The Cedar Project: risk factors for transition to injection drug use among young, urban Aboriginal people

Background:

Studies suggest that Aboriginal people in Canada are over-represented among people using injection drugs. The factors associated with transitioning to the use of injection drugs among young Aboriginal people in Canada are not well understood.

Methods:

The Cedar Project is a prospective cohort study (2003–2007) involving young Aboriginal people in Vancouver and Prince George, British Columbia, who use illicit drugs. Participants’ venous blood samples were tested for antibodies to HIV and the hepatitis C virus, and drug use was confirmed using saliva screens. The primary outcomes were use of injection drugs at baseline and tranisition to injection drug use in the six months before each follow-up interview.

Results:

Of 605 participants, 335 (55.4%) reported using injection drugs at baseline. Young people who used injection drugs tended to be older than those who did not, female and in a relationship. Participants who injected drugs were also more likely than those who did not to have been denied shelter because of their drug use, to have been incarcerated, to have a mental illness and to have been involved in sex work. Transition to injection drug use occurred among 39 (14.4%) participants, yielding a crude incidence rate of 19.8% and an incidence density of 11.5 participants per 100 person-years. In unadjusted analysis, transition to injection drug use was associated with being female (odds ratio OR] 1.98, 95% confidence interval (CI) 1.06–3.72), involved in sex work (OR 3.35, 95% CI 1.75–6.40), having a history of sexually transmitted infection (OR 2.01, 95% CI 1.07–3.78) and using drugs with sex-work clients (OR 2.51, 95% CI 1.19–5.32). In adjusted analysis, transition to injection drug use remained associated with involvement in sex work (adjusted OR 3.94, 95% CI 1.45–10.71).

Interpretation:

The initiation rate for injection drug use of 11.5 participants per 100 person-years among participants in the Cedar Project is distressing. Young Aboriginal women in our study were twice as likely to inject drugs as men, and participants who injected drugs at baseline were more than twice as likely as those who did not to be involved in sex work.Aboriginal leadership in Canada is deeply concerned about substance use, more specifically injection drug use and its association with the spread of HIV and the hepatitis C virus among Aboriginal young people.^1,2 Recent studies in Canada suggest that Aboriginal people are over-represented among people who use injection drugs.^3,4 For Aboriginal young people in Canada under the age of 24 years, injection drug use accounts for the majority of infections with the hepatitis C virus (70%–80%)^5,6 and over half (59%) of HIV infections.⁷Indigenous scholars have stated that research on substance use within Aboriginal communities must consider the context of colonization, including the intergenerational impacts of the residential school and child welfare systems.^8–11 It is now well documented that Aboriginal children experienced extensive psychological, sexual, physical and emotional abuses within those systems.^12,13 As former students of residential schools raise children and grandchildren, the intergenerational effects of abuse and familial fragmentation are evident in communities where interpersonal violence and drug dependence are pervasive.^14–16A priority for preventing infections with HIV and hepatitis C among young Aboriginal people is the development of programs and rights-based,^18,19 youth-informed¹⁷ policies aimed at preventing the use of injection drugs. However, research to date has not provided sufficient evidence to inform such development.^2,19 Concerns over this paucity of information led to the launch of a two-city cohort study in 2003 to address HIV-related vulnerabilities among young Aboriginal people in British Columbia — a unique study centred on at-risk youth and supported by and partnered with Aboriginal investigators and collaborators.We report here baseline and longitudinal data on the factors associated with injection drug use and the transition to injection drug use to inform the development of prevention programs and policies.