[Prevalence of human immunodeficiency virus type 1 and Mycobacterium tuberculosis infections in a prison population in the years 1989 to 1995].

BACKGROUND

This study was carried out to know the prevalence of human immunodeficiency virus type 1 (HIV-1) and Mycobacterium tuberculosis infection in a penitentiary center, the risk factors and the prevention measures to reduce this infection.

SUBJECTS AND METHODS

1,173 men from a penitentiary center between 1989-1995 were included. Demographic data, risk factors and penitentiary variables were studied. Antibodies against HIV were found and confirmed using Western blot; tuberculin skin reaction (PPD) and CD4 lymphocyte cant were studied.

RESULTS

The mean age was 31.8 (SD 8.8 years). They were 61.5% Spanish people and 48.1% were in prison for second time. The 49.7% used illegal drugs. Overall prevalence of HIV-1 infection was 24.3%. The differences of percentages for HIV-1 infection in intravenous drug users (IVDU) were 67.7% and in non IVDU were 3.8% with a significant statistical difference (chi 2 = 557.5; p < 0.0001). Using a multivariate test (stepwise method) we found that the probability to be HIV-1 positive in a penitentiary center was 21.9 times higher in IVDU, 5.6 times in Spanish prisoners, 2.6 times in subjects with more than one prison stay and 1.7 times if they had tatoos. The global prevalence of tuberculosis infection (PPD positive) was a 43.8%, and was associated to the second time inmates in this penitentiary center (chi 2 = 22.1; p < 0.001). A 54.4% of HIV-1 positive people showed a CD4 T lymphocyte count > or = 500 x 10(6)/l.

CONCLUSIONS

We found a high prevalence of HIV-1 and tuberculosis infection and drug use in this penitentiary center. HIV-1 was transmitted and related by sharing syringes between IVDU independent of the stay in prison. The diagnosis of HIV-1 infection was made soon. The treatments of drug users in penitentiary centers and programs for lowering the risk are very important.