The prevalence of tuberculosis infection and related risk factors were assessed using tuberculin skin test (TST) and interferon-γ release assay (IGRA) among rural populations with a wide range of local tuberculosis epidemiology in China. We also assessed the risk of development of active disease in those infected to provide a scientific basis for the definition of the at-risk population and explored the compatible laboratory diagnostic criteria by comparing the correlation of two testing methods.

  • General Information of Study
    • Overview
      Name Rural residents (≥5 years old) with latent Mycobacterium tuberculosis infection
      Project Number CCC2018081401
      Website N.A.
      Investigators
      Gao Lei
      Institutions Institute of Pathogen Biology, Chinese Academy of Medical Sciences
      Contacts
      Zhang Haoran
      Funding the National Science and Technology Major Project of China, 2013ZX10003004002
      Objectives The prevalence of tuberculosis infection and related risk factors were assessed using tuberculin skin test (TST) and interferon-γ release assay (IGRA) among rural populations with a wide range of local tuberculosis epidemiology in China. We also assessed the risk of development of active disease in those infected to provide a scientific basis for the definition of the at-risk population and explored the compatible laboratory diagnostic criteria by comparing the correlation of two testing methods.
      Start Date June 2013
      End Date September 2018
    • Study Design
      Number of Participants 21,000
      Age Range ≥5 years old
      Geographic Distribution Xiangtan County, Hunan Province; Longxi County, Gansu Province; Danyang City, Jiangsu Province; Zhongmu County, Henan Province
      General Information of Study Design and Sample Methods Cluster sampling was used and each site was divided into several groups by the township. According to the sample size, we computed the number of the groups should be selected. All individuals in the selected group were investigated.
      Inclusion Criteria (1) ≥5 years old (was born earlier than June 1, 2008 ); (2) local household registration or resident population; (3) ability to complete the investigations and tests during the study duration; (4) provision of voluntary written informed consent.
      Exclusion Criteria (1) Failure to meet the above inclusion criteria; (2) present active tuberculosis; (3) pregnancy, lactation or prepared for pregnancy.
    • Other Information
      Key Achievements (1) On the basis of fi ndings showing that the performance of the tuberculin skin test might be aff ected by various factors including BCG vaccination and age, our results suggest that the prevalence of latent tuberculosis in China might be overestimated by skin tests compared with interferon-γ release assays. (2) this is the first population-based multicentre cohort study to track TB infection (using both IGRA and TST) and the elderly were found to be a promising target population for TB infection control and management in rural China due to the higher acquisition and persistence of infection found in this study. (3) This is the first population-based, multicentre, prospective study done in China assessing the development of active disease in individuals with tuberculosis infection defined with IGRA and TST. Our results suggest that key populations in communities in rural China, such as individuals at high risk of disease reactivation of previous tuberculosis, could be targeted for infection screening and treatment, which would provide an important reference for the establishment of intervention strategy for TB infection in China.
      Marker Papers (1) Gao L, Li X, Liu J, et al. Incidence of active tuberculosis in individuals with latent tuberculosis infection in rural China: follow-up results of a population-based, multicentre, prospective cohort study. Lancet Infect Dis. 2017;17(10):1053-1061. doi: 10.1016/S1473-3099(17)30402-4. (2) Li H, Xin H, Qian S, et al. Testing of tuberculosis infection among Chinese adolescents born after terminating the Bacillus Calmette-Guérin booster vaccination: subgroup analysis of a population-based cross-sectional study. Front Med. 201711(4):528-535. doi: 10.1007/s11684-017-0573-0. (3) Zhang H, Xin H, Li X, et al.A dose-response relationship of smoking with tuberculosis infection: A cross-sectional study among 21008 rural residents in China. PLoS One. 2017;12(4):e0175183. doi: 10.1371/journal.pone.0175183. (4) Zhang H, Li X, Xin H, et al.Association of Body Mass Index with the Tuberculosis Infection: a Population-based Study among 17796 Adults in Rural China.Sci Rep. 2017 Feb 8;7:41933. doi: 10.1038/srep41933. (5) Gao L, Bai L, Liu J, et al. Annual risk of tuberculosis infection in rural China: a population-based prospective study.Eur Respir J. 2016;48(1):168-78. doi: 10.1183/13993003.00235-2016. (6) Gao L, Lu W, Bai L, et al. Latent tuberculosis infection in rural China: baseline results of a population-based, multicentre, prospective cohort study. Lancet Infect Dis. 2015;15(3):310-9. doi: 10.1016/S1473-3099(14)71085-0.
      Strength (1) Good sample representation. The sample was stratified by study site (central, eastern and western regions), which we selected on the basis of a wide range of local tuberculosis epidemiology,economic conditions, and geographical locations. (2) First-hand information on exposure (close contact history, etc.) and outcome (active detection of tuberculosis) can be prospectively obtained and during cohort follow-up. (3) The sample size was large and there were 21 thousands participants were included and followed. (4) The cohort was relatively stable and the measures including strict inclusion and exclusion and regular follow-up were conducted to maintain the stablity of cohort.
      Weakness Bias was inevitable because of the long duration of follow-up, death and emigration.