Relation between Recurrent Abdominal Pain and Helicobacter pylori Stool Antigen in Children

designed the study, the and interpreted the data. KA anchored the field study, gathered the initial data and performed preliminary data analysis. and NS managed the literature searches and the ABSTRACT Introduction: Recurrent abdominal pain (RAP) is the most common gastrointestinal problem in children. The role of Helicobacter pylori ( H. pylori ) with recurrent abdominal pain is not known precisely. Since H. pylori infection may be one of the symptoms of abdominal pain. The aim of this study was to determine the prevalence of H. pylori Stool antigen in children with recurrent abdominal pain and compared with the control group. Materials and Methods: In this cross-sectional study, 107 children with recurrent abdominal pain and 107 healthy children were enrolled. Children in both groups did not have history of the liver, the kidney and the digestive disease and at least 2 weeks before the sampling had no history of using antibiotics, pump inhibitors (PPI) and antacids. Both groups were compared for age, sex, location, type of feeding in infancy, history of gastro-intestinal problems in the family. Morning Stool antigen of H. pylori of both groups were measured with ELISA, The kits containing polyclonal antibody against H. pylori in the reference laboratory. After data collection Descriptive statistics were used to calculate ratios and frequency, SPSS software was used for data analysis. To compare the frequency of HpSA in two groups, Chi-square test was used. Findings: The average age of children with RAP and control group was 6.1±3.1 and 6.04±2.7 year respectively, the difference was not statistically significant (P =0. 94). There was no difference between the two groups in terms of gender. 83 children with RAP and 78 children in the control group were in urban areas. Distribution of location in groups was not statistically significant (P =0.426). In 73 children with RAP (68.2%), HpSA was positive while only 12.1% in the control group were positive for it and this difference was statistically significant (P =0.001). positive family history of gastrointestinal problems in children with RAP and control group was 54.7% and 27.1% respectively which this difference was also statistically significant (P =0.001). Conclusion: In this study, HpSA is significantly higher than in children with RAP especially who have a family history of gastritis. This study suggests that in children with RAP, HpSA measurement which is a noninvasive method can help


INTRODUCTION
H. pylori is a spiral, microaerophilic, gramnegative bacterium with four to six unipolar sheathed flagella with a widely prevalent and important component of gastric microbiology. It is usually acquired in childhood. It is more common in poorer sections of society especially of developing countries. It can cause peptic ulcer disease and dyspepsia. It may be spread by unclean food and water, but researchers aren't sure. H. pylori usually can be found in gastric. Being infected by this pathogen plays a role in gastritis, peptic ulcer [1][2][3][4][5]. In addition, this bacterium is associated with MALT lymphoma and regression of lymphoma is verified by eradication of this factor [3,6,7]. Infection is more prevalent in developing countries, in some studies the prevalence in individuals is up to 66% [7][8][9][10]. Different invasive and non-invasive diagnosis ways are available to diagnose infection by this bacterium and among invasive methods endoscopy and biopsy could be mentioned, which are exact methods but they may not be desirable for families and children. Non-invasive methods are rapid urea breath test and Detecting bacterial antigens in stool. The H. pylori stool antigen (HpSA) test is a noninvasive immunoassay to diagnose active infection with H. pylori. Its performance in children and teenagers has been tested in some developed countries, showing a sensitivity and specificity above 90% [11].
Recurrent abdominal pain (RAP) is the most common digestive problem in children that results in recurrent visits to pediatric clinics. It is defined as three cycles of severe abdominal pain at least that affects the child's activity and its symptoms last more than 3 months. RAP could be the result of organic disorders such as being infected by parasites, urogenital diseases, inflammatory bowel disease, peptic ulcer and other factors. In some countries, H. pylori related to pediatric RAP [12,13]. However, some studies show that there is no relation between abdominal pain and H. Pylori infection [14]. Therefore, the aim of the current study is investigating the relation to RAPs and H. Pylori infection in children visiting to Pediatric Clinic of Khorram Abad city (the capital of Lorestan province, Iran) compared to healthy children.

MATERIALS AND METHODS
To conduct this cross sectional descriptiveanalytic study, children with RAP visiting to Khorram Abad pediatric clinic from 23 July 2014 to 19 February 2015 were selected on a voluntary basis; children with the history of digestive, liver, kidney diseases and parasitic infections were excluded from the study. After selecting the group of pediatric patients, the control group was selected from those healthy children with no history of previous disease, who were visiting to evaluate their health status without any history of disease and had no history of using antibiotics, proton pump inhibitors (PPIs) and H2 blocker was considered in 2 recent weeks. Both groups hadn't the history of infection with pinworm parasite and were similar in age and gender. HpSA was measured in children's morning stool sample. The samples were stored at -20°C until analyzed. The presence of H. pylori organisms in stool was determined by an enzyme-linked immune sorbent assay using a commercially available polyclonal antibody kit. Stool samples were diluted, and incubated. H. pylori -specific polyclonal antibodies conjugated to horseradish peroxidase were added, incubated, and washed before peroxidase was added; a visible blue reaction indicated the presence of H. pylori.

Statistical Analysis
Statistical analysis of the data was performed with SPSS 11.0 computer program. The mean age of both groups were compared by student t test. Other comparisons were evaluated by chisquare test and Odd ratios with 95% confidence intervals. A p value ≤ 0.05 was considered significant.

RESULTS
In this study, 107 children with RAP and 107 healthy children were investigated in terms of the frequency of H. pylori Stool Antigen (HpSA). The average age of children with RAP and healthy children were 6.1±3.1 and 6.04±2.7 year respectively; this difference was not statistically significant (P =0.94). In groups under study, there were 51 males (47.7%) and 56 females (52.3%) and frequency distribution of gender was similar in both groups. 83 children with RAP and 78 children in the control group were in urban areas. Frequency distribution of habitat for both groups was not statistically significant (p = 0.426). 51.4% of children with RAP and 57.9% of control group children have been breastfed since birth and frequency distribution of type of feeding in childhood was not statistically significant according to chi-square test (p= 0.621) ( Table 1). According to the results of Table 1, family history was positive in 54.7% of children with RAP and in 27.1% of control group, which was statistically significant (p=0.001). Family numbers in the majority of children with RAP was 5 members (36.4%) and in the majority of children of control group, it was 4 members (36.4%). However, according to chi-square test, difference between family numbers was not statistically significant in both groups (p=0.198). HpSA was positive in 73 children with RAP (68.2%); while it was positive only in 13 children of control group (12.1%) and this difference was statistically significant (p=0.001) ( Table 2).
According to the results of independent T-test shown in Table 3, in children with RAP, the difference between average age of children with positive HpSA compared to children with negative HpSA, was not statistically significant (p =0.25). This difference was not significant in control group as well (p=0.134). In Table 4, frequency distribution of in children in terms of location is mentioned.
According to the results of Table 5, difference in frequency distribution of HpSA in children with RAP was statistically significant in terms of their nutrition in childhood (p =0.004); such that in formula-fed children and children who are   Table 4, frequency distribution of HpSA status in children in terms of location is mentioned.
According to the results of Table 5, difference in frequency distribution of HpSA in children with RAP was statistically significant in terms of their =0.004); such that in fed children and children who are formula-fed combined with breast positivity of HpSA was significantly higher than children who were merely breast-fed.
In control group, in spite of higher positivity of HpSA in formula-fed children compared to other subjects, this difference was not statistically significant according to chi-square (p=0.054).
According to the results of Table 6, the in frequency distribution of HpSA in children with RAP and control group was not statistically significant in terms of the number of family members.

87.9%
; Article no.ARRB.20141 fed combined with breast-feeding, the positivity of HpSA was significantly higher than fed.
In control group, in spite of higher positivity of fed children compared to other subjects, this difference was not statistically square (p=0.054).
According to the results of Table 6

CONCLUSION
In this study, the prevalence of HpSA in children with RAPs was 68.2% and in children without symptoms, it was 12.1%, which was statistically significant. There was a significant association between RAP and H Pylori infection. This relation was not dependent on sex or the number of family members, however; in children with family history of gastritis and those who were not exclusively breast-fed, it is observed more. RAP is an indication for a stool test for H. pylori infection in children. It seems that exclusive breast feeding have an important role in reducing pollution with H. pylori and RAP in childhood.
Unfortunately, there are not sufficient studies to support the effectiveness of the treatment of individuals infected by H. pylori to treat digestive symptoms. Therefore, it is better to conduct studies in this regard as well.

SUGGESTION
The presented data suggest that recurrent abdominal pain in children may be associated with H. pylori infection. It is recommended to conduct more studies with a higher population of patients to reduce the possibility of errors.