[Comparative study of the prevalence of hepatitis B virus infection and human immunodeficiency virus type 1 infection in the prison population between 1985 and 1992].

The prisoner population of the penitentiaries presents an elevated prevalence of hepatitis B virus (HBV) and human immunodeficiency type 1 (HIV-1) infection markers. In the last few years different measures have been developed to prevent infection. This study evaluates whether there have been changes in the prevalence of infection by these virus over the last few years within a penitentiary. A group of prisoners (n = 163) studied in 1985 were therefore compared with another group (n = 750) studied in 1992. Demographic, social, risk and penitentiary factors were included. In each of the subjects studied alanine aminotransferase (ALT), hepatitis B virus (HBsAG, antiHBs and antiHBc) and anti-HIV-1 markers were determined. It was globally observed that following the 7 years between the two studies there was a decrease in the prevalence of HBV (X = 14.63, p = 0.0001, OR = 2; CI 95%: 1.38-2.9), which was mainly observed in the group of prisoners with no drug addiction habits. No differences were observed with regard to the prevalence of anti-HIV-1 which remained similar among the IV drug consumers and not consumers (64% and 66.6% in 1985 and 1992, respectively). In conclusion, from 1985 to 1992 a decrease has been observed in the prevalence of hepatitis B virus infection in the penitentiary population while the prevalence of anti-HIV-1 has remained unchanged.