One dose of vitamin D boosts TB immunity

NEW YORK (Reuters Health) - In healthy people who have been exposed to tuberculosis, a single oral dose of vitamin D enhances their immunity against this bacterial infection.

"Vitamin D was used to treat tuberculosis in the pre-antibiotic era," Dr. Adrian R. Martineau, of Queen Mary's School of Medicine and Dentistry, London, and colleagues note. Studies that have evaluated the effects of vitamin D supplements on tuberculosis immunity have not been performed, they point out in their report, published in the American Journal of Respiratory and Critical Care Medicine.

Martineau's group therefore conducted a clinical trial in which they assigned 192 healthy adults who had been exposed to tuberculosis to receive a single oral dose of 2.5 milligrams of vitamin D or a placebo.

Of the 192 subjects, 43 were lost to follow-up and 18 were excluded, so that 131 participants were included in the analysis of primary outcome. Of these, 64 received placebo and 67 received vitamin D. After 6 weeks, the subjects were tested for evidence of Mycobacterium tuberculosis.

The researchers found that the vitamin D supplement significantly enhanced the subjects' immunity to M. tuberculosis compared with those who received the placebo.

Based on these findings, Martineau's team suggests that "clinical trials should be performed to determine whether vitamin D supplementation prevents reactivation of latent tuberculosis infection."

SOURCE: American Journal of Respiratory and Critical Care Medicine, July 15, 2007.