title: Declining incidence of hepatitis C virus infection among people who inject drugs in a Canadian setting, 1996-2012.
abstract: BACKGROUND
  People who inject drugs (PWID) are at high risk of hepatitis C virus (HCV) infection. Trends in HCV incidence and associated risk factors among PWID recruited between 1996 and 2012 in Vancouver, Canada were evaluated.
  
  
  METHODS
  Data were derived from a long-term cohort of PWID in Vancouver. Trends in HCV incidence were evaluated. Factors associated with time to HCV infection were assessed using Cox proportional hazards regression.
  
  
  RESULTS
  Among 2,589, 82% (n = 2,121) were HCV antibody-positive at enrollment. Among 364 HCV antibody-negative participants with recent (last 30 days) injecting at enrollment, 126 HCV seroconversions were observed [Overall HCV incidence density: 8.6 cases/100 person-years (py); 95% confidence interval (95% CI): 7.2, 10.1; HCV incidence density among those with injecting during follow-up: 11.5 cases/100 py; 95% CI 9.7, 13.6]. The overall HCV incidence density declined significantly from 25.0/100 py (95% CI: 20.2, 30.3) in 1996-99, as compared to 6.0/100 py (95% CI: 4.1, 8.5) in 2000-2005, and 3.1/100 py (95% CI: 2.0, 4.8) in 2006-2012. Among those with injecting during follow-up, the overall HCV incidence density declined significantly from 27.9/100 py (95% CI: 22.6, 33.6) in 1996-99, as compared to 7.5/100 py (95% CI: 5.1, 10.6) in 2000-2005, and 4.9/100 py (95% CI: 3.1, 7.4) in 2006-2012. Unstable housing, HIV infection, and injecting of cocaine, heroin and methamphetamine were independently associated with HCV seroconversion.
  
  
  CONCLUSIONS
  HCV incidence has dramatically declined among PWID in this setting. However, improved public health strategies to prevent and treat HCV are urgently required to reduce HCV-associated morbidity and mortality.
authors.affiliation: The Kirby Institute, UNSW Australia, Sydney, New South Wales, Australia.
authors.forename: Jason
authors.initials: J
authors.lastname: Grebely
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, Vancouver, British Columbia, Canada; Division of AIDS, Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Viviane Dias
authors.initials: VD
authors.lastname: Lima
authors.affiliation: Department of Epidemiology, Brown University, Providence, Rhode Island, United States of America.
authors.forename: Brandon D L
authors.initials: BD
authors.lastname: Marshall
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, Vancouver, British Columbia, Canada; Department of Family Practice, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: M-J
authors.initials: MJ
authors.lastname: Milloy
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, Vancouver, British Columbia, Canada; School of Public Policy, Simon Fraser University, Vancouver, British Columbia, Canada.
authors.forename: Kora
authors.initials: K
authors.lastname: DeBeck
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, Vancouver, British Columbia, Canada; Division of AIDS, Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Julio
authors.initials: J
authors.lastname: Montaner
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, Vancouver, British Columbia, Canada; Division of AIDS, Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Annick
authors.initials: A
authors.lastname: Simo
authors.affiliation: British Columbia Centre for Disease Control, Vancouver, British Columbia, Canada.
authors.forename: Mel
authors.initials: M
authors.lastname: Krajden
authors.affiliation: The Kirby Institute, UNSW Australia, Sydney, New South Wales, Australia.
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Dore
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, Vancouver, British Columbia, Canada; Division of AIDS, Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kerr
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, Vancouver, British Columbia, Canada; Division of AIDS, Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Evan
authors.initials: E
authors.lastname: Wood
mesh_terms: D000328:Adult; D002170:Canada / Q000453:epidemiology; D005260:Female; D006526:Hepatitis C / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D015994:Incidence; D008297:Male; D012307:Risk Factors; D015819:Substance Abuse, Intravenous / Q000150:complications*; D011795:Surveys and Questionnaires