Background: Helicobacter pylori (H. pylori) infection is one of the most common infections world-wide. A cohort effect model has been proposed to clarify the differences in the prevalence among the different age-class with a rate of infection higher in old individuals than in younger ones. The source of bacterial acquisition as well as the mode of transmission (oral-oral or fecal-oral) are still unknown and studies have confirmed the role of socio-economic factors and characteristics of childhood living conditions for the acquisition of H. pylori. In this study we analysed the age and gender-specific prevalence of H. pylori infection in a population of apparently healthy subjects, i.e. blood donors attending the blood bank of our hospital.
Methods: From April 1995 to July 1995, 619 consecutive volunteer blood donors (523 males, 96 females, mean age 47+/-5.3 years, range 18-65 years), attending the Molinette Hospital's Blood Bank (Torino), were recruited. H. pylori seroprevalence was assessed by presence of antibodies (IgG) against the bacterium in serum, by means of a commercial enzyme linked immunosorbent assay (ELISA, Helori-test Eurospital).
Results: The overall H. pylori seroprevalence in the population was 47%: 265/523 males (51%) were seropositive versus 26/96 females (27%) (p<0.0001, OR 2.77 [confidence interval 95% 1.674.61]). When subdivided into sex and decade of age-groups the difference was significative in three subgroups: among male subjects between 20-29 years, male subjects between 40-49 years and male subjects between 50-59 years. The seroprevalence was also significatively higher in older than younger both in males than females.
Conclusions: This study confirms the cohort effect and for a future survey an equilibrated number of persons belonging to the different groups will be planned.