Theme: Epidemiology & Public Health Research Year: 2024
Background: A substantial decline in prevalence of Hepatitis C virus (HCV) infection has been observed in Oslo over the past years, and elimination of HCV infection among people who inject drugs (PWID) is imminent. To monitor the potential for a new surge in HCV infections, changes in risk factors needs to be monitored.
The aim of this study was to assess changes in the frequency of sharing of needles/syringes among PWID in Oslo between 2002-2023, and to identify factors associated with recent risk behaviour.
Methods: Point prevalence studies of HCV infection and sharing of syringes, needles and paraphernalia were conducted in 2018, 2021, 2022, and 2023, and compared with results from a similar study conducted in 2002. Assessments included blood samples and a questionnaire. We calculated prevalence estimates of risk behaviour for each year with Clopper-Pearson 95% confidence intervals and used logistic regression analysis to identify factors associated with risk behaviour in the most recent point prevalent studies (2018-2023).
Results: A total of 1041 participants were included in the study (median age 41.9; 74.6% men; 78.3% reported recent injecting drug use [past 4 weeks]). Prevalence of sharing of needles/syringes decreased from 16.4% (95% CI 12.4-21.0) in 2002, to 9.3% (95% CI 5.6-14.3) in 2018. In 2021, 2022 and 2023, 6.0% (95% CI 3.1-10.2), 8.3% (95% CI 4.9-12.9), and 8.5% (95% CI 4.9-13.4), respectively, reported sharing. In adjusted analysis, recent sharing of needles/syringes was negatively associated with increasing age (per 10-year increase; aOR 0.47; 95% CI 0.34-0.67).
Conclusion: A 50% decrease in self-reported sharing of needles/syringes was observed between 2002-2023. Increasing age was negatively associated with recent sharing of syringes.