Ten-Year Changes in the Hepatitis B Prevalence in the Birth Cohorts in Korea: Results From Nationally Representative Cross-Sectional Surveys

To compare the prevalence of hepatitis B virus (HBV) infection over a 10-year period in terms of population-level trends, we established hypothetical birth cohorts that represented each 10-year interval age group. We used data from the Korean National Health and Nutrition Examination Surveys conducted between 1998 to 2001 and 2008 to 2011. Trends in the HBV infection were calculated using data from individuals aged 20 to 59 years in 1998 to 2001 and those aged 30 to 69 years in 2008 to 2011. In 2008 to 2011, the prevalence of HBV infection, as measured using serum HBV surface antigen (HBsAg) seroprevalence, among participants aged 30 to 69 years was 4.2% (95% CI = 3.7–4.7%), which represents a 1.3% absolute change and 20% change in prevalence ratio, which was significant compared with the prevalence among those aged 20 to 59 years in 1998 to 2001 (5.5%, 95% CI = 4.7–6.3%). The prevalence of HBV infection decreased most in the lowest income group, with marginal significance in males (P = 0.06) and significance in females (P = 0.03). In terms of education, females with at least a high school education showed a significant decrease (P = 0.03). Using a birth cohort approach, the prognosis for HBV infection in terms of death or hospitalization, or resolution upon antiviral treatment of their HBV infections, identified by a decrease in the HBsAg seroprevalence was worse in the lower income group and in females with higher education. We postulate that these socioeconomic inequalities were caused by alcohol consumption, disparities in liver cancer surveillance, and access to antiviral treatment because of cost and reimbursement guidelines.