Frequency and factors associated with providing injection initiation assistance in Tallinn, Estonia.

Unlabelled: Injection drug use is expanding in numerous regions in the world. Persons who inject drugs (PWID) play an important role encouraging new persons into injecting, by providing injection initiation assistance ("assisting" behaviors) and stimulating interest in injection ("promoting" behaviors).

Objectives: To describe the prevalence of assisting and promoting behaviors, and to identify factors associated with assisting, among PWID in Tallinn, Estonia.

Methods: In 2016, PWID were recruited through respondent-driven sampling (RDS), interviewed, and HIV tested. RDS weights were used to estimate the prevalence of assisting and promoting behaviors and, in multivariable regression modeling, to identify factors associated with assisting.

Results: Among 299 PWID recruited, 13.7% had ever assisted a non-PWID with their first injection. Regarding past-six-month promoting behaviors: 9.4% talked positively about injecting to non-PWID, 16.2% injected in front of non-PWID, and 0.6% offered to help with a first injection. Significant predictors of ever assisting with a first injection included: gender (men: aOR 6.31, 95% CI 2.02-19.74); age (30 years or younger: aOR 3.89, 95% CI 1.40-10.16); receptive sharing of syringes or needles (aOR 4.73, 95% CI 1.32-16.98); ever testing for HIV (aOR 8.44, 95% CI 1.15-62.07); and having peers who helped someone with their first injection (aOR 3.44, 95% CI 1.31-9.03).

Conclusion: Demographic and drug-use related factors are associated with having initiated someone into injecting. Interventions targeting PWID and non-PWID are needed to prevent injection initiation.