Hepatitis B virus and cigarette smoking: risk factors for hepatocellular carcinoma in Hong Kong.

One hundred seven Chinese patients with primary hepatocellular carcinoma (PHC) were compared with 107 hospital controls for the presence of hepatitis B surface antigen and smoking, drinking, and dietary habits. Eighty-two % of PHC cases were hepatitis B surface antigen positive compared to 18% of controls (relative risk, 21.3; 95% confidence limits, 10.1 and 45.9). Prior history of jaundice was significantly related to PHC, independent of hepatitis B surface antigen status. There was a significant association between cigarette smoking and PHC negative for hepatitis B surface antigen. The relative risk of hepatitis B surface antigen-negative PHC for heavy smokers (20 + cigarettes/day) was 3.3 compared to light smokers and nonsmokers (95% confidence limits, 1.0 and 13.4). Our data indicated that infection by the hepatitis B virus and cigarette smoking were independent risk factors for PHC.