Serum vitamin D levels and VDR polymorphisms (BsmI and FokI) in patients and their household contacts susceptible to tuberculosis.

Vitamin D, an immunomodulator of macrophage function, can activate human antimycobacterial activity. Vitamin D deficiency (VDD) is associated with an impaired mycobacterial immunity and susceptibility to tuberculosis. It has been found that vitamin D and its receptor may be essential for immune function. In this study, we examined the serum 25(OH) vitamin D levels and its receptor (VDR) polymorphisms with susceptibility to tuberculosis in patients, household contacts and healthy controls. Serum 25(OH) vitamin D levels were measured in 75 cases (25 patients, 25 household contacts and 25 healthy controls), and polymorphisms (BsmI and FokI) were carried out in 335 cases (110 patients, 110 household contacts and 115 healthy controls). The proportion of serum 25(OH) vitamin D deficiency and insufficiency was high in patients (44, 58%) and household contacts (40, 48%) compared to controls (48%). The BB and Bb genotypes of BsmI were significantly associated in patients (P < 0.014; OR: 0.509; CI: 0.265-0.876) (P < 0.001; OR: 2.351; CI: 1.368-4.041) and household contacts (P < 0.04; OR: 0.575; CI: 0.336-0.985); (P < 0.002; OR: -2.267; CI: 1.32-3.895) when compared to healthy controls. The diplotype and MDR analysis showed the high-risk genotypes of BsmI and FokI polymorphisms. Vitamin D deficiency and its association with VDR gene polymorphisms may be useful to identify the high-risk group individuals.