title: Latent tuberculosis infection in rural China: baseline results of a population-based, multicentre, prospective cohort study.
abstract: BACKGROUND
  Prophylactic treatment of individuals with latent Mycobacterium tuberculosis infection is an essential component of tuberculosis control in some settings. In China, the prevalence of latent tuberculosis infection, and preventive interventions against this disease, have not been systematically studied. We aimed to assess the prevalence of latent tuberculosis and its associated risk factors in rural populations in China.
  
  
  METHODS
  Between July 1, and Sept 30, 2013, we undertook a baseline survey of a population-based, multicentre, prospective cohort study of registered residents (≥5 years old) at four study sites in rural China. Eligible participants were identified by door-to-door survey with a household sampling design. We screened participants for active tuberculosis and history of tuberculosis then used a tuberculin skin test and an interferon-γ release assay (QuantiFERON [QFT]) to test for latent infection. We used odds ratios (ORs) and 95% CIs to assess variables associated with positivity of QFT and tuberculin skin tests.
  
  
  RESULTS
  21,022 (90%) of 23,483 eligible participants completed a baseline survey. Age-standardised and sex-standardised rates of skin-test positivity (≥10 mm) ranged from 15% to 42%, and QFT positivity rates ranged from 13% to 20%. Rates of positivity for the tuberculin skin test and the QFT test were low in study participants younger than 20 years and gradually increased with age (p for trend <0·0001). Rates of latent tuberculosis infection were higher for men than women (p<0·0001). Overall agreement between the tuberculin skin test and the QFT test was moderate (81·06%; kappa coefficient 0·485), with skin-test-only positive results associated with the presence of BCG scar, male sex, and ages of 60 years and older, and QFT-only positive results associated with male sex and ages of 60 years and older.
  
  
  CONCLUSIONS
  On the basis of findings showing that the performance of the tuberculin skin test might be affected 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.
  
  
  BACKGROUND
  The National Science and Technology Major Project of China, the Program for Changjiang Scholars and Innovative Research Team in University of China.
authors: Ministry of Health Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors: Lei
authors: L
authors: Gao
authors: Jiangsu Provincial Center for Diseases Control and Prevention, Nanjing, China.
authors: Wei
authors: W
authors: Lu
authors: Hunan Provincial Institute of Tuberculosis Prevention and Control, Xiangtan, China.
authors: Liqiong
authors: L
authors: Bai
authors: Gansu Provincial Center for Diseases Control and Prevention, Lanzhou, China.
authors: Xinhua
authors: X
authors: Wang
authors: The Sixth People's Hospital of Zhengzhou, Zhengzhou, China.
authors: Jinsheng
authors: J
authors: Xu
authors: Department of Medicine, University of California, San Diego, California, USA.
authors: Antonino
authors: A
authors: Catanzaro
authors: Aeras, Rockville, MD, USA.
authors: Vicky
authors: V
authors: Cárdenas
authors: Ministry of Health Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors: Xiangwei
authors: X
authors: Li
authors: Ministry of Health Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors: Yu
authors: Y
authors: Yang
authors: Ministry of Health Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors: Jiang
authors: J
authors: Du
authors: Ministry of Health Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors: Hongtao
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authors: Sui
authors: Chinese Center for Disease Prevention and Control, Beijing, China.
authors: Yinyin
authors: Y
authors: Xia
authors: Ministry of Health Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors: Mufei
authors: M
authors: Li
authors: Ministry of Health Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors: Boxuan
authors: B
authors: Feng
authors: Ministry of Health Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors: Zhen
authors: Z
authors: Li
authors: Ministry of Health Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors: Henan
authors: H
authors: Xin
authors: Ministry of Health Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors: Rong
authors: R
authors: Zhao
authors: The Sixth People's Hospital of Zhengzhou, Zhengzhou, China.
authors: Jianmin
authors: J
authors: Liu
authors: Zhongmu County Center for Diseases Control and Prevention, Zhongmu, China.
authors: Shouguo
authors: S
authors: Pan
authors: The Sixth People's Hospital of Zhengzhou, Zhengzhou, China.
authors: Fei
authors: F
authors: Shen
authors: Gansu Provincial Center for Diseases Control and Prevention, Lanzhou, China.
authors: Jian
authors: J
authors: He
authors: Gansu Provincial Center for Diseases Control and Prevention, Lanzhou, China.
authors: Shumin
authors: S
authors: Yang
authors: Gansu Provincial Center for Diseases Control and Prevention, Lanzhou, China.
authors: Hongyan
authors: H
authors: Si
authors: Longxi County Center for Diseases Control and Prevention, Longxi, China.
authors: Yi
authors: Y
authors: Wang
authors: Hunan Provincial Institute of Tuberculosis Prevention and Control, Xiangtan, China.
authors: Zuhui
authors: Z
authors: Xu
authors: Hunan Provincial Institute of Tuberculosis Prevention and Control, Xiangtan, China.
authors: Yunhong
authors: Y
authors: Tan
authors: Xiangtan County Center for Diseases Control and Prevention, Xiangtan, China.
authors: Tianzhu
authors: T
authors: Chen
authors: Jiangsu Provincial Center for Diseases Control and Prevention, Nanjing, China.
authors: Weiguo
authors: W
authors: Xu
authors: Jiangsu Provincial Center for Diseases Control and Prevention, Nanjing, China.
authors: Hong
authors: H
authors: Peng
authors: Danyang City Center for Diseases Control and Prevention, Danyang, China.
authors: Zhijian
authors: Z
authors: Wang
authors: Danyang City Center for Diseases Control and Prevention, Danyang, China.
authors: Tao
authors: T
authors: Zhu
authors: Ministry of Health Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors: Feng
authors: F
authors: Zhou
authors: Ministry of Health Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors: Haiying
authors: H
authors: Liu
authors: Chinese Center for Disease Prevention and Control, Beijing, China.
authors: Yanlin
authors: Y
authors: Zhao
authors: Chinese Center for Disease Prevention and Control, Beijing, China.
authors: Shiming
authors: S
authors: Cheng
authors: Ministry of Health Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China. Electronic address: zdsys@vip.sina.com.
authors: Qi
authors: Q
authors: Jin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D059425:Interferon-gamma Release Tests; D055985:Latent Tuberculosis / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D012424:Rural Population; D014374:Tuberculin Test; D055815:Young Adult