Follow‐up study of hbs ag‐positive blood donors with special reference to effect of drinking and smoking on development of liver cancer

Abstract

In order to confirm the close association between chronic hepatitis B virus (HBV) infection and primary hepatocellular carcinoma (PHC) in Japan, 8,646 male hepatitis B surface antigen (HBs Ag)-positive blood donors (GPT ± 35 Karmen units) were followed up. Twenty liver cancer cases were observed during the follow-up period (average 6.2 years), the expected number calculated on the basis of age-specific incidence rates among the general population being 3.03. Therefore, the observed to expected ratio of liver cancer was 6.60, that is significantly higher than 1.0. During the same follow-up period, a total of 76 deaths were observed, of which 20 were due to liver cancers and 9 to liver cirrhoses, meaning that nearly 40% of deaths among the study subjects due to chronic liver diseases. Drinking and smoking habits in the liver cancer cases were compared with those observed in healthy male HBV carriers. A strong positive association between drinking habits and liver cancer was observed and there was a significant dose-response relationship after adjustment for cigarette smoking habits. A high risk of liver cancer was also observed among heavy smokers, but a significant dose-response relationship could not be found between smoking habits and liver cancer, partly because of the limited number of the study subjects. These findings suggest that HBV is a major etiologic agent of PHC in Japan where the HBs Ag prevalence rate is about 2%, and alcohol drinking and cigarette smoking may promote the process of HB viral hepato-carcinogenesis.