, and lacking prior HIV testing. CONCLUSIONS: Our application of a sex work harm reduction framework to the study of FSWs' HIV knowledge is an important first step in enhancing HIV prevention efforts in Northern Mexican border cities. Our findings imply that interventions should identify and discredit local HIV misconceptions to improve knowledge of specific HIV transmission routes and self-protective strategies (e.g., condom negotiation). Interventions will require materials appropriate for women from diverse socio-economic backgrounds and may benefit from innovative harm reduction approaches such as peer education and outreach.

Mujer Mas Segura (Safer Women): a combination prevention intervention to reduce sexual and injection risks among female sex workers who inject drugs.

BACKGROUND: Female sex workers who inject drugs (FSW-IDUs) are at risk of acquiring HIV, sexually transmitted infections (STI) and blood-borne infections through unprotected sex and sharing injection equipment. We conducted a 2×2 factorial randomized controlled trial to evaluate combination interventions to simultaneously reduce sexual and injection risks among FSW-IDUs in Tijuana and Ciudad Juarez, Mexico. METHODS/DESIGN: FSW-IDUs ≥18 years reporting sharing injection equipment and unprotected sex with clients within the last month were randomized to one of four conditions based on an a priori randomization schedule, blinding interviewer/counselors to assignment. Due to the extreme vulnerability of this population, we did not include a control group that would deny some women access to preventive information. All women received similar information regardless of group allocation; the difference was in the way the information was delivered and the extent to which women had an interactive role. Each condition was a single 60-minute session, including either an interactive or didactic version of an injection risk intervention and sexual risk intervention. Women underwent interviewer-administered surveys and testing for HIV, syphilis, gonorrhea, Chlamydia, and Trichomonas at baseline and quarterly for 12 months. Combined HIV/STI incidence will be the primary outcome. Secondary outcomes are proportionate reductions in sharing of injection equipment and unprotected sex with clients. DISCUSSION: Of 1,132 women, 548 (48.4%) were excluded (88.9% were ineligible; 11.1% refused to participate or did not return); 584 eligible women enrolled (284 in Tijuana; 300 in Ciudad Juarez). All 584 participants completed the baseline interview, provided biological samples and were randomized to one of the four groups. During follow-up, 17 participants (2.9%) were lost to follow-up, of whom 10 (58.8%) had died, leaving 567 participants for analysis. This study appears to be the first intervention to attempt to simultaneously reduce injection and sexual risk behaviors among FSW-IDUs. The factorial design will permit analysis to determine whether the combination of the two interactive interventions and/or its respective components are effective in reducing injection and/or sexual risks, which will have direct, tangible policy implications for Mexico and potentially other resource-poor countries. TRIAL REGISTRATION: NCT00840658.

Tuberculosis testing among populations with high HIV risk in Tijuana, Baja California, Mexico.

OBJECTIVE: To assess the prevalence of prior tuberculin skin testing (TST) among populations at risk for HIV infection in Tijuana, Mexico, and to identify factors associated with TST. METHODS: Sex workers, injection drug users, noninjecting drug users, and homeless persons > 18 years old were recruited by using targeted sampling for risk assessment interviews and serologic testing for HIV and Mycobacterium tuberculosis infection. Univariate and multivariate logistic regression were used to identify correlates of self-reported TST history. RESULTS: Of 502 participants, 38.0% reported prior TST, which was associated with previous incarceration in the United States of America [odds ratio (OR) = 13.38; 95% confidence interval (CI) = 7.37-24.33] and injection drug use (OR = 1.99; 95% CI = 1.27- 3.11). Positive results on serologic tests for M. tuberculosis infection (57%) and HIV (4.2%) were not associated with a prior TST. CONCLUSIONS: A history of TST was lower in HIV-positive participants even though TST is indicated for persons with HIV in Mexico. Fewer than half the individuals at high risk for HIV in this study had a history of TST; however, TST was fairly common among those individuals with a prior history of incarceration. Increased tuberculosis screening is needed for populations at risk of contracting HIV in Tijuana, particularly those outside of criminal justice settings.

Mexico's northern border conflict: collateral damage to health and human rights of vulnerable groups.

OBJECTIVE: To compare distributions of human rights violations and disease risk; to juxtapose these patterns against demographic and structural environmental variables, and to formulate implications for structural interventions. METHODS: Female sex workers who inject drugs were surveyed in Tijuana and Ciudad Juarez, Mexico. Structured interviews and testing for sexually transmitted infections (STIs) were conducted (October 2008 to October 2009). Frequencies of individual and environmental factors, including police abuse, risk of HIV infection, and protective behaviors, were compared between sites using univariate logistic regression. RESULTS: Of 624 women, almost half reported police syringe confiscation despite syringes being legal; 55.6% reported extortion (past 6 months), with significantly higher proportions in Ciudad Juarez (P < 0.001). Reports of recent solicitation of sexual favors (28.5% in Tijuana, 36.5% in Ciudad Juarez, P = 0.04) and sexual abuse (15.7% in Tijuana, 18.3% in Ciudad Juarez) by police were commonplace. Prevalence of STIs was significantly lower in Tijuana than in Ciudad Juarez (64.2% and 83.4%, P < 0.001), paralleling the lower prevalence of sexual risk behaviors there. Ciudad Juarez respondents reported significantly higher median number of monthly clients (6.8 versus 1.5, P < 0.001) and lower median pay per sex act (US$ 10 versus US$ 20, P < 0.001) (in the past month). Relative to Tijuana, security deployment, especially the army's presence, was perceived to have increased more in Ciudad Juarez in the past year (72.1% versus 59.2%, P = 0.001). CONCLUSIONS: Collateral damage from police practices in the context of Mexico's drug conflict may affect public health in the Northern Border Region. Itinerant officers may facilitate disease spread beyond the region. The urgency for mounting structural interventions is discussed.