title: Vitamin D, tuberculin skin test conversion, and latent tuberculosis in Mongolian school-age children: a randomized, double-blind, placebo-controlled feasibility trial.
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.
  
  
  METHODS
  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.
authors: Department of Nutrition, Harvard School of Public Health, Boston, MA, USA. gdavaasa@hsph.harvard.edu
authors: Davaasambuu
authors: D
authors: Ganmaa
authors: Edward
authors: E
authors: Giovannucci
authors: Barry R
authors: BR
authors: Bloom
authors: Wafaie
authors: W
authors: Fawzi
authors: Winthrop
authors: W
authors: Burr
authors: Dulguun
authors: D
authors: Batbaatar
authors: Nyamjav
authors: N
authors: Sumberzul
authors: Michael F
authors: MF
authors: Holick
authors: Walter C
authors: WC
authors: Willett
mesh_terms: D000293:Adolescent; D002648:Child; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D055985:Latent Tuberculosis / Q000175:diagnosis / Q000453:epidemiology*; D008297:Male; D008986:Mongolia / Q000453:epidemiology; D014374:Tuberculin Test / Q000379:methods*; D014807:Vitamin D / Q000008:administration & dosage* / Q000097:blood*
chemical_list: D014807:Vitamin D