Seroprevalence of hepatitis A virus and Helicobacter pylori infections in the general population of a developed European country (the San Marino study): evidence for similar pattern of spread.

Objective: To evaluate the role of faecal-oral transmission in the spread of Helicobacter pylori. Design: A cross-sectional comparison of the patterns of hepatitis A and H. pylori seropositivity. Methods: At interview, blood samples and questionnaire data were collected from a random sample of 1528 healthy subjects aged 20-85 years from the Republic of San Marino. Serum samples from each subject were then tested for anti-H. pylori and anti-hepatitis A antibodies. Results: Overall, 529 of 670 H. pylori-seropositive subjects (78.9%) and 460 of 858 H. pylori-seronegative subjects (53.6%) were hepatitis A seropositive (P < 0.01; odds ratio = 3.2; confidence interval 95% = 2.6-4.1). This association remained after adjustment by a multiple logistic regression analysis for the confounding effect of age and length of schooling, as surrogate for socio-economic status (OR = 2.0; CI 95% = 1.3-3.3). The age-specific prevalence curves for H. pylori and hepatitis A infections showed a parallel increase by age, although to a lesser extent for H. pylori. Conclusion: These findings provide evidence that in the community studied H. pylori may have spread in a manner similar to that of hepatitis A.