Predictors of crack cocaine initiation among Montréal street youth: a first look at the phenomenon.

Background: Crack cocaine use is increasing in Montréal. However, initiation risk factors among street youth are unknown. The goal of this project is to estimate the incidence of first crack cocaine use among these youth and to identify the associated risk factors.

Methods: A prospective cohort study of HIV and hepatitis C incidence was conducted among street youth from 2001 to 2005. A questionnaire on sexual and drug use behaviours was administered every 6 months. Incidence was estimated (a) for youth who had never used crack cocaine at recruitment (n=203) and, among them, (b) for those who had snorted cocaine before (n=122). The risk factors for initiation of crack use as well for initiation into a new route of cocaine administration among youth who had snorted cocaine before were determined using Cox regression.

Results: Incidence rates for crack cocaine use were (a) 136.6/1000 person-years (p-y) (95% confidence interval [CI]: 104.5-175.5) and (b) 205.8/1000 p-y (95% CI: 150.2-275.3). The number of substance types used recently increased the risk of initiating crack use (adjusted hazard ratio [AHR]=1.84 per substance type, 95% CI: 1.55-2.18), whereas having a parent with a substance abuse problem decreased that risk (AHR=0.48, 95% CI: 0.26-0.89). The risk factors were identical among youth who had snorted cocaine before.

Conclusions: Our analyses show a high incidence of crack use among street youth. It is important to delve more deeply into the phenomenon of initiation if we wish to develop effective prevention measures for these young people.