Systematic review of time trends in the prevalence of Helicobacter pylori infection in China and the USA.

Peter Nagy,Saga Johansson,Michael Molloy-Bland

doi:10.1186/s13099-016-0091-7

Abstract

It has been suggested that the prevalence of Helicobacter pylori infection has stabilized in the USA and is decreasing in China. We conducted a systematic literature analysis to test this hypothesis. PubMed and Embase searches were conducted up to 19 January 2015. Trends in the prevalence of H. pylori infection over time were assessed by regression analysis using Microsoft Excel. Overall, 25 Chinese studies (contributing 28 datasets) and 11 US studies (contributing 11 datasets) were included. There was a significant decrease over time in the H. pylori infection prevalence for the Chinese studies overall (p = 0.00018) and when studies were limited to those that used serum immunoglobulin G (IgG) assays to detect H. pylori infection (p = 0.014; 20 datasets). The weighted mean prevalence of H. pylori infection was 66 % for rural Chinese populations and 47 % for urban Chinese populations. There was a significant trend towards a decreasing prevalence of H. pylori infection for studies that included only urban populations (p = 0.04; 9 datasets). This trend was no longer statistically significant when these studies were further restricted to those that used serum IgG assays to detect H. pylori infection, although this may have been because of low statistical power due to the small number of datasets available for this analysis (p = 0.28; 6 datasets). There were no significant trends in terms of changes in the prevalence of H. pylori infection over time for studies conducted in the USA. In conclusion, the prevalence of H. pylori infection is most likely decreasing in China, due to a combination of increasing urbanization, which we found to be associated with lower H. pylori infection rates, and possibly also decreasing rates of H. pylori infection within urban populations. This will probably result in a gradual decrease in peptic ulcer and gastric cancer rates in China over time.Electronic supplementary materialThe online version of this article (doi:10.1186/s13099-016-0091-7) contains supplementary material, which is available to authorized users.

Highlights

Helicobacter pylori infection is well recognized as the main pathogenic factor for peptic ulcer disease and chronic gastritis, and in a subset of patients it is a major risk factor for gastric cancer and mucosa-associated lymphoid tissue lymphoma [1–3]
Search results and study characteristics Of 762 unique hits, 25 studies conducted in China [16– 40] and 10 conducted in the USA [41–50] were included in the analysis
Our study shows that urban populations in China have much lower rates of H. pylori infection than rural populations

Summary

Introduction

Helicobacter pylori infection is well recognized as the main pathogenic factor for peptic ulcer disease and chronic gastritis, and in a subset of patients it is a major risk factor for gastric cancer and mucosa-associated lymphoid tissue lymphoma [1–3]. Helicobacter pylori infection has been associated with increased risks of colon cancer [4], idiopathic thrombocytopenic purpura, iron deficiency anemia, vitamin B12 deficiency, and, more recently, neurodegenerative disorders and metabolic syndrome [5]. Given the potential health consequences of H. pylori infection it is important to understand its prevalence in a population at any given time. Perhaps even more importantly from a healthcare planning perspective, it is useful to look at past trends in the prevalence of H. pylori infection so that its future prevalence and impact may be estimated.

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Conclusion