Marijuana smoking is not associated with the promotion of liver disease in subjects coinfected with both hepatitis C and the human immunodeficiency virus (HIV), according to data published online in the journal Clinical Infectious Diseases. Researchers concluded: “[I]n this first prospective evaluation of liver disease progression among HIV-HCV infected persons, we could not demonstrate any important effect of marijuana on liver disease outcomes. A causal association is unlikely: hazard ratios were weak and … there was no dose-response relationship. It is likely that previous studies have been biased by reverse causality as patients use more marijuana to relieve symptoms as liver disease progresses.”