High-risk behaviors associated with transition from illicit non-injection to injection drug use among adolescent and young adult drug users: a case-control study
Introduction
Young, recent onset injection drug users (IDUs) are at high-risk for acquiring hepatitis B and C virus as well as HIV infection (Vlahov et al., 1991, Nicolosi et al., 1992, van Ameijden et al., 1993, Nelson et al., 1995, Garfein et al., 1996, Fennema et al., 1997, Garfein et al., 1998, Thorpe et al., 2000, Hahn et al., 2001). In a study that examined prevalence of four blood borne infections, Garfein and colleagues noted that even within the first 2 years of starting injection drug use, rates of HBV and HCV infection exceeded 50% (Garfein et al., 1996). Follow-up studies of young, recent onset injectors showed a high incidence of infection within the first 3 years of starting injection (Nicolosi et al., 1992, van Ameijden et al., 1993, Nelson et al., 1995, Garfein et al., 1998, Fennema et al., 1997, Doherty et al., 2000).
A problem with interventions among young recent onset IDUs is that most existing programs (drug treatment and syringe exchange programs (SEPs)) are ineffective in reaching young populations. Drug treatment facilities require that persons demonstrate evidence of chronic injection (e.g. track marks), which is a problem since risk of infection for many occurs prior to developing signs of chronic drug injection. While a few cities across the US have demonstrated relative success in attracting young injectors to SEPs (Weiker et al., 1999, Brahmbhatt et al., 2000, Sears et al., 2001), Baltimore SEPs have fallen short in reaching young injectors (Valente et al., 2001). It is conceivable that low utilization of SEP by young injectors may be due to a reluctance to reveal injection status as well as limited hours of operation. This could explain in part why ‘evening’ as opposed to ‘daytime’ SEP venues have been able to attract younger injectors in Chicago (Brahmbhatt et al., 2000). As such, existing programs are limited in terms of their ability to attract younger populations at highest risk in Baltimore as well as other cities that lack innovative SEP venues.
To date, studies have concentrated mainly on identifying behaviors and circumstances surrounding initiation of injection drug use (Garfein et al., 1998, Doherty et al., 2000), with the goal of identifying individuals and their behaviors that might be most amenable to intervention. However, recruiting newer IDUs has shown limited feasibility while recruiting non-injection drug users (non-IDUs) has shown much success (Thorpe et al., 2001, Fuller et al., 1999, Ouellet et al., 1995). This has led to the next strategy which is to identify individuals within a community who are prone to transition into injection drug use and determine if it is possible to develop strategies of primary prevention for transition into a parenteral route of administration for illicit drugs. While other programs are directed at primary substance abuse prevention in general, the goal here would be to identify those who use illicit drugs by oral or inhalation routes whose risk for infection would increase if they started injection. In accomplishing this goal, public health professionals would be able to provide a more comprehensive approach toward reducing risk among young injection and illicit non-injection users.
While many studies have described factors associated with adolescent substance use (Kandel and Faust, 1975, Chen and Kandel, 1995, Golub and Johnson, 2001), these studies have lacked sufficient proportions of illicit non-IDUs and IDUs (heroin, crack or cocaine). Rather, such studies have almost exclusively measured the use of tobacco, alcohol and/or marijuana (Kandel and Faust, 1975, Golub and Johnson, 2001) which makes it difficult to study transition into injection drug use. However, from these studies there have been factors identified as being associated with adolescent substance use. These factors include sexual and physical abuse, delinquency, young age at first sexual experience, low educational commitment, and various psychiatric conditions (Kandel and Faust, 1975, Rounsaville et al., 1982, Downs and Rose, 1991, Rounsaville et al., 1991, Yates et al., 1991, Hawkins et al., 1992, Swaim et al., 1996, Golub and Johnson, 2001). Many of these factors contribute to HIV risk and other high-risk behavior (Doherty et al., 2000, Fuller et al., 2001a, Fuller et al., 2001b) among young IDUs as well. Studies that have included illicit substance users have primarily used samples derived from drug treatment programs, schools or households to determine predictors of adolescent substance use which may underestimate risks and limit generalizability (Hawkins et al., 1992, Yates et al., 1991, Rounsaville et al., 1982, Downs and Rose, 1991, Rounsaville et al., 1991, Swaim et al., 1996).
A recent study using data from the National Household Survey on Drug Abuse examined transition from non-illicit to any illicit drug use (Golub and Johnson, 2001); however, transition from illicit non-injection to injection drug use was not reported. Earlier studies that have included illicit drug users exclusively have suggested that snorting heroin alone, snorting heroin and cocaine together and snorting heroin while smoking crack might be efficient predictors of progression to injection drug use (Des Jarlais et al., 1992, van Ameijden et al., 1994). However, ethnographic studies (Ouellet et al., 1995) as well as findings from national survey data (Chen and Kandel, 1995) have indicated that a sizeable subgroup of illicit drug users do not transition into injection drug use suggesting that there may be other circumstances that better predict the onset of injection drug use.
To date, there has been one study that prospectively examined initiation of injection drug use among street-youth and identified younger age (<19 years) and having sex before age 14 as significant predictors of initiation (Roy et al., 1998). Another study examined ‘early misbehavior’ prior to age 16 (i.e. running away from home, getting into fights, truancy, juvenile arrests, etc.) in a case-control study of adult IDUs and residence/gender matched community controls (Tomas et al., 1990) and strong associations with early misbehavior were observed, as well as in later replicated studies (Dinwiddie et al., 1992, Obot and Anthony, 1999, Obot and Anthony, 2000). One study has identified social network characteristics such as having sex with an IDU and having an IDU friend or relative as predictors of ‘relapsing’ into injection drug use (Des Jarlais et al., 1992); however, published reports on risk factors of ‘initiating’ injection drug use remain sparse, particularly among younger drug users. Clearly, a more detailed analysis of sociodemographic and psychosocial factors that distinguish who becomes an injection drug user and who does not is warranted.
In Baltimore, we conducted a matched case-control study of young recent onset IDUs (cases) and non-IDUs (controls) and compared histories of putative risk factors for transition into injection drug use between these groups. The purpose of this analysis was to identify discrete high-risk circumstances occurring early on in a young drug user's life (i.e. age at first sexual experience, trading sex, rape or sexual assault, high school dropout, juvenile detention) that would help determine whether such factors known to be associated with adolescent substance use and HIV were, in fact, also associated with being a recent onset IDU. Since illicit drug use typically begins during adolescence among IDUs, we felt that examining factors known to be associated with adolescent substance abuse would be early, salient predictors of transition. Thus, identifying early circumstances could help to better target a subgroup that could be isolated for the development of intense interventions to reduce the risk of transitioning into injection as well as the risk of acquiring parenterally transmitted blood borne infections. In addition, we were interested in identifying other high-risk circumstances that differentiated recent onset IDUs from their age matched non-IDU peers (i.e. suicidal ideation, exposure to physical violence, and homelessness) IDUs to identify specific needs that might be addressed in prevention programs targeted to this group.
Section snippets
Study population
Between July 1997 and May 1999 we recruited 452 adolescent and young adult drug users into a prospective study of HIV infection (Risk Evaluation and Assessment of Community Health—REACH II Study) through extensive community-based street outreach in Baltimore, Maryland. Given the fact that adolescent and young adult IDUs were difficult to locate, a recreational vehicle (mobile clinic) was used to enhance accessibility to this hidden population. The REACH II mobile clinic parked in areas of high
Results
Of the 270 young IDUs and non-IDUs selected for this case-control study, the majority of the sample was African–American (78%), and female (61%) (Table 1). The median ages of the cases and controls at study entry were both 26 (ranges 15–30 and 16–30 years, respectively). Recently transitioned IDUs were more likely than age-matched controls (who remained non-IDUs) to test seropositive for HIV antibodies (odds ratio (OR)=2.80) and were less likely to be African–American (OR=0.13). There were no
Discussion
Several important circumstances identified in this study were associated with transition into injection drug use. Firstly, in terms of early psychosocial circumstances, transition from non-injection to injection drug use was significantly associated with early sex-trading specifically during the year immediately preceding transition into injection. Trading sex among IDUs and non-IDUs has been well documented as a risk factor for HIV infection (Fullilove et al., 1990, Edlin et al., 1994,
Acknowledgements
The authors would like to thank the REACH II Study team and all the staff at the Ferne Johnson Center. Ferne Johnson was a community advisory board member and was one of the first activists in East Baltimore to dedicate her life to those struggling with HIV disease, particularly IDUs, early on in the epidemic. We also thank Dr Carl Latkin and Dr David Celentano for the wealth of support and technical advice they contributed to the development of this manuscript. Supported by funds from the
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