Objective: Hepatitis B is a major public health problem in China. However, in the past 10 years, estimates of the prevalence of hepatitis B virus (HBV) have been sparse, with results that do not always agree. The purpose of this study was to investigate the epidemiology of HBV in adults and to provide the most recent baseline data for planning and monitoring of health.
Methods: The prevalence of HBV was determined in a community-based, cross-sectional, age-stratified sample of adults (aged 20 years or older). The study population was selected using random multistage cluster sampling. Demographic information and serological samples were obtained from 19 933 participants.
Results: The prevalence of anti-HBV core antibody, HBV surface antigen (HBsAg), and anti-HBV surface antibody was 38.6, 7.9, and 44.9%, respectively. We found statistically significant differences in hepatitis B infection between men and women (P<0.001). The prevalence of HBV infection increased with age. The rates of HBsAg positivity and HBV infection in individuals living on an island were higher than those of individuals living in plains. The alanine aminotransferase level was elevated (≥38 IU/l) in 15.7 and 7.2% of HBsAg-positive and HBsAg-negative patients; the proportion of elevated alanine aminotransferase was markedly higher in men (12.7%) than in women (4.7%) (P<0.001). The α-fetoprotein-positive rate was 2% in HBsAg-positive individuals who were aged 30 years or older.
Conclusion: Borderline intermediate/high endemicity was found among adults in the northern region of Zhejiang Province. The vaccination program has contributed to a reduction in infection over the last 20 years, although further efforts are required to turn the region into a 'low-endemicity' area.