Prior to correction for multiple analyses, statistically significant associations between profound vitamin D deficiency and delayed sputum smear conversion were found in patients with the GG genotype of rs2228570,VDR (adjusted HR 6.53, 95 % CI 3.99 to 10.66, P < 0.001) and in those with the GA genotype (adjusted HR 3.02, 95 % CI 1.82 to 5.01, P < 0.001) but not in those with the AA genotype (adjusted HR 4.58, 95 % CI 0.56 to 37.25, P = 0.16; P for interaction = 0.03). The gene discussed is VDR; the disease is vitamin D deficiency.