RESUMO
OBJECTIVE: To characterize HIV seroprevalence and risk behavior among injecting drug users (IDUs) in Rio de Janeiro, Brazil, between 1990 and 1996. DESIGN: We report data from three separate cross-sectional samples of IDUs in Rio de Janeiro: the World Health Organization (WHO) sample (n = 479), the Proviva sample (n = 138) and the Brasil sample (n = 110). These data provide the most comprehensive view available, to date, of this understudied population in Rio. METHODS: Demographic characteristics, HIV/AIDS risk behavior and HIV seroprevalence were compared across the three samples and combined analyses were performed to determine the factors associated with injecting risk behavior, sexual risk behavior and HIV seropositivity. RESULTS: The overall HIV seroprevalence among IDUs was 25%. Two encouraging findings of the present analysis were the lower levels of needle-sharing among participants recruited in the latest years (1995-1996) and the lower HIV seroprevalence in the Proviva sample composed mainly of less educated, poorer IDUs living in deprived neighborhoods. No trends toward safer behavior were found for sexual risk, younger age being the principal factor associated with high risk. CONCLUSIONS: Levels of needle-sharing and sexual risk among IDUs in Rio remain high, demonstrating the urgent need to increase the limited preventive measures undertaken so far. Seroprevalence levels for HIV remain significantly lower in the most deprived sample, arguing for the fundamental importance of prompt and effective prevention strategies to keep infection rates from rising among the poorest and largest strata of Rio's IDUs.