Income level and drug related harm among people who use injection drugs in a Canadian setting

Background: Higher income is generally associated with better health outcomes; however, among people who inject drugs (IDU) income generation frequently involves activities, such as sex work and drug dealing, which pose significant health risks. Therefore, we sought to examine the relationship between level of income and specific drug use patterns and related health risks. Methods: This study involved IDU participating in a prospective cohort study in Vancouver, Canada. Monthly income was categorized based on non-fixed quartiles at each follow-up with the lowest level serving as the reference category in generalized linear mixed-effects regression. Results: Among our sample of 1032 IDU, the median average monthly income over the study follow-up was $1050 [interquartile range=785-2000]. In multivariate analysis, the highest income category was significantly associated with sex work (adjusted odds ratio [AOR]=7.65), drug dealing (AOR=5.06), daily heroin injection (AOR=2.97), daily cocaine injection (AOR=1.65), daily crack smoking (AOR=2.48), binge drug use (AOR=1.57) and unstable housing (AOR=1.67). The high income category was negatively associated with being female (AOR=0.61) and accessing addiction treatment (AOR=0.64), (all p<. 0.05). In addition, higher income was strongly associated with higher monthly expenditure on drugs (>$400) (OR=97.8). Conclusion: Among IDU in Vancouver, average monthly income levels were low and higher total monthly income was linked to high-risk income generation strategies as well as a range of drug use patterns characteristic of higher intensity addiction and HIV risk. These findings underscore the need for interventions that provide economic empowerment and address high intensity addiction, especially for female IDU.