Hepatitis B and C virus, Clonorchis sinensis for the risk of liver cancer: A case-control study in Pusan, Korea

Background. Liver cancer mortality in Korea is the highest in the world. Hepatitis B and C viruses (HBV, HCV) are known to be the major risk factors of hepatocellular carcinoma (HCC). Cholangiocarcinoma (CLG) accounts for more than 20% of liver cancer in the Pusan area. In Korea, the different roles of known risk factors in the development of HCC or CLG have not been adequately evaluated. Methods. Case-control studies involved 203 incident HCC cases, 406 controls matched to the HCC cases for age (+/- 4 years) and sex, and 41 CLG cases (the HCC controls were used). They were carried out from August 1990 to August 1993. Results. Relative risk (RR) of HBsAg (87.4; 95% confidence interval [CI]:22.2-344.3) and RR of anti-HCV positivity (30.3; 95% CI : 6.1-150.6) were significant for the risk of HCC after adjustment for potentially confounding factors. In contrast, RR of Clonorchis sinensis in stool (2.7; 95% CI : 1.1-6.3) and RR of heavy drinking (4.6; 95% CI : 1.4-15.2) were significant for the risk of CLG. Transfusion history, acupuncture history, and cigarette smoking were not associated with the risk of HCC or CLG. Conclusions. Strong evidence indicated that both HBV and HCV infection were independent risk factors for HCC. In contrast, C. sinensis in stools and heavy drinking were associated with the risk of CLG in Korea.