Zhou Z, et al. - In this study including extrahepatic cholangiocarcinoma (ECC) cases (n=200) and matched controls (n=200), researchers focused on risk factors for ECC in China. They used conditional logistic regression and estimated odds ratios and 95% confidence intervals. A higher prevalence of cigarette smoking, alcohol drinking, and choledocholithiasis was found in ECC patients vs controls. Current smoking, heavy alcohol drinking, and choledocholithiasis were identified in multivariate analysis as the important risk factors for the development of ECC. Cases and controls did not differ significantly in terms of the prevalence of hepatitis B virus infection and diabetes mellitus. In this study, smoking, alcohol drinking, and choledocholithiasis were documented as positive risk factors for the development of ECC in China.