Tuberculosis prevalence among university freshmen in Zhengzhou, China, during 2004-2013

Background: Tuberculosis (TB) is a major public health concern worldwide, and spreads more easily in densely populated areas such as school campuses. Objectives: The aim of this study was to determine the prevalence of positive TB skin tests among freshmen, i.e. newly-enrolled college students, in Zhengzhou City, China. Methods: We reviewed the data of purified protein derivative (PPD) skin tests in 656,212 freshmen in 2004-2013. Results: A positive test showed a diameter of swelling ≥ 5 mm. The PPD positive rate was 40.69 %, with a prevalence of 146.29 per 100,000. During the 10-year study period, the rate of students with positive PPD test increased from 34.19 % in 2004 to 40.69 % in 2013. The positive PPD rate was significantly higher in males than in females (41.68 % vs 39.61 %, P<0.0001), and in rural compared with urban areas (42.04 % vs 38.03 %, P<0.0001). Conclusion: These findings indicated a high prevalence of PPD positivity among participants during the study period, with an increasing trend. Therefore, this population needs to be targeted by TB prevention and control programs. Keywords: Tuberculosis; PPD test; freshmen; positive rate; prevalence