Epidemiology of Helicobacter pylori in Bhutan: The Role of Environment and Geographic Location

BACKGROUND: Bhutan is small mountainous country bordering India and China and consists of four geographic regions, west, east, central, and south. The epidemiology of Helicobacter pylori infection and risk factors associated with in Bhutan are not previously studied. The World Health Organization reported the incidence of stomach cancer to be very high in Bhutan. AIM: We conducted a cross-sectional study to determine the seroepidemiologic pattern of H. pylori among Bhutanese from the four regions with emphasis on water source and household sanitation. METHODS: Between June and November 2012, blood samples from patients with complaints of dyspepsia were collected after obtaining an informed consent. Demographic information, occupation, family size living in the same household, consumption of betel nut, and aspects of household environment including type of latrines, source of drinking water were collected. All serum samples were tested for H. pylori immunoglobulin G (IgG) by enzyme-linked immunosorbent assay (ELISA) using MAGIWELL ELISA kit from United Biotech, USA. RESULTS: Two hundred and forty-four patients between 17 and 75 years of age participated in the study, of them, 102 were men, and the mean age was 38 (±14.2) years. The overall prevalence of H. pylori among patients was 86% with no difference between men and women (90 vs 83%, respectively, p = .12). The prevalence was almost identical among all age groups: 81% at 17-20, 84% at 20-29, 93% at 30-39, 82% at 40-49, 87% at 50-59, and 82% at ≥60 years (p = .51). H. pylori prevalence was lower in the southern region of Bhutan (78%) compared with the central region (97%) (OR = 8.6; 95% CI = 1.1-55; p = .02), eastern region (91%) (OR = 2.7; 95% CI = 1.1-7.2, p = .004) or the western region (83%) (OR = 1.4, 95% CI = 0.8-3.1, p = .07). The prevalence of H. pylori was significantly lower among household with less than 4 persons living in the same household. Source of drinking water, type of occupation, type of latrines, or consumption of betel nut showed no association with H. pylori prevalence. Logistic regression analysis revealed that residing region was the only significant variable. CONCLUSIONS: The high prevalence of antibodies to H. pylori among patients and in all groups could contribute to the high incident rate of gastric cancer in Bhutan. Crowded living condition and the residing region contribute to the variation of the prevalence of the infection. The lowest prevalence in southern part of the country could be due to the difference in the ethnicity as most of its population is of Indian and Nepal origin. Further data regarding H. pylori in Bhutan are critical to developing surveillance and prevention strategies for gastric cancer.