Hepatitis C Virus infection is a widespread condition that affects up to 170 million people worldwide. Liver cirrhosis and hepatocellular carcinoma are well-known complications of Hepatitis C Virus infection, but problems outside the liver develop in up to two-thirds of patients with Hepatitis C Virus.
Up to 30% of patients with Hepatitis C Virus have insulin resistance or T2D and patients with Hepatitis C Virus are 1.5 to 3.8 times as likely to have T2D than the general population. Patients with Hepatitis C Virus who are at high risk for T2D due to non-Hepatitis C Virus-related risk factors have an 11-fold greater risk of developing T2D than individuals without Hepatitis C Virus. Epidemiological data largely support the association between Hepatitis C Virus infection and T2D.
Several hypotheses have been proposed to explain how Hepatitis C Virus infection might increase the risk for T2D. According to Dr Tomer, co-author of the study, one way Hepatitis C Virus might influence the development of T2D is through promoting inflammation. “We know that inflammation is associated with T2D, and one hypothesis is that the virus causes inflammation by inducing cytokines, which are inflammatory mediators.”
Another hypothesis is that viral replication within infected cells may disturb normal insulin signaling, particularly in the liver, Dr Tomer said. He added that Hepatitis C Virus may also induce reactive oxygen species and create oxidative stress in the liver, disrupting glucose metabolism and glucose homeostasis.
Lastly, Hepatitis C Virus may not only infect liver cells, but also the pancreatic islet beta cells that secrete insulin, according to Dr Tomer. “Some studies have shown virus-like particles inside the islets,” he said. “But just seeing virus particles does not prove that Hepatitis C Virus infects islet cells. Hepatitis C Virus could be attaching to the cells and not actually infecting them. But this is a very intriguing hypothesis if indeed the virus can somehow cause direct infection of the pancreatic islets.”
 Desbois, Cacoub: Diabetes mellitus, insulin resistance and hepatitis C virus infection: A contemporary review in World Journal of Gastroenterology - 2017
 Hammerstad et al: Diabetes and hepatitis C: a two-way association in Frontiers in Endocrinology - 2015
 Gastaldi et al: Current level of evidence on causal association between hepatitis C virus and type 2 diabetes: A review in Journal of Advanced Research – 2017. See here.