Vitamin D, tuberculin skin test conversion, and latent tuberculosis in Mongolian school-age children: a randomized, double-blind, placebo-controlled feasibility trial.
What this study found
Vitamin D supplementation clearly improved vitamin D status and was associated with modestly greater linear growth, but the reduction in tuberculin skin test conversion did not reach statistical significance in this small trial. Serum 25(OH)D rose from 7.0 ng/mL at baseline to 18.2 ng/mL at 3 months and 19.8 ng/mL at 6 months in the vitamin D group, versus 4.1 and 9.6 ng/mL in placebo. Height gain over 6 months was 2.9 cm with vitamin D versus 2.0 cm with placebo (95% CI for difference 2.16, 2.81; P = 0.0025). TST conversion occurred in 5 of 45 children (11%) with vitamin D versus 11 of 41…
- Study & population
- Randomized, double-blind, placebo-controlled feasibility trial in Mongolian public schoolchildren aged 12 to 15 years living in a high-tuberculosis-incidence district of Ulaanbaatar.
- Intervention
- The active intervention was oral vitamin D3 (cholecalciferol) 800 IU daily by capsule for 6 months, compared with matched placebo.
- Key limitation
- This was a small feasibility trial with limited power for tuberculosis outcomes, so the TST conversion analysis was underpowered and imprecise.
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Open PDFOriginal abstract
BACKGROUND By modulating immune function, vitamin D might increase innate immunity and inhibit the growth of initial bacterial invasion and protect against tuberculosis infection. OBJECTIVE We examined the effect of vitamin D supplementation on tuberculin skin test (TST) conversion. DESIGN A double-blind, placebo-controlled study was conducted in 120 Mongol schoolchildren. We estimated the prevalence of latent tuberculosis infection at baseline and examined the effect of vitamin D (800 IU/d) on serum concentrations of 25-hydroxyvitamin D [25(OH)D] and TST conversion. RESULTS At baseline, the mean (±SD) 25(OH)D concentration was 7 ± 4 ng/mL, and all concentrations were <20 ng/mL. Vitamin D supplementation increased serum 25(OH)D by a mean of 12.7 ng/mL compared with placebo (P < 0.0001). At baseline, 16 children in the vitamin D group and 18 in the placebo group were TST positive (P = 0.7). Over 6 mo, TSTs converted to positive in 5 (11%) children receiving vitamin D compared with 11 (27%) receiving placebo (RR: 0.41; 95% CI: 0.16, 1.09; P = 0.06). Only one TST conversion occurred among those whose serum 25(OH)D concentration increased to >20 ng/mL, whereas 8 TST conversions occurred in those whose final 25(OH)D concentration remained <10 ng/mL (P = 0.05). The mean increase in stature was 2.9 ± 1.6 cm in the vitamin D group and 2.0 ± 1.7 cm in the placebo group (95% CI: 2.16, 2.81; P < 0.003). CONCLUSIONS Vitamin D supplementation for 6 mo had significant favorable effects on serum 25(OH)D concentrations and on growth in stature. A trend was seen toward fewer TST conversions in the vitamin D group. This trial was registered at clinicaltrials.gov as NCT01244204.