Paediatric Helicobacter pylori infection and allergic and inflammatory diseases: a contemporary systematic review with meta-analysis.

UNLABELLED: Helicobacter pylori (H. pylori) infection is prevalent worldwide, and its potential protective role in allergic and immune diseases has been a topic of speculation. This systematic review aims to analyse recent literature to establish a consensus on this relationship. Articles published in the past 12 years regarding association of H. pylori and various allergic diseases were screened. Thirty-five articles from three databases were assessed for bias using the ROBINS-E tool. Objective data from each article were collected for this review. Among the reviewed articles, 14 focused on asthma, 10 on eliac disease(CeD), 5 on eosinophilic esophagitis (EoE), 7 on inflammatory bowel disease (IBD), and 8 on mixed conditions. In the asthma meta-analysis, H. pylori infection was not significantly associated with asthma overall (OR 0.75, 95% CI 0.54-1.05; I2 = 67.3%). Subgroup analyses showed an inverse association in studies using UBT/SAT, whereas histology-based studies showed no association. Low-risk-of-bias studies likewise showed no significant association. Results for celiac and IBD were mixed. No clear trends were observed for the other conditions analysed.

CONCLUSION: Current paediatric evidence does not demonstrate a significant overall association between H. pylori infection and asthma. Apparent inverse associations were confined to specific diagnostic and risk-of-bias subgroups. Evidence for celiac disease, IBD, EoE, and other immune-mediated disorders remains inconsistent. More prospective paediatric studies are needed to understand the immune modulation of H. pylori infection.

WHAT IS KNOWN: • The relationship between Helicobacter pylori infection and allergic or immune-mediated diseases remains complex and incompletely understood. • Previous studies, including mixed studies with adult and paediatric populations, have reported inconsistent and sometimes conflicting associations.

WHAT IS NEW: • This is the first comprehensive paediatric review covering multiple conditions simultaneously, synthesising evidence on the association between Helicobacter pylori infection and allergic and immune-mediated diseases. • Analysis of paediatric data found no overall association between H. pylori infection and asthma risk. Histology-based studies confirmed this finding, whereas a slight inverse association was observed only in studies using non-invasive diagnostic methods (UBT or SAT) and in those with a higher risk of bias.