Le Tran Ngoan1, Takesumi Yoshimura. 1. Dept. of Clinical Epidemiology, Inst. of Industrial Ecological Sciences, Univ. of Occupational and Environmental, Kitakyushu 807-8555, Japan. letngoan@med.uoeh-u.ac.jp
Abstract
Background: The estimated number of carriers of HBsAg (+) in the world significantly increased from 120 to 350 million from the 1970s to the 1990s. Eighty per cent of liver cancers are estimated to be due to chronic HBV infection. However, only limited data are available regarding liver cancer rates among carriers of HBsAg (+). The aim of the present study was to estimate the incidence of liver cancer among carriers of HBsAg (+) in the general population of Hanoi City, Viet Nam. Method: Data were derived from published reports for incidence of liver cancer (population-based cancer registry), the risk of HBV infection for liver cancer (case-control study), and the prevalence of HBV infection (stratified random sampling of the general population) in the same population of Hanoi City. The Method of Indirect Estimation in a Case Control Study was used in this study. Results: Crude incidence rates per 100,000 were 114 and 37 for carriers of HBsAg (+) in males and females, respectively. The age-standardized incidence rate per 100,000 among carriers of HBsAg (+) for liver cancer was 166 in males and 58 in females, (ASR, world population). The annual incidence of liver cancer among carriers of HBsAg (+) was strongly correlated with increased age in both males and females: the estimated value sharply increased from 6 to 655 per 100,000 for persons aged 0-9 and 50+, respectively, in males. Similarly, the estimated incidence of liver cancer also sharply increased from 8 to 233 per 100,000 for the age groups 10-19 and 50+, respectively, in females. Conclusion: The present results indicate a high age-dependent incidence of liver cancer among carriers of HBsAg (+) in a general population. These results for Hanoi City, Viet Nam point to the magnitude of the problem and provide a basis for intervention.
Background: The estimated number of carriers of HBsAg (+) in the world significantly increased from 120 to 350 million from the 1970s to the 1990s. Eighty per cent of liver cancers are estimated to be due to chronic HBV infection. However, only limited data are available regarding liver cancer rates among carriers of HBsAg (+). The aim of the present study was to estimate the incidence of liver cancer among carriers of HBsAg (+) in the general population of Hanoi City, Viet Nam. Method: Data were derived from published reports for incidence of liver cancer (population-based cancer registry), the risk of HBV infection for liver cancer (case-control study), and the prevalence of HBV infection (stratified random sampling of the general population) in the same population of Hanoi City. The Method of Indirect Estimation in a Case Control Study was used in this study. Results: Crude incidence rates per 100,000 were 114 and 37 for carriers of HBsAg (+) in males and females, respectively. The age-standardized incidence rate per 100,000 among carriers of HBsAg (+) for liver cancer was 166 in males and 58 in females, (ASR, world population). The annual incidence of liver cancer among carriers of HBsAg (+) was strongly correlated with increased age in both males and females: the estimated value sharply increased from 6 to 655 per 100,000 for persons aged 0-9 and 50+, respectively, in males. Similarly, the estimated incidence of liver cancer also sharply increased from 8 to 233 per 100,000 for the age groups 10-19 and 50+, respectively, in females. Conclusion: The present results indicate a high age-dependent incidence of liver cancer among carriers of HBsAg (+) in a general population. These results for Hanoi City, Viet Nam point to the magnitude of the problem and provide a basis for intervention.