title: Drug users in Amsterdam: are they still at risk for HIV?
abstract: OBJECTIVE
  To examine whether drug users (DU) in the Amsterdam Cohort Study (ACS) are still at risk for HIV, we studied trends in HIV incidence and injecting and sexual risk behaviour from 1986 to 2011.
  
  
  METHODS
  The ACS is an open, prospective cohort study on HIV. Calendar time trends in HIV incidence were modelled using Poisson regression. Trends in risk behaviour were modelled via generalized estimating equations. In 2010, a screening for STI (chlamydia, gonorrhoea and syphilis) was performed. Determinants of unprotected sex were studied using logistic regression analysis.
  
  
  RESULTS
  The HIV incidence among 1298 participants of the ACS with a total follow-up of 12,921 person-years (PY) declined from 6.0/100 PY (95% confidence interval [CI] 3.2-11.1) in 1986 to less than 1/100 PY from 1997 onwards. Both injection and sexual risk behaviour declined significantly over time. Out of 197 participants screened for STI in 2010-2011, median age 49 years (IQR 43-59), only 5 (2.5%) were diagnosed with an STI. In multivariable analysis, having a steady partner (aOR 4.1, 95% CI 1.6-10.5) was associated with unprotected sex. HIV-infected participants were less likely to report unprotected sex (aOR 0.07, 95% CI 0.02-0.37).
  
  
  CONCLUSIONS
  HIV incidence and injection risk behaviour declined from 1986 onwards. STI prevalence is low; unprotected sex is associated with steady partners and is less common among HIV-infected participants. These findings indicate a low transmission risk of HIV and STI, which suggests that DU do not play a significant role in the current spread of HIV in Amsterdam.
authors.affiliation: Cluster of Infectious Diseases, Public Health Service, Amsterdam, The Netherlands.
authors.forename: Nienke
authors.initials: N
authors.lastname: van der Knaap
authors.forename: Bart P X
authors.initials: BP
authors.lastname: Grady
authors.forename: Maarten F
authors.initials: MF
authors.lastname: Schim van der Loeff
authors.forename: Titia
authors.initials: T
authors.lastname: Heijman
authors.forename: Arjen
authors.initials: A
authors.lastname: Speksnijder
authors.forename: Ronald
authors.initials: R
authors.lastname: Geskus
authors.forename: Maria
authors.initials: M
authors.lastname: Prins
mesh_terms: D000328:Adult; D055030:Drug Users / Q000706:statistics & numerical data*; D005260:Female; D015658:HIV Infections / Q000453:epidemiology* / Q000209:etiology*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D011446:Prospective Studies; D012309:Risk-Taking; D012725:Sexual Behavior; D012749:Sexually Transmitted Diseases / Q000453:epidemiology / Q000209:etiology