Vitamin D Supplements for Prevention of Tuberculosis Infection and Disease

Abstract

Background: Vitamin D metabolites support innate immune responses to Mycobacterium tuberculosis. Data from phase 3, randomized, controlled trials of vitamin D supplementation to prevent tuberculosis infection are lacking.

Methods: We randomly assigned children who had negative results for M. tuberculosis infection according to the QuantiFERON-TB Gold In-Tube assay (QFT) to receive a weekly oral dose of either 14,000 IU of vitamin D3 or placebo for 3 years. The primary outcome was a positive QFT result at the 3-year follow-up, expressed as a proportion of children. Secondary outcomes included the serum 25-hydroxyvitamin D (25[OH]D) level at the end of the trial and the incidence of tuberculosis disease, acute respiratory infection, and adverse events.

Results: A total of 8851 children underwent randomization: 4418 were assigned to the vitamin D group, and 4433 to the placebo group; 95.6% of children had a baseline serum 25(OH)D level of less than 20 ng per milliliter. Among children with a valid QFT result at the end of the trial, the percentage with a positive result was 3.6% (147 of 4074 children) in the vitamin D group and 3.3% (134 of 4043) in the placebo group (adjusted risk ratio, 1.10; 95% confidence interval [CI], 0.87 to 1.38; P = 0.42). The mean 25(OH)D level at the end of the trial was 31.0 ng per milliliter in the vitamin D group and 10.7 ng per milliliter in the placebo group (mean between-group difference, 20.3 ng per milliliter; 95% CI, 19.9 to 20.6). Tuberculosis disease was diagnosed in 21 children in the vitamin D group and in 25 children in the placebo group (adjusted risk ratio, 0.87; 95% CI, 0.49 to 1.55). A total of 29 children in the vitamin D group and 34 in the placebo group were hospitalized for treatment of acute respiratory infection (adjusted risk ratio, 0.86; 95% CI, 0.52 to 1.40). The incidence of adverse events did not differ significantly between the two groups.

Conclusions: Vitamin D supplementation did not result in a lower risk of tuberculosis infection, tuberculosis disease, or acute respiratory infection than placebo among vitamin D-deficient schoolchildren in Mongolia. (Funded by the National Institutes of Health; ClinicalTrials.gov number, NCT02276755.).

Conflict of interest statement

No potential conflict of interest relevant to this article was reported.

Copyright © 2020 Massachusetts Medical Society.

Figures

Figure 1.. Screening, Randomization, and Follow-up.

QFT denotes QuantiFERON-TB Gold In-Tube assay.

Figure 2.. Mean Serum 25-Hydroxyvitamin D (25[OH]D) Level According to Time and Trial Group.

Levels of 25(OH)D were higher at the end of the trial in the group that received vitamin D supplementation than in the placebo group (mean between- group difference, 20.3 ng per milliliter; 95% CI, 19.9 to 20.6). To convert the 25(OH)D values to nanomoles per liter, multiply by 2.496. I bars indi- cate the standard deviation. The plus–minus values are means ±SD. The values in parentheses are the numbers of children.