Compared with the estimated prevalence of HCV infection in the Canadian general population (0.8%),2
the prevalence was higher (12.6%) in the Montreal street youth population. This rate was also much higher than that reported for other street youth populations (4% in Ottawa,18
1% and 3% in Goiania, Brazil,20
and 5% in Oregon19
). The higher prevalence of drug injection use among the Montreal participants (46%, as compared with 17% in Ottawa18
and 37% in Oregon19
) or their higher age may explain this observation.
In the multivariate analysis, drug injection was the factor most strongly associated with HCV infection. Other factors were higher age and crack cocaine use. Having more than 1 tattoo was marginally associated with HCV infection.
The association between age and HCV infection may reflect the cumulative effect of risk behaviours (duration and frequency of injection) or an interaction between risk behaviours and risk networks, as noted in studies of HIV infection.23
Younger street youths, especially minors, usually interact with people of their own age, with a low prevalence of infection, which may protect them somewhat from acquiring hepatitis C.
An association between crack cocaine use and HCV infection has previously been reported.5
>A similar association between crack cocaine use and HIV infection was observed by Faruque and associates,24
>who linked the increased prevalence of HIV infection with the presence of oral sores among crack cocaine users.
Finally, tattooing, but not body piercing, was associated with HCV infection. The association was borderline significant and was present only for more than 1 tattoo. Nevertheless, tattooing was retained in the model because of its p
value, close to statistical significance, and its biological plausibility. An association between tattooing and HCV infection has previously been reported in Canada and elsewhere.9,10,11,12,13,14,15,16
One study demonstrated an increased risk when tattooing was performed by a nonprofessional.15
Although we detected such an association in the univariate analysis, it was not retained in the multivariate model.
Among the 55 HCV-infected youths identified in our study, only 15 (27.3%) reported being HCV-positive in their questionnaire. This low proportion of subjects aware of their infection status suggests that surveillance data, based on reported infections, may not be accurate for this population.
In this HBV21
and HCV study, 3 risk factors were associated with both infections: higher age, injection drug use and tattooing. Sexual activity and body piercing played a role only in HBV transmission, and crack cocaine use was associated only with HCV transmission.
The generalizability of our results to other street youths is unknown. Participants were recruited through all major community organizations. Because of this sampling strategy, we may have missed street youths not frequenting such organizations. However, a recent census of the Montreal street population showed that about 90% frequent community organizations.25
Another limitation to our study is that most of the subjects were participating in a cohort study. Since the cohort study started only 1 year before we began the current study, no significant “cohort effect” is expected. However, because cohort participants may be more compliant and less disorganized and, thus, less vulnerable to acquiring HCV infection than other street youths, we may have underestimated the true rate of HCV infection. On the other hand, because the participants were given $10, those living in more precarious situations and experiencing greater poverty may have been oversampled, which could have led to an overestimated infection rate.
We found that during the study period, drug injection was highly prevalent among Montreal street youths and represented the main risk factor for HCV infection. To curb the HCV infection epidemic in Canada, increased intervention efforts are needed to prevent initiation into drug injection among vulnerable youths. In addition, access to low-threshold programs (e.g., needle exchange programs), substance abuse treatments, and HCV antibody testing and counselling should be facilitated for vulnerable youths.