In 1984, hepatitis B vaccination of newborns began in Taiwan. This vaccination program decreased the overall incidence of childhood hepatocellular carcinoma.
In this study, researchers assessed whether the vaccination program had the same effect on both boys and girls. Their findings are published in the January issue of Cancer Epidemiology Biomarkers and Prevention.
The team collected data on liver carcinoma deaths from 1974 to 1999 from the Taiwan Mortality Registry, and from 1974 to 1999 population data from the Taiwan Ministry of Interior. From this they calculated the liver carcinoma mortality rate.
They used population ages 0 to 14 and 15 to 100 in each calendar year, as the study group and the reference group, respectively.
|Liver carcinoma mortality decreased significantly in both males and females after 1984.|
|Cancer Epidemiology Biomarkers and Prevention|
They then divided the 1974 to 1999 calendar years into 4-year strata, and calculated the mortality rates of each 4-year period.
The researchers used the 1980 to 1983 mortality rate as the standard to calculate 4-year-interval mortality rate ratios.
Vaccination effects by age and gender were then estimated, dividing the study, and the reference groups into male and female subgroups.
The team used a double-comparison method to confirm the effects of hepatitis B vaccination:
- The mortality rate trend of the study group (ages 0 to 14) compared with the reference group (ages 15 to100) between 1984 and 1999.
- The mortality rate trend of the study group (age 0 to 14) compared with itself in the pre- and post-vaccination periods (1974 to 1983, 1984 to1999).
The researchers determined that liver carcinoma mortality decreased significantly in both males and females after 1984.
In the study group, the male mortality rate had decreased by 70%, while female mortality decreased by 62%, in the 1996 to 1999 interval, compared with 1980 to 1983.
Both the male and the female study groups' mortality rate trends decreased from 1983 to 1999, compared with the 1974 to 1983 period, or compared with the same period of the reference groups.
Dr Cheng-Liang Lee's team concluded, "Our results indicate hepatitis B vaccination decreases childhood hepatocellular carcinoma in both boys and girls".