Does Helicobacter pylori Protect against Eosinophilic Esophagitis in Children? Yoram Elitsur,* Baraa Alabd Alrazzak,* Deborah Preston* and Yulia Demetieva † *Gastroenterology Division, Department of Pediatrics, Marshall University School of Medicine, Huntington, WV, USA, † Department of Mathematics, Emmanuel College, Boston, MA, USA Keywords Helicobacter pylori, eosinophilic esophagitis, children. Reprint requests to: Yoram Elitsur, Gastroenterology Division, Department of Pediatrics, Marshall University School of Medicine, 1600 Medical center drive, Huntington, WV 25701, USA. E-mail: elitsur@marshall.edu Summary Background: Helicobacter pylori infection and eosinophilic esophagitis (EoE) in children seem to have a reversed association with socioeconomic status (hygienic condition) and allergy conditions. While Hp infection (Hp) is highly associated with poor hygiene and/or poor socioeconomic status, but not with allergic conditions (asthma, rhinitis, etc.), EoE has the opposite epidemiological relationship (high association with allergy but low with low hygienic conditions). Aim: To investigate the association between Hp infection and EoE in chil- dren. Methods: A retrospective chart review of all children who undergo the first upper endoscopy procedure in the gastroenterology clinic, between 2007 and 2012, was performed. Demographic, endoscopic and histological data were collected. The data was divided into 4 diagnostic groups: Hp infection, EoE, reflux esophagitis, and children who had normal histology. The rela- tionship between Hp positive children and the other groups was performed. Results: A total of 966 charts were available for review. Esophagitis, idio- pathic gastritis, EoE, and Hp infection were detected in 268 (28%), 480 (49%), 62 (6%), and 31 (3%) children, respectively. The mean age of the EoE group was significantly lower compared to all reference groups (p < .002), but no significant different was detected among the reference groups (gastritis, GERD, and Hp infection; p = 1.00). Simple logistic regres- sion analysis using Hp infection as a predictor for EoE did not find a signifi- cant relationship between these two variables (p-value = .471, OR = 0.478, 95% CI 0.06–3.56). However, multivariable logistic regression analysis between EoE and the reference groups indicated a significant negative rela- tionship between Hp infection and EoE (p-value = .023, adjusted OR = 0.096, 95%CI 0.013–0.72). Neither gastritis nor GER showed signifi- cant relationship with EoE (p-values are 1.000 and .992, respectively). Conclusion: A reversed association between Hp and EoE was found in a cohort of West Virginia children. The possible explanations for these findings are discussed. Helicobacter pylori infection in children has been well characterized, and treatment guidelines have been established [1]. Helicobacter pylori infection is associated with poor hygiene, low socioeconomic conditions, and family crowding [2]. Indeed, the rate of H. pylori infec- tion in children from developing countries is higher compared with children living in developed countries [3]. On the contrary, an inverse association between the prevalence of H. pylori infection and allergic dis- eases was reported. For example, the prevalence of asthma, rhinitis, eczema, or other allergies was lower in H. pylori-infected compared with non-H. pylori-infected children [4–8]. Eosinophilic esophagitis (EoE) is a newly established chronic esophageal disease in adults and children with clinical and pathological characterizations [9]. Previous © 2014 John Wiley & Sons Ltd, Helicobacter 1 Helicobacter ISSN 1523-5378 doi: 10.1111/hel.12129