Preventing Injection Drug use Initiation: State of the Evidence and Opportunities for the Future

Decrease in injection and rise in smoking and snorting of heroin and synthetic opioids, 2000-2021

BACKGROUND

Injecting, smoking, and snorting heroin/synthetic opioids is each associated with unique health risks. It is unclear how route of administration (ROA) preferences have shifted during the opioid epidemic.

METHODS

Using 2000-2021 admissions data from SAMHSA TEDS-A, we analyzed trends in heroin/synthetic opioid ROA preferences and factors associated with these preferences.

RESULTS

7,881,318 heroin/synthetic opioid admissions reported injection, smoking, or snorting preference. Nationally, injection peaked in 2014 (69.9 %) and nadired in 2021(52.2 %), snorting nadired in 2014 (24.9 %) and peaked in 2021 (36.4 %), and smoking rose steadily from 2.5 % in 2005 to a peak of 11.4 % in 2021. From 2000-2021, the number of states with ≥10 % smoking rates grew from 2 to 27 (highest: 57.0 % in Arizona in 2021). In 2021, increased adjusted prevalence ratios (APR) of non-injection versus injection use were associated with older age at first opioid use (APR 1.52 [95 % CI: 1.51, 1.54] for those 30+ relative to ≤20), and all race/ethnicities relative to non-Latino White individuals (highest: Black individuals, APR 1.77 [1.75, 1.78]). Geography strongly predicted smoking versus snorting (Mountain APR 6.91 [6.64, 7.19], Pacific APR 6.61 [6.35, 6.88], reference: New England).

CONCLUSIONS

ROA preferences of heroin/synthetic opioids have changed substantially since 2000, with: 1) recent decreases in injection nationally; 2) increased smoking, particularly in the western US; and, 3) recent increased snorting in the eastern US. Smoking is now prevalent and growing. Public health implications include an increasing number of smoking-related fatal overdoses and the probable reduction of injection-specific morbidity and increase in smoking-specific morbidity.

Three noteworthy idiosyncrasies related to Canada's opioid-death crisis, and implications for public health-oriented interventions

Canada has been experiencing a prolonged public health-crisis of high rates of overdose deaths caused by exceptionally potent/toxic, illicit opioid use. While many key features of this drug death epidemic are well-documented, several idiosyncratic aspects with relevance for public health-oriented interventions are not adequately recognised. These include: (i) the discrepant opioid patterns pan-Canada, with large majorities of opioid deaths caused by illicit fentanyl drugs in Western, but not Eastern regions where prescription-type opioid prevail; (ii) the environments of overdose deaths, where vast majorities occur in 'residential' or other shelter-type settings, presenting barriers for emergency interventions rather than health protection; and (iii) shifting drug use modes, where now majorities of overdose deaths are associated with drug 'inhalation' (instead of 'injection') in contexts of potent/toxic drug supply. We briefly describe these factors and related implications for intervention programming towards an improved response to the drug death-crisis.

Health risks associated with smoking versus injecting fentanyl among people who use drugs in California

BACKGROUND

Given the attention, funding, and services that seek to reduce overdose mortality from fentanyl, it is important to understand whether a potential solution is for more people to switch from injecting to smoking fentanyl. As such, we set out to conduct a study to compare health and healthcare utilization outcomes associated with different modes of illicit fentanyl administration.

METHODS

From January to February 2023, we recruited people who use drugs from 34 syringe services programs across California, USA (N=999) and surveyed their substance use, health outcomes, and healthcare utilization. We compared health risks among people who injected fentanyl (78% of whom also smoked) to people who solely smoked fentanyl (n=563).

RESULTS

Of the 563 participants, forty-one percent injected fentanyl and 59% only smoked fentanyl. People who injected fentanyl were 40% more likely to have experienced a non-fatal overdose in the past 3 months (27% vs. 19%; aRR=1.40; 95% CI=1.03, 1.93) and 253% more likely to have had a skin and soft tissue infection in the past 3 months (39% vs. 15%; aRR=2.53; 95% CI=1.74, 3.67), compared to people who only smoked fentanyl. The average number of nights spent in the hospital was higher among people who injected fentanyl (average 1.2 nights vs. 0.7 nights; aIRR=1.78; 95% CI=1.02, 3.09; p=0.04).There were non-significant associations between mode of fentanyl administration and number of emergency department visits and probability of hospitalization.

CONCLUSIONS

Findings suggested that people who injected fentanyl were at higher risk for overdose and skin and soft tissue infections than people who only smoked fentanyl. Distribution of safe smoking supplies may facilitate transitions from injecting to smoking fentanyl, thereby reducing health risks associated with fentanyl use.

Gender, sexual orientation identity, and initiation of amphetamine injecting among people who inject drugs: Examination of an expanding drug era in Montreal, Canada, 2011-19

BACKGROUND

Amphetamine injection is expanding in North America and has been associated with male homosexuality among people who inject drugs (PWID). Applying subcultural evolution theory, we examined overall and gender-stratified trends in amphetamine injection and assessed sexual orientation as a gender-specific predictor of initiation among PWID in Montreal, Canada.

METHODS

Data were from HEPCO, an open prospective cohort of PWID. Gender and sexual orientation were self-identified at enrolment. Interviewer-administered questionnaires at three-monthly (HCV RNA-negative participants) or yearly (RNA-positive) intervals captured past three-month amphetamine injection and covariates. Annual prevalence and linear trends in amphetamine injection were estimated using GEE. Incidence was computed among naïve individuals and hazard ratios for initiation estimated using gender-stratified, time-varying Cox regression models.

RESULTS

803 participants contributed 8096 observations between March 2011 and December 2019. Annual prevalence of amphetamine injecting increased from 3.25% [95%CI: 2.06-4.43%] to 12.7% [9.50-16.0] (trend p<0.001). Bivariate Cox regression models suggested similar and divergent predictors of initiation by gender. Incidence was 3.27 per 100 person-years [95%CI: 2.51-4.18] among heterosexual men, 7.18 [3.50-13.2] among gay/bisexual men, 1.93 [0.78-4.02] among heterosexual women and 5.30 [1.69-12.8] among gay/bisexual women. Among men, gay/bisexual identity doubled risk of initiation after adjusting for age, ethnicity, calendar year (aHR 2.16 [1.07-4.36]) and additional covariates (2.56 [1.24-5.30]). Among women, evidence for an association with gay/bisexual identity was inconclusive (aHR 2.63 [0.62-11.2]) and sample size precluded further adjustment CONCLUSIONS: Prevalence of amphetamine injection among PWID increased four-fold from 2011 to 2019, with elevated risk of initiation in gay and bisexual men.

Latent polydrug use patterns and the provision of injection initiation assistance among people who inject drugs in three North American settings

INTRODUCTION

We sought to identify latent profiles of polysubstance use patterns among people who inject drugs in three distinct North American settings, and then determine whether profile membership was associated with providing injection initiation assistance to injection-naïve persons.

METHODS

Cross-sectional data from three linked cohorts in Vancouver, Canada; Tijuana, Mexico; and San Diego, USA were used to conduct separate latent profile analyses based on recent (i.e., past 6 months) injection and non-injection drug use frequency. We then assessed the association between polysubstance use patterns and recent injection initiation assistance provision using logistic regression analyses.

RESULTS

A 6-class model for Vancouver participants, a 4-class model for Tijuana participants and a 4-class model for San Diego participants were selected based on statistical indices of fit and interpretability. In all settings, at least one profile included high-frequency polysubstance use of crystal methamphetamine and heroin. In Vancouver, several profiles were associated with a greater likelihood of providing recent injection initiation assistance compared to the referent profile (low-frequency use of all drugs) in unadjusted and adjusted analyses, however, the inclusion of latent profile membership in the multivariable model did not significantly improve model fit.

DISCUSSION AND CONCLUSIONS

We identified commonalities and differences in polysubstance use patterns among people who inject drugs in three settings disproportionately impacted by injection drug use. Our results also suggest that other factors may be of greater priority when tailoring interventions to reduce the incidence of injection initiation. These findings can aid in efforts to identify and support specific higher-risk subpopulations of people who inject drugs.

First-line opioid agonist treatment as prevention against assisting others in initiating injection drug use: A longitudinal cohort study of people who inject drugs in Vancouver, Canada

Background

Among people who inject drugs, frequent injecting and experiencing withdrawal are associated with facilitating others' first injections. As these factors may reflect an underlying substance use disorder, we investigated whether first-line oral opioid agonist treatment (OAT; methadone or buprenorphine/naloxone) reduces the likelihood that people who inject drugs help others initiate injecting.

Methods

We used questionnaire data from semi-annual visits between December 2014-May 2018 on 334 people who inject drugs with frequent non-medical opioid use in Vancouver, Canada. We estimated the effect of current first-line OAT on subsequent injection initiation assistance provision (i.e., helped someone initiate injecting in the following six months) using inverse-probability-weighted estimation of repeated measures marginal structural models to reduce confounding and informative censoring by time-fixed and time-varying covariates.

Results

By follow-up visit, 54-64% of participants reported current first-line OAT whereas 3.4-6.9% provided subsequent injection initiation assistance. Per the primary weighted estimate (n = 1114 person-visits), participants currently on first-line OAT (versus no OAT) were 50% less likely, on average, to subsequently help someone initiate injecting (relative risk [RR]=0.50, 95% CI=0.23-1.11). First-line OAT was associated with reduced risk of subsequent injection initiation assistance provision in participants who, at baseline, injected opioids less than daily (RR=0.15, 95% CI=0.05-0.44) but not in those who injected opioids daily (RR=0.86, 95% CI=0.35-2.11).

Conclusions

First-line OAT seemingly reduces the short-term likelihood that people who inject drugs facilitate first injections. However, the extent of this potential effect remains uncertain due to imprecise estimation and observed heterogeneity by baseline opioid injecting frequency.

Determinants of health among people who use illicit drugs in the conflict-affected countries of Afghanistan, Colombia and Myanmar: a systematic review of epidemiological evidence

BACKGROUND

Afghanistan, Colombia and Myanmar are the world's leading heroin and cocaine producers and have also experienced prolonged periods of armed conflict. The link between armed conflict and drug markets is well established but how conflict impacts on the health and social determinants of people who use drugs is less clear. The aim was to investigate health outcomes and associated factors among people who use illicit drugs in Afghanistan, Colombia and Myanmar.

METHODS

We conducted a systematic review searching Medline, EMBASE, PsychINFO and Global Health databases using terms relating to Afghanistan, Colombia and Myanmar; illicit drug use (all modes of drug administration); health and influencing factors. Quality assessment was assessed with the Newcastle-Ottawa-Scale and papers were analysed narratively.

RESULTS

35 studies were included in Afghanistan (n = 15), Colombia (n = 9) and Myanmar (n = 11). Health outcomes focused predominantly on HIV, Hepatitis C (HCV), Hepatitis B and sexually transmitted infections (STIs), with one study looking at human rights violations (defined as maltreatment, abuse and gender inequality). Drug use was predominantly injection of heroin, often alongside use of amphetamines (Myanmar), cocaine and cocaine-based derivatives (Colombia). Only one study measured the effect of a period of conflict suggesting this was linked to increased reporting of symptoms of STIs and sharing of needles/syringes among people who inject drugs. Findings show high levels of external and internal migration, alongside low-income and unemployment across the samples. External displacement was linked to injecting drugs and reduced access to needle/syringe programmes in Afghanistan, while initiation into injecting abroad was associated with increased risk of HCV infection. Few studies focused on gender-based differences or recruited women. Living in more impoverished rural areas was associated with increased risk of HIV infection.

CONCLUSIONS

More research is needed to understand the impact of armed-conflict and drug production on the health of people who use drugs. The immediate scale-up of harm reduction services in these countries is imperative to minimize transmission of HIV/HCV and address harms associated with amphetamine use and other linked health and social care needs that people who use drugs may face.

Factors Associated with Likelihood of Initiating Others into Injection Drug Use Among People Who Inject Drugs in West Virginia

People who inject drugs (PWID) play a critical role in injection-naïve individuals transitioning to injection drug use. We investigated factors associated with future likelihood of initiating injection-naïve individuals using multivariable logistic regression among 418 PWID in rural Appalachia (Cabell County, West Virginia). Less than 10% reported they were likely to initiate someone in the future. Acquiring syringes from a syringe services program was associated with decreased odds of being likely to initiate someone in the future (adjusted odds ratio [aOR] 0.46, 95% CI 0.23, 0.95), while having previously initiated someone into injection drug use was associated with increased odds (aOR 8.65, 95% CI 4.07, 18.41). Among our sample of PWID in Appalachia, a small proportion reported that they would be likely to initiate an injection-naïve individual in the future. Efforts to reduce injection initiation assistance should focus on this subpopulation of PWID who indicate a willingness to engage in this behavior.

Poly-drug use among female and male commercial sex workers visiting a drop in centre in Mombasa County, Kenya

The relationship between commercial sex work and drug use is complex and the two exacerbate each other. In Kenya, Mombasa County has one of the highest populations of drug users and commercial sex workers. Despite documentation of drug use among sex workers, most of the studies are based on self-reported history which is prone to social desirability and memory recall biases. It is in this context that we sought to establish actual drug use is this sub-population. A cross-sectional study was conducted to determine self-reported and confirmed drug use among 224 commercial sex workers accessing services at Mvita Drop-in. Actual drug use was determined qualitatively using 6 panel plus alcohol Saliva Test kit. The overall prevalence of self-reported and confirmed current use for at least one drug was 98% and 99% respectively. Regardless of the technique used, alcohol and tobacco products were the most consumed substances. Alcohol use increased significantly with age (P = 0.03). Risk of cigarette use and testing positive for cotinine was higher among those age 18 to 35 years compared to >35years at P = 0.001 and P = 0.002 respectively. Poly-drug use was common with 98% testing positive for more than one drug. The reason for drug use was sex work related pressure (88%) with 60% of the respondents reporting they cannot transact this business without drugs. Almost every commercial sex worker is a poly-drug user. We recommend targeted interventions for commercial sex workers.

"I would rather do it myself": injection initiation and current injection patterns among women who inject drugs in Tijuana, Mexico

BACKGROUND

Women who inject drugs (WWID) experience unique risks and adverse health outcomes related to injection initiation and patterns of injection drug use. However, there is limited information on injection initiation experiences and injection patterns among women and the protective strategies employed to limit injection-related harms, especially in low- and middle-income settings. Therefore, this study sought to explore injection initiation and current injection patterns (e.g., relying on someone else to inject) among women who inject drugs and engage in sex work in Tijuana, Mexico.

METHODS

Semistructured in-depth interviews were conducted with 30 WWID on the following topics: injection initiation, current injection patterns, places where women inject, and protective strategies (i.e., risk reduction). All interviews were audio-recorded, transcribed, and de-identified. An inductive thematic analysis was conducted to identify and compare common themes and patterns across participants.

RESULTS

The interviews revealed that the vast majority of study participants were first initiated by another person who injects drugs (PWID), often a male sexual partner. However, the majority of the women transitioned to become self-injectors in order to avoid risks associated with relying on others for injection, including overdose, interpersonal violence, sexual abuse, and wounds. Those who relied on others indicated that they would prefer to inject themselves without assistance from others if they were able to.

CONCLUSIONS

The narratives uncovered in this study reveal the importance of multiple risk environments in shaping perceived risks associated with injection drug use among women in Tijuana, Mexico. Specifically, the interviews elucidate the connection between interpersonal relationships with other PWID and protective strategies used to minimize risk and harm. These findings highlight the need for women-centered harm reduction programs to facilitate the development of safer drug use environments among WWID in Tijuana, Mexico.

Investigating a bidirectional relationship between overdose and provision of injection initiation assistance among persons who inject drugs in Vancouver, Canada and Tijuana, Mexico

BACKGROUND

Individuals who initiate injection drug use often receive assistance from an injection-knowledgeable peer. Persons who assist peers in injection initiation events often inject frequently, which heightens overdose risk. As such, overdose and injection initiation events may be correlated. To explore a potential relationship, we assessed temporal associations between experiencing a non-fatal overdose and assisting others in initiating injection drug use among persons who inject drugs in two North American cities - Vancouver, Canada and Tijuana, Mexico.

METHODS

From 2014 to 2018, this retrospective cohort study included people who inject drugs from Vancouver (n=1332) and Tijuana (n=666) who completed a baseline and six-month follow-up interview. Within each site, we assessed bidirectional temporal associations using two separate multivariable logistic regression models: for model 1, recent provision of injection initiation assistance (at six months) was the outcome and recent overdose (at baseline) was the exposure; for model 2, recent overdose (at six months) was the outcome and recent provision of injection initiation assistance (at baseline) was the exposure. Both models adjusted for potential confounders.

RESULTS

Vancouver-based participants reporting overdose at baseline had 163% greater odds of reporting provision of injection initiation assistance at follow-up (adjusted Odds Ratio [aOR] 2.63; 95% Confidence Interval [CI] 1.41-4.90); while participants reporting provision of injection initiation assistance at baseline had 89% greater odds of reporting a non-fatal overdose at follow-up (aOR 1.89; 95% CI 1.00-3.57). Among Tijuana-based participants, we did not observe a statistically significant association in either direction.

CONCLUSION

Findings in Vancouver suggest that injection initiation assistance and overdose are bidirectionally-associated phenomena. The present findings highlight the need for interventions that ensure that persons who provide injection initiation assistance are given overdose prevention support, both for themselves and for those they assist to initiate injection drug use. While our Tijuana-based results did not suggest a bidirectional relationship, preventative approaches should nonetheless be undertaken.

Do sexual expectancies and inhibitions predict high-risk sexual behaviours? Evidence from a cross-sectional survey among young psychoactive substance users in informal settlements in Kampala, Uganda

BACKGROUND

Psychoactive substance use is a public health challenge among young people in informal settlements. Though rarely examined, psychoactive substance use is linked to sexual expectancies and inhibitions, and consequently high-risk sexual behaviours. This study examined the association between sexual expectancies and inhibitions, and high-risk sexual behaviours among young psychoactive substance users (PSUs) in informal settlements in Kampala, Uganda.

METHODS

This cross-sectional study recruited 744 young PSUs from informal settlements in Kampala. Respondent driven sampling was used to recruit respondents. A 'modified' Poisson regression model was used for inferential statistics. Data were analysed using the Stata 14 software.

RESULTS

Of the 744 study participants, 45.6% believed that psychoactive substance use improves sexual performance; 43.3% believed that psychoactive substances make sex more pleasurable, and 53.3% believed that psychoactive substances give courage or confidence to approach a partner for sex. The belief that psychoactive substance use improves sexual performance (PR 1.14, 95% CI: 1.01-1.30), increases the likelihood of engaging in sex (PR 1.20, 95% CI: 1.04-1.40) or gives courage or confidence to approach a sexual partner (PR 1.21, 95% CI: 1.05-1.39) were associated with having sex while under the influence of psychoactive substances. The belief that a psychoactive substance user under the influence of psychoactive substances is more likely to engage in sex (PR 1.48, 95% CI: 1.15-1.90), and likely to find it difficult to refuse sex (PR 1.28, 95% CI: 1.06-1.55) were positively associated with engaging in multiple sexual partnerships. The belief that one easily forgets to use a condom when under the influence of psychoactive substances was positively associated with inconsistent condom use (PR 1.26, 95% CI: 1.09-1.45).

CONCLUSION

Psychoactive substance use expectancies associated with high-risk sexual behaviours included the belief that psychoactive substances improve sexual performance and improve confidence in approaching a sexual partner. Psychoactive substance use inhibitions associated with high-risk sexual behaviours included an increased likelihood of engaging in sexual intercourse, difficulties in refusing to engage in sexual intercourse, and forgetting to use condoms while intoxicated. Interventions targeting a reduction in high-risk sexual behaviour should integrate the impact of psychoactive substance use on sexual behaviour.

Examining the gender composition of drug injecting initiation events: A mixed methods investigation of three North American contexts

BACKGROUND

Gender influences the health and social risks faced by individuals initiating drug injecting. Using mixed methods across three settings in North America, we investigated the gender composition of injection initiation events and the gendered risk environments in which they occurred.

METHODS

The PReventing Injecting by Modifying Existing Responses (PRIMER) study pooled data from three prospective community-recruited cohorts of people who inject drugs (PWID) in San Diego, USA, Vancouver, Canada, and Tijuana, Mexico. A qualitative subsample provided narrative data on their experiences of, and the contexts for, injection initiation events. Guided by Rhodes' risk environment framework, we examined the gender composition of initiation events stratified by city, and analyzed qualitative data using abductive thematic analyses.

RESULTS

Among 2,622 PWID (Tijuana: n = 531; San Diego: n = 352; Vancouver: n = 1,739), 112 (4.3%) reported providing initiation assistance to injection-naïve individuals in the previous six months. The proportion of gender concordant (e.g., male-male) initiation pairs varied, (χ2 = 10.32, p <0.001) with greater than expected concordance among pairs in Tijuana compared with those in Vancouver or San Diego. Sixty-one interviews provided context for the discrepancy across sites by highlighting the gendered injection initiation risk environments of prison/jail detention in Tijuana, intimate partnerships in San Diego, and overdose risk in Vancouver.

CONCLUSIONS

These results highlight how gender influences injection initiation events within spatial, social, and economic risk environments, and how this influence varies across settings. These findings can inform interventions to reduce the risk of injection initiation and related harms.

A Multistage Process Model of How a Person Who Currently Injects Drugs Comes to Assist Persons Who Do not Inject with Their First Injections

Injecting drugs for the first time almost always requires assistance from an experienced person who injects drugs (PWID). While there has been moderate amount of research on PWID who assist with first injections, most of this research has focused on identifying characteristics of PWID who assist with first injections. We do not have a formal model that describes how the minority of PWID come to assist do so, while the majority never assist. Through comparison of persons who did or did not recently assist with first injections using data from PWID in Tallinn, Estonia (N = 286) and Staten Island, New York City (N = 101), we developed a formal multi-stage model of how PWID come to assist with first injections. The model had a primary pathway 1) of engaging in "injection promoting" behaviors, 2) being asked to assist, and 3) assisting. Statistical testing using odds ratios showed participation in each stage was strongly associated with participation in the next stage (all odds ratios >3.0) and the probabilities of assisting significantly increased with participation in the successive stages. We then used the model to compare engagement in the stages pre-vs. post participation in an intervention, and to compare persons who recently assisted to persons who had assisted in the past but had not recently assisted and to persons who had never assisted. Advantages of a formal model for how current PWID come to assist with first injections include: facilitating comparisons across different PWID populations and assessing strengths and limitations of interventions to reduce assisting with first injections.

"I Know It Is Going to Ruin Their Life:" Fortune-Telling, Agency, and Harm Reduction in Narratives Concerning Injection Initiation Assistance

BACKGROUND

Considering most people who inject drugs (PWID) received help with the first injection, understanding the perspective of potential 'initiators' is a priority to inform harm reduction interventions. This paper examines how PWID narrate their experiences with injection initiation and assistance from the lens of their lived experience and perceptions of harm reduction.

METHODS

In-depth interviews were conducted with individuals who reported injection drug use and recent (past 30 days) opioid use in Baltimore (N = 19) and Anne Arundel County (N = 4), Maryland and analyzed using a narrative approach.

RESULTS

Respondents cast initiation events as meaningful transitions to a life characterized by predictable harms, including homelessness, infections, and social stigma. Respondents used examples from their personal experience to explain experiences with initiation and assistance by strategically attributing personal agency and predicting specific injection-related harms for initiates. In their narratives, respondents balanced notions of individual agency with harm reduction intentions by distinguishing between two forms of harm: perceived inevitable distal harm caused by long-term injection (e.g. socioeconomic decline) and potentially avoidable proximal harm caused by risky injection practices (e.g. overdose, HIV).

CONCLUSIONS

These findings highlight opportunities for interventions targeting injection initiation events and support the implementation of safer injection training in interventions. This identity of the 'responsible drug user' could be leveraged to support employing peers to help mitigate harm among inexperienced PWID either through peer outreach or formal venues, such as overdose prevention sites.

Peer Influence in Initiation to Heroin Use

Much research on heroin initiation shows that most people use heroin initially with friends or family. However, there is little research examining why those who use heroin would initiate others to its use, and conversely, whether and why one might try to prevent initial heroin use in others. Following recent work on peer influence on crime and delinquency, we test the hypothesis that those with higher levels of self-control are less likely to initiate others to heroin use and are more likely to try to prevent others from using for the first time. The sample included 370 persons entering an opioid withdrawal program. We find that those with low self-control are more likely to initiate others, but there is no relationship between self-control and trying to prevent initiation. We further investigate self-reported motives for initiating others, and find a mix of self-interested and more altruistic motives for initiating others.

A Review of Factors Associated with Age of First Injection

Injection drug use (IDU) is of increasing public health concern in the United States. Misuse of and addiction to opioids has contributed to declining life expectancies and rebounding risk of HIV and HCV acquisition among people who inject drugs. While some effective treatment strategies for individuals with substance use disorders have been established, effective interventions to prevent IDU require greater tailoring to subpopulations and social contexts. To better understand contextual variables associated with initiation of IDU, we conducted a narrative review of the existing literature that assessed correlates of age of first injection. We found sixteen studies that met our inclusion criteria. Across studies, later IDU initiation was associated with being African American and female, while early initiation was associated with earlier illicit substance use, childhood trauma, and incarceration. We also found that early initiation was associated with riskier substance-using behaviors, though the findings were mixed with respect to differences between early and late initiates in infectious disease prevalence. These correlates of age of first injection can potentially inform tailored injection prevention strategies. By identifying the features and behaviors of relevant subpopulations before they inject, interventions to prevent IDU could become more effective.

The role of drug treatment and recovery services: an opportunity to address injection initiation assistance in Tijuana, Mexico

BACKGROUND

In the U.S. and Canada, people who inject drugs' (PWID) enrollment in medication-assisted treatment (MAT) has been associated with a reduced likelihood that they will assist others in injection initiation events. We aimed to qualitatively explore PWID's experiences with MAT and other drug treatment and related recovery services in Tijuana Mexico, a resource-limited setting disproportionately impacted by injection drug use.

METHODS

PReventing Injecting by Modifying Existing Responses (PRIMER) seeks to assess socio-structural factors associated with PWID provision of injection initiation assistance. This analysis drew on qualitative data from Proyecto El Cuete (ECIV), a Tijuana-based PRIMER-linked cohort study. In-depth qualitative interviews were conducted with a subset of study participants to further explore experiences with MAT and other drug treatment services. Qualitative thematic analyses examined experiences with these services, including MAT enrollment, and related experiences with injection initiation assistance provision.

RESULTS

At PRIMER baseline, 607(81.1%) out of 748 participants reported recent daily IDU, 41(5.5%) reported recent injection initiation assistance, 92(12.3%) reported any recent drug treatment or recovery service access, and 21(2.8%) reported recent MAT enrollment (i.e., methadone). Qualitative analysis (n = 21; female = 8) revealed that, overall, abstinence-based recovery services did not meet participants' recovery goals, with substance use-related social connections in these contexts potentially shaping injection initiation assistance. Themes also highlighted individual-level (i.e., ambivalence and MAT-related stigma) and structural-level (i.e., cost and availability) barriers to MAT enrollment.

CONCLUSION

Tijuana's abstinence-based drug treatment and recovery services were viewed as unable to meet participants' recovery-related goals, which could be limiting the potential benefits of these services. Drug treatment and recovery services, including MAT, need to be modified to improve accessibility and benefits, like preventing transitions into drug injecting, for PWID.

Self-perception of assisting with future injection drug initiation: The influence of relationships in the process of drug injecting initiation

INTRODUCTION AND AIMS

People who inject drugs (PWID) play critical roles in assisting others into injection drug use (IDU) initiation. Understanding perceptions of PWID's risk of initiating others is needed to inform interventions for prevention. The objective was to examine factors associated with self-perception of assisting with future IDU initiation events. The primary variables of interest are the relationships of PWID with the person(s) they assisted and their reasons for previously providing initiation assistance.

DESIGN AND METHODS

Data from Preventing Injecting by Modifying Existing Responses, a multi-site prospective community-recruited cohort study, were analysed. Analyses were restricted to PWID who reported ever providing IDU initiation assistance. Site-specific (Vancouver, Canada [n = 746]; San Diego, USA [n = 95] and Tijuana, Mexico [n = 92]) multivariable logistic regression analyses were performed to determine factors associated with self-perception of assisting with future IDU initiation.

RESULTS

Having provided IDU initiation assistance to a family member or intimate partner decreased the odds of self-perception of assisting with future IDU initiation in Vancouver (AOR = 0.4; 95% CI 0.2-0.8); however, previous IDU initiation assistance to an 'other' increased the odds of self-perception of assisting with future IDU in Tijuana (AOR = 12.0; 95% CI 2.1-70.3). Daily IDU (Vancouver: AOR = 3.7; 95% CI 2.1-6.4) and less than daily IDU (San Diego: AOR = 5.9; 95% CI 1.3-27.1) (Vancouver: AOR = 2.6; 95% CI 1.4-2.9) were associated with increased self-perception of assisting with future IDU compared to current non-injectors.

DISCUSSION AND CONCLUSIONS

Relationship to past initiates and IDU frequency might increase PWID's self-perception of assisting with future IDU. Interventions focused on social support and reducing IDU frequency may decrease occurrences of IDU initiation assistance.

Trajectories of initiation for the heroin-based drug whoonga - qualitative evidence from South Africa

BACKGROUND

Whoonga is a smoked heroin-based street drug that first emerged in South Africa a decade ago. While previous scientific reports suggest that use is growing and youth are particularly vulnerable, trajectories of initiation are not well characterized.

METHODS

In 2015, 30 men undergoing residential addiction treatment for this smoked heroin drug in KwaZulu-Natal, South Africa participated in semi-structured interviews about their experiences using the drug. Interview data were coded using qualitative content analysis.

RESULTS

Participant trajectories to initiating smoked heroin were "vertical" in the context of marijuana use or "horizontal" in the context of other hard drug use. Participants reporting vertical trajectories began smoking heroin as youth at school or in other settings where people were smoking marijuana. Several participants with horizontal trajectories started smoking heroin to address symptoms of other drug or alcohol addiction. Social influences on initiation emerged as an overarching theme. Members of participants' social networks who were smoking or distributing heroin figured prominently in initiation narratives. Surprisingly, references to injection drug use were absent from initiation narratives. Participants reported people who smoke heroin differ from those who inject heroin by race.

CONCLUSION

Consistent with theories implicating social and structural influences on substance use initiation, people who started smoking heroin had social contacts who smoked heroin and frequented places where substance use was common. Smoked heroin initiation for several participants with horizontal trajectories may have been averted if they accessed evidence-based treatments for stimulant or alcohol use disorders. With increasing reports of heroin use across Africa, a coordinated approach to address this growing epidemic is needed. However, because smoked heroin and injection heroin use occur in distinct risk environments, interventions tailored to people who use smoked heroin will be needed to prevent smoked heroin use, prevent transition to injection use, and mitigate other social harms.

Preventing transitions into injection drug use: A call for gender-responsive upstream prevention

In 2017, there were large increases (260-500%) in overdose deaths among women in the United States across age groups (30-64 years and 55-64 years). In addition, U.S. women who inject drugs (WWID) are at increased risk for substance use-related disease transmission, bacterial infections, as well as sexual and physical violence compared to men who inject drugs. Relatedly, women face unique access barriers to substance use-related services, such as stigma and low coverage of gender-specific drug use-related services. Despite these heightened risks experienced by WWID, interventions specifically tailored to preventing women from transitioning into injection drug use have not been developed to date. As such, we advocate for the development of gender-responsive programs to prevent injection drug use initiation. This is critical to ensuring a comprehensive approach to preventing injection drug use initiation among those populations at highest risk of injection-related morbidity and mortality.

Recent incarceration and risk of first-time injection initiation assistance: A prospective cohort study of persons who inject drugs

BACKGROUND

Given the prevalence and harms of incarceration among persons who inject drugs (PWID) and their role in injection drug use initiation, we aimed to investigate whether recent incarceration influences the likelihood PWID assist others in their first-ever injection.

METHODS

Prospective cohort study of PWID in Vancouver, Canada who had their PReventing Injecting by Modifying Existing Responses (PRIMER) baseline visit between December 2014 and May 2017, reported never providing injection initiation assistance previously, and had ≥1 follow-up visit. The primary outcome, provision of injection initiation assistance, was defined via self-report as helping anybody inject for the first time in the past six months. The primary exposure was recent incarceration, i.e., self-report of being jailed, imprisoned or detained in the past six months. Participants were assessed biannually until November 2017, drop-out, or their first report of the primary outcome.

RESULTS

1,199 PWID (62.1% male; mean (SD) age, 44.4 (12.3) years) were included in our study. Across 4,171 follow-up visits, 67 participants (5.6%) reported providing injection initiation assistance. The proportion of participants reporting recent incarceration varied between 2.4% to 5.1% per follow-up visit. Based on a multivariable discrete-time proportional hazards regression analysis, recent incarceration was associated with an increased risk of providing injection initiation assistance during the same six-month period (adjusted hazard ratio, 2.64; 95% CI, 1.19 to 5.86).

CONCLUSIONS

The observed association between recent incarceration and risk of providing injection initiation assistance suggests that incarceration could be contributing to the expansion of injection drug use practices within vulnerable populations over time.

The fentanyl epidemic in Estonia: factors in its evolution and opportunities for a comprehensive public health response, a scoping review

BACKGROUND

The spread of illicitly manufactured fentanyl has the potential to greatly increase the fatal overdoses in many places in the world. The purpose of this paper is to analyse the evolution of fentanyl use epidemic in Estonia.

METHODS

this scoping review is based on extensive review and synthesis of broad range of literature: research reports, newspaper, magazine, coverage of illicit fentanyl use; policy documents, position papers, reports released by government agencies, and surveillance data.

RESULTS

For an over a decade up to 2017, Estonia has had the highest overdose death mortality in Europe. The use of (injected) fentanyl is a major contributor to the Estonian overdose death epidemic. Shutting down a major producer and distributor of illicit fentanyl has been extremely effective in curbing the number of overdose deaths. Unfortunately, this supply-side intervention came ten years into the epidemic, and might be difficult to replicate in settings with decentralized production. In areas faced by fentanyl we would recommend large-scale implementation of opiate substitution treatment and naloxone distribution, syringe service programs to provide for safer injecting and link to other services (high frequencies of fentanyl injection create high risk for HIV and HCV transmission), and programs, such as "Break the Cycle," to reduce initiation into injecting drug use. Further, the means of responding to emerging substances should match the world in which different substances can be rapidly introduced, and where people who use drugs can change preferences based on market availability.

CONCLUSION

Addressing illicitly manufactured fentanyl may serve as a public health learning experience for developing early detection and rapid response programs in rapidly changing drug use environments.

Drivers of opioid use in Appalachian Pennsylvania: Cross-cutting social and community-level factors

BACKGROUND

Four Appalachian states including Pennsylvania (PA) have the highest drug overdose rates in the country, calling for better understanding of the social and economic drivers of opioid use in the region. Using key informant interviews, we explored the social and community drivers of opioid use in a non-urban Appalachian Pennsylvania community.

METHODS

In 2017, we conducted qualitative interviews with 20 key stakeholders from a case community selected using the results from quantitative spatial models of hospitalizations for opioid use disorders. In small town located 10 miles outside Pittsburgh, PA, we asked participants to share their perceptions of contextual factors that influence opioid use among residents. We then used qualitative thematic analysis to organize and generate the results.

RESULTS

Participants identified several contextual factors that influence opioid use among residents. Three cross-cutting thematic topics emerged: 1) acceptance and denial of use through familial and peer influences, community environments, and social norms; 2) impacts of economic shifts and community leadership on availability of programs and opportunities; and 3) the role of coping within economic disadvantage and social depression.

CONCLUSION

Uncovering multi-level, contextual drivers of opioid use can benefit the development of future public health interventions. These results suggest that social and community-level measures of structural deprivation, acceptance and/or denial of the opioid epidemic, community engagement and development, social support, and social depression are important for future research and programmatic efforts in the Appalachian region.

Risk perception, changing social context, and norms prevent transition to regular injection among people who smoke heroin

BACKGROUND

There is a lack of research examining what prevents people who smoke heroin from transitioning to regular injection. This qualitative study aims to improve understanding of environmental influences preventing people who smoke heroin from transitioning to regular injection.

METHODS

In-depth, semi-structured interviews (n = 15) were conducted with people who currently smoked heroin but never injected (n = 10) and those who injected on a few occasions but did not transition to regular injection (n = 5) in Northern Ireland. Multiple recruitment strategies were utilized to generate a community-based sample. Interviews were thematically analysed.

MAIN FINDINGS

Participants identified two main, interconnected influences preventing transition to injecting heroin. Firstly, resistance towards injecting was rooted in micro level perceptions of risks primarily arising from meso level social interactions with people who inject drugs and, to a lesser extent, harm reduction agencies. Secondly, participants identified meso and macro environments defined as changing social contexts and normative beliefs surrounding the acceptability of injecting within their drug-using social networks, facilitated by expanding heron markets, negative interactions with people who inject drugs and new groups of people choosing to smoke heroin due to perceptions of injection risks.

CONCLUSIONS

Findings illuminate environmental influences surrounding and shaping drug consumption practices. Harm reduction strategies should develop and implement safer smoking rooms, community and peer interventions, and improve accessibility to opioid substitution therapy and low threshold outreach services to prevent transitioning to regular heroin injecting.

The Risk Environment for Adopting and Continuing Injecting Drug Use: A Qualitative Study in Uyo, Nigeria

Background: The bulk of research on adoption of injecting is from Europe and America, despite the existence of syndemics of drug injecting, HIV, and viral hepatitis globally. Objectives: This study explores adoption and continuation of injecting drug use. Methods: The study draws on in-depth interviews with 41 (n = 41) current male and female people who inject drugs recruited via snow-ball sampling in Uyo, Nigeria. A thematic and descriptive analysis was undertaken informed by the risk environment framework and focused on accounts of the factors influencing the process. Results: Accounts emphasized injecting adoption and continuation as a process influenced by individual, social, and structural factors within the risk environment, including concerns for pleasure/efficiency, prestige, exposure to/support for injecting within peer and sexual relationships, availability and purity of drugs, and dependence and increased cost of drug use. Conclusions/implications: Findings highlight the need to prevent adoption of injecting, reduce prevalence of injecting, and promote safe injecting through multi-level interventions, including peer-driven education, drug treatment services, needle and syringe distribution, oral drug substitution, and law enforcement targeting drug suppliers. The need for equivalent pleasure with minimal risk points to the strategic importance of peer interactions for inculcating new understandings of drug use and pleasure.

When and how do individuals transition from regular drug use to injection drug use in Uganda? Findings from a rapid assessment

BACKGROUND

In Uganda, injection drug use is a growing but less studied problem. Preventing the transition to injection drug use may help prevent blood-borne viral transmission, but little is known about when and how people transition to injection drug use. A greater understanding of this transition process may aid in the country's efforts to prevent the continued growth of injection drug use, HIV, and hepatitis C Virus (HCV) infection among people who inject drugs (PWID).

METHODS

Using a rapid situation assessment framework, we conducted semi-structured interviews among 125 PWID (102 males and 23 females)-recruited through outreach and snow-ball sampling. Participants were interviewed about their experiences on when and how they transitioned into injection drug use and these issues were also discussed in 12 focus groups held with the participants.

RESULTS

All the study participants started their drug use career with non-injecting forms including chewing, smoking, and sniffing before transitioning to injecting. Transitioning was generally described as a peer-driven and socially learnt behavior. The participants' social networks and accessibility to injectable drugs on the market and among close friends influenced the time lag between first regular drug use and first injecting-which took an average of 4.5 years. By the age of 24, at least 81.6% (95.7% for females and 78.4% for males) had transitioned into injecting. Over 84.8% shared injecting equipment during their first injection, 47.2% started injecting because a close friend was already injecting, 26.4% desired to achieve a greater "high" (26.4%) which could reflect drug-tolerance, and 12% out of curiosity.

CONCLUSIONS

Over 81% non-injecting drug users in Kampala and Mbale districts transitioned into injecting by the age of 24; a process that reproduces a population of PWID but also puts them at increased risk of HIV and HCV infection. As Uganda makes efforts to introduce and/or strengthen harm reduction services, interventions targeting non-injecting drug users before they transition into injecting should be considered as a key component for HIV/HCV epidemic control efforts, and their evaluation considered in future researches.

Implementing an Updated "Break the Cycle" Intervention to Reduce Initiating Persons into Injecting Drug Use in an Eastern European and a US "opioid epidemic" Setting

We tested the hypothesis that an updated "Break the Cycle" (BtC) intervention, based in social cognitive theory and motivational interviewing, would reduce the likelihood that current persons who inject drugs (PWID) would assist persons who do not inject drugs (non-PWID) with first injections in Tallinn, Estonia and Staten Island, New York City. 402 PWID were recruited, a baseline interview covering demographics, drug use, and assisting non-PWID with first drug injections was administered, followed by BtC intervention. 296 follow-up interviews were conducted 6 months post-intervention. Percentages assisting with first injections declined from 4.7 to 1.3% (73% reduction) in Tallinn (p < 0.02), and from 15 to 6% (60% reduction) in Staten Island (p < 0.05). Persons assisted with first injections declined from 11 to 3 in Tallinn (p = 0.02) and from 32 to 13 in Staten Island. (p = 0.024). Further implementation research on BtC interventions is urgently needed where injecting drug use is driving HIV/HCV epidemics and areas experiencing opioid epidemics.

Opioid use and misuse: health impact, prevalence, correlates and interventions

Objective: To provide a broad overview of the state of drug misuse research, particularly focusing on opioid drug use in the U.S.A. Design: An overview of published reviews of the literature. Results: Prescription opioid use has increased globally from 2008 to 2013, while use of opiates such as heroin and opium have remained stable in many countries, although, decreases have been observed in parts of Europe. Opioid misuse is highest in the United States; approximately 11.8 million Americans misused opioids in 2016. Demographic, genetic, psychosocial and structural/environmental factors all play a role in determining who will become an opioid misuser. Strategies such as increased prescribing of non-opioid derived pain relievers, expansion of medication treatment, distribution of naloxone for overdose reversal and supervised consumption sites are some of the solutions posed to reduce the spread and consequences of opioid misuse. Conclusion: Research focused on understanding of opioid neurobiology, as well as empirically based, effective alternatives to pain management and implementation studies on combined prevention and treatment approaches are needed. It will take the combined effort of community members, healthcare professionals, policymakers and researchers in order to prevent and treat opioid misuse.

Factors Associated with Frequency of Recent Initiation of Others into Injection Drug Use Among People Who Inject Drugs in Los Angeles and San Francisco, CA, USA, 2016-17

Objective: Drug injection initiation is often assisted by a person who injects drugs (PWID). How often PWID provide this assistance has not been examined. We examine frequency of injection initiation assistance and factors associated with high (4+) and low frequency (1-3) initiation assistance as compared to no initiation assistance among PWID. Methods: Participants were 979 Californian PWID. PWID were interviewed about providing injection initiation assistance in the last 6 months among other items. Multinomial regression analysis was used to examine factors associated with levels of frequency of injection initiation assistance. Results: Among participants, 132 (14%) had initiated 784 people into injection (mean = 5.94 [standard deviation = 20.13]; median = 2, interquartile range = 1,4) in the last 6 months. PWID engaged in high frequency initiation (26% of sample) assisted 662 new initiates (84% of total). Using multinomial regression analysis with no initiating as the referent group, we found that high frequency initiating was statistically associated with higher injection frequency, having a paying sex partner, taking someone to a shooting gallery, and providing injection assistance. Lower frequency initiation was statistically associated with having a paying sex partner, illegal income source, and providing injection assistance. Conclusion: Differences between high and low frequency initiators were not found. Sex work and assisting with drug injection were linked to initiating others. Individual-level interventions that reduce this behavior among PWID and structural interventions such as safe consumption sites and opioid medication treatments that interrupt the social process of injection initiation should be considered as ways to reduce injection initiations.

Navigating social norms of injection initiation assistance during an overdose crisis: A qualitative study of the perspectives of people who inject drugs (PWID) in Vancouver, Canada

Despite the proliferation of fentanyl and fentanyl-adulterated opioids in North America, the impacts of this drug market change on injection initiation processes have not been examined. With the aim of informing structural interventions to address injection initiation and related harms, we explore how people who inject drugs (PWID) in Vancouver, Canada understand and navigate social norms of initiating others into injecting within the context of an overdose crisis. In-depth qualitative interviews were conducted with 19 PWID who reported helping someone inject for the first time. Participants were recruited from two cohort studies of PWID. Participants articulated moral dilemmas about assisting others with injecting. While participants described a 'moral code' prohibiting assisting injection-naïve individuals, this code was not the sole consideration shaping social action around injection initiation. Rather, PWID exercised agency about whether and how to assist novice injectors within the context of constraining and enabling social norms around practicing interpersonal responsibility. Changes to the drug market heightened feelings of moral culpability and criminal liability among PWID who assisted others into injection, given that injecting heightened initiates' risk of overdose. These concerns operated in tension with the aim of protecting novice injectors from harms associated with an increasingly potent and unpredictable drug supply by providing them with injection assistance, education and supervision. Our analysis of how PWID practice interpersonal responsibility helps conceptualise how 'moral codes' prohibiting initiation assistance are managed and negotiated amidst structural vulnerability. Structural interventions reducing the vulnerability of novice injectors should be prioritized, including the implementation of supervised injection sites allowing for assisted injection, Good Samaritan laws, and policy changes conducive to a safer drug supply.

Opioid agonist treatment and the process of injection drug use initiation

BACKGROUND

Opioid agonist treatment (OAT) is an effective biomedical intervention to manage opioid use disorder among persons who inject drugs (PWID). Preliminary evidence suggests that OAT may also disrupt the social communicability of injection drug use (IDU) practices by established PWID. We therefore aim to investigate the association between OAT enrollment and initiating others into IDU among PWID in Vancouver, Canada.

METHODS

Preventing Injecting by Modifying Existing Responses (PRIMER; NIDA DP2-DA040256-01) is a prospective multi-cohort study seeking to identify structural interventions that reduce the risk that PWID initiate others into IDU. The present analysis was conducted using data from a participating cohort of PWID in Vancouver, Canada, between December 2014 and May 2017. Multivariable logistic regression models were built to assess the association between reporting active (i.e., within the past six months) OAT enrollment and assisting others in injection initiation. A final model was determined using a manual stepwise approach whereby covariates were excluded if their removal altered the coefficient of interest by <5%.

RESULTS

Participants (n = 1740) were predominantly male (62.3%); 35.1% reported daily injecting (n = 611); 860 (49.4%) reported active OAT enrollment, and 80 (4.6%) reported recently providing injection initiation assistance. In a multivariable model, participants who reported active OAT enrollment had significantly lower odds of recently providing injection initiation assistance (Adjusted Odds Ratio = 0.52, 95% Confidence Interval: 0.31-0.87, P = 0.01).

CONCLUSION

Results suggest a protective association between OAT and the expansion of IDU practices among vulnerable populations, suggesting its potential use as 'addiction treatment as prevention.'

Rising role of prescription drugs as a portal to injection drug use and associated mortality in Baltimore, Maryland

INTRODUCTION

Prescription drug abuse is a major public health problem in rural and suburban areas of the United States, however its emergence in large urban settings with endemic injection drug use remains understudied. We examined temporal trends in injection drug use initiation and mortality among people who inject drugs (PWID) in Baltimore, Maryland.

METHODS

Data were derived from the baseline assessment of PWID enrolled in a community-based cohort study with longitudinal follow-up for mortality assessment. PWID were recruited from 2005-2008 (N = 1,008) and 2015-2018 (N = 737). We compared characteristics by birth cohort (before/after 1980) and type of drug initiated (prescription opioids, prescription non-opioids, non-injection illicit drugs, or injection drugs). We calculated standardized mortality ratios (SMR) using the US general population as the reference.

RESULTS

PWID born after 1980 were more likely to initiate drug use with prescription opioids and non-opioids and had higher levels of polysubstance prior to injection initiation, compared to individuals born before 1980. Overall mortality was high: 2.59 per 100 person-years (95% CI: 2.27-2.95 per 100 person-years). Compared to the US population, the highest SMRs were observed among participants between 40-44 years of age, with especially high mortality among women in this age group (SMR:29.89, 95% CI: 15.24-44.54).

CONCLUSIONS

Mirroring national trends, the profile of PWID in Baltimore has changed with increased prescription drug abuse and high levels of polysubstance use among younger PWID. Interventions need to reach those using prescription drugs early after initiation of use in order to reduce transition to injecting. Urgent attention is warranted to address premature mortality, particularly among middle-aged and female PWID.

Differences in time to injection onset by drug in California: Implications for the emerging heroin epidemic

BACKGROUND

Heroin use is increasing in the US. Heroin use may predispose users towards injection routes of drug administration as compared to other illicit substances.

OBJECTIVE

To explore the relationship between heroin use and drug injection, we compared time from first use to first injection (referred to as time to injection onset by drug [TTIOD]) of heroin, methamphetamine/speed, cocaine, and crack cocaine among people who inject drugs (PWID).

METHODS

Age of first use and first injection by drug was collected from 776 PWID. Survival analyses were used to determine TTIOD and to examine demographic factors associated with TTIOD. Cox regression analysis was used to determine demographic factors associated with drug-specific injection onset.

RESULTS

The eventual injection onset rate by the drug was 99% for participants who used heroin, 85% for participants who used methamphetamine/speed, 80% for participants who used powder cocaine, and 38% for participants who used crack cocaine. Hazard ratios for injection use within one year of first use by drug were: 1.37 (median survival time [MST] = 0.61 years) for heroin, 0.66 (MST = 1.10 years) for methamphetamine/speed, 0.50 (MST = 2.93 years) for powder cocaine, and 0.12 (MST = 39.59 years) for crack cocaine. Demographic differences in TTIOD were found for each drug. Demographic differences were found for eventual injection by drug for all substances except heroin.

CONCLUSION

Among PWID, heroin use was associated with a more rapid transition to injection and a higher rate of eventual heroin injection regardless of demographics. More robust, innovative efforts to reduce heroin use and prevent injection initiation are urgently needed.

Transition from First Drug Use to Regular Injection among People Who Inject Drugs in Iran

BACKGROUND

The study aimed to evaluate the interval between first drug use and regular injection and factors associated with transition from first injection into premature regular injection among people who inject drugs (PWIDs).

METHODS

In a multicenter cross-sectional study, we recruited 400 PWIDs using snowball sampling. Age of first drug use, age of initiation of regular injection, and demographic and behavioral data were collected using face to face interview. Premature transition to regular injection was defined as initiation of regular injection within the five years of first injection. Data were analyzed using bivariate and multivariate logistic regression survey analysis.

FINDINGS

The mean age of first drug use and age of initiation of regular injection was 29.87 ± 6.54 years, respectively. Having history of sexual abuse in childhood [adjusted odds ratio (AOR) = 3.1], history of imprisonment (AOR = 3.4), use of heroin as the first drug (AOR = 4.3), and doing the first injection at friends' houses (AOR = 2.2) or in ruins (AOR = 2.2) significantly increased the chance of premature transition to regular injection, while being a female decreased the chance of premature transition to regular injection (AOR = 0.4). Compared to curiosity, being friend with a drug user (AOR = 0.4), having withdrawal symptoms (AOR = 0.2), and low cost of injection (AOR = 0.3) at the first occasion of drug injection reduced the chance of premature transition to regular injection.

CONCLUSION

New interventions to prevent injection initiation among drug users are needed and should be integrated in harm reduction programs.