Association between injection practices and duration of injection among recently initiated injection drug users

Background: Earlier studies suggest higher infection risk among recently initiated injection drug users (IDUs) than more experienced users. Whether IDUs' risky injection practices rise progressively with duration of injection or frequency of practices is higher near initiation and then taper remains an open question. Methods: Recently initiated IDUs were street recruited and interviewed between 1997 and 1999 as part of a multisite cohort study in five US urban cities. Recent risky injection practices (injecting with others and injecting on average more now) were examined across three cross-sections defined by duration of injection: 0-1 year, 2-3 years, and 4-6 years. Results: The IDU groups of <2 years duration (n=691) and 2-3 years duration (n=697) had higher odds than the 4-6 year group (n=520) of reporting injecting with others (Odds Ratio, OR=1.52, and OR=1.47, respectively) and injecting on average more now (OR=1.44 and OR=1.44, respectively). The associations remained after multivariate adjustment for demographic variables. Conclusions: These data on recently initiated IDUs suggest that risky injection practices were more frequent earlier than later within the first 6 years of initiation, emphasizing that outreach prevention needs to identify and intervene with IDUs early.