Aim: H. pylori infection is predominantly acquired in early childhood. The aim of the present study was to determine the prevalence of H. pylori infection and to identify factors associated with the infection in Muong children living in Vietnam.

Materials and methods: In a cross-sectional study 918 asymptomatic individuals of all generations living together in the same home were selected from 219 households, based on cluster sampling of residential location in Hoabinh Province, Vietnam. H. pylori infection status was determined by serology test on samples obtained at each visit. A questionnaire was filled out at the start of the study. H. pylori serology data were analyzed using χ2 test and logistic regression models.

Results: An overall H. pylori seroprevalence was 48.8%. H. pylori seroprevalence was 52.1% in adults versus 48.2% in children ≤18 years old (p=0.05). Monthly income more than 50 US/capita, no regularly receiving chewed food and breastfeeding over 12 months were protective factors for H. pylori infection (OR: 0.62, 95% CI: 0.39-0.99); 0.58, (0.34-0.80); 0.58 (0.35-0.94); respectively). Risk factors for H. pylori infection in children were no regularly hand washing after defecation [OR, 38.6; 95% CI: 11.8-126.3), H. pylori infected mothers (OR, 1.34; 95% CI: 1.01-2.32] and infected grandfather (OR, 1.73; 95% CI: 1.01-4.34); father's occupation (OR: 1.38, 95%CI: 1.01-1.98), mother’s education (OR: 2.61, 95%CI: 1.61-4.31) and size of households (OR, 1.46; 95% CI: 1.08-2.68). No other factors such as size of sibling, infected fathers, regular sharing bed, collective life initiation and antibiotic use were found to be significant risk factors for infection.

Conclusion: The first community-based study in Muong population showed familial clustering in multi-generation population and supported the hypothesis of person-toperson transmission in H. pylori infection