Journal of urban health : bulletin of the New York Academy of Medicine
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Research on behavioral HIV risk reduction interventions for injection drug users (IDUs) has focused on primary outcomes (e.g., reduced injection drug use, increased condom use) but has not fully examined the respective roles played by intervention components on these primary outcomes. In this paper, we present a structural equation modeling (SEM) approach in which we specify the causal pathways leading from theory-based intervention components to risk reduction outcomes among a sample of primarily IDUs (n = 226) participating in an inner-city community-based methadone maintenance program. Similar pathways were found leading to both drug- and sexual-related risk reduction outcomes. ⋯ Findings also indicate that our intervention may be optimized by focusing more on participants' risk reduction motivation within the sexual-related content and placing equivalent emphasis on participants' risk reduction knowledge, motivation, and behavioral skills within the drug-related content. By quantifying the specific linkage between intervention components and risk reduction outcomes, our SEM findings offer empirical guidance for optimizing this intervention. This strategy may also serve as a useful theory- and data-driven means to inform the refinement of other behavioral interventions.
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Respondent-driven sampling (RDS), a chain referral sampling approach, is increasingly used to recruit participants from hard-to-reach populations, such as injection drug users (IDUs). Using RDS, we recruited IDUs in Tijuana and Ciudad (Cd.) Juárez, two Mexican cities bordering San Diego, CA and El Paso, TX, respectively, and compared recruitment dynamics, reported network size, and estimates of HIV and syphilis prevalence. Between February and April 2005, we used RDS to recruit IDUs in Tijuana (15 seeds, 207 recruits) and Cd. ⋯ RDS was an effective method to rapidly recruit IDUs in these cities. Although the frequency of HIV was low, syphilis prevalence was high, particularly in Tijuana. RDS-corrected estimates of syphilis prevalence were sensitive to model assumptions, suggesting that further validation of RDS is necessary.