Effect of red, processed, and white meat consumption on the risk of gastric cancer: An overall and dose-response meta-analysis

Whether the risk of gastric cancer varies by the types of meat consumption still remains disputable. The purpose of this meta-analysis was to identify the exact associations that red, processed, and white meat have with gastric cancer. We searched relevant studies in Medline, EMBASE, and the Cochrane Library before November 2018, including cohort and case-control studies. We used random-effect models to estimate the adjusted relative risk (RR), and Egger’s tests to evaluate publication bias. Through stepwise screening, 43 studies were included in this analysis (11 cohort studies and 32 case-control studies with 16,572 cases). In a meta-analysis for the highest versus lowest categories of meat consumption, both red (RR: 1.41, 95% confidence interval (CI): 1.21-1.66) and processed (RR: 1.57, 95% CI: 1.37-1.81) meat consumption were positively associated with gastric cancer risk, while white meat consumption was negatively associated with gastric cancer risk (RR: 0.80, 95% CI: 0.69-0.92). In a dose-response meta-analysis, the RRs of gastric cancer were 1.26 (95% CI: 1.11-1.42) for every 100 g/day increment in red meat consumption, 1.72 (95% CI: 1.36-2.18) for every 50 g/day increment in processed meat consumption, and 0.86 (95% CI: 0.64-1.15) for every 100 g/day increment in white meat consumption. The increase of white meat consumption may reduce the risk of gastric cancer, while red or processed meat may increase the risk of gastric cancer. Further studies are required to identify these associations, especially between white meat and gastric cancer.