new study that gives fresh insight into how vitamin D may affect the immune
response was published in
The Lancet, a leading medical journal. Tuberculosis
patients who have a particular type of vitamin D receptor are very responsive
to vitamin D therapy. Vitamin D hastened sputum culture conversion in people
with tt genotype of the TaqI vitamin D receptor polymorphism.
revealed by the World Health Organization says that 'with 2 million new
tuberculosis cases in 2009
carries the highest tuberculosis burden in the world
'. Standard treatment
regimens are aimed at bringing faster sputum conversions. A diagnosis of TB is
usually made if two out of three sputum sample cultures yield mycobacterium
, the pathogen that causes
TB. Once treatment is initiated the response is assessed based on repeated
sputum cultures. There are two phases in the treatment of TB: an initial
(intensive) phase and a continuation phase. An effective therapy is one that
brings a sputum conversion, i.e. when the culture doesn't yield microbes
D was used to treat tuberculosis in the pre-antibiotic era.
The metabolic end products of vitamin D have
been shown to induce anti-mycobacterial immunity in vitro, i.e. in an
artificial environment outside the living body. There are no clinical trials
that investigate the effect of adjunctive vitamin D on sputum
A multicentre randomised controlled trial of
adjunctive vitamin D in adults with sputum smear-positive pulmonary
tuberculosis was performed in London, UK. Vitamin D occurs in two major forms: D2
and D3. D3 (cholecalciferol) is the form made in the
body in response to sun exposure. Doses
of 2.5 mg vitamin D3 were given to patients receiving intensive-phase treatment for pulmonary TB.
Vitamin D did not significantly affect time to sputum culture conversion in the
whole study population. But it was found that sputum culture conversion
hastened in people with a particular genotype.
D receptors occur in two genetic variants or polymorphisms: Taq
I and Fok
I polymorphisms. People with theTaqI
vitamin D receptor polymorphism may further
exhibit a particular genetic makeup (genotype) called tt
genotype. It was in the participants with tt
genotype that the positive effect of vitamin D became evident.
findings show great promise in speeding up the antibiotic treatment of TB. The DOTS strategy implemented under the
Revised National Tuberculosis Control Programme (RNTCP) in India is the
international standard for TB control programmes.
typically lasts for 6 to 8 months. Any headway
made in the medical research field for Tuberculosis will help to improve
outcomes for patients. The current study is not devoid of limitation but it
does raise hopes. Being in a nation with 1.96 million new cases of TB annually, every tiny speck of hope is
: The Lancet, January 6, 2010
: Martineau AR, et al "High-dose vitamin D3 during
intensive-phase antimicrobial treatment of pulmonary tuberculosis: a
double-blind randomised controlled trial" Lancet