Molecular Epidemiology of Helicobacter pylori Infection in a Minor Ethnic Group of Vietnam: A Multiethnic, Population-Based Study

Abstract

The Helicobacter pylori-induced burden of gastric cancer varies based on geographical regions and ethnic grouping. Vietnam is a multiethnic country with the highest incidence of gastric cancer in Southeast Asia, but previous studies focused only on the Kinh ethnic group. A population-based cross-sectional study was conducted using 494 volunteers (18-78 years old), from 13 ethnic groups in Daklak and Lao Cai provinces, Vietnam. H. pylori status was determined by multiple tests (rapid urease test, culture, histology, and serology). cagA and vacA genotypes were determined by PCR-based sequencing. The overall H. pylori infection rate was 38.1%. Multivariate analysis showed that variations in geographical region, age, and ethnicity were independent factors associated with the risk of H. pylori acquisition. Therefore, multicenter, multiethnic, population based study is essential to assess the H. pylori prevalence and its burden in the general population. Only the E De ethnicity carried strains with Western-type CagA (82%) and exhibited significantly lower gastric mucosal inflammation compared to other ethnic groups. However, the histological scores of Western-type CagA and East-Asian-type CagA within the E De group showed no significant differences. Thus, in addition to bacterial virulence factors, host factors are likely to be important determinants for gastric mucosal inflammation and contribute to the Asian enigma.

Keywords: Asian enigma; Helicobacter pylori; molecular epidemiology; virulence factor.

Figure 1

Map of Vietnam showing the geographical location and the frequency of the studied minority ethnic groups residing in Daklak and Lao Cai.

Figure 2

H. pylori and histology. (A) The distribution of atrophic gastritis (atrophy) and intestinal metaplasia (IM) based on age groups within H. pylori infected subjects. (B) The distribution of OLGA score (high risk: OLGA 2 and 3, and low risk: OLGA 0 and 1) based on age groups within H. pylori-infected subjects.