Sex, Age, and Race are Associated With Increased Risk of Exposure to Hepatitis E in the USA

Abstract

Introduction: Little is known of epidemiology of hepatitis E (HEV) in the USA. We sought to examine the association between demographic variables such as age, sex, and race and the risk of exposure to HEV in a large sample of the U.S. population. Methods: Ddata from the last 2 cycles of NHANES from 2009-2012 were combined and analyzed. The NHANES is a nationally representative survey of non-institutionalized participants with oversampling of certain minorities. Weighted estimates were calculated and reported. Logistic regression was used to assess associations and control for potential interactions. Participants were categorized into 4 age groups: A1: <20 years, A2: 20-39 years, A3: 40-59 years, and A4: >60 years. Race was categorized as R1: Mexican, R2: other Hispanic, R3: non-Hispanic white, R4: non-Hispanic black, and R5: other/multi-racial. Results: Testing for anti-HEV IgG and IgM was performed on the sera of 14,951 participants (50.2% female). HEV IgG Ab was positive in 5.9% of participants (95% confidence interval [CI] 5.2-6.6), while IgM Ab was positive in 1.1% of participants (95% CI: 0.8-1.4%), and both were positive in 0.37% (95% CI: 0.18, 0.55). Female gender was associated with increased prevalence of positive anti-HEV IgM (odds ratio [OR] 1.55; 95% CI 1.12-2.14), but not IgG (OR 1; 95% CI 0.81-1.23). Conversely, older age was associated with increased prevalence of anti-HEV IgG. The OR of being positive for IgG (compared to A1) was 28.22 for A4 (95% CI 15.79-50.44), 12.62 for A3 (95% CI 6.48-24.61) and 3.98 for A2 (95% CI 2.06-7.68). There was marginal association between age and IgM positivity (OR 1.77; 95% CI 0.98-3.22). R3 and R5 races had significantly higher prevalence of anti-HEV IgG and IgM than other races. However, after controlling for age and sex, there was no association between race and anti-HEV IgM. In addition, R2, R3, and R4 were significantly associated with lower prevalence of positive anti-HEV IgG with OR of 0.58 (95% CI 0.34-0.98), 0.63 (95% CI 0.46-0.86), and 0.42 (95% CI 0.28-0.63), respectively. Conclusion: Recent and remote exposure to HEV is significantly influenced by sex, age, and race. Females had higher prevalence of anti-HEV IgM and risk of exposure increased with age significantly. When controlled for age and sex, Mexican American and multi-race groups appear to have higher exposure rate compared to other races.