What groups of people are most at risk of developing cholangiocarcinoma?

Several groups. The following is a partial list of conditions that some studies (but not necessarily all) have found to be associated with an increased risk for cholangiocarcinoma (cancer of bile ducts).Chronic liver disease (eg from hepatitis c or alcohol), gallstones, hepatolithiasis (liver stones), primary sclerosing cholangitis, liver fluke infection, obesity, diabetes, congenital bile duct cysts, others...
Cholangiocarcina. People with chronic inflammatory state of the bile duct, genetics susceptibility and with some infection.