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1.  Methodology for Evaluating a Partially Controlled Longitudinal Treatment Using Principal Stratification, With Application to a Needle Exchange Program 
We consider studies for evaluating the short-term effect of a treatment of interest on a time-to-event outcome. The studies we consider are only partially controlled in the following sense: (1) Subjects’ exposure to the treatment of interest can vary over time, but this exposure is not directly controlled by the study; (2) subjects’ follow-up time is not directly controlled by the study; and (3) the study directly controls another factor that can affect subjects’ exposure to the treatment of interest as well as subjects’ follow-up time. When factors 1 and 2 are both present in the study, evaluating the treatment of interest using standard methods, including instrumental variables, does not generally estimate treatment effects. We develop the methodology for estimating the effect of treatment 1 in this setting of partially controlled studies under explicit assumptions using the framework for principal stratification for causal inference. We illustrate our methods by a study to evaluate the efficacy of the Baltimore Needle Exchange Program to reduce the risk of human immunodeficiency virus (HIV) transmission, using data on distance of the program’s sites from the subjects.
PMCID: PMC4332568
Causal inference; HIV; Needle exchange; Partially controlled studies; Potential outcomes; Principal stratification
2.  Prevalence and correlates of HIV among men who have sex with men in Tijuana, Mexico 
Men who have sex with men (MSM) in developing countries such as Mexico have received relatively little research attention. In Tijuana, Mexico, a border city experiencing a dynamic HIV epidemic, data on MSM are over a decade old. Our aims were to estimate the prevalence and examine correlates of HIV infection among MSM in this city.
We conducted a cross-sectional study of 191 MSM recruited through respondent-driven sampling (RDS) in 2012. Biological males over the age of 18 who resided in Tijuana and reported sex with a male in the past year were included. Participants underwent interviewer-administered surveys and rapid tests for HIV and syphilis with confirmation.
A total of 33 MSM tested positive for HIV, yielding an RDS-adjusted estimated 20% prevalence. Of those who tested positive, 89% were previously unaware of their HIV status. An estimated 36% (95% CI: 26.4–46.5) had been tested for HIV in the past year, and 30% (95% CI: 19.0–40.0) were estimated to have ever used methamphetamine. Independent correlates of being infected with HIV were methamphetamine use (odds ratio [OR]=2.24, p=0.045, 95% CI: 1.02, 4.92) and active syphilis infection (OR=4.33, p=0.01, 95% CI: 1.42, 13.19).
Our data indicate that MSM are a key sub-population in Tijuana at higher risk for HIV. Tijuana would also appear to have the highest proportion among upper-middle-income countries of HIV-positive MSM who are unknowingly infected. More HIV prevention research on MSM is urgently needed in Tijuana.
PMCID: PMC4323407  PMID: 25669423
men who have sex with men; correlates of HIV infection; HIV prevalence; US–Mexico border; global public health; respondent-driven sampling
3.  Early sex work initiation independently elevates odds of HIV infection and police arrest among adult sex workers in a Canadian setting 
To explore factors associated with early sex work initiation, and model the independent effect of early initiation on HIV infection and prostitution arrests among adult sex workers (SWs).
Baseline data (2010–2011) were drawn from a cohort of SWs who exchanged sex for money within the last month and were recruited through time-location sampling in Vancouver, Canada. Analyses were restricted to adults ≥18 years old.
SWs completed a questionnaire and HIV/STI testing. Using multivariate logistic regression, we identified associations with early sex work initiation (<18 years old) and constructed confounder models examining the independent effect of early initiation on HIV and prostitution arrests among adult SWs.
Of 508 SWs, 193 (38.0%) reported early sex work initiation, with 78.53% primarily street-involved SWs and 21.46% off-street SWs. HIV prevalence was 11.22%, which was 19.69% among early initiates. Early initiates were more likely to be Canadian-born (Adjusted Odds Ratio (AOR): 6.8, 95% Confidence Interval (CI): 2.42–19.02), inject drugs (AOR: 1.6, 95%CI: 1.0–2.5), and to have worked for a manager (AOR: 2.22, 95%CI: 1.3–3.6) or been coerced into sex work (AOR: 2.3, 95%CI: 1.14–4.44). Early initiation retained an independent effect on increased risk of HIV infection (AOR: 2.5, 95% CI: 1.3–3.2) and prostitution arrests (AOR: 2.0, 95%CI: 1.3–3.2).
Adolescent sex work initiation is concentrated among marginalized, drug and street-involved SWs. Early initiation holds an independent increased effect on HIV infection and criminalization of adult SWs. Findings suggest the need for evidence-based approaches to reduce harm among adult and youth SWs.
PMCID: PMC4056677  PMID: 23982660
sex work; youth; adolescent; HIV; sexually transmitted infections; criminalization; policing
4.  Cigarette Smoking and Quit Attempts Among Injection Drug Users in Tijuana, Mexico 
Nicotine & Tobacco Research  2013;15(12):2060-2068.
Injection drug use and cigarette smoking are major global health concerns. Limited data exist regarding cigarette smoking behavior and quit attempts among injection drug users (IDUs) in low- and middle-income countries to inform the development of cigarette smoking interventions. We conducted a cross-sectional study to describe cigarette smoking behavior and quit attempts among IDUs in Tijuana, Mexico.
IDUs were recruited through community outreach and administered in-person interviews. Multivariable Poisson regression models were constructed to determine prevalence ratios (PRs) for quit attempts.
Of the 670 participants interviewed, 601 (89.7%) were current smokers. Of these, median number of cigarettes smoked daily was 10; 190 (31.6%) contemplated quitting smoking in the next 6 months; 132 (22.0%) had previously quit for ≥1 year; and 124 (20.6%) had made a recent quit attempt (lasting ≥1 day during the previous 6 months). In multivariable analysis, recent quit attempts were positively associated with average monthly income (≥3,500 pesos [US$280] vs. <1,500 pesos [US$120]; PR = 2.30; 95% CI = 1.57–3.36), smoking marijuana (PR = 1.38; 95% CI = 1.01–2.90), and smoking heroin (PR = 1.85; 95% CI = 1.23–2.78), and they were negatively associated with number of cigarettes smoked daily (PR = 0.96; 95% CI = 0.94–0.98).
One out of 5 IDUs attempted to quit cigarette smoking during the previous 6 months. Additional research is needed to improve the understanding of the association between drug use patterns and cigarette smoking quit attempts, including the higher rate of quit attempts observed among IDUs who smoke marijuana or heroin compared with IDUs who do not smoke these substances.
PMCID: PMC3819980  PMID: 23873979
5.  Mexico’s “ley de narcomenudeo” drug policy reform and the international drug control regime 
Harm Reduction Journal  2014;11(1):31.
It has been over half a century since the landmark Single Convention on Narcotic Drugs was adopted, for the first time unifying international drug policy under a single treaty aimed at limiting use, manufacture, trade, possession, and trafficking of opiates, cannabis, and other narcotics. Since then, other international drug policy measures have been adopted, largely emphasizing enforcement-based approaches to reducing drug supply and use. Recently, in response to concerns that the historic focus on criminalization and enforcement has had limited effectiveness, international drug policies have begun to undergo a paradigm shift as countries seek to enact their own reforms to partially depenalize or deregulate personal drug use and possession. This includes Mexico, which in 2009 enacted national drug policy reform partially decriminalizing possession of small quantities of narcotics for personal consumption while also requiring drug treatment for repeat offenders. As countries move forward with their own reform models, critical assessment of their legal compatibility and effectiveness is necessary. In this commentary we conduct a critical assessment of the compatibility of Mexico’s reform policy to the international drug policy regime and describe its role in the current evolving drug policy environment. We argue that Mexico’s reform is consistent with flexibilities allowed under international drug treaty instruments and related commentaries. We also advocate that drug policy reforms and future governance efforts should be based on empirical evidence, emphasize harm reduction practices, and integrate evidence-based evaluation and implementation of drug reform measures.
PMCID: PMC4234880  PMID: 25395346
International drug policy; Single convention; Harm reduction; Mexico drug policy; Drug policy reform; UN office of drugs and crime; Global health
6.  Context matters: The moderating role of bar context in the association between substance use during sex and condom use among male clients of female sex workers in Tijuana, Mexico 
AIDS and behavior  2013;17(8):2577-2587.
Tijuana is situated on Mexico’s northern border with the U.S., where sex work is quasi-legal. Whereas previous work has focused on the risk behaviors of female sex workers (FSWs), less is known about the risk behaviors of their male clients. Further, research has not examined structural factors as moderators of the association between substance use and condom use, including the contexts in which sex takes place. The purpose of the current study is to examine whether having sex with FSWs in a bar moderates the link between alcohol intoxication during sex and condom use. We recruited 375 male clients of FSWs in Tijuana, Mexico from San Diego, California and Tijuana. Using computer assisted interviewing, we surveyed participants on their alcohol use, condom use, and physical contexts of sex with FSWs in the past four months. Results showed that more frequent intoxication during sex with FSWs is associated with more unprotected sex, but only among clients having sex with FSWs in a bar context. Results point to potential reasons for inconsistent condom use with FSWs in this context, including lower risk perceptions of sex with FSWs in bars. Future research should examine structural factors that underlie clients’ risk behavior in bars in order to inform structural-level HIV prevention interventions.
PMCID: PMC3778075  PMID: 23640653
HIV risk; male clients; female sex workers; alcohol use; risk environment; structural interventions
7.  Law Enforcement Practices Associated with HIV Infection Among Injection Drug Users in Odessa, Ukraine 
AIDS and behavior  2013;17(8):2604-2614.
Despite HIV prevention efforts over the past 10 years in Odessa, Ukraine, HIV rates among injection drug users (IDUs) remain high. We explored whether IDUs’ experiences with the police and court system in Odessa were associated with HIV serostatus, after controlling for other factors. Qualitative methods, including semi-structured interviews with the police and members of court (N = 19), and focus groups with IDUs (N = 42), were employed to aid in developing a survey instrument for a larger quantitative phase and to assist in interpreting the findings from the quantitative phase, which included 200 participants who were interviewed and tested for HIV. Overall, 55 % tested positive for HIV. Negative experiences with the police were noted by 86 % and included having preloaded syringes taken (66 %), rushed injections due to fear of the police (57 %), police planting drugs (18 %), paying police to avoid arrest (61 %) and threatened by the police to inform on other IDUs (23 %). HIV positive participants were more likely than those who were negative to report these experiences. In a multiple logistic regression, the most significant correlate of HIV infection was rushed injections due to fear of the police. Police actions in Odessa may be contributing to the continued escalation of HIV among IDUs, underscoring the need for structural interventions.
PMCID: PMC3787985  PMID: 23754613
Injection drug user (IDU); Law enforcement; Ukraine
10.  Sex workers’ non-commercial male partners who inject drugs report higher risk sexual behaviors 
Sexually transmitted diseases  2013;40(10):801-803.
Female sex workers (FSWs) are less likely to use condoms with non-commercial male partners than clients. We compare non-commercial male partners who do and do not inject drugs in Tijuana and Ciudad Juárez, Mexico. Sexual risk behaviors were more prevalent among injectors, who could promote HIV/STI transmission in this region.
PMCID: PMC3890981  PMID: 24275732
female sex workers; male partners; couples; sexually transmitted infections; injection drug use
11.  Client demands for unsafe sex: the socio-economic risk environment for HIV among street and off-street sex workers 
Among sex workers (SWs) in Vancouver, Canada, this study identified social, drug use, sex work, environmental-structural and client-related factors associated with being offered and accepting more money after clients' demand for sex without a condom.
Cross-sectional study using baseline (February/10-October/11) data from a longitudinal cohort of 510 SWs.
A two-part multivariable regression model was used to identify factors associated with two separate outcomes: (1) being offered and (2) accepting more money for sex without a condom in the last six months, among those who had been offered more money.
The sample included 490 SWs. In multivariable analysis, being offered more money for sex without a condom was more likely for SWs who used speedballs, had higher average numbers of clients per week, had difficulty accessing condoms and had clients who visited other SWs. Accepting more money for sex without a condom was more likely for SWs self-reporting as a sexual minority and who had experienced client violence and used crystal methamphetamine use less than daily (vs. none), and less likely for SWs who solicited for clients mainly indoors (vs. outdoor/public places).
These results highlight the high demand for sex without a condom by clients of SWs. HIV prevention efforts should shift responsibility toward clients to reduce offers of more money for unsafe sex. Programs that mitigate the social and economic risk environments of SWs alongside the removal of criminal sanctions on sex work to enable condom use within safer indoor work spaces are urgently required.
PMCID: PMC3706016  PMID: 23614990
condom use; sex workers; Canada; HIV risk; clients
12.  Barriers to accessing substance abuse treatment in Mexico: national comparative analysis by migration status 
We examined Mexican migrants’ perceived barriers to entering substance abuse treatment and potential differences by gender.
This study analyzed a subset of household data collected in Mexico in 2011 via the Encuesta Nacional de Adicciones (National Survey of Addictions). A sample of 1,143 individuals who reported using illicit drugs was analyzed using multivariate negative binomial models to determine direct and moderated relationships of gender, migrant status, and drug dependence with perceived barriers to accessing treatment.
Significant findings included disparities in drug dependence by migrant status. Compared with non-migrant men, women who have traveled to the United States was associated with fewer (1.3) barriers to access treatment. Fewer barriers to access care were associated with individuals residing in other regions of the country, compared to those living in Mexico City.
Drug dependence, gender, migration status and regional location are factors associated with access to needed treatment. Implications for health care policy to develop treatment services infrastructure and for future research are discussed in the context of ongoing drug policy reform in Mexico.
PMCID: PMC4118628  PMID: 25074067
Barriers to treatment; Migrant status; Gender; Mexico; Drug dependence
13.  Not Just the Needle: The State of HIV Prevention Science among Substance Users and Future Directions 
Successes in preventing HIV transmission among substance using populations have focused primarily among injection drug users, which have produced measurable reductions in HIV incidence and prevalence. By contrast, the majority of substances used worldwide are administered by non-injectable means, and there is a dearth of HIV prevention interventions that target non-injecting substance users. Increased surveillance of trends in substance use, especially cocaine (including crack) and methamphetamine in addition to new and emerging substances (e.g., synthetic cannabinoids, cathinones and other amphetamine analogs) are needed to develop and scale-up effective and robust interventions for populations at risk for HIV-transmission via sexual behaviors related to non-injection substance use. Strategies are needed that address unique challenges to HIV prevention for substance users who are HIV-infected and those who are HIV- uninfected and at high risk. We propose a research agenda that prioritizes: (1) ) combination HIV prevention strategies in substance users; (2) behavioral HIV prevention programs that reduce sexual transmission behaviors in non-treatment seeking individuals; (3) medical and/or behavioral treatments for substance abuse that reduce/eliminate substance-related sexual transmission behaviors; and (4) structural interventions to reduce HIV incidence.
PMCID: PMC3739052  PMID: 23764632
14.  Association between Childhood Physical Abuse, Unprotected Receptive Anal Intercourse and HIV Infection among Young Men Who Have Sex with Men in Vancouver, Canada 
PLoS ONE  2014;9(6):e100501.
The association between childhood sexual abuse and HIV risk among men who have sex with men (MSM) is well established. However, no studies have examined the potential impact of other forms of childhood maltreatment on HIV incidence in this population.
We explored the impact of child physical abuse (CPA) on HIV seroconversion in a cohort of gay/bisexual men aged 15 to 30 in Vancouver, Canada. Cox proportional hazard models were used, controlling for confounders.
Among 287 participants, 211 (73.5%) reported experiencing CPA before the age of 17, and 42 (14.6%) reporting URAI in the past year. After a median of 6.6 years follow-up, 16 (5.8%) participants HIV-seroconverted. In multivariate analysis, CPA was significantly associated with HIV seroconversion (adjusted hazard ratio [AHR] = 4.89, 95% confidence interval (CI): 1.65–14.48), after controlling for potential confounders.
Our study uncovered a link between childhood physical violence and HIV incidence. Results highlight an urgent need for screening of young gay and bisexual men for histories of violence, and social and structural supports to prevent HIV transmission in this population.
PMCID: PMC4070929  PMID: 24963804
15.  Sex Work and Its Associations With Alcohol and Methamphetamine Use Among Female Bar and Spa Workers in the Philippines 
To assess the prevalence of sex work and its associations with substance use among female bar/spa workers in the Philippines (N = 498), workers from 54 bar or spa venues in Metro Manila (2009–2010) were surveyed on demographics, drug/alcohol use, abuse history, and sex work. Their median age was 23 years and 35% engaged in sex work. Sex work was independently associated with methamphetamine use (19% vs 4%; adjusted odds ratio [AOR] =2.9, 95% confidence interval [CI] = 1.3–6.2), alcohol use with patrons (49% vs. 27%;AOR = 1.9, 95% CI = 1.1–3.4), and alcohol intoxication during sex (50% vs. 24%; AOR = 2.0, 95% CI = 1.2–3.5), but inversely associated with daily alcohol use (13% vs. 16%;AOR = 0.2, 95% CI = 0.1–0.5). Additional significant covariates included sexual abuse history, younger age, and not having a higher education. Findings suggest that interventions with sex workers in bars and spas should focus on methamphetamine use, alcohol use contexts, and violence victimization, to better meet the needs of this population.
PMCID: PMC4065166  PMID: 23343641
female sex workers; Philippines; methamphetamine use; alcohol use; violence; substance use
16.  Concurrent sexual partnerships among female sex workers and their non-commercial male partners in Tijuana and Ciudad Juárez, Mexico 
Sexually transmitted infections  2012;89(4):330-332.
To investigate the prevalence and correlates of concurrent (overlapping) sexual partnerships among female sex workers (FSWs) and their non-commercial male partners in two Mexico-U.S. border cities.
A cross-sectional survey of FSWs and their non-commercial male partners was conducted in Tijuana and Ciudad Juárez, Mexico (2010–2011). Eligible FSWs and verified non-commercial partners were aged ≥18 years; FSWs had ever used hard drugs (lifetime) and recently exchanged sex for money, drugs, or other goods (past month). Participants underwent baseline questionnaires obtaining dates of sex and condom use with ≤5 other recurring partners, including FSWs’ regular clients. These dates were compared to dates of sex with enrolled study partners to determine overlap (i.e., “recurring” concurrency). Bivariate probit regression identified recurring concurrency correlates.
Among 428 individuals (214 couples), past-year recurring concurrency prevalence was 16% and was higher among women than their non-commercial male partners (26% vs. 6%). In 10 couples (5%), both partners reported recurring concurrency. The majority of couples (64%) always had unprotected sex, and most of the individuals (70%) with recurring concurrency “sometimes” or “never” used condoms with their concurrent partners. Recurring concurrency was positively associated with FSWs’ income, men’s caballerismo (a form of traditional masculinity), and men’s belief that their FSW-partners had STIs.
Recurring concurrency, representing sustained periods of overlapping partnerships in which unprotected sex was common, should be addressed by couple-based STI prevention interventions.
PMCID: PMC3638049  PMID: 23172036
Sexual behavior; concurrent sexual partners; sexually transmitted diseases/*transmission; epidemiology; cross-sectional study
17.  “Eyes that don’t see, heart that doesn’t feel”: Coping with sex work in intimate relationships and its implications for HIV/STI prevention 
Partner communication about HIV sexual risk behaviors represents a key area of epidemiologic and social importance in terms of infection acquisition and potential for tailored interventions. Nevertheless, disclosing sexual risk behaviors often presents myriad challenges for marginalized couples who engage in stigmatized behaviors. Using qualitative data from a social epidemiology study of risk for HIV and other sexually transmitted infections (STIs) among female sex workers and their intimate, non-commercial male partners along the Mexico-U.S. border, we examined both partners’ perspectives on sex work and the ways in which couples discussed associated HIV/STI risks in their relationship. Our thematic analysis of individual and joint interviews conducted in 2010 and 2011 with 44 couples suggested that broader contexts of social and economic inequalities profoundly shaped partner perspectives of sex work. Although couples accepted sex work as an economic contribution to the relationship in light of limited alternatives and drug addiction, it exacted an emotional toll on both partners. Couples employed multiple strategies to cope with sex work, including psychologically disconnecting from their situation, telling “little lies,” avoiding the topic, and to a lesser extent, superficially discussing their risks. While such strategies served to protect both partners’ emotional health by upholding illusions of fidelity and avoiding potential conflict, non-disclosure of risk behaviors may exacerbate the potential for HIV/STI acquisition. Our work has direct implications for designing multi-level, couple-based health interventions.
PMCID: PMC3647366  PMID: 23631772
Mexico; sex work; HIV risk disclosure; communication; coping; sexual risk; emotions; couple-based interventions
18.  Correlates of Drug Dealing in Female Methamphetamine Users 
Female drug dealers have been a neglected population despite their potentially elevated risk for social, legal, family, and psychological health problems. This study examined correlates of drug-dealing behavior in a sample of 209 female methamphetamine users in San Diego, CA. Twenty-five percent of the sample reported dealing methamphetamine in the past 2 months. Women who dealt methamphetamine were significantly more likely than their nondealing counterparts to have started using illicit drugs before the age of 13 years (68 % versus 44.7 %, p = .003); to have been introduced to methamphetamine by a parent (15.1 % versus 5.8 %, p = .037); and to report currently using methamphetamine to stay awake (84.9 % versus 64.7 %, p = .004), enhance self-confidence (62.3 % versus 45.5 %, p = .025), and feel more attractive (54.7 % versus 38.5 %, p = .029). In a multivariate logistic regression, factors independently associated with methamphetamine dealing were: having a spouse or live-in partner (Adjusted Odds Ratio, AOR = 2.89), using methamphetamine with a broader range of types of person (AOR = 1.46), and reporting lower levels of emotional support (AOR = 0.57). These findings suggest that female methamphetamine dealers are in urgent need of access to substance use treatment, therapies to enhance self-worth and emotional support, and family-based substance use prevention interventions for dependent children and those at risk.
PMCID: PMC3665979  PMID: 22821407
Methamphetamine; Dealers; Women; Emotional support; Self-concept
19.  The influence of having children on HIV-related risk behaviors of female sex workers and their intimate male partners in two Mexico–US border cities 
Journal of Tropical Pediatrics  2013;59(3):214-219.
Among female sex workers who use drugs, the experience of having children and its effect on HIV risk behaviors remains underexplored. We draw from a study of 214 female sex workers and their intimate non-commercial partners in Tijuana and Ciudad Juárez, México (n = 428), approximately 30% of whom have children living with them. During qualitative interviews with 41 of these couples, having children emerged as an important topic. Children influenced partners’ lives and HIV-related risk behaviors in positive and negative ways. Couples perceived that children strengthened their relationships. Concern for children’s well-being motivated couples to contemplate healthier lifestyle changes. However, childrearing costs motivated sex work and structural constraints prevented couples from enacting lifestyle changes. Case studies illustrate these themes and highlight implications for couple- and family-based harm reduction interventions. Specifically, our results suggest a need for economic alternatives to sex work while working with families to develop risk reduction skills.
PMCID: PMC3667590  PMID: 23418131
children; couple-based research; female sex workers; HIV; Mexico
20.  Hombre Seguro (Safe Men): a sexual risk reduction intervention for male clients of female sex workers 
BMC Public Health  2014;14:475.
Male clients of female sex workers (FSWs) are at risk of HIV and other sexually transmitted infections (STIs). We conducted a two-arm randomized controlled trial to test the efficacy of a sexual risk reduction intervention for male clients of FSWs in Tijuana, Mexico.
Male clients of FSWs who were at least 18, were HIV-negative at baseline, and reported recent unprotected sex with FSWs were randomized to the Hombre Seguro sexual risk reduction intervention, or a time-attention didactic control condition. Each condition lasted approximately one hour. Participants underwent interviewer-administered surveys and testing for HIV and other STIs at baseline, and at 4, 8, and 12 month follow-ups. Combined HIV/STI incidence and unprotected vaginal and anal sex acts with FSWs were the primary outcomes.
A total of 400 participants were randomized to one of the two conditions. Analyses indicated that randomization was successful; there were no significant differences between the participants in the two conditions at baseline. Average follow-up was 84% across both conditions. This is the first study to test the efficacy of a sexual risk reduction intervention for male clients of FSWs using the rigor of a randomized controlled trial.
Trial registration
NCT01280838, Date of registration: January 19, 2011.
PMCID: PMC4045912  PMID: 24885949
21.  Where Sex Ends and Emotions Begin: Love and HIV Risk among Female Sex Workers and their Intimate, Non-Commercial Partners along the Mexico-U.S. Border 
Culture, health & sexuality  2013;15(5):540-554.
This study explores the affective dimensions of female sex workers’ relationships with their intimate, non-commercial partners and assesses how emotions shape each partner’s sexual and drug-related risk within their relationship. We draw on qualitative data from a study of HIV, sexually transmitted infections, and high risk behaviours among female sex workers and their non-commercial partners in Tijuana and Ciudad Juárez, Mexico, to illustrate that these couples share relationships based on love, trust, respect, and emotional and material support. These relationships ranged in emotional intensity, which shaped partners’ decisions not to use condoms with each other. Drugs were important in most couples’ relationships. Among injectors, syringe sharing was common and represented both a sign of care and a pragmatic reaction to conditions of material scarcity. Our findings suggest that couple-based HIV interventions to address dual sexual and drug-related risks should be tailored to the emotional dynamics of sex workers’ intimate relationships.
PMCID: PMC3674135  PMID: 23473586
sex workers; HIV; relationships; couple-based intervention; Mexico-USA border
22.  Dose-response association between salivary cotinine levels and Mycobacterium tuberculosis infection 
Tijuana, Mexico.
To describe the association between salivary cotinine levels and interferon-γ release assay results.
We conducted a cross-sectional study among persons who inject drugs. Salivary cotinine levels were measured using NicAlert, a semi-quantitative dipstick assay. QuantiFERON TB Gold In-tube (QFT) was used to determine Mycobacterium tuberculosis (Mtb) infection.
Among 234 participants, the prevalence of QFT positivity for NicAlert cotinine categories 0 (nonsmoking), 1 (secondhand smoke exposure or low-level smoking), and 2–6 (regular smoking) were 42.1%, 46.4%, and 65.2%, respectively (Ptrend = 0.012). We found increasing trends in QFT positivity (Ptrend = 0.003) and interferon-γ concentrations (Spearman’s r=0.200; P = 0.002) across cotinine levels 0 to 6. In multivariable log-binomial regression models adjusted for education, cotinine levels were not associated with QFT positivity when included as smoking categories (1 and 2–6 vs. 0), but were independently associated with QFT positivity when included as an ordinal variable (prevalence ratio = 1.09 per +1 cotinine level; 95% confidence interval = 1.02 – 1.16).
Our findings suggest that a dose-response relationship exists between tobacco smoke exposure and Mtb infection. Longitudinal studies that use biochemical measures for smoking status are needed to confirm our findings.
PMCID: PMC3801225  PMID: 24125450
tuberculosis; tobacco; substance abuse; mycobacterium infections; smoking; interferon gamma release assay
23.  Acceptability of vaginal microbicides among female sex workers and their intimate male partners in two Mexico-U.S. border cities: a mixed methods analysis 
Global public health  2013;8(5):619-633.
Female sex workers (FSWs) may benefit from pre-exposure prophylaxis (PrEP) including microbicides for HIV prevention. Since adherence is a key factor in PrEP efficacy, we explored microbicide acceptability and potential barriers to use within FSWs’ intimate relationships in Tijuana and Ciudad Juárez, Mexico, where HIV prevalence is increasing.
FSWs and their verified intimate (non-commercial) male partners completed quantitative and qualitative interviews from 2010–2012. Our complementary mixed methods design followed an iterative process to assess microbicide acceptability, explore related relationship dynamics, and identify factors associated with concern about male partners’ anger regarding microbicide use.
Among 185 couples (n=370 individuals), interest in microbicides was high. In qualitative interviews with 28 couples, most participants were enthusiastic about microbicides for sex work contexts but some explained that microbicides could imply mistrust/infidelity within their intimate relationships. In the overall sample, nearly 1 in 6 participants (16%) worried that male partners would become angry about microbicides, which was associated with higher self-esteem among FSWs and lower self-esteem and past year conflict causing injury within relationships among men.
HIV prevention interventions should consider intimate relationship dynamics posing potential barriers to PrEP acceptability and adherence, involve male partners, and promote risk communication skills.
PMCID: PMC3674154  PMID: 23398385
HIV; pre-exposure prophylaxis; microbicides; relationships; adherence
24.  HIV and people who use drugs in central Asia: Confronting the perfect storm 
Drug and alcohol dependence  2013;132(0 1):S2-S6.
PMCID: PMC4006578  PMID: 23953656
25.  Social and Structural Factors Associated with Consistent Condom Use Among Female Entertainment Workers Trading Sex in the Philippines 
AIDS and behavior  2013;17(2):523-535.
This paper examined socio-structural factors of consistent condom use among female entertainment workers at high risk for acquiring HIV in Metro Manila, Quezon City, Philippines. Entertainers, aged 18 and over, from 25 establishments (spa/saunas, night clubs, karaoke bars), who traded sex during the previous 6 months, underwent cross-sectional surveys. The 143 entertainers (42% not always using condoms, 58% always using condoms) had median age (23), duration in sex work (7 months), education (9 years), and 29% were married/had live-in boyfriends. In a logistic multiple regression model, social-structural vs. individual factors were associated with inconsistent condom use: being forced/deceived into sex work, less manager contact, less STI/HIV prevention knowledge acquired from medical personnel/professionals, not following a co-workers’ condom use advice, and an interaction between establishment type and alcohol use with establishment guests. Interventions should consider the effects of physical (force/deception into work), social (peer, manager influence), and policy (STI/HIV prevention knowledge acquired from medical personnel/professionals) environments on consistent condom use.
PMCID: PMC3987851  PMID: 22223297
Condom use; Philippines; Female sex workers; HIV/AIDS; Socio-structural; Trafficking

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