Prevalence and incidence of hepatitis C virus infection among Aboriginal young people who use drugs: results from the Cedar Project

BACKGROUND: We sought to estimate the prevalence and incidence of hepatitis C virus (HCV) infection among Aboriginal young people who use drugs and to identify risk factors associated with HCV infection in this population. METHODS: The Cedar Project is a longitudinal study involving Aboriginal young people living in Vancouver and Prince George, British Columbia. Eligibility criteria include age from 14 to 30 years and self-reported use (smoking or injection) of illicit drugs (e.g., crystal methamphetamine, crack cocaine, heroin or other opiates, and cocaine) at least once in the month before enrolment. At each visit, participants completed a detailed questionnaire administered by an Aboriginal interviewer. For this analysis, we included information for 512 participants who were recruited between September 2003 and April 2005. RESULTS: Among the 512 participants, the prevalence of HCV infection was 34.8% (95% confidence interval [CI] 30.6%–38.9%); the rates were similar in Prince George and Vancouver (34.5% and 35.0% respectively, p = 0.37). Among those who reported the use of injection drugs at baseline (n = 286), the prevalence of HCV infection was 59.4% (95% CI 53.8%–65.1%); the rate in this group was slightly higher in Prince George than in Vancouver (62.4% v. 57.1% respectively, p = 0.37). The prevalence was 3.5% among participants who reported smoking drugs (n = 226). In the multivariate logistic regression analysis, factors significantly associated with HCV infection among participants who used injection drugs included daily injection of opiates (adjusted odds ratio [OR] 2.7, 95% CI 1.0–7.4), reuse of syringes (adjusted OR 2.4, 95% CI 1.3–4.4), having at least 1 parent who attended residential school (adjusted OR 1.9, 95% CI 1.1–3.4), female sex (adjusted OR 1.9, 95% CI 1.1–3.4) and duration of injection drug use (per year) (adjusted OR 1.4, 95% CI 1.3–1.5). The crude incidence rate of HCV infection was 10.6% and the incidence density estimate was 9.9 per 100 person-years in this cohort. INTERPRETATION: The prevalence of HCV infection was elevated among Aboriginal young people living in Prince George and Vancouver who use drugs. Culturally based prevention, treatment and harm-reduction programs are urgently needed in this population.