CYP2R1 and vitamin D deficiency: We therefore conducted an observational study to determine a) the prevalence and determinants of vitamin D deficiency among a cohort of patients with newly-diagnosed pulmonary tuberculosis in Lahore, Pakistan; b) whether baseline vitamin D status and / or polymorphisms in VDR, DBP or CYP2R1 associated with response to intensive-phase antituberculous therapy in these patients as main effects, and c) whether any associations between vitamin D deficiency and response to treatment were genotype-dependent.