EVOLUTION OF THE PREVALENCE OF INFECTION OF MYCOBACTERIUM-TUBERCULOSIS IN A PENITENTIARY POPULATION ON ADMISSION TO PRISON FROM 1991 TO 1996

BACKGROUND: In Spanish prisons tuberculosis is a serious problem of pu blic health. The analysis of temporal trends of tuberculous infection can show the efectiveness of interventions developped. PATIENTS, MATER IAL AND METHODS: All admisions in a prison between July 1991 and June 1996, without antecedents of chemotherapy or chemoprophylaxis, were in cluded. We gathered sociodemographic variables as well as prison-relat ed variables and HIV-risk factors. Tuberculin skin test was performed with 2 U of PPD RT-23 following the Spanish Consensus to Criterion of Tuberculous Infection. Statatistic analysis was based on multivariate analysis (logistic regression). RESULTS: 37% of 1,459 prisoners analiz ed were infected with M. tuberculosis. The tuberculous infection was m ore frequent among older prisoners (p < 0.001) and those with more tim e spent in prison (p < 0.001), Those with BCG-vaccination showed lesse r levels of tuberculin reaction (p = 0.001). Temporal trends of tuberc ulous infection didn't show variations, but in intravenous drug users IVDU (p = 0.012) and those with time spent in prison (p = 0.08) it was increased. CONCLUSIONS: We detected a high prevalence of tuberculous infection and the time spent in prison was one of the risk factors. Th e infection was probably underestimate among those with BCG-vaccinatio n because of the criterion used, The tuberculous infection was increas ed among IVDU and those with antecedent of time spent in prison.