Antenatal hepatitis B surface antigen serological status and maternal asthma prevalence

Abstract

The global prevalence of both chronic hepatitis B virus (HBV) infection and asthma vary greatly, and asthma tends to be less common in regions endemic with chronic HBV infection. This retrospective cohort study was conducted to explore the relationship between chronic HBV infection, determined by routine antenatal screening of hepatitis B surface antigen (HBsAg), with asthma history in 145644 gravidae managed in our hospital from 1997 to 2019. Asthma history was present in 1.73% (2528/145644) gravidae, who were slightly but significantly younger, taller, heavier, with more nulliparas, teenagers, and gravidae with medical history, but no difference in incidence of advanced age (≥35 years), short stature (<151 cm), and body mass index (BMI) ≥25 mg/m2 (compatible with the categories of overweight and obesity by World Health Organization criteria), or Chinese ethnicity. Gravidae with asthma had lower prevalence of HBsAg seropositivity (5.8% versus 8.6%, p<0.001), and gravidae with HBV infection had reduced asthma prevalence overall (1.2% versus 1.8%, relative risk (RR) 0.657, 95% confidence intervals (CI) 0.556-0.775), and the association was significant for gravidae at ages 20-34.9 years, and BMI in the normal and overweight categories. Multiple logistic regression analysis confirmed the independent association between maternal HBsAg seropositivity with reduced asthma prevalence (aRR 0.677, 95% CI 0.572-0.801). This finding is in line with the reported reduction of asthma among subjects with childhood infections such as hepatitis A virus and is likely to have contributed to the variably lower prevalence of asthma in Asian countries and Asian immigrants in Western countries.