Classical and Emerging Roles of Vitamin D in Hepatitis C Virus Infection

Abstract

The risk of clinically-significant vitamin D deficiency increases at 25-hydroxyvitamin D levels below 20 ng/mL, according to the Institute of Medicine. By this standard, most cirrhotic hepatitis C virus (HCV)-positive patients and many non-cirrhotic patients are vitamin D deficient. The high prevalence of vitamin D deficiency among HCV patients is a cause for concern for several specific reasons. Classic studies established the importance of vitamin D and calcium in maintaining bone. Vitamin D's beneficial effects on bone are likely to be vital for HCV-infected patients because these individuals have a high prevalence of low bone mineral density. Many pharmaceutical agents reduce bone density and exposure to these drugs may increase bone disease in HCV-positive patients. Bone loss occurs following liver transplantation and bone density is often low in patients with HIV/HCV co-infection who are on combination antiretroviral therapy. Some evidence suggests that ribavirin reduces bone density, underscoring the special need to monitor vitamin D in patients receiving HCV treatment and to prescribe supplements, as appropriate. In addition to its role in calcium metabolism, vitamin D is also an immune modulator that reduces inflammation while enhancing protective immune responses. Higher vitamin D levels are associated with less liver fibrosis and less inflammation in HCV patients. Recent studies show that low vitamin D levels are associated with treatment failure among HCV-infected patients receiving pegylated-interferon and ribavirin. If confirmed, these findings will provide an additional reason to ensure adequate levels of vitamin D. The article concludes with information about how to monitor vitamin D status and how to use vitamin D supplements most effectively in HCV-infected patients.

Is there an association between vitamin D and liver fibrosis in patients with chronic hepatitis C?

“…Some studies examined the relationship between the vitamin D serum level and the progression of the disease in patients with chronic hepatitis C (5,10,12) , but this is a controversial issue.…”

“…Some studies show that vitamin D serum levels are inversely related to liver fibrosis, showing a relationship between the anti-inflammatory effects (10,14,20) . Thus, vitamin D deficiency could contribute to a (5) .…”

Impact of host gene polymorphisms on susceptibility to chronic hepatitis B virus infection

“…Further, Bellamy showed that homozygotes genotype tt for a polymorphism at codon 352 were significantly lower among those with persistent hepatitis B infection compared to the other genotypes. Gutierrez et al (2011) reported that vitamin D improve immune responses of the host against infection with HCV. On the other hand, Garcıa-Martın et al (2013) showed that rs2228570TC polymorphism in vitamin D receptor gene is a good predictor of the outcome of PEG-IFN/RBV therapy in HCV patients.…”

Mechanisms of Virologic Failure with Direct-Acting Antivirals in Hepatitis C and Strategies for Retreatment

“…36 Vitamin D status was previously shown to be associated with SVR rates; however, it is not known whether vitamin D or other predictors of IFN response will consistently impact IFN-free therapy. 37 …”