@article {626485, title = {Prevalence and determinants of QuantiFERON-diagnosed tuberculosis infection in 9,810 Mongolian schoolchildren}, journal = {Clinical Infectious Disease}, year = {2018}, abstract = { BACKGROUND: There is controversy regarding the potential influence of vitamin D deficiency, exposure to environmental tobacco smoke, BCG vaccination, season and body habitus on susceptibility to Mycobacterium tuberculosis (MTB) infection. METHODS: We conducted a cross-sectional analysis to identify determinants of a positive QuantiFERON{\textregistered}-TB Gold (QFT) assay result in children aged 6-13 years attending 18 schools in Ulaanbaatar, Mongolia. Data relating to potential risk factors for MTB infection were collected by questionnaire, physical examination and determination of serum 25-hydroxyvitamin D (25[OH]D) concentrations. Risk ratios were calculated using generalized estimating equations with adjustment for potential confounders, and population attributable fractions (PAFs) were calculated for modifiable risk factors identified. RESULTS: 946/9,810 (9.6\%) participants had a positive QFT result. QFT-positivity was independently associated with household exposure to pulmonary TB (adjusted risk ratio [aRR] 4.75, 95\% CI 4.13-5.46, P\<0.001; PAF 13.1\%, 95\% CI 11.1\%-15.0\%), vitamin D deficiency (aRR 1.23, 95\% CI 1.08-1.40, P=0.002; PAF 5.7\%, 1.9\%-9.3\%), exposure to environmental tobacco smoke (one indoor smoker, aRR 1.19, 95\% CI 1.04-1.35; two or more indoor smokers, aRR 1.30, 95\% CI 1.02-1.64; P for trend, 0.006; PAF 7.2\%, 95\% CI 2.2\%-12.0\%) and increasing age (aRR per additional year 1.14, 95\% CI 1.10-1.19, P\<0.001). No statistically significant independent association was seen for presence of a BCG scar, season of sampling or body mass index. CONCLUSIONS: Our findings underline the importance of contact tracing in TB-exposed households as a strategy to identify MTB-infected children. Vitamin D deficiency and exposure to environmental tobacco smoke may be modifiable risk factors for MTB infection. }, url = {https://academic-oup-com.ezp-prod1.hul.harvard.edu/cid/advance-article/doi/10.1093/cid/ciy975/5210883}, author = {Davaasambuu Ganmaa and Polyna Khudyakov and Uyanga Buyanjargal and Badamtsetseg Jargalsaikhan and Delgerekh Baigal and Oyunsuren Munkhjargal and Narankhuu Yansan and Sunjidmaa Bolormaa and Enkhsaikhan Lkhagvasuren and Christopher T Sempos and Sabri Bromage and Zhenqiang Wu and Batbayar Ochirbat and Batbaatar Gunchin and Adrian R Martineau} }