[Show abstract][Hide abstract] ABSTRACT: Aims: Risk environment factors may influence unprotected sex between female sex workers who are also injection drug users (FSW-IDUs) and their regular and non-regular clients differently. Our objective is to identify correlates of unprotected vaginal sex in the context of client type. Methods: A cross-sectional survey of 583 FSW-IDUs in Tijuana and Ciudad Juarez, Mexico, was analyzed using negative binomial regression to determine physical, social, economic, and policy risk-environment factors that affect the frequency of unprotected sex with regular and non-regular clients. Results: Median number of unprotected vaginal sex acts in the past month among FSW-IDUs and their regular and non-regular clients was 11 (IQR 3–30) and 13 (IQR 5–30), respectively. Correlates differed by site and client type and were most closely associated with the risk environment. In Tijuana, social factors (e.g., injecting drugs with clients) were independently associated with more unprotected sex. Factors independently associated with less unprotected sex across client type and site included social and economic risk environment factors (e.g., receiving more money for unprotected sex). In the policy risk environment, always having free access to condoms was independently associated with less unprotected sex among non-regular clients in Tijuana (Risk rate ratio = 0.64; 95% confidence interval 0.43–0.97). Conclusions: Primarily physical, social, and economic risk-environment factors were associated with unprotected vaginal sex between FSW-IDUs and both client types, suggesting potential avenues for intervention. Unprotected sex between female sex workers who are also injection drug users (FSW-IDUs) and their clients represents an intersection of multiple high-risk behaviors for transmission of HIV and other sexually transmitted infections (STIs) (Alary & Lowndes, 2004). Rates of condom use are lower among IDU populations compared to those who do not inject, and injection drug use is associated with unprotected sex among HIV-positive women (
[Show abstract][Hide abstract] ABSTRACT: Background:
Although most people who inject drugs (PWID) in Tijuana, Mexico, primarily inject heroin, injection and non-injection use of methamphetamine and cocaine is common. We examined patterns of polydrug use among heroin injectors to inform prevention and treatment of drug use and its health and social consequences.
Participants were PWID residing in Tijuana, aged ≥18 years who reported heroin injection in the past six months and were recruited through respondent-driven sampling (n = 1,025). Latent class analysis was conducted to assign individuals to classes on a probabilistic basis, using four indicators of past six-month polydrug and polyroute use: cocaine injecting, cocaine smoking or snorting, methamphetamine injecting, and methamphetamine smoking or snorting. Latent class membership was regressed onto covariates in a multinomial logistic regression.
Latent class analyses testing 1, 2, 3, and 4 classes were fit, with the 3-class solution fitting best. Class 1 was defined by predominantly heroin use (50.2%, n = 515); class 2 by methamphetamine and heroin use (43.7%, n = 448), and class 3 by methamphetamine, cocaine, and heroin use (6.0%, n = 62). Bivariate and multivariate analyses indicated a group of methamphetamine and cocaine users that exhibited higher-risk sexual practices and lower heroin injecting frequency, and a group of methamphetamine users who were younger and more likely to be female.
Discrete subtypes of heroin PWID were identified based on methamphetamine and cocaine use patterns. These findings have identified subtypes of heroin injectors who require more tailored interventions to reduce the health and social harms of injecting drug use.
[Show abstract][Hide abstract] ABSTRACT: Injection drug-using men from the US and Mexico who purchase sex in Tijuana, Mexico are at risk for transmitting HIV to their contacts in both countries via syringe sharing. We used social network methods to understand whether place of residence (US vs. Mexico) moderated the effect of emotional closeness on syringe sharing. We interviewed 199 drug-using men who reported paying/trading for sex in Tijuana, Mexico using an epidemiological and social network survey and collected samples for HIV/STI testing. Seventy-two men reported using injection drugs with 272 network contacts. Emotional closeness was strongly associated with syringe sharing in relationship where the partner lives in the US, while the relationship between emotional closeness and syringe sharing was considerably less strong in dyads where the partner lives in Mexico. Efforts to reduce HIV risk behaviors in emotionally close relationships are needed, and could benefit from tailoring to the environmental context of the relationship.
AIDS and Behavior 01/2015; 19(6). DOI:10.1007/s10461-015-1001-6 · 3.49 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background
Girl education is believed to be the best means of reducing girl child marriage (marriage <18 years) globally. However, in South Asia, where the majority of girl child marriages occur, substantial improvements in girl education have not corresponded to equivalent reductions in child marriage. This study examines the levels of education associated with female age at marriage over the previous 20 years across four South Asian nations with high rates (>20%) of girl child marriage- Bangladesh, India, Nepal and Pakistan.
Cross-sectional time series analyses were conducted on Demographic and Health Surveys (DHS) from 1991 to 2011 in the four focal nations. Analyses were restricted to ever-married women aged 20–24 years. Multinomial logistic regression models were used to assess the effect of highest level of education received (none, primary, secondary or higher) on age at marriage (<14, 14–15, 16–17, 18 and older).
In Bangladesh and Pakistan, primary education was not protective against girl child marriage; in Nepal, it was protective against marriage at <14 years (AOR = 0.42) but not for older adolescents. Secondary education was protective across minor age at marriage categories in Bangladesh (<14 years AOR = 0.10; 14–15 years AOR = .25; 16–17 years AOR = 0.64) and Nepal (<14 years AOR = 0.21; 14–15 years AOR = 0.25; 16–17 years AOR = 0.57), but protective against marriage of only younger adolescents in Pakistan (<14 years AOR = 0.19; 14–15 years AOR = 0.23). In India, primary and secondary education were respectively protective across all age at marriage categories (<14 years AOR = 0.34, AOR = 0.05; 14–15 years AOR = 0.52, AOR = 0.20; 16–17 years AOR = 0.71, AOR = 0.48).
Primary education is likely insufficient to reduce girl child marriage in South Asia, outside of India. Secondary education may be a better protective strategy against this practice for the region, but may be less effective for prevention of marriage among older relative to younger adolescents.
PLoS ONE 09/2014; 9(9):e106210. DOI:10.1371/journal.pone.0106210 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background:
In light of accumulated scientific evidence of the secondary preventive benefits of antiretroviral therapy, a growing number of jurisdictions worldwide have formally started to implement HIV Treatment as Prevention (TasP) programs. To date, no gold standard for TasP program monitoring has been described. Here, we describe the design and methods applied to TasP program process monitoring in British Columbia (BC), Canada.
Monitoring indicators were selected through a collaborative and iterative process by an interdisciplinary team including representatives from all 5 regional health authorities, the BC Centre for Disease Control (BCCDC), and the BC Centre for Excellence in HIV/AIDS (BC-CfE). An initial set of 36 proposed indicators were considered for inclusion. These were ranked on the basis of 8 criteria: data quality, validity, scientific evidence, informative power of the indicator, feasibility, confidentiality, accuracy, and administrative requirement. The consolidated list of indicators was included in the final monitoring report, which was executed using linked population-level data.
A total of 13 monitoring indicators were included in the BC TasP Monitoring Report. Where appropriate, indicators were stratified by subgroups of interest, including HIV risk group and demographic characteristics. Six Monitoring Reports are generated quarterly: 1 for each of the regional health authorities and a consolidated provincial report.
We have developed a comprehensive TasP process monitoring strategy using evidence-based HIV indicators derived from linked population-level data. Standardized longitudinal monitoring of TasP program initiatives is essential to optimize individual and public health outcomes and to enhance program efficiencies.
[Show abstract][Hide abstract] ABSTRACT: Few studies assessing the relationship between active and passive smoking and tuberculosis have used biomarkers to measure smoke exposure. We sought to determine the association between active and passive smoking and LTBI in a representative sample of US adults and children.
We used the 1999-2000 US National Health and Nutrition Examination Survey (NHANES) dataset with tuberculin skin test (TST) data to assess the association between cotinine-confirmed smoke exposure and latent tuberculosis infection (LTBI) among adults ages ≥20 years (n = 3598) and children 3-19 years (n = 2943) and estimate the prevalence of smoke exposure among those with LTBI. Weighted multivariate logistic regression was used to measure the associations between active and passive smoking and LTBI.
LTBI prevalence in 1999-2000 among cotinine-confirmed active, passive, and non-smoking adults and children was 6.0%, 5.2%, 3.3% and 0.3%, 1.0%, 1.5%, respectively. This corresponds to approximately 3,556,000 active and 3,379,000 passive smoking adults with LTBI in the US civilian non-institutionalized population in 1999-2000. Controlling for age, gender, socioeconomic status, race, birthplace (US vs. foreign-born), household size, and having ever lived with someone with TB, adult active smokers were significantly more likely to have LTBI than non-smoking adults (AOR = 2.31 95% CI 1.17-4.55). Adult passive smokers also had a greater odds of LTBI compared with non-smokers, but this association did not achieve statistical significance (AOR = 2.00 95% CI 0.87-4.60). Neither active or passive smoking was associated with LTBI among children. Among only the foreign-born adults, both active (AOR = 2.56 (95% CI 1.20-5.45) and passive smoking (AOR = 2.27 95% CI 1.09-4.72) were significantly associated with LTBI.
Active adult smokers and both foreign-born active and passive smokers in the United States are at elevated risk for LTBI. Targeted smoking prevention and cessation programs should be included in comprehensive national and international TB control efforts.
PLoS ONE 03/2014; 9(3):e93137. DOI:10.1371/journal.pone.0093137 · 3.23 Impact Factor
International journal of gynaecology and obstetrics: the official organ of the International Federation of Gynaecology and Obstetrics 10/2013; 124(1). DOI:10.1016/j.ijgo.2013.07.027 · 1.54 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We examined the relationship between venue stability and consistent condom use (CCU) among female sex workers who inject drugs (FSW-IDUs; n = 584) and were enrolled in a behavioural intervention in two Mexico-USA border cities. Using a generalized estimating equation approach stratified by client type and city, we found venue stability affected CCU. In Tijuana, operating primarily indoors was significantly associated with a four-fold increase in the odds of CCU among regular clients (odds ratio [OR]: 3.77, 95% confidence interval [CI]: 1.44, 9.89), and a seven-fold increase among casual clients (OR: 7.18, 95% CI: 2.32, 22.21), relative to FSW-IDUs spending equal time between indoor and outdoor sex work venues. In Ciudad Juarez, the trajectory of CCU increased over time and was highest among those operating primarily indoors. Results from this analysis highlight the importance of considering local mobility, including venue type and venue stability, as these characteristics jointly influence HIV risk behaviours.
International Journal of STD & AIDS 07/2013; 24(7):523-9. DOI:10.1177/0956462412473890 · 1.05 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Abstract 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.
Global Public Health 03/2013; 8(4). DOI:10.1080/17441692.2013.779386 · 0.92 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background
Employing innovative mapping and spatial analyses of individual and neighborhood environment data, we examined the social, physical and structural features of overlapping street-based sex work and drug scenes and explored the utility of a ‘spatial isolation index’ in explaining exchanging sex for drugs and exchanging sex while high.
Analyses drew on baseline interview and geographic data (Jan/10-Oct/11) from a large prospective cohort of street and off-street sex workers (SWs) in Metropolitan Vancouver and external publically-available, neighborhood environment data. An index measuring ‘spatial isolation’ was developed from seven indicators measuring features of the built environment within 50 m buffers (e.g. industrial or commercial zoning, lighting) surrounding sex work environments. Bivariate and multivariable logistic regression was used to examine associations between the two outcomes (exchanged sex for drugs; exchanged sex while high) and the index, as well as each individual indicator.
Of 510 SWs, 328 worked in street-based/outdoor environments (e.g. streets, parks, alleys) and were included in the analyses. In multivariable analysis, increased spatial isolation surrounding street-based/outdoor SWs’ main places of servicing clients as measured with the index was significantly associated with exchanging sex for drugs. Exchanging sex for drugs was also significantly positively associated with an indicator of the built environment suggesting greater spatial isolation (increased percent of parks) and negatively associated with those suggesting decreased spatial isolation (increased percent commercial areas, increased count of lighting, increased building footprint). Exchanging sex while high was negatively associated with increased percent of commercial zones but this association was removed when adjusting for police harassment.
The results from our exploratory study highlight how built environment shapes risks within overlapping street-based sex work and drug scenes through the development of a novel index comprised of multiple indicators of the built environment available through publicly available data, This study informs the important role that spatially-oriented responses, such as safer-environment interventions, and structural responses, such as decriminalization of sex work can play in improving the health, safety and well-being of SWs.
The International journal on drug policy 01/2013; 25(3). DOI:10.1016/j.drugpo.2013.12.002 · 2.54 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The northwest border city of Tijuana is Mexico's fifth largest and is experiencing burgeoning drug use and human immunodeficiency virus (HIV) epidemics. Because local geography influences disease risk, we explored the spatial distribution of HIV among injection drug users (IDUs). From 2006-2007, 1,056 IDUs were recruited using respondent-driven sampling and then followed for eighteen months. Participants underwent semiannual surveys, mapping, and testing for HIV, tuberculosis, and syphilis. Using average nearest neighbor and Getis-Ord Gi* statistics, locations where participants lived, worked, bought drugs, and injected drugs were compared with HIV status and environmental and behavioral factors. Median age was thirty-seven years; 85 percent were male. Females had higher HIV prevalence than males (10.2 percent vs. 3.4 percent; p = 0.001). HIV cases at baseline (n = 47) most strongly clustered by drug injection sites (Z score = -6.173, p < 0.001), with a 16-km 2 hotspot near the Mexico-U.S. border, encompassing the red-light district. Spatial correlates of HIV included syphilis infection, female gender, younger age, increased hours on the street per day, and higher number of injection partners. Almost all HIV seroconverters injected within a 2.5-block radius of each other immediately prior to seroconversion. Only history of syphilis infection and female gender were strongly associated with HIV in the area where incident cases injected. Directional trends suggested a largely static epidemic until July through December 2008, when HIV spread to the southeast, possibly related to intensified violence and policing that spiked in the latter half of 2008. Although clustering allows for targeting interventions, the dynamic nature of epidemics suggests the importance of mobile treatment and harm reduction programs.
Annals of the Association of American Geographers 09/2012; 102(5-5):1190-1199. DOI:10.1080/00045608.2012.674896 · 2.09 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background Sex work is quasi-legal in Tijuana, with a zone of tolerance (Zona Roja, or Red Light district), and a registration card system whereby female sex workers (FSW) pay an annual cost to cover HIV and STI testing. As healthcare efforts are concentrated in the Zona Roja, we set out to assess the frequency of Pap testing among FSW working outside this zone.
Methods Proyecto Amantes de la Salud (Lovers of Health Project) conducted baseline surveys among 403 FSW working in bars outside of Tijuana's Zona Roja using time-location sampling. Surveys included demographics, sexual and substance use behaviour, sex work characteristics and sexual healthcare practices. Average number of annual Pap tests over the past 5 years was calculated using left censoring for the denominator based on: (1) years sexually active and (2) years in sex trade. Descriptive statistics and logistic regression were used to assess factors associated with Pap testing in the past year.
Results Participants ranged in age from 18 to 55 (Median: 28; IQR: 23–32); all were born in Mexico and 98% reported being registered as an FSW. Sex partners included regular, non-client (25%), regular clients (79%) and non-regular clients (99%). Overall, 85% of women reported a pap test in the past year; however, only 35% of sexually active women and 52% of FSW had an average of at least one Pap test per year over the past 5 years see Abstract P5-S6.31 table 1. A small proportion (4%) indicated they had never had a Pap test. In multivariate models, having a Pap test in the past year was negatively associated with income >3500 pesos/month, more years in the sex trade and having regular clients. Marginal positive associations remained with older age, reporting condom use less than half the time with non-regular clients and having any children.
Discussion Prevalence of pap tests in the past year was higher than expected and may be attributed to recent efforts by the Tijuana Municipal Health Services to increase outreach to FSWs in these areas. However, since initiating sex work, only half reported the recommended yearly Pap testing which is concerning given the increased risk for HPV infection and cervical cancer among FSW. Sexual health education, including where access services, is needed to encourage regular cancer screening among this high risk population, especially among younger women and women who have been working in the sex trade for longer durations.
[Show abstract][Hide abstract] ABSTRACT: FSWs who inject drugs (FSW-IDUs) can acquire HIV through high risk sexual and injection behaviors. We studied correlates of HIV infection among FSW-IDUs in northern Mexico, where sex work is quasi-legal and syringes can be legally obtained without a prescription.
FSW-IDUs>18 years old who reported injecting drugs and recent unprotected sex with clients in Tijuana and Ciudad Juarez underwent surveys and HIV/STI testing. Logistic regression identified correlates of HIV infection.
Of 620 FSW-IDUs, prevalence of HIV, gonorrhea, Chlamydia, trichomonas, syphilis titers ≥1:8, or any of these infections was 5.3%, 4%, 13%, 35%, 10% and 72%, respectively. Compared to other FSW-IDUs, HIV-positive women were more likely to: have syphilis titers ≥1:8 (36% vs. 9%, p<0.001), often/always inject drugs with clients (55% vs. 32%, p = 0.01), and experience confiscation of syringes by police (49% vs. 28%, p = 0.02). Factors independently associated with HIV infection were syphilis titers ≥1:8, often/always injecting with clients and police confiscation of syringes. Women who obtained syringes from NEPs (needle exchange programs) within the last month had lower odds of HIV infection associated with active syphilis, but among non-NEP attenders, the odds of HIV infection associated with active syphilis was significantly elevated.
Factors operating in both the micro-social environment (i.e., injecting drugs with clients) and policy environment (i.e., having syringes confiscated by police, attending NEPs) predominated as factors associated with risk of HIV infection, rather than individual-level risk behaviors. Interventions should target unjustified policing practices, clients' risk behaviors and HIV/STI prevention through NEPs.
PLoS ONE 04/2011; 6(4):e19048. DOI:10.1371/journal.pone.0019048 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Sex work is regulated in the Zona Roja (red light district) in Tijuana, Mexico, where HIV and sexually transmitted disease (STD) prevalence is high among female sex workers (FSWs). We examined the spatial distribution of STDs by work venue among FSWs in Tijuana.
FSWs aged 18 years and older who reported unprotected sex with ≥ 1 client in the past 2 months underwent testing for HIV, syphilis, gonorrhea, and Chlamydia. HIV/STDs were mapped by venue (i.e., bar, hotel) and Getis-Ord Gi statistics were used to identify geographic hotspots. High-risk venues were then identified using a standardized STD ratio (high risk defined as a ratio ≥ 1.25). Logistic regression was used to assess correlates of working at a high risk venue.
Of 474 FSWs, 176 (36.4%) had at least 1 bacterial sexually transmitted infection (STI); 36 (7.6%) were HIV-positive. Within the Zona Roja, 1 venue was identified as a geographic "hotspot," with a higher than expected number of HIV/STD-positive FSW (P < 0.05) as compared to neighboring venues. Using the STD ratio definition, 11 venues were identified as high-risk; FSWs working in these locations had higher education, were more likely to report always using drugs with sex, and having mostly US clients. They were less likely to be registered FSWs or to live at their work venue.
A relatively few number of sex work venues accounted for a large proportion of the HIV/STI burden among FSWs in Tijuana. Structural interventions that focus on sex work venues could help increase STI diagnosis, prevention, and treatment among FSWs in Tijuana.
[Show abstract][Hide abstract] ABSTRACT: To identify correlates of active syphilis infection among female sex workers (FSWs) in Tijuana and Ciudad Juarez.
Cross-sectional analyses of baseline interview data. Correlates of active syphilis (antibody titers >1 : 8) were identified by logistic regression. Setting Tijuana and Ciudad Juarez, two Mexican cities on the US border that are situated on major drug trafficking routes and where prostitution is quasi-legal.
A total of 914 FSWs aged > or =18 years without known human immunodeficiency virus (HIV) infection who had had recent unprotected sex with clients.
Baseline interviews and testing for syphilis antibody using Treponema pallidum particle agglutination (TPPA) and rapid plasma reagin (RPR) tests.
Median age and duration in sex work were 32 and 4 years, respectively. Overall, 18.0% had ever injected drugs, 14.2% often or always used illegal drugs before or during sex in the past month, 31.4% had clients in the last 6 months who injected drugs, and 68.6% reported having clients from the United States. Prevalence of HIV and active syphilis were 5.9% and 10.3%, respectively. Factors independently associated with active syphilis included injecting drugs (AOR: 2.39; 95% CI: 1.40, 4.08), using illegal drugs before or during sex (AOR: 2.06; 95% CI: 1.16, 3.65) and having any US clients (AOR: 2.85; 95% CI: 1.43, 5.70).
Among female sex workers in Tijuana and Ciudad Juarez, drug-using behaviors were associated more closely with active syphilis than were sexual behaviors, suggesting the possibility of parenteral transmission of T. pallidum. Syphilis eradication programs should consider distributing sterile syringes to drug injectors and assisting FSWs with safer-sex negotiation in the context of drug use.