Research ArticleVitamin D deficiency and a CYP27B1-1260 promoter polymorphism are associated with chronic hepatitis C and poor response to interferon-alfa based therapy

Background & AimsVitamin D is an important immune modulator and preliminary data indicated an association between vitamin D deficiency and sustained virologic response (SVR) rates in hepatitis C virus (HCV) genotype 1 patients. We, therefore, performed a comprehensive analysis on the impact of vitamin D serum levels and of genetic polymorphisms with functional relevance within the vitamin D cascade on chronic hepatitis C and its treatment.MethodsVitamin D serum levels, genetic polymorphisms within the vitamin D receptor and 1α-hydroxylase were determined in a cohort of 468 HCV genotype 1, 2, and 3 infected patients who were treated with interferon-alfa based regimens.ResultsChronic hepatitis C was associated with a high incidence of severe vitamin D deficiency compared to controls (25(OH)D3 <10 ng/ml in 25% versus 12%, p <0.00001). 25(OH)D3 deficiency correlated with SVR in HCV genotype 2 and 3 patients (50% and 81% SVR for patients with and without severe vitamin D deficiency, respectively, p <0.0001). In addition, the CYP27B1-1260 promoter polymorphism rs10877012 had substantial impact on 1,25-dihydroxyvitamin D serum levels (72, 61, and 60 pmol/ml for rs10877012 AA, AC, and CC, respectively, p = 0.04) and on SVR rates in HCV genotype 1, 2, and 3 infected patients (77% and 65% versus 42% for rs10877012 AA, AC, and CC, respectively, p = 0.02).ConclusionsChronic hepatitis C virus infection is associated with vitamin D deficiency. Reduced 25-hydroxyvitamin D levels and CYP27B1-1260 promoter polymorphism leading to reduced 1,25-dihydroxyvitamin D levels are associated with failure to achieve SVR in HCV genotype 1, 2, and 3 infected patients.