BACKGROUND: Korea is an epidemic area of hepatitis B. There are needs for longitudinal study to measure quantity of hepatitis B infection status in Korea. This study was designed to observe natural course of hepatitis B markers in the same person for three years. The objective of this study was to investigate incidence of new infection and persistence of previous infection. METHODS: The study subjects were clients who visited a health examination center in Seoul twice with an interval of three years, from 1995 to 2000. They replied as nonvaccinee on both occasions for hepatitis B by self-administered questionnaire. Hepatits B markers were measured by radioimmunoassay on all visits. There were 103 subjects with 61 men and 42 women. RESULTS: The positive rate of hepatitis B surface antigen was 20.4% initially, which changed to 18.5% after three years. The positive rate of hepatitis B surface antigen was 20.4% initially, that was changed as 18.5% after three years. The positive rate of hepatitis B surface antibody was 61.2% initially, which increased to 66.0% after three years. The positive rates of hepatitis B surface antibody in men were 63.9% initially and 68.9% after three years, which showed statistically significant trend. (P=0.08). The positive rate of hepatitis B core antibody was 89.3%, which remained the same after three years. There was no positive conversion case of hepatitis B surface antigen. The negative conversion rate of hepatitis B surface antigen was 2/63(3.2%). The positive conversion rate of hepatitis B surface antibody was 7/40(17.5%), and negative conversion rate of that was 2/63(3.2%). The positive conversion rate of hepatitis B core antibody was 3/11(27.3%), and negative conversion rate of that was 3/92(3.3%). CONCLUSION: Hepatitis B markers changed in the direction of increase of infection incidence, rather than natural disappearance of markers in nonvaccinees. The mechanism was postulated as occurrence of new infection mainly, but the possibility of double infection by variants of hepatitis B virus could not be ruled out. We confirmed that positive rate of hepatitis B marker in males was not only higher cross-sectionally, but also increased higher longitudinally. We suggest a follow-up study of hepatits B markers to be performed because hepatits B markers showed dynamic changes. We think the high risk groups of hepatitis B infection have a priority in follow-up study.
Female ; Follow-Up Studies* ; Hepatitis B Surface Antigens ; Hepatitis B virus ; Hepatitis B* ; Hepatitis* ; Humans ; Incidence ; Korea ; Longitudinal Studies ; Male ; Radioimmunoassay ; Seoul ; Surveys and Questionnaires