Vitamin D did not influence time to sputum culture conversion in the study population overall. Effects of the intervention were modified by SNPs in VDR and CYP27B1. Clinical trial registered with www.clinicaltrials.gov (NCT01657656).

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.

Objectiveto test whether vitamin D supplementation in vivo may be a useful adjunct to anti‐TB drugs and could lead to the development of shorter drug regimens.Methods: Double‐blind, placebo‐controlled randomized clinical trial among TB patients in Mongolia. The baseline clinical assessment consisted of chest radiography, measurement of height, weight, mid‐upper arm circumference, and triceps, biceps and subscapular skinfolds and collection of a sputum, a urine, and a blood samples.Results: The results were available for the subsample of the patients and were analyzed by cavity status at baseline. Fewer of the participants were female (31%) compared to the males (69%). At baseline, 46 patients had a cavity (Cav +) and 94 did not have a cavity (Cav ‐) on chest radiograph. The participants in the Cav (‐) and Cav (+) groups were similar in age (mean 34.9 + 11.9 sd cm vs. 34.9 + 15.4 sd cm). Sputum samples are collected and cultured every two weeks. For each subject, the date of conversion from positive to negative was determined. Since un‐blinding has not occurred, we are presenting here pooled time to sputum culture conversion.ConclusionsMean serum concentration of albumin at baseline was 34.7 + 60.5 g/L in the Cav (+) compared to 37.2+4.9 g/L in the Cav (‐) group (p<0.05). Mean concentrations of C Reactive Protein (CRP) and neutrophils were significantly higher in the Cav (+) group compared to the Cav (‐) group.