Availability of body art facilities and body art piercing do not predict hepatitis C acquisition among injection drug users in Montreal, Canada: Results from a cohort study

Background: Cross-sectional associations suggest that body art piercing (BAP) is a risk factor for hepatitis C (HCV) infection among injection drug users. The temporal basis of the relationship has not been established. Methods: Associations between HCV seropositivity, HCV incidence, recent BAP and BAP facility availability were evaluated among IDUs followed biannually between 2004 and 2008 in Montreal, Canada. A geographic information system was used to determine the availability of BAP facilities for each participant. Statistical models included individual and neighbourhood covariates. Logistic regression was used for analysis of HCV seropositivity. Cox proportional hazards regression was used for analysis of HCV incidence. Results: Of 784 IDUs, 73% were seropositive for HCV. In multivariable logistic regression, HCV seropositivity was associated with BAP availability (OR: 1.32 95% confidence interval (CI): 1.1, 1.6) but not recent BAP. Of 145 initially HCV-negative participants, 52 seroconverted to HCV for an incidence of 27.7/100 person-years (95%CI: 20.9, 36.0). Crude hazard ratios (HR) for the association between HCV infection and BAP variables were: recent BAP, HR 0.98 (95%CI: 0.4, 2.7) and BAP facilities availability, HR 1.43 (95%CI: 1.1, 1.9). After accounting for individual and neighbourhood factors, crude associations between HCV infection and recent BAP and BAP facilities availability were: HR recent BAP, 0.96, 95%CI: 0.3, 2.7; and HR BAP facility availability, 1.21, 95%CI: 0.9, 1.7. Conclusion: BAP facility availability is a marker of neighbourhood disadvantage associated with HCV seropositivity. Longitudinal analyses accounting for behaviour risk factors and neighbourhood characteristics do not support a temporal association between BAP acquisition, BAP facility availability, and HCV infection among IDUs.