Natural acquisition of Helicobacter pylori in adultdyspeptic patients with or without previousinfection—a 7-year follow-up study

Abstract

Background and Aim Epidemiological studies have suggestedthat H. pylori infection is acquired mainly in childhood, but rarely inadults. The aim of this study was to prospectively determine the inci-dence of exposure to Helicobacter pylori and subsequent successful col-onization in adults.Methods A total of 252 dyspeptic patients, 147 with successful H.pylori eradication therapy and 105 without previous H. pylori infec-tion, were scheduled for visits at 3, 6, 12, 18, 24, 30, 36, 48, 60, 72and 84 months. A validated 13C-urea urea breath test and a validatedIgG serological test were used to detect H. pylori status at each visit.Clinical, demographic and socio-economic factors were collected atthe entry of the study.Results Overall, 227 patients were followed up for at least 3months. Of these patients, 30 (13.2%) were exposed to H. pyloriduring the follow-up; 20 with previous H. pylori infection and 10without, giving an annual incidence of 3.2% and 2.6%, respectively.The high crude incidence of exposure to H. pylori was associated witha fewer number of bedrooms at home (OR = 0.38, 95% CI:0.18–0.84, c2= 5.98, P = 0.014), and multivariate analysis alsoshowed that number of bedrooms was the independent risk factor forthe exposure to H. pylori (OR = 0.33, 95% CI: 0.12–0.91, c2= 4.61,P = 0.033). H. pylori successfully colonized in the stomachs of 11patients; 10 with previous H. pylori infection and one without, givingan annual rate of 1.6% and 0.3%, respectively. Kaplan-Meier analy-sis revealed that previous H. pylori infection was associated with sub-sequent successful H. pylori colonization (Log Rank Test, P = 0.042).Conclusion There is a constant exposure to H. pylori in adults,regardless of previous infection. However, the incidence of successfulH. pylori colonization is significantly higher in patients with previousH. pylori infection than in those without the infection.