(18-07-12) Vitamin D, tuberculin skin test conversion, and latent tuberculosis in Mongolian school-age children

(18-07-12) Vitamin D, tuberculin skin test conversion, and latent tuberculosis in Mongolian school-age children: a randomized, double-blind, placebo-controlled feasibility trial.
Ganmaa D, Giovannucci E, Bloom BR, Fawzi W, Burr W, Batbaatar D, Sumberzul N, Holick MF, Willett WC.
Source
Department of Nutrition, Harvard School of Public Health and Channing Laboratory, Brigham and Women's Hospital and Harvard Medical School, Boston, MA.
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.

Source: Am J Clin Nutr. 2012 Jul 3. [Epub ahead of print]

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