Cardia and non-cardia gastric cancer risk associated with Helicobacter pylori in East Asia and the West: A systematic review, meta-analysis, and estimation of population attributable fraction.

ABSTRACT

OBJECTIVES: To assess the region-specific relative risk of cardia/non-cardia gastric cancer (CGC/NCGC) associated with Helicobacter pylori (H. pylori) and quantify its contribution to gastric cancer burden using population attributable fraction (PAF). METHODS: PubMed, EMBASE, Web of Science, and Cochrane Central databases were searched by two reviewers until April 20, 2022. The association between H. pylori infection and NCGC/CGC was assessed using pooled odds ratios (ORs) with 95% confidence intervals (CIs). PAF was calculated using the formula of H. pylori prevalence and the pooled OR. RESULTS: One hundred and eight studies were included. A significant association was observed between H. pylori infection and NCGC in East Asia (OR, 4.36; 95% CI 3.54-5.37) and the West (OR, 4.03; 95% CI 2.59-6.27). Regarding CGC, a significant association was found only in East Asia (OR, 2.86; 95% CI 2.26-3.63), not in the West (OR, 0.80; 95% CI 0.61-1.05). For studies with a follow-up time of ≥10 years, pooled ORs for NCGC and CGC in East Asia were 5.58 (95% CI 4.08-7.64) and 3.86 (95% CI 2.69-5.55), respectively. Pooled OR for NCGC was 6.80 (95% CI 3.78-12.25) in the West. PAFs showed that H. pylori infection accounted for 71.2% of NCGC, 60.7% of CGC in East Asia, and 73.2% of NCGC in the West. CONCLUSIONS: Gastric cancer burden associated with H. pylori infection exhibits important geographical differences. Prolonged follow-up period could overcome the underestimation of the magnitude of the association between H. pylori infection and CGC/NCGC. Customized strategies for H. pylori screening and eradication should be implemented to prevent gastric cancer.