Prevalence of latent tuberculosis in students of Qazvin University of Medical Sciences (2014)

The tuberculin test is one of the available tests to detect latent tuberculosis. The aim of this study was to determine the prevalence of latent tuberculosis in students of Qazvin University of Medical Sciences. This cross-sectional study was conducted in a total of 213 medical sciences students by census method in 2014. The tuberculin test was performed for all students. Induration of 10 mm or greater was considered as positive. Data were analyzed using Chi-square test, T-test, Pearson’s correlation coefficient and regression analysis. The prevalence of latent tuberculosis was 14.6%. The mean induration in students with history of exposure to tuberculosis was significantly different from students without history of exposure. The association of exposure to tuberculosis and positive tuberculin test was statistically significant. Age and body mass index were poorly correlated with the size of induration (r= 0.166 and 0.146, respectively). In the regression analysis, only contact with tuberculosis patients was independent predictor of positive tuberculin test. With regards to the results, it seems that the most important factor for positive tuberculin test is a history of contact with tuberculosis patients in medical sciences student. Increasing mean induration size with age may be due to increased contact with subjects infected with tuberculosis.