[Determinants of the prevalence of hepatitis B viral infection in parenteral drug abusers].

In order to study the frequency of hepatitis B viral infection and its determinants, we studied 2337 intravenous drug users who visited three AIDS information and prevention centers between 1987 and 1991. The presence of three markers for HBV (AntiHBc, AntiHBs, and AgHBs) and of HIV-1 antibodies was analyzed. A structured questionnaire was used to gather data on sociodemographic information and risk factors for infection. The prevalence of HBV infection (at least one positive marker) was 78% (95% CI: 76%-80%). After adjustment via logistic regression, duration of drug addiction (OR-5.04), the number of sexual partners (OR = 1.70), and the presence of antibodies for HIV-1 (OR = 2.44) were associated with increased HBV infection were higher level of education (OR = 0.67) and residence in a smaller city (OR = 0.66). The marginalization of the practice of drug use makes prevention activities very difficult, and by the time they use health services, the majority of users have already been in contact with HBV. Other infectious agents which share parenteral transmission can reach a similar prevalence if preventive efforts are not intensified.