Changes in Risk Behaviour Among People With Recent Injecting Drug Use in Oslo 2002–2024

Introduction Sharing needles, syringes and drug preparation paraphernalia among people who inject drugs poses a significant risk of transmission of blood‐borne infections. To achieve and maintain the elimination of viral hepatitis by 2030, risk behaviour must be kept at a low level. The aim of this study was to assess changes in injecting risk behaviour among people who inject drugs in Oslo between 2002 and 2024. Methods This was an analysis of eight cross‐sectional studies among people who inject drugs in Oslo conducted in 2002, 2012, 2015, 2018, 2021, 2022, 2023 and 2024. We calculated prevalence estimates of recent (past 4 weeks) risk behaviour each year and used generalised estimating equations to identify factors associated with recent risk behaviour. Results A total of 1648 participants were included. The median age was 39.4 years, 71.7% were men and 54.2% reported daily injecting drug use. Recent sharing of needles/syringes decreased from 17.8% (95% CI 13.6, 22.5) in 2002 to 4.2% (95% C: 1.9, 7.8) in 2024. Recent sharing of needles/syringes was negatively associated with increasing age (every 10‐year increment; aOR 0.62; 95% CI 0.50, 0.76) and was associated with daily injecting (aOR 2.07; 95% CI 1.38, 3.12) compared to less than daily and with mixed heroin and amphetamine as the drug most frequently injected (aOR 1.63; 95% CI: 1.04, 2.55) compared to heroin alone. Discussion and Conclusions A decline in the prevalence of recent risk behaviour among people who inject drugs in Oslo was observed between 2002 and 2024. Risk behaviour remains common among younger individuals.