There are growing numbers of young injection drug users (IDUs) in the United States, 1 and multiperson use of syringes and other injection equipment is common in this population. 2,3 Consequently, the potential for new infection with bloodborne pathogens may be substantial. Interventions known to reduce the risk practices associated with drug injection should be targeted toward this group, but the potential effectiveness of these strategies for young IDUs is largely unknown. Needle exchange programming (NEP) is a particularly understudied strategy among youth in the United States, even though accumulated evidence generally shows it to be effective with older, long-term IDUs. 4,5
The purpose of this study is to examine the prevalence and correlates of NEP use among 700 young IDUs in Chicago. The significance of our sample is that we can determine the prevalence of NEP use among a large sample of young IDUs, rather than simply the proportion of all NEP users who are young, a far more common approach.
MATERIALS AND METHODS
Study participants were aged 18–30 years, had injected drugs at least once in the past 6 months, and were recruited between 1997–1999. The study was conducted from storefront offices in 4 Chicago neighborhoods with high concentrations of drug use. A full description of sampling methods has been provided elsewhere. 6 Briefly, participants were recruited through street outreach, targeted advertising, and chain referral, including respondent-driven sampling. The cohort was developed as part of the Collaborative Injection Drug Users Study II (CIDUS II), a multisite longitudinal study that was conducted under a cooperative agreement with the Centers for Disease Control and Prevention (CDC) and that focused on new initiates to drug injection.
Trained interviewers administered a standardized face-to-face interview in a private room.
Study protocols were explained to participants and informed consent was obtained prior to data collection. Study protocols and consent agreements were approved by institutional review boards at the CDC and the University of Illinois at Chicago. All participants were reimbursed $25.00 for their time and travel expenses.
Demographic measures included as correlates or control measures in analyses comparing NEP use to nonuse were age, gender, race/ethnicity, residence, and recruitment method. Measures of injection behavior included duration of injection, frequency of injection, change in the average frequency of injection, and frequency of injecting with others (the last 3 measures in the past 6 months).
The main measures of interest as potential behavioral correlates of NEP use were (1) frequency in the past 6 months of injecting with a needle known to have been used by another person (2); using cookers, cottons, or rinse water with or after other people used them (3); backloading (injecting with a needle after someone else squirts drugs into it from their needle) (4); using the same needle for >1 injection; and (5) frequency of condom use for penetrative sex with steady and nonsteady partners. Most of these measures were recoded based on conceptual and distributional considerations.
For the measure of NEP use, respondents were asked the number of times they visited an NEP in the past 6 months. The distribution of this measure was quite skewed, so we combined the categories into three groups: 0, 1–6, and ≥7 times. We defined those who visited ≥7 times in the past 6 months as frequent users; those who visited 1–6 times as infrequent users; and those who never visited an NEP as nonusers. NEPs have operated legally in Chicago since 1992.
We examined associations between NEP use and study variables in univariate analyses, using Pearson χ2. We also estimated adjusted odds ratios (ORs) and 95% CIs in a series of dichotomous and ordinal logistic regressions, in which each risk behavior was regressed on the measure of NEP use. For each of the analyses, adjusted factors included age, gender, race/ethnicity, recruitment method, and frequency and duration of injection. Both univariate and multivariate analyses were conducted using Statistical Analysis Software (SAS Institute, Inc., Cary, NC).
The majority of study participants were younger than 26 years old (64%), male (65%), white (58%), and were referred to the study by their peers through respondent-driven sampling (54%). Despite recruiting only in urban areas, 40% of participants lived in the suburbs. The median duration of injection was 2 years (range: <1–20 years). Nearly ½ (47%) of study participants injected daily, and most injected with others at least half the time they had injected during the previous 6 months (66%). Almost 2/3 (65%) of the sample reported never attending an NEP in the 6 months before baseline; 13% attended an NEP on average more than once a month.
Univariate comparisons of nonusers, infrequent users, and frequent users of NEPs are presented in Table 1. A greater proportion of frequent users compared with the other 2 groups were older than 25 years (P = 0.03), white or Hispanic (P < 0.001), had been injecting for >4 years (P = 0.008), and injected at least daily (P <0 .001). A lower proportion of frequent NEP users, however, shared needles (P < 0.001) and other injection equipment (P = 0.02), or used the same needle for >1 injection (P < 0.001). Frequent NEP users also had the highest proportion of those who reported always using a condom with steady partners (P = 0.004). Factors that were not significantly associated with NEP use were gender, urban residence, typically injecting with others, recent changes in injection frequency, backloading, and always using a condom with casual partners.
Results of multivariate analyses of NEP use are presented in Table 2. After adjusting for age, gender, race/ethnicity, recruitment method, and frequency and duration of injection, a significant positive relationship was found between the prevalence of daily injection and frequency of NEP use. With the exception of frequency of injection, there were no significant differences between participants who infrequently used (1–6 visits) and never used the NEP in the previous 6 months. Significant differences in frequency of sharing needles and other injection equipment, backloading, using needles only once, and always wearing condoms with regular partners were found only for study participants who had visited NEPs more than once a month in the previous 6 months.
This study compared the sociodemographic characteristics, IDU patterns, and other high-risk behaviors of young IDUs who used versus those who did not use NEPs. Perhaps the most significant result of this study is that although NEP use was associated with several protective factors, only 13% of these young injectors had visited an NEP more than once a month in the previous 6 months. This level of NEP use appears particularly low, given the presence of >20 NEP sites in Chicago and the existence of prescription requirements for the legal purchase of syringes in Illinois.
During the study period, NEPs appear not to have been reaching most young IDUs and, therefore, were unable to promote risk reduction or provide them with sterile injection equipment and referrals to needed services. Among those who do attend NEPs, attendance was infrequent (typically once or month or less). With such infrequent contact between clients and staff, it is difficult to establish the level of rapport that promotes the use of other health and social services, including drug treatment.
Consistent with studies of older IDUs, 7,8 NEPs in our study appeared to attract the most regular and frequent injectors among our sample of young IDUs. Although the NEPs in our study attracted frequent injectors to the programs, participation in the programs was not significantly associated with any type of change in injection frequency.
Given that the goal of NEPs is to reduce the spread of life-threatening pathogens, the most important desirable association of NEP use measured by this study is lower prevalence of injection and sexual risk behaviors. These results are consistent with most studies of older NEP users that show desirable associations between NEP participation and injection risk. 9,10
Similar to the results of 1 recent study of young NEP users, 11 we found a strong association between NEP use and infrequent reuse of the same needle. Such consistent use of new sterile needles reduces the risk of abscesses and systemic bacterial infections among IDUs, as well as the risk of unknowingly injecting with a needle someone else has used.
In addition, frequent NEP users compared with nonusers had 3 times larger proportions of subjects who reported always using a condom with their regular partners. This strong association between NEP use and safer sex behavior is made even more significant in light of results of other studies showing that NEP participation has little or no effect on risky sexual behaviors. 4
This study has several limitations to consider when interpreting findings. First, because the analysis was based on cross-sectional data, the temporal and causal relationship of NEP use to reductions in risk behavior cannot be determined. In addition, the possibility of some 3rd factor affecting both NEP participation and risk reduction, such as high motivation for health promotion, cannot be ruled out.
Second, behavioral data were self-reported and therefore subject to biases associated with differences in the accuracy or completeness of reporting past behaviors or experiences. To minimize recall bias, most behavioral questions concerned the past 6 months, and interviewers asked about significant life circumstances during that time to help participants remember specific behaviors. Third, socially desirable responding might have caused some participants to underreport their levels of high-risk behavior or overreport their frequency of NEP use. 12 However, because interviews were conducted in storefront offices largely operated by staff with personal experience in using injected drugs, participants may have been more likely to speak truthfully about their behaviors. In addition, the fact that we did not see consistently desirable relationships between NEP use and risk reduction suggests that subjects were being honest about their level of risk, even after NEP participation.
Fourth, although we used multiple recruiting sites and methods to reduce bias in the sample, the sample was not randomly selected, and the extent to which findings can be generalized to other young IDUs is unknown. Finally, our study was not designed to be a formal evaluation of NEPs, so we cannot rule out contamination between NEP users and nonusers. Similarly, we did not assign subjects to user and nonuser groups, so we cannot be certain about the extent of self-selection for program participation.
Keeping these limitations in mind, our findings suggest that although young IDUs who are frequent users of NEPs inject drugs more often, they practice safer injection behaviors than the non-NEP users. These positive results are tempered by the fact that only 13% of our sample visited NEPs on average more than once a month during the 6 months preceding the baseline interview. Given the apparent benefit of participation in NEPs, more rigorous outreach efforts encouraging NEP participation among young injectors may be appropriate. Staff should also identify and remove barriers to NEP participation that may be particular to young IDUs.
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