Objective: To explore the potential role of vitamin D receptor (VDR) gene and natural-resistance-associated macrophage protein 1 (NRAMP1) gene polymorphisms in susceptibility to pulmonary tuberculosis (PTB) in the Chinese Han population.
Design: In an unmatched case-control study, 120 well defined PTB patients and 240 unrelated normal controls were enrolled. Information on potential risk factors of PTB was collected using a standard questionnaire. Genetic polymorphisms of VDR gene (TaqI and FokI) and NRAMP1 gene (INT4, D543N and 3'UTR) were analysed using PCR and RFLP. Unconditional logistic regression was performed, and odds ratios (ORs), their 95% confidence intervals (CI) and P values were estimated using maximum likelihood methods.
Results: Univariate analysis demonstrated that FokI-ff homozygotes, D543N G/A and 3'UTR TGTG+/del heterozygotes occurred more frequently in patients than in controls. The crude ORs were 2.345 (95%CI 1.222-4.499), 2.590 (95%CI 1.043-6.434) and 1.890 (95%CI 1.171-3.051), respectively, compared with their corresponding common genotypes. The P values were 0.033, 0.041 and 0.030, respectively. After adjusting for exposure history and BCG immunisation in the multivariate analysis, the adjusted ORs were 4.625 (95%CI 1.737-12.312), 2.415 (95%CI 1.079-8.759) and 2.187 (95%CI 1.146-4.175), with P values of 0.002, 0.036 and 0.018, respectively. Neither univariate nor multivariate analysis disclosed any significant association between the disease and TaqI or INT4.
Conclusions: Polymorphisms in the VDR and NRAMP1 gene are statistically associated with susceptibility to PTB in the Chinese Han population.