Although around 170 million people worldwide are currently infected with hepatitis C virus (HCV), its course is still not well understood. Predicting the course of infection is essential to deciding who and when to treat with the powerful available drugs—pegylated interferons and ribavirin—and anticipating the need for liver transplants and other interventions for end stage liver disease.

Several factors influence the clinical course of HCV infection. Being older than 40 at the time of infection, male sex, coinfection with hepatitis B virus or HIV, steatohepatitis, immunosuppression, and predisposing human leukocyte antigen (HLA) haplotypes have all been associated with progression of fibrosis and possible development of cirrhosis. The main risk factor for faster progression to cirrhosis in HCV infection remains, however, the consumption of alcohol.1 2 Moreover, many intravenous drug users, the main population still at risk of HCV infection in developed countries, consume alcohol regularly.

Despite this evidence about risk factors, studies of the course of HCV infection have so far led to conflicting conclusions, …