BMC Infectious Diseases (Jun 2019)

Risk factors for active tuberculosis in 938 QuantiFERON-positive schoolchildren in Mongolia: a community-based cross-sectional study

  • Davaasambuu Ganmaa,
  • Polyna Khudyakov,
  • Uyanga Buyanjargal,
  • Delgerekh Baigal,
  • Munkhzul Baatar,
  • Nomin Enkhamgalan,
  • Sumiya Erdenebaatar,
  • Batbayar Ochirbat,
  • Buyankhishig Burneebaatar,
  • Enkhtamir Purevdorj,
  • Yanjindulam Purevsuren,
  • Gantsetseg Garmaa,
  • Erdenetuya Ganbaatar,
  • Adrian R. Martineau

DOI
https://doi.org/10.1186/s12879-019-4160-7
Journal volume & issue
Vol. 19, no. 1
pp. 1 – 9

Abstract

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Abstract Background There is controversy regarding the relative influence of ‘exogenous’ versus ‘endogenous’ factors on the risk of progression from latent tuberculosis infection to active tuberculosis (TB) disease in children. Methods We conducted a cross-sectional analysis to identify risk factors for active tuberculosis in QuantiFERON®-TB Gold (QFT-G)-positive children aged 6–13 years attending 18 schools in Ulaanbaatar, Mongolia. Children underwent clinical and radiological screening for active tuberculosis, and data relating to potential risk factors for disease progression were collected by questionnaire and determination of serum 25-hydroxyvitamin D (25[OH]D) concentrations. Risk ratios were calculated using generalized estimating equations with adjustment for potential confounders. Results 129/938 (13.8%) QFT-positive children were diagnosed with active tuberculosis. Risk of active tuberculosis was independently associated with household exposure to pulmonary TB (adjusted risk ratio [aRR] 2.40, 95% CI 1.74 to 3.30, P < 0.001), month of sampling (adjusted risk ratio [aRR] for March–May vs. June–November 3.31, 95% CI 1.63 to 6.74, P < 0.001; aRR for December–February vs. June–November 2.53, 95% CI 1.23 to 5.19, P = 0.01) and active smoking by the child (aRR 5.23, 95% CI 2.70 to 10.12, P < 0.001). No statistically significant independent association was seen for age, sex, socio-economic factors, presence of a Bacillus Calmette–Guérin (BCG) scar, tobacco exposure or vitamin D status. Conclusions Household exposure to active TB, winter or spring season and active smoking were independently associated with risk of active tuberculosis in QFT-positive children. Our findings highlight the potentially high yield of screening child household contacts of infectious index cases for active tuberculosis in low- and middle-income countries.

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