Trends in the incidence of hepatocellular carcinoma in boys and girls in Taiwan after large-scale hepatitis B vaccination.

Abstract

In July 1984, large-scale hepatitis B vaccination of newborns began in Taiwan. Vaccination decreased the overall incidence of childhood hepatocellular carcinoma (HCC). We conducted this study to learn whether the vaccination program had the same effect on boys and girls. We collected liver carcinoma (including HCC and hepatoblastoma) deaths from 1974 to 1999 from the Taiwan Mortality Registry and the 1974-1999 population data from the Taiwan Ministry of Interior to calculate the liver carcinoma mortality rate. The populations ages 0-14 and ages 15-100 in each calendar year were treated as the study group and the reference group, respectively. We divided the 1974-1999 calendar years into 4-year strata and calculated the mortality rates of each 4-year period. We used the 1980-1983 mortality rate as the standard to calculate 4-year-interval mortality rate ratios. Vaccination effects by age and gender were estimated dividing the study and the reference groups into male and female subgroups. We used a double-comparison method to confirm the effects of hepatitis B vaccination: the mortality rate trend of the study group (ages 0-14) compared with the reference group (ages 15-100) in the same period (1984-1999), and the mortality rate trend of the study group (age 0-14) compared with itself in the pre- and postvaccination periods (1974-1983, 1984-1999). Liver carcinoma mortality decreased significantly among both males and females after 1984. In the study group, the male mortality rate decreased by up to 70%, and the female mortality rate decreased by up to 62% in the 1996-1999 interval compared with the 1980-1983 period. Both the male and the female study groups' mortality rate trends decreased from 1983 to 1999 compared with the 1974-1983 period or compared with the same period of the reference groups. Our results indicate hepatitis B vaccination decreases childhood HCC in both boys and girls.