The participants of the ACS on HIV and AIDS among DU started enrolment in 1985 [41]. Asymptomatic men and women who were living in the Amsterdam area and who reported intravenous drug use in the preceding 6 months were enrolled in a prospective study on the prevalence and incidence of HIV-1 infection and risk factors for AIDS. We included 83 individuals who seroconverted for HIV antibodies during active follow-up. At entry in the cohort study 37 individuals were positive for HIV antibodies but had a negative test result before entry (i.e., retrospective seroconverters). For all 120 HIV-1 infected DU (76 men and 44 women) used for our present analysis, the imputed seroconversion date was calculated and used for further analysis [42]. Mean survival time was similar for male and female participants of the DU cohort and for the DU versus MSM cohorts. Most seropositive DU (n = 69 [58%]) did not receive any early treatment, 28 (23%) received zidovudine monotherapy, and 23 (19%) received other ineffective antiretroviral therapy before AIDS-diagnosis. The mean age of DU participants at the time of
