Accumulated evidence on Helicobacter pylori infection and the risk of asthma

• Published in: Annals of allergy, asthma, & immunology Vol. 119; no. 2; pp. 137 - 145.e2
• Main Authors: Chen, Cheng, MS, Xun, Pengcheng, PhD, Tsinovoi, Cari, PhD, He, Ka, MD, ScD
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.08.2017
• Subjects: Allergy and Immunology
• ISSN: 1081-1206; 1534-4436
• DOI: 10.1016/j.anai.2017.05.021

Abstract Background Helicobacter pylori ( H pylori ) infection has been suggested to be related to a decreased risk of asthma, but findings in the literature are inconsistent. Objective To quantitatively summarize the existing evidence on the association between H pylori infection and asthma risk. Methods The PubMed database was searched for observational studies of H pylori infection in relation to the risk of asthma published in English through May 2017. Measurements of association were pooled using a meta-analytic approach and expressed as odds ratios (ORs) with 95% confidence intervals (95% CIs). Results Twenty-four studies were identified in this meta-analysis, including 8 case-control studies composed of 1,247 cases and 2,410 controls, and 16 cross-sectional studies composed of 50,290 participants (4,185 cases and 46,105 noncases). The average H pylori infection rates were 40.01% and 48.74% in case-control and cross-sectional studies, respectively. Five studies subcategorized H pylori infection according to CagA status, in which 59.37% of H pylori –infected participants were identified as having CagA positivity. Helicobacter pylori infection was significantly inversely associated with the risk of asthma in case-control studies (OR 0.83, 95% CI 0.71–0.98) but was borderline significant in cross-sectional studies (OR 0.88, 95% CI 0.76–1.02). The observed inverse association persisted for CagA-positive H pylori infection (OR 0.77, 95% CI 0.63–0.93, P for interaction = .03) but not for CagA-negative strains (OR 1.08, 95% CI 0.66–1.78). No significant difference was observed across age or region subgroups. Conclusion The accumulated evidence supports that H pylori infection, especially CagA-positive H pylori infection, is inversely associated with the risk of asthma.