Arch Pediatr Infect Dis. 2014 January; 2(1):e14202. DOI: 10.5812/pedinfect.14202 Published online 2013 November 25. Brief Report The Association of Childhood Asthma and Helicobacter pylori Infection in Sardinia Maria Pina Dore 1,2,* , Marco Massidda 1 , Gian Franco Meloni 3 , Sara Soro 1 , Giovanni Mario Pes 1 , David Yates Graham 2 1 Medical Clinic, Department of Clinical and Experimental Medicine, University of Sassari, Sassari, Italy 2 Baylor College of Medicine, Michael E. DeBakey VA Medical Center, Houston, USA 3 Department of Surgical, Microsurgical and Medical Sciences, University of Sassari, Sassari, Italy * Corresponding author: Maria Pina Dore, Department of Clinical and Experimental Medicine, University of Sassari, n 8; 07100 Sassari, Italy. Tel: +39-079229886, Fax: +39-079228207, E-mail: mpdore@uniss.it. Received: August 13, 2013; Revised: October 8, 2013; Accepted: October 23, 2013 Background: It has been suggested that Helicobacter pylori infection might reduce the risk of atopic conditions, such as asthma, in childhood. This risk reduction could relate to the “hygiene hypothesis” which proposes an association between childhood exposure to microbes and risk of atopy. Objectives: To examine the association between Hp infection and childhood acquired asthma in Sardinia. Patients and Methods: Children from Northern Sardinia who were between the ages of 10 months to 6 years and were screened for Hp infection in 1994-1995 using IgG serology, were asked in 2012, whether they had developed asthma and/or allergic disease in pediatric age, using the global initiative on asthma guidelines questionnaire. Results: A total of 64 children participated in the study. The sero-positivity for Hp infection was 14.1%. Eleven (17.2%) children had a confirmed diagnosis of asthma with onset before the age of 5 years, 85.9% were Hp negative and 14.1% Hp positive. Eight children of the 53 without asthma were Hp positive (15%) compare to one children positive for the infection of the 11 patients (0.09%) with asthma (8/53 vs. 1/11; P = 0.6). The majority of children (73%) were from urban areas and 43.8% had a family history of asthma or allergies. Multiple logistic regression analysis was not able to find a studied variable, including Hp infection, significantly associated with pediatric asthma. Conclusions: Our results speak against Hp infection itself playing a role to protect from the risk to develop childhood asthma although household hygiene was not directly assessed. Keywords: Child; Asthma; Helicobacter pylori Implication for health policy makers/practice/research/medical education: It has been suggested that the inverse relationship between the increase in atopic diseases and fall in acquisition of H. pylori infections might be causal. Our study did not confirm any protective role for H. pylori infection in childhood asthma. Copyright © 2014, Pediartric Infections Research Center; Published by Kowsar Corp. This is an open-access article distributed under the terms of the Creative Com- mons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 1. Background Helicobacter pylori (H. pylori) is one of the most common chronic bacterial infections of mankind affecting ap- proximately 50% of the world's population (1). The risk of acquiring H. pylori infection is related to socioeconomic status and living conditions early in life and is inversely related to household hygiene practices (1, 2). Once ac- quired, the bacterium becomes the dominant member of the gastric microbiota (3). Asthma is the most common chronic disease in child- hood in developed countries (4, 5). In Western nations, the rate of acquisition of H. pylori has declined whereas the incidence of childhood asthma has increased. For example, in the USA the prevalence of childhood asthma increased more than 50% between the 1980’s and 1990’s and by about 10% in the last decade (6). One hypothesis to explain this phenomenon is the so called “hygiene hypothesis” which links a reduced exposure to microbes in childhood with the increased incidence of atopy (7). This link is postulated to relate to the alterations in the balance between a Th1 and Th2 response to antigenic stimuli. Chen and Blaser (8) suggested that the inverse relationship between the increase in atopic diseases and fall in acquisition of H. pylori infections might be causal (i.e. H. pylori might occupy a metabolically active com- partment in the stomach involved in the immunological barrier process that protects against allergic diseases). Al- ternately, H. pylori infection could be a surrogate marker for the level of household hygiene (i.e. general exposure to microbes). 2. Objectives In this study we examined the association between H. pylori and childhood asthma in a cohort of children from Northern Sardinia. 3. Patients and Methods Children from Northern Sardinia who were between the