Risk factors for developing tuberculosis in remand prisons in St. Petersburg, Russia - a case-control study

Background: Detainees have a substantial risk to develop tuberculosis ( TB) due to a higher incidence of TB in remand prison compared to the civil community. They develop TB during incarceration not only due to poor living conditions in remand prison, but also due to some factors affecting their life before imprisonment. Prevention measures against TB spread from penitentiary institutions to society include study of factors, which contribute to TB development. Current study aims at identification of important risk factors of TB development in remand prison in St. Petersburg, Russia. Methods: A retrospective matched case-control study was performed from May 2002 to May 2003 in two remand prisons in St. Petersburg. One hundred and fourteen prisoners ( 57 cases, 57 controls) were interviewed by using standardised questionnaire. Logistic regression analysis was performed to identify risk factors. Results: Six factors were significantly linked to the risk of developing TB: narcotic drug use ( odds ratio ( OR): 2.6, 95% confidence interval (CI): 1.0-6.9), low income ( OR: 3.2, CI: 1.2-8.6), high ratio of prisoners per available bed ( OR: 4.0, CI: 1.1-15.0), not having own bed clothes ( OR: 13.0, CI: 2.7-61.6), and little time outdoors ( OR: 3.3,CI: 1.3-8.5). However, good housing before imprisonment ( OR: 4.2, CI: 1.1-15.7) was a separate risk factor for TB. Conclusions: Three of the risk factors ( high number of prisoners per bed, not having own bed clothes, and little time outdoors) are certainly possible to approach by improvement of conditions in remand prisons. The remaining three factors ( narcotic drug use, good housing before imprisonment, and low income) provide knowledge about study population, but cannot be intervened by prison's medical staff.