Drug and HIV-related risk behaviors after geographic migration among a cohort of injection drug users.

To determine whether migration impacted on drug use and HIV-related risk behaviors among injection drug users (IDU), we identified participants in a prospective cohort of IDU (Vancouver Injection Drug User Study) who had reported migrating out of Greater Vancouver between May 1996 and November 2005. We compared risk behaviors before and after a move for individuals who migrated (movers) and for a similar period for non-movers using linear growth curve analyses. In total, 1,122 individuals were included, including 430 (38.3%) women and 331 (29.5%) Aboriginal participants. Among these, 192 (17.1%) individuals reported migrating out of Greater Vancouver between 1996 and 2005 while 930 (82.9%) did not. Movers were significantly younger than non-movers: 32.0 (Interquartile Range [IQR]: 24.3-39.2) and 34.6 (IQR: 26.9-40.8) respectively. A significant decrease in those reporting unstable housing, frequent heroin and cocaine injection occurred only in movers. Our findings suggest that, in this setting, risk-taking among IDU declines following periods of migration out of Greater Vancouver.