Red and Processed Meat Intake Is Associated with Higher Gastric Cancer Risk: A Meta-Analysis of Epidemiological Observational Studies

BACKGROUND Red and processed meat was concluded as a limited-suggestive risk factor of gastric cancer by the World Cancer Research Fund. However, recent epidemiological studies have yielded inconclusive results. METHODS We searched Medline, EMBASE, and the Cochrane Library from their inception to April 2013 for both cohort and case-control studies which assessed the association between red and/or processed meat intake and gastric cancer risk. Study-specific relative risk estimates were polled by random-effect or fixed-effect models. RESULTS Twelve cohort and thirty case-control studies were included in the meta-analysis. Significant associations were found between both red (RR: 1.45, 95% CI: 1.22-1.73) and processed (RR: 1.45, 95% CI: 1.26-1.65) meat intake and gastric cancer risk generally. Positive findings were also existed in the items of beef (RR: 1.28, 95% CI: 1.04-1.57), bacon (RR: 1.37, 95% CI: 1.17-1.61), ham (RR: 1.44, 95% CI: 1.00-2.06), and sausage (RR: 1.33, 95% CI: 1.16-1.52). When conducted by study design, the association was significant in case-control studies (RR: 1.63, 95% CI: 1.33-1.99) but not in cohort studies (RR: 1.02, 95% CI: 0.90-1.17) for red meat. Increased relative risks were seen in high-quality, adenocarcinoma, cardia and European-population studies for red meat. And most subgroup analysis confirmed the significant association between processed meat intake and gastric cancer risk. CONCLUSIONS Our findings indicate that consumption of red and/or processed meat contributes to increased gastric cancer risk. However, further investigation is needed to confirm the association, especially for red meat.