Patient Genotype Affects Response to Supplemental Vitamin D in TB Treatment

Calcitriol, a vitamin D metabolite, modulates the host immune response to mycobacteria. Although published studies have demonstrated that vitamin D supplementation can decrease the time to sputum-smear conversion, sputum culture is a better indicator of failure and relapse.

To determine whether supplemental vitamin D can reduce time to sputum-culture conversion, investigators in the U.K. (with partial support from industry) conducted a multicenter trial involving adults with smear-positive pulmonary tuberculosis (TB). Participants received standard TB therapy (isoniazid, rifampicin, ethambutol, and pyrazinamide) and were randomized to receive either placebo or oral 2.5-mg doses of vitamin D at baseline and at 14, 28, and 42 days. Participant…