Prevalence and Determinants of QuantiFERON-Diagnosed Tuberculosis Infection in 9810 Mongolian Schoolchildren

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-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 (RRs) were calculated with adjustment for potential confounders, and population attributable fractions (PAFs) were calculated for modifiable risk factors identified. Results Nine hundred forty-six of 9810 (9.6%) participants had a positive QFT result. QFT positivity was independently associated with household exposure to pulmonary tuberculosis (adjusted RR [aRR], 4.75 [95% confidence interval {CI}, 4.13–5.46, P < .001]; PAF, 13.1% [95% CI, 11.1%–15.0%]), vitamin D deficiency (aRR, 1.23 [95% CI, 1.08–1.40], P = .002; PAF, 5.7% [95% CI, 1.9%–9.3%]), exposure to environmental tobacco smoke (1 indoor smoker, aRR, 1.19 [95% CI, 1.04–1.35]; ≥2 indoor smokers, aRR, 1.30 [95% CI, 1.02–1.64]; P for trend = .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 < .001). No statistically significant independent association was seen for presence of a BCG scar, season of sampling, or body mass index. Conclusions Vitamin D deficiency and exposure to environmental tobacco smoke are potentially modifiable risk factors for MTB infection.

Implementing contact tracing for tuberculosis in Kyrgyz Republic and risk factors for positivity using QuantiFERON-TB Gold plus

“…However, when stratifying by age, this association completely dissipated for contacts below 15 years of age suggesting that children are also at high risk to be infected by smear negative cases. Particularly for children, living in a densely populated household was a much stronger risk factor for TB infection than the smear status of the index case, as finding that is supported in the literature [3,8,15,19]. Currently, WHO defines only household contacts per se as high risk [14], but our findings suggest that the average household density should be considered as criterion for risk-stratified contact investigation among children in Kyrgyz Republic.…”

Consensus statement from 2nd International Conference on Controversies in Vitamin D

“…In the discussion above, data from the Canadian Health Measures Surveys, the three German national surveys and the meta-analysis data cited by Cashman et al were all retrospectively standardized. Three examples of prospectively standardized studies are NHANES 2011-2014 [27], Australian Health Survey [28], and a recent study on determinants of QuantiFERON-diagnosed tuberculosis infection in Mongolian schoolchildren [29].…”

Paediatric tuberculosis transmission outside the household: challenging historical paradigms to inform future public health strategies

“…Despite the complexity in quantifying where M tuberculosis transmission occurs in children at the population level, understanding this key question is essential to design appropriate and effective public health programmes to detect, diagnose, and treat children with tuberculosis. 13 studies [14][15][16][17][18][19][20][21][22][23][24][25][26] published between 2003 and 2018 that made use of diverse methodologies and designs shed light on this topic. This description is specific to the type of study, and is thus described for each study type in later sections.…”

“…Five similar studies that were not included in this review 18 also found similar results (table 1). [19][20][21][22][23] A community-based survey of 3170 children from Malawi was done. 19 Using mixture analysis of tuberculin data, the authors found that 1•1% of all children were infected.…”