Association between Body Mass Index and Hepatitis B antibody seropositivity in children

The seropositivity rate of antibodies against hepatitis B surface antigen (anti-HBs) is known to be ≥95% after Hepatitis B virus (HBV) vaccination during infancy. However, low or absence of anti-HBs in healthy children are discovered in many cases. Recent, studies in adults have reported that reduction in the rate of anti-HBs production is related to obesity. The present study investigated whether body mass index (BMI) affects anti-HBs level in healthy children following three serial dose vaccination in infancy. We recruited 1200 healthy volunteers aged 3, 5, 7, or 10 years old from four day care centers and four elementary schools. All the subjects completed a questionnaire including body weight, height, and type of vaccine received. Levels of serum hepatitis B surface antigen (HBsAg) and anti-HBs in all subjects were analyzed using electrochemiluminescence immunoassay. The standardized scores (Z-score) for each gender and age were obtained using the LMS method in the 2017 Korean Child and Adolescent Growth Chart. Our subjects (n=1200) comprised 750 males (62.5%) and 450 females (37.5%). The overall anti-HBs seropositivity rate was 57.9% (695/1200). We identified significant differences in mean BMI values between seronegative and seropositive groups (17.45 vs. 16.62; p