Regular coffee drinking is associated with a reduced risk of primary sclerosing cholangitis, an autoimmune liver disease, U.S. researchers say. Study author Dr. Craig Lammert, a Mayo Clinic gastroenterologist, said PSC is an inflammatory disease of the bile ducts that results in inflammation and subsequent fibrosis that can lead to cirrhosis of the liver, liver failure and biliary cancer. \"While rare, PSC has extremely detrimental effects,\" Lammert said in a statement. \"We\'re always looking for ways to mitigate risk, and our first-time finding points to a novel environmental factor that also might help us to determine the cause of this and other devastating autoimmune diseases.\" The study involved a large group of patients with PSC and primary biliary cirrhosis and a group of healthy patients. The study found coffee consumption was associated with reduced risk of PSC, but not PBC. However, PSC patients were much likelier not to consume coffee than healthy patients were. The PSC patients also spent nearly 20 percent less of their time regularly drinking coffee than the control group. Senior author Dr. Konstantinos Lazaridis, a Mayo Clinic hepatologist, said the findings suggested PSC and PBC differ more than originally thought. \"Moving forward, we can look at what this finding might tell us about the causes of these diseases and how to better treat them,\" Lazaridis said.