Association of hepatitis A virus infection with allergic sensitization in a population with high prevalence of hepatitis A virus exposure.

Background:  An inverse association between allergic sensitization and markers of exposure to food-borne and orofecal infections (particularly hepatitis A virus, HAV) has been reported. The prevalence of HAV exposure and allergic sensitization vary widely in different areas, and vary along with age within a given area. Aim:  To investigate the association between HAV exposure and allergic sensitization in adults from a mostly rural area of Spain. Methods:  An age-stratified random sample of 720 subjects was drawn from the population older than 18 years of A-Estrada, Spain. From 697 eligible subjects, 469 (67.2%, median age 54 years, range: 18–92) participated in the study. Positive skin prick tests to a panel of aeroallergens defined allergic sensitization. Positive serum HAV antibodies (assayed in 465 subjects) defined HAV exposure. Results:  The prevalence of HAV exposure was 83.6% (95% CI: 80.7–86.5). The prevalence of allergic sensitization was lower in subjects with HAV exposure than in patients without it (25.0%vs 40.0%, OR 0.44, 95% CI: 0.25–0.77, P = 0.004), but this association became substantially altered after adjusting for age, which was closely linked to both allergic sensitization and HAV exposure (adjusted OR 1.15, 95% CI: 0.60–2.19, P = 0.66). Conclusions:  In a population with high prevalence of HAV exposure, no significant association between HAV exposure and allergic sensitization is observed after controlling for the confounding effect of age.