Vitamin D level and vitamin D receptor genetic variations contribute to HCV infection susceptibility and chronicity in a Chinese population

Vitamin D and vitamin D receptor (VDR) are involved in multiple immune-mediated disorders including chronic hepatitis C virus (HCV) infection. The aim of this study was to determine the association between plasma vitamin D level, VDR genetic polymorphisms and risk of HCV infection susceptibility and chronicity. Seven single nucleotide polymorphisms (SNPs) in VDR gene were genotyped and plasma 25-hydroxyvitamin D [25(OH)D] levels were measured in a Han Chinese population of 898 HCV persistent infection cases, 558 spontaneous clearance subjects and 1136 uninfected controls with high risk of HCV infection. In this case–control study, the average plasma 25(OH)D level in persistent infection patients was significantly lower than that in spontaneous clearance cases (P=0.039) and controls (P=0.005). Logistic analyses indicated that rs7975232-C, rs2239185-T and rs11574129-T alleles were significantly associated with a decreased risk of HCV infection susceptibility (all PBonferroni<0.05, in additive/dominant models; Ptrend=9.000×10−4, combined effects in a locus-dosage manner). The protective effects of three favorable alleles were more evident among males, females and subjects aged ≤50years (all P<0.05). Haplotype analyses suggested that compared with the most frequent haplotype Ars7975232Trs731236Crs11574129, CTT was correlated with a reduced risk of HCV infection susceptibility (P=2.200×10−3). These findings implied that low vitamin D levels might be associated with an increased risk for HCV infection and chronicity, and favorable VDR variants (rs7975232-C, rs2239185-T and rs11574129-T) might contribute to a decreased susceptibility to HCV infection in a high-risk Chinese population.