Review
Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jan 28, 2018; 24(4): 445-460
Published online Jan 28, 2018. doi: 10.3748/wjg.v24.i4.445
Vitamin D deficiency and hepatitis viruses-associated liver diseases: A literature review
Nghiem Xuan Hoan, Hoang Van Tong, Le Huu Song, Christian G Meyer, Thirumalaisamy P Velavan
Nghiem Xuan Hoan, Le Huu Song, Institute of Clinical Infectious Diseases, 108 Military Central Hospital, Hanoi 10004, Vietnam
Nghiem Xuan Hoan, Christian G Meyer, Thirumalaisamy P Velavan, Molecular Genetics of Infectious Diseases, Institute of Tropical Medicine, University of Tübingen, Tübingen 72074, Germany
Nghiem Xuan Hoan, Hoang Van Tong, Le Huu Song, Christian G Meyer, Thirumalaisamy P Velavan, Vietnamese-German Center of Medical Research (VG-CARE), Hanoi 10004, Vietnam
Hoang Van Tong, Institute of Biomedicine and Pharmacy, Vietnam Military Medical University, Hanoi 10004, Vietnam
Christian G Meyer, Thirumalaisamy P Velavan, Medical Faculty, Duy Tan University, Da Nang, Vietnam
Author contributions: Meyer CG and Velavan TP shared senior authorship; Hoan NX, Tong HV, Song LH, Meyer CG and Velavan TP searched the publications, extracted data, summarized data in tables and discussed the literature and wrote the review; all authors approved the final version of this review.
Conflict-of-interest statement: We declare that we have no conflicts of interest.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Thirumalaisamy P Velavan, PhD, Professor, Molecular Genetics of Infectious Diseases, Institute of Tropical Medicine, University of Tübingen, Wilhelmstrasse 27, Tübingen 72074, Germany. velavan@medizin.uni-tuebingen.de
Telephone: +49-7071-2985981 Fax: +49-7071-294684
Received: November 28, 2017
Peer-review started: November 29, 2017
First decision: December 13, 2017
Revised: January 8, 2018
Accepted: January 16, 2018
Article in press: January 16, 2018
Published online: January 28, 2018
Abstract

The secosteroid hormone vitamin D has, in addition to its effects in bone metabolism also functions in the modulation of immune responses against infectious agents and in inhibiting tumorigenesis. Thus, deficiency of vitamin D is associated with several malignancies, but also with a plethora of infectious diseases. Among other communicable diseases, vitamin D deficiency is involved in the pathogenesis of chronic liver diseases caused by hepatitis B and C viruses (HBV, HCV) and high prevalence of vitamin D deficiency with serum levels below 20 mg/mL in patients with HBV and HCV infection are found worldwide. Several studies have assessed the effects of vitamin D supplementation on the sustained virological response (SVR) to interferon (IFN) plus ribavirin (RBV) therapy in HBV and HCV infection. In these studies, inconsistent results were reported. This review addresses general aspects of vitamin D deficiency and, in particular, the significance of vitamin D hypovitaminosis in the outcome of HBV- and HCV-related chronic liver diseases. Furthermore, current literature was reviewed in order to understand the effects of vitamin D supplementation in combination with IFN-based therapy on the virological response in HBV and HCV infected patients.

Keywords: Vitamin D, Vitamin D deficiency, Chronic liver disease, Hepatitis B virus infection, Hepatitis C virus infection, Liver cirrhosis, Hepatocellular carcinoma, Sustained virological response, Vitamin D supplementation

Core tip: Vitamin D deficiency is common and associated with chronic liver diseases. Several studies have ascribed a strong association of vitamin D insufficiency with unfavorable clinical courses and progression of liver disease in hepatitis B virus (HBV) and hepatitis C virus (HCV) infections. However, any causal relation is so far not fully understood. In addition, there are inconsistent results with regard to the impact of vitamin D supplementation on the virological response to IFN-based therapy; this applies particularly to HCV infections. The present review addresses general aspects of vitamin D deficiency and focuses on its association with HBV and HCV infection. Furthermore, the effects of vitamin D supplementation in combination with IFN-based therapy on the virological response in HBV and HCV infected patients are reviewed.