title: Daily alcohol use as an independent risk factor for HIV seroconversion among people who inject drugs.
abstract: To estimate the relationship between daily alcohol use and HIV seroconversion among people who inject drugs (PWID) in a Canadian setting.
  
  
  
  Data from an open prospective cohort study of PWID in Vancouver, Canada, recruited via snowball sampling and street outreach between May 1996 and November 2013. An interviewer-administered questionnaire including standardized behavioural assessment and HIV antibody testing were conducted semi-annually. Baseline HIV-seronegative participants completing ≥ 1 follow-up visits were eligible for the present analysis.
  
  
  
  A total of 1683 eligible participants, were followed for a median of 79.8 [interquartile range (IQR) = 33.3-119.1] months.
  
  
  
  The primary end-point was time to HIV seroconversion, with the date of HIV seroconversion estimated as the mid-point between the last negative and the first positive antibody test results. The primary explanatory variable was self-reported daily alcohol use in the previous 6 months assessed semiannually. Other covariates considered included demographic, behavioural, social/structural and environmental risk factors for HIV infection among PWID (e.g. daily cocaine injection, methadone use, etc.).
  
  
  
  Of 1683 PWID, there were 176 HIV seroconversions during follow-up with an incidence density of 1.5 [95% confidence interval (CI) = 1.3-1.7] cases per 100 person-years. At baseline, 339 (20.1%) consumed alcohol at least daily in the previous 6 months. In multivariable extended Cox regression analyses, daily alcohol use remained associated independently with HIV seroconversion (adjusted hazard ratio: 1.48; 95% CI = 1.00-2.17).
  
  
  
  Daily alcohol use appears to be an independent risk factor for HIV seroconversion among our cohort of PWID.
authors.affiliation: Department of Medicine, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Samantha V
authors.initials: SV
authors.lastname: Young
authors.affiliation: Department of Medicine, University of British Columbia, Vancouver, BC, Canada.|British Columbia Centre for Excellence in HIV/AIDS, St Paul's Hospital, Vancouver, BC, Canada.
authors.forename: Evan
authors.initials: E
authors.lastname: Wood
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, St Paul's Hospital, Vancouver, BC, Canada.
authors.forename: Huiru
authors.initials: H
authors.lastname: Dong
authors.affiliation: Department of Medicine, University of British Columbia, Vancouver, BC, Canada.|British Columbia Centre for Excellence in HIV/AIDS, St Paul's Hospital, Vancouver, BC, Canada.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kerr
authors.affiliation: Department of Medicine, University of British Columbia, Vancouver, BC, Canada.|British Columbia Centre for Excellence in HIV/AIDS, St Paul's Hospital, Vancouver, BC, Canada.
authors.forename: Kanna
authors.initials: K
authors.lastname: Hayashi
mesh_terms: D000328:Adult; D000428:Alcohol Drinking / Q000453:epidemiology*; D001955:British Columbia / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D015658:HIV Infections / Q000453:epidemiology*; D006679:HIV Seropositivity / Q000453:epidemiology; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D016017:Odds Ratio; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D015819:Substance Abuse, Intravenous / Q000453:epidemiology*
keywords: Alcohol; Canada; HIV; injection drug use