Abstract:
Objective To investigate the prevalence of latent tuberculosis (TB) in senior high school students from a western province in Qingdao, Shandong province, and provide data support for the screening of latent TB in students in Qingdao.
Methods The information of 621 senior high school students from a western province and the information about their TB exposure histories were collected by using questionnaire. Tuberculin skin test (TST), interferon-Gamma release assay (IGRA) and chest X-ray examination were performed for them by designated medical institutions. Kappa consistency test was used to analyze the consistency of the results of the two methods, and χ2 test was used for comparison between groups and univariate analysis. Multivariate Logistic regression model was used to identify the influencing factors of latent tuberculosis.
Results A total of 621 subjects were included in this study, in whom 121 were positive in IGRA (19.48%) and 61 were strong positive in TST (9.82%), the difference in positive/strong positive rate was significant (χ2=47.368, P<0.001). The consistency of the two detection methods was medium (Kappa=0.5197). The differences in the positive rate among different gender, ethnic, grade, household registration, body mass index and TB exposure groups were significant (P<0.05), and the consistency was medium or good. The results of multivariate Logistic regression analysis showed that the student in grade 3 odds ratio (OR)=2.23, 95% confidence interval (95%CI): 1.37–3.60 and the student with TB exposure history (OR=2.12, 95%CI: 1.12–4.20) had higher risk for latent TB. One student with latent infection was diagnosed with TB at follow up three months later, his IGRA result was positive and TST result was strong positive, and he had TB exposure history but had no suspected TB symptoms.
Conclusion This study suggested that IGRA detection is more effective in the screening of population with high risk for TB. It is necessary to strengthen the screening of TB in freshmen and students returning after vacation to provide evidence for the prevention and control of TB in schools.