Abstract: Objective To investigate the infection of different virulent strains of Helicobacter pylori (H. pylori) in the Tibetan population of the Tibet Autonomous Region and the correlation between the genotyping of different virulent strains and upper gastrointestinal diseases, such as chronic gastritis, intestinal metaplasia, and peptic ulcers. Methods The data of H. pylori infected patients who were admitted to the digestive department of Lassa people's Hospital from April 2019 to December 2020 were collected, including gender, age, occupation, serum H. pylori antibody typing test and gastroscopy and pathological examination results. Correlations between the different toxin typing and the patients' clinicopathological characteristics were analyzed. Results The majority of H. pylori infected in the Tibetan population of the Tibet Autonomous Region were hypervirulent type Ⅰ strains (CagA and/ or VacA antibody positive), accounting for 56.8%, and the proportion of type Ⅱ strains (both CagA and VacA antibody negative) was 43.2%. There were no significant differences between the CagA and VacA antibody positive population and the CagA and VacA antibody negative population in the prevalence of chronic non atrophic gastritis (49.7% vs 44.2%), atrophic gastritis and intestinal metaplasia (17.1% vs 22.9%), or peptic ulcer (33.2% vs 32.9%) (P>0.05). When stratified by age, patients older than 40 years were more prone to suffer from chronic atrophic gastritis and intestinal metaplasia (62% vs 44%, P=0.002), whereas prevalence of peptic ulcer was higher in patients younger than 40 years (40% vs 25%, P<0.001). When stratified by occupation, the prevalence of peptic ulcer was higher among non-farmers and herdsmen than among farmers and herdsmen (39% vs 30%, χ²=5.342,P=0.027); However, the prevalence of chronic nonatrophic gastritis, atrophic gastritis and intestinal metaplasia did not differ significantly among different occupational populations (P>0.05). Conclusions In this study, the majority of H. pylori infection in the Tibetan population of the Tibet Autonomous Region was the hypervirulent type I strain, but no significant differences were found in the prevalence among patients infected with different virulent strains in the upper gastrointestinal diseases, such as chronic nonatrophic gastritis, atrophic gastritis and intestinal metaplasia, and peptic ulcer. In H. pylori infected patients, the prevalence of chronic atrophic gastritis and intestinal metaplasia increased with age, while the prevalence of peptic ulcers was higher in younger age groups and in non-farmers and herdsmen.

Key words: Helicobacter pylori antibody typing, atrophic gastritis, intestinal metaplasia, peptic ulcer