Epidemiological findings of hepatitis B infection based on 1998 National Health and Nutrition Survey in Korea.

The purpose of this study was to investigate the epidemiological characteristics of hepatitis B virus (HBV) infection in Korea based on the 1998 National Health and Nutrition Survey. Study subjects consisted of 9,771 aged 10 yr or over, who were selected from across Korea using a stratified multistage probability sampling design. The prevalence of hepatitis B surface antigen (HBsAg) was compared by age, sex, residency, household income, education, family history, family size, and frequency of eating out. The prevalence of HBsAg was 5.1% (95% confidence interval (CI): 4.5-5.7) in males and 4.1% (95% CI: 3.6-4.6) in females with a low prevalence in those under 20 yr old. Generally, HBsAg seropositivity by administrative area was similar with the exception of Jeju province. HBsAg seropositivity of Jeju island was approximately three times higher in both men and women, as compared with the national average. HBsAg seropositivity by socioeconomic status unexpectedly showed a very consistent positive association in both gender. Comparing HBsAg seropositivity by the frequency of eating out, in both gender, the more frequent they ate out, the higher it was. Our study suggested that there might be another transmission route of HBV, which is possibly related to diet.