[Correlation between hepatitis B virus infection and chronic liver disease in Okinawa]

In Okinawa prefecture, prevalence of hepatitis B surface antigen (HBsAg) among blood donors is 3.5% and is twice as high as the average for the whole of Japan (1.5%), and is the highest in Japan (p less than 0.005). In contrast, mortality rates of both liver cirrhosis (LC) and primary liver cancer (PLC) in Okinawa are the lowest in Japan. Many epidemiological studies have shown that the positive rate of HBsAg correlates with mortality rate of PLC. To elucidate the cause of this epidemiological discrepancy, cross-sectional seroepidemiological studies and a prospective clinical study were conducted. In the cross-sectional studies, the following results were obtained; (1) Positive rate of HBsAg among patients with LC in Okinawa was 15.2% and lower than the average for the whole of Japan (23.4%). A similar comparison among patients with hepatocellular carcinoma showed 24.4% in Okinawa Vs. 31.4% in the whole of Japan. (2) The age-specific hepatitis B e antigen positive rate among 829 HBsAg positive health examinees tend to decrease with increase in age; 50% in less than 20 years old age group, 15.7% in third decade and 2-3% or less in 30 or more age group. Of the 829, 431 HBsAg positive subjects were referred our liver out-patient clinic. Then, of the 431, 27 (6.3%) were diagnosed or suspected as having chronic hepatitis and one (0.2%) was diagnosed as having cirrhosis. Of the 431, 381 (88.4%) were diagnosed as healthy HBsAg carrier, the great majority (94.0%) of whom had positive reaction of anti-HBe antibody and normal values of both GOT and GPT.(ABSTRACT TRUNCATED AT 250 WORDS)