A tale of two cities: Social and environmental influences shaping risk factors and protective behaviors in two Mexico–US border cities
Introduction
In recent years, there has been growing appreciation that the social and structural environment in which behaviors are exhibited plays a crucial role in shaping the natural history of addiction and associated risk behaviors that predispose to blood-borne and sexually transmitted infections (STIs), including HIV (Rhodes et al., 2005). Many theories of health behavior, such as the Health Belief model (Becker, 1974; Janz and Becker, 1984; Rosenstock, 1966) and the Theory of Reasoned Action (Fishbein and Ajzen, 1975; Jazen and Fishbein, 1980) place the responsibility for health and disease on the individual. Interventions based on these theories primarily aim to reduce high-risk behaviors by modifying individual beliefs and attitudes. The Social–Ecological Model (McLeroy et al., 1988; Stokols, 1996) and the Risk Environment framework (Rhodes et al., 1999) are examples of theories that attempt to incorporate macro-, meso-, and micro-level factors that influence how diseases are transmitted. In this context, we refer to structural factors arising from the risk environment, which Rhodes describes as the social or physical space in which a variety of factors exogenous to the individual interact to increase HIV transmission risks (Rhodes et al., 1999, Rhodes et al., 2005).
The influence of social and environmental factors on health varies according to the culture, economy, and geographical location of groups or populations, and these factors may act as barriers or facilitators for health-related risk behaviors. Border regions are particularly appropriate environments to examine these influences, since there are often stark differences in policies, priorities, and available resources in response to major health problems in neighboring countries. The 2000-mile Mexico–US border region is a “natural laboratory” for studying these differences, since both countries differ in language, culture, and stage of economic development. The Mexican side of this border is home to approximately five million people, most of whom are poor and without access to a comprehensive health prevention and care (US–Mexico Border Health Commission, 2002). Some authors maintain that US influences have created a new cultural identity among inhabitants of these border communities (Myers, 1997; Weaver, 2001). In their assessment of six Mexican–US border cities, (Ciudad (Cd.) Juárez, Matamoros, Tijuana, Reynosa, Nogales, and Camargo), Arreola and Curtis posit that certain structural characteristics appear distinctive to the border region, such as tourist districts, maquiladora industrial parks, and street networks oriented toward ports of entry to facilitate the movement of trade goods (Arreola and Curtis, 1993). We agree with these observations and stress that the location of Cd. Juárez and Tijuana on major commercial transport routes, through which illicit drugs are also transported, may increase access to drugs and their negative health consequences.
There is growing concern among health care providers along the Mexico–US border about the twin threats of drug addiction and HIV and types of prevention interventions that would be the most effective in this bi-national context (Maxwell et al., 2006; Strathdee and Magis-Rodriguez, 2008), although HIV prevalence among male injecting drug users (IDUs) in Cd. Juárez and Tijuana appears to be low at 3% (Frost et al., 2006). To date, most studies of IDUs have focused on individual risk behaviors that place them at risk of disease. The social, cultural, economic, and political milieus where IDUs live—which are equally important to inform the design of appropriate behavioral interventions—have not been given adequate consideration.
Located in the Mexican state of Chihuahua, Cd. Juárez, Mexico, is situated at the approximate mid-point along the border between Mexico and the United States and is part of a 2-million people metroplex that includes the cities of El Paso in Texas and Las Cruces in New Mexico. Cd. Juárez had a population of 1,313,338 in 2005 with a 1.32% growth rate per year between 2000 and 2005 (INEGI, 2005). In 2005, there were 29 million northbound border crossings from Cd. Juárez to El Paso (US Department of Transportation, 2004). Situated on a major trafficking route for heroin and cocaine, Cd. Juárez is ranked second only to Tijuana in the prevalence of illicit drug use and is estimated to have twice the national average of drug users (CONADIC, 1998). A 2001 study, using a capture–recapture methodology, estimated that there were approximately 6000 IDUs and as many as 186 picaderos (drug injecting locations) in Cd. Juárez (Cravioto et al., 2003).
Tijuana is located in the Mexican state of Baja California adjacent to San Diego, CA. The border crossing between Tijuana and San Diego is the busiest in the world; in 2005 alone, there were 45 million registered northbound crossings from Tijuana to San Diego County (US Department of Transportation, 2004). Tijuana is also situated on a major drug trafficking corridor, whereby heroin, cocaine, and methamphetamine are transported into the US (Brouwer et al., 2006; Bucardo et al., 2005). Tijuana, as well as Cd. Juárez, has witnessed local drug consumption markets grow, and is reported to have three times the national average of individuals consuming illicit drugs (Rodriguez et al., 2002). It is estimated that there are about 10,000 IDUs and over 200 shooting galleries [“picaderos”] in the city (Strathdee et al., 2005). There is rising HIV prevalence among female sex workers and pregnant women that has been linked to drug use (Strathdee et al., 2008c; Viani et al., 2006)
We hypothesized that IDU populations in these two Mexican cities differ in terms of behavioral factors that constitute both risk factors and protective factors, as well as social and environmental factors, which may differentially influence the spread of HIV and related blood-borne infections. We also describe failings in the health delivery system—which represent opportunities still left to explore—as well as successful structural interventions in both cities.
Section snippets
Study population
Cross-sectional interviewer-administered surveys were conducted among 206 IDUs in Cd. Juárez and 222 IDUs in Tijuana between February and April 2005. As previously described (Frost et al., 2006), participants were selected through respondent-driven sampling (RDS), which is a variation of snowball sampling that enables researchers to obtain a more representative sample of hard-to-reach populations and to adjust for bias in recruitment (Heckathorn, 2002). Briefly, a diverse group of
Results
Analyses were based on 427 subjects (205 subjects in Cd. Juárez and 222 subjects in Tijuana); one subject in Cd. Juárez was excluded due to a missing value for HIV testing history. Table 1 summarizes basic demographic data relating to the Cd. Juárez (9 seeds, 196 recruits) and Tijuana (15 seeds, 207 recruits) study populations. Both populations were predominantly male, with a median age of 34 years. Approximately one third had completed high school, and less than half earned more than 3000
Discussion
In our comparison of IDUs recruited in two Mexico–US border cities, participants in Cd. Juárez and Tijuana were similar in terms of many socio-demographic characteristics traditionally examined in epidemiologic studies of IDU populations, including age, gender, education, income, and time since first injection. HIV and HCV prevalences were also nearly identical, at 3% and 96%, respectively. However, these similarities on the surface masked a number of important contextual differences on closer
Acknowledgements
Proyecto El Cuete was funded by the National Institute on Drug Abuse (NIDA) (R01DA09227 and DA019829). The authors gratefully acknowledge the study participants and PRO-COMUSIDA and Programa Companeros staff for assistance with data collection.
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