Helicobacter pylori infection in asymptomatic rural Bangladeshi population

Background and objectives: The prevalence of Helicobacter pylori infection differs in urban and rural population. In our country, no previous study investigated the H. pylori infection in rural population. The aim of the present study was to find out the status of H. pylori infection among the Bangladeshi asymptomatic rural adult population. Material and Methods: This cross-sectional study was carried out in a rural area located about 40 km north-east of capital Dhaka. Apparently healthy non-diabetic, pre-diabetic and diabetic adults (18 years and above) were enrolled in this study. A structured questionnaire was developed to record the socio-demographic and clinical information. H. pylori infection status was determined by the presence of antiH. pylori IgG antibody in blood. Serum anti-H.pylori IgG antibodies were determined by immunochromatographic test (ICT) method. Results: A total number of 180 apparently healthy adult individuals were enrolled of which 112, 40 and 28 were non-diabetic, pre-diabetic and diabetic respectively. Out of 180 individuals, antiH. pylori IgG was present in 70 (38.9%, CI: 32.1, 46.2) cases. Infection rate was 50%, 27.5% and 43.5% in 19-30, 31-50 and >50 years age group respectively. Infection rate was significantly (p< 0.05) low in 31-50 years age group compared to 19-30 and > 50 years age groups. H. pylori infection rates in male and female were 42.6% (CI: 29.2, 56.8) and 37.3% (CI: 28.9, 46.4) respectively (p=0.50). There was no significant (p>0.05) association of H. pylori infection with economic status, education level, occupation and tobacco consumption of the study population. The rate of H. pylori infection in non-diabetic, pre-diabetic and diabetic individuals were not significantly different from each other. Conclusion: The study revealed a low prevalence of H. pylori infection in rural population of Bangladesh. There was no significant association of H. pylori infection with several sociodemographic status and diabetes. IMC J Med Sci 2021; 15(1): 007


Introduction
H. pylori, a gastroduodenal pathogen, causes chronic gastritis and peptic ulcer disease and is associated with gastric cancer [1]. The prevalence of H. pylori infection is more in developing countries. Poverty-related factors including overcrowding, poor sanitation, unclean water and low education level are the main risk factors of acquiring H. Pylori [2]. The infection tends to become chronic unless it is treated with antimicrobials [3].
In our country, no previous study investigated the H. pylori infection in asymptomatic rural population. Therefore, the primary aim of the present study was to find out the current prevalence status of H. pylori infection among the Bangladeshi asymptomatic adult rural population.

Study place and population:
This cross-sectional study was carried out in a rural area named Sreepur under Gazipur district. The rural area is located about 40 km north-east of capital Dhaka. Apparently healthy non-diabetic, pre-diabetic and diabetic adults (18 years and above) were enrolled in this study. Diabetes mellitus (DM) and pre-diabetes were defined according to the criteria of American Diabetes Association [18]. Informed written consent was obtained from all the participants after explaining the nature and purpose of the study. A structured questionnaire (close ended) was developed and used to record the socio-demographic information and clinical history. It was pretested and checked for applicability before it was finally launched at the field to interview for data collection from the respondents.

Collection of blood and estimation of anti-H.pylori
IgG antibody: H. pylori infection status was determined by the presence of anti-H. pylori IgG antibody in blood. Blood samples (2.5 mL) were collected aseptically from each participant by peripheral venipuncture under aseptic conditions. After collection, the serum was separated, aliquoted, refrigerated at 4 0 C and then transported to the microbiology laboratory in a cold box. Serum anti-H. pylori IgG antibodies were determined by ICT (immunochromatographic test) method using AimStep™ H. Pylori Rapid Cassette test device (Germaine® Laboratories, Inc, USA). The test was performed and interpreted according to the manufacturer's instruction.

Result
A total number of 180 apparently healthy adult individuals were enrolled of which 112, 40 and 28 were non-diabetic, pre-diabetic and diabetic respectively. Out of 180 individuals, IgG antibody for H. pylori was present in 70 (38.9%; CI: 32.1,  Table-3).

Discussion
The present study, using ICT, found a low prevalence of H. pylori infection (38.9%) in asymptomatic adult Bangladeshi rural population. Previously in 1997 and 2008, the seroprevalence rate of ˃90% and ˃70% were reported respectively in asymptomatic urban people from Bangladesh [13,14]. Similar decreasing trend was observed in South Korea [12]. Similar observation was made previously in Nepal where the infection rate in urban was 67.2% compared to 41.5% in rural population [19]. An Ethiopian study found a two-  fold higher prevalence in an urban population than rural [20]. The explanation behind this difference might be increasing migration of people from rural to urban area causing higher urban density with crowded accommodation and poor living condition [21]. The low prevalence found in our study might be due to the improvement in socioeconomic standard of the local people and improved sanitation, hygiene or water supply in rural areas. Also, there could be some other unidentified factors that might inhibit H. pylori infection in our rural population. Though H. pylori has no known environmental reservoir, in Peru, the infection rate was lower in people using water from private wells than from municipal supply [22]. Also, exceptionally low (7.0%) prevalence of H. pylori infection was reported among Malay peptic ulcer patients in north-eastern peninsular Malaysia [23]. Also, studies found that use of local strain to detect antibodies to H. pylori yielded a significantly improved sensitivity and specificity [17,24,25].
In our study, the maximum infection rate was found in ≤30 years of age group. People mostly acquire H. pylori during young age of life through feco-oral, oro-oral or gastro-oral transmission. The rate of infection becomes lower during later age due to lower exposure risk and decrease in susceptible individuals [3]. No significant difference between male and female was demonstrated in this study. Many previous studies reported similar finding [26,27] whereas significantly higher prevalence of infection among men was also found in other studies [28,29].
The study did not find any significant association of economic status, education and occupation with H. pylori infection suggesting that other risk factors likely exist which were not assessed in the current study. Additionally, the present study was conducted on a small number of relatively homogenous populations. We did not find any significant difference in H. pylori infection among non-diabetic, pre-diabetic and diabetic population having no symptom of gastritis or peptic ulcer disease. Also, in our previous study we did not find any significant difference in H. pylori infection in peptic ulcer patients with and without diabetes mellitus [30]. Thus, it appeared that diabetes was not a predisposing factor for H. pylori infection.