Vitamin D and the risk of tuberculosis

Researchers at the Centers for Disease Control and Prevention report that low vitamin D levels were associated with a 5-fold increased risk for progression to tuberculosis.

First, the details.

• 109 household contacts of 20 patients with recently diagnosed pulmonary TB were enrolled.
• Blood samples were collected at the start, and at 6, 12, and 24 months follow-up.
• Visiting health workers reviewed the records every 3 months for the first 24 months and at a final home study visit (45 to 74 months from the start).
• 129 blood samples were analyzed for vitamin D levels.
• Total circulating 25[OH] vitamin D was measured.

And, the results.

• Most (79%) persons showed a vitamin D deficiency.
• Vitamin D levels were about 9.6 ng/mL in disease-free contacts.
  • 7.9 ng/mL in TB patients,
  • 4.6 ng/mL in 2 TB patients who were receiving antituberculous treatment at the time of study recruitment, and
  • 5.1 ng/mL in 6 household contacts with a history of TB treatment.
• Low vitamin D levels were associated with a 5-fold increased risk for progression to TB.
• Risk for TB progression, by baseline vitamin D levels.
  • Lowest risk: Less than 7.4 ng/mL
  • Middle risk: Levels 7.4 to 13 ng/mL
  • Highest risk: Levels greater than 13 ng/mL

The bottom line?

The importance of administering vitamin D during TB treatment is controversial.

However, a study conducted at Guy’s and St Thomas’ Foundation Trust, in London, UK reported, “Patients with active TB have lower serum vitamin D concentrations than contacts from similar ethnic and social backgrounds and with comparable dietary intake and sun exposure, and do not show the expected seasonal variation.” Furthermore, “These observations indicate that other factors are contributing to vitamin D deficiency in patients with TB and suggest abnormal handling of this vitamin.”

Accordingly, the authors of the current study would like to know if giving TB patients vitamin D might result in changes in blood levels or even treatment response. They concluded, “Our findings indicate that further studies should be conducted regarding use of vitamin D as a supplement for persons undergoing treatment for TB and those with latent TB infection.”

5/11/10 19:47 JR