Helicobacter pylori infection and gastric histology in first-degree relatives of gastric cancer patients: a meta-analysis

Abstract

Helicobacter pylori (H. pylori) is believed to predispose to gastric cancer by inducing the precancerous changes, that is, atrophy and intestinal metaplasia (IM). First-degree relatives of patients with gastric cancer might be at an increased risk of developing gastric cancer. However, this evidence is based on the scattered individual studies. The aim of this study was to examine the risk of first-degree relatives developing gastric cancer, in comparison with controls that have no family history of gastric cancer, by meta-analyzing all relevant studies. Extensive English language medical literature searches for human studies were performed up to the end of November 2009, using suitable keywords. Inclusion and exclusion criteria were identified and in eligible studies data on three parameters, that is, H. pylori prevalence, atrophy and IM, were extracted. Pooled estimates (odds ratio with 95% confidence intervals) were obtained using either the fixed or random-effects model as appropriate. Heterogeneity between studies was evaluated with the Cochran Q test, whereas the likelihood of publication bias was assessed by constructing funnel plots. Their symmetry was estimated by the Egger's regression asymmetry test. Out of 155 initially identified studies, 11 studies, from various countries, fulfilling the inclusion criteria, examined the risk of first-degree relatives developing gastric cancer (n=1500) in comparison with controls (n=2638). For H. pylori prevalence, the pooled odds ratio with 95% confidence interval was 1.925 (1.419-2.611) and the test for overall effect Z was 4.211 (P=0.000). The respective values for atrophy and IM were 2.200 (1.266-3.824), Z=2.797, (P=0.005) and 1.982 (1.363-2.881), Z=3.582 (P=0.000) respectively. The results of this meta-analysis showed that first-degree relatives of patients with gastric cancer might be at an increased risk of developing gastric cancer, as judged by significantly higher prevalence of H. pylori, gastric atrophy and IM, in comparison with controls. Consequently, H. pylori detection and prophylactic eradication of the infection should be offered to such individuals. However, follow-up studies are required to prove the above.